Long-term effects of weight-reducing diets in hypertensive patients

Institute for General Practice, Goethe University, Theodor-Stern-Kai 7, Frankfurt am Main, Germany, 60590.
Cochrane database of systematic reviews (Online) (Impact Factor: 6.03). 09/2011; 7(9):CD008274. DOI: 10.1002/14651858.CD008274.pub2
Source: PubMed
ABSTRACT
All major guidelines for antihypertensive therapy recommend weight loss. Thus dietary interventions that aim to reduce body weight might be a useful intervention to reduce blood pressure and adverse cardiovascular events associated with hypertension.
Primary objectivesTo assess the long-term effects of weight-reducing diets in hypertensive patients on- all cause mortality - cardiovascular morbidity - adverse events (including total serious adverse events, withdrawal due to adverse events and total non-serious adverse events)Secondary objectivesTo assess the long-term effects of weight-reducing diets in hypertensive patients on- change from baseline in systolic blood pressure - change from baseline in diastolic blood pressure - body weight reduction
Studies were obtained from computerised searches of Ovid MEDLINE, EMBASE, CENTRAL and from searches in reference lists and systematic reviews.
Randomised controlled trials (RCT) in adult hypertensive patients were included if they had a study duration of at least 24 weeks and compared weight reducing dietary interventions to no dietary intervention in adult patients with primary hypertension.
Two authors independently assessed risk of bias and extracted data. Studies were pooled using fixed-effect meta-analysis. In case of moderate or larger heterogeneity as measured by Higgins I(2), a random effects model was used.
Eight studies involving a total of 2100 participants with high blood pressure and a mean age of 45 to 66 years met our inclusion criteria. Mean treatment duration was 6 to 36 months. No study included mortality as a pre-defined outcome. One RCT evaluated the effects of dietary weight loss on a combined endpoint, consisting of the necessity of reinstating antihypertensive therapy and severe cardiovascular complications. In this RCT weight reducing diet lowered the endpoint, hazard ratio 0.70 (95% confidence interval [CI], 0.57 to 0.87) compared to no diet. None of the studies evaluated adverse events as designated in our protocol. Blood pressure was reduced in patients assigned to weight loss diets as compared to controls: systolic blood pressure (SBP): weighted mean difference (WMD): -4.5 mm Hg; 95% CI, -7.2 to -1.8 mm Hg (3 of 8 studies included in analysis), and diastolic blood pressure (DBP): WMD -3.2 mm Hg; 95% CI, -4.8 to -1.5 mm Hg (3 of 8 studies included in analysis). Patients' body weight was also reduced in dietary weight loss groups as compared to controls, WMD of -4.0 kg (95% CI: -4.8 to -3.2) (5 of 8 studies included in analysis). Two studies used withdrawal of antihypertensive medication as their primary outcome. Even though this was not considered a relevant outcome for this review, the results of these studies strengthen the finding of reduction of blood pressure by dietary weight loss interventions.
In patients with primary hypertension, weight loss diets reduced body weight and blood pressure, however the magnitude of the effects are uncertain as a result of the small number of patients and studies that could be included in the analyses. It is not known whether weight loss reduces mortality and morbidity. No useful information on adverse effects was reported in the relevant trials.

Full-text

Available from: Andreas Waltering, Apr 24, 2014
Long-term effects of weight-red ucing diets in hypertensive
patients (Review)
Siebenhofer A, Jeitler K, Berghold A, Waltering A, Hemkens LG, Semlitsch T, Pachler C,
Strametz R, Horvath K
This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library
2011, Issue 9
http://www.thecochranelibrary.com
Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 1
T A B L E O F C O N T E N T S
1HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2PLAIN LANGUAGE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
13DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14AUTHORS’ CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23CHARACTERISTICS OF STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
47DATA AND ANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analysis 1.1. Comparison 1 Weight reducing diet versus no weight reducing diet, Outcome 1 Change in systolic blood
pressure fr om baseline to endpoint. . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Analysis 1.2. Comparison 1 Weight reducing diet versus no weight reducing diet, Outcome 2 Change in diastolic blood
pressure fr om baseline to endpoint. . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Analysis 1.3. Comparison 1 Weight reducing diet versus no weight reducing diet, Outcome 3 Change in body weight from
baseline to endpoint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
49ADDITIONAL TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
54HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
55CONTRIBUTIONS OF AUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
55DECLARATIONS OF INTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
55SOURCES OF SUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
56DIFFERENCES BETWEEN PROTOCOL AND REVIEW . . . . . . . . . . . . . . . . . . . . .
56INDEX TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
iLong-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 2
[Intervention Review]
Long-term effects of weight-red ucing diets in hypertensive
patients
Andrea Siebenhofer
1
, Klaus Jeitler
2
, Andrea Berghold
3
, Andreas Waltering
4
, Lars G Hemkens
4
, Thomas Semlitsch
5
, Christoph Pachler
6
, Reinhard Strametz
1
, Karl Horvath
7
1
Institute for General Practice, Goethe University, Frankfurt am Main, Germany.
2
EBM Review Center, Department of Internal
Medicine and Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria.
3
Institute
for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria.
4
Institute for Quality and Efficiency
in Health Care (IQWiG), Cologne, Germany.
5
EBM Review Center, Department of Internal Me dicine, Medical University of Graz,
Graz, Austria.
6
Department of Anesthesiology and Intensive Care Medicine, Medical University Graz, Graz, Austria.
7
Department of
Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria
Contact address: Andrea Siebenhofer, Institute for General Practice, Goethe University, Theodor-Stern-Kai 7, Frankfur t am Main,
60590, Germany.
andrea.siebenhofer@medunigraz.at.
Editorial group: Cochrane Hypertension Group.
Publication status and date: New, published in Issue 9, 2011.
Review content assessed as up-to-date: 19 May 2011.
Citation: Siebenhofer A, Jeitler K, Berghold A, Waltering A, Hemkens LG, Semlitsch T, Pachler C, Strametz R, Hor vath K. Long-term
effects of weight-reducing diets in hypertensive patients. Cochrane Database of Systematic Reviews 2011, Issue 9. Art. No.: CD008274.
DOI: 10.1002/14651858.CD008274.pub2.
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
A B S T R A C T
Background
All major guidelines for antihypertensive therapy recommend weight loss. Thus dietary interventions that aim to reduce body weight
might be a useful intervention to reduce blood pressure and adverse cardiovascular events associated with hyper tension.
Objectives
Primary objectives
To assess the long-term effects of weight-reducing diets in hypertensive patients on
- all cause mortality
- cardiovascular morbidity
- adverse events (including total serious adverse events, withdrawal due to adverse events and total non-serious adverse events)
Secondary objectives
To assess the long-term effects of weight-reducing diets in hypertensive patients on
- change from baseline in systolic blood pressure
- change from baseline in diastolic blood pressure
- body weight reduction
1Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 3
Search strategy
Studies were obtained from computerised searches of Ovid MEDLINE, EMBASE, CENTRAL and from searches in reference lists and
systematic reviews.
Selection criteria
Randomised controlled trials (RCT) in adult hypertensive patients were included if they had a study duration of at least 24 weeks and
compared weight reducing dietary interventions to no dietary intervention in adult patients with primary hypertension.
Data collection and analysis
Two authors independently assessed risk of bias and extracted data. Studies were pooled using fixed-effect me ta-analysis. In case of
moderate or larger heterogeneity as measured by Higgins I
2
, a r andom effects model was used.
Main results
Eight studies involving a total of 2100 participants with high blood pressure and a me an age of 45 to 66 years met our inclusion
criteria. Mean treatment duration was 6 to 36 months. No study included mortality as a pre-defined outcome. One RCT evaluated
the effects of dietary weight loss on a combined endpoint, consisting of the nece ssity of reinstating antihypertensive therapy and severe
cardiovascular complications. In this RCT weight reducing diet lowered the endpoint, hazard ratio 0.70 (95% confidence interval
[CI], 0.57 to 0.87) compared to no diet. None of the studies evaluated adverse events as designated in our pr otocol. Blood pressure
was reduced in patients assigned to weight l oss diets as compared to controls: systolic blood pressure (SBP): weighted mean difference
(WMD): -4.5 mm Hg; 95% CI, -7.2 to -1.8 mm Hg (3 of 8 studies included in analysis), and diastolic blood pressure (DBP): WMD
-3.2 mm Hg; 95% CI, -4.8 to -1.5 mm Hg (3 of 8 studies included in analysis). Patients body weight was also reduced in dietary
weight loss groups as compared to controls, WMD of -4.0 kg (95% CI: -4.8 to -3.2) (5 of 8 studies included in analysis). Two studies
used withdrawal of antihypertensive medication as their primary outcome. Even though this was not considered a relevant outcome
for this review, the results of these studies strengthen the finding of reduction of blood pressure by dietary weight loss interventions.
Authors’ conclusions
In patients with primary hypertension, weight loss diets reduced body weight and blood pressure, however the magnitude of the effects
are uncertain as a result of the small number of patients and studies that could be included in the analyses. It is not known whether
weight loss reduces mortality and morbidity. No useful information on adverse effects was reported in the relevant trials.
P L A I N L A N G U A G E S U M M A R Y
Weight reducing diets for patients with elevated blood pressure
Compared to the general population, patients with high blood pressure have a higher risk for death and complications such as heart
attack or stroke. Based on the association of increased weight and increased blood pressure, dietary interventions to lower body weight
are commonly recommended as a first the rapeutic step for overweight patients with high blood pressure. However, whethe r weight loss
has a long-term effect on blood pressure and reduces the adverse effects of elevated blood pressure remains unclear. As only randomised
controlled trials (RCT) comparing groups with and without a weight reducing diet can answer these issues, we only included RCTs in
our systematic review. 30 articles reporting on eight studies met the inclusion criteria. The 8 included studies involved a total of 2100
participants with high blood pressure and a mean age of 45 to 66 years. Mean treatment duration was 6 to 36 months and there was
little or no information about deaths or other long-term complications. In three of eight studies, effects on systolic and diastolic blood
pressure were provided, showing that systolic and diastolic blood pressure were reduced by weight l oss interventions by 4.5 mm Hg
and 3.2 mm Hg, respectively. Five out of eight studies reported body weight, and weight loss interventions reduced weight by 4.0 kg
as compared to controls. No useful information on possible adverse effects was reported in the included trials.
In conclusion, there is no evidence for effects of weight loss diets on death or long-term complications and adverse events. In addition,
results on blood pressure and body weight could be considered uncertain, because not all studies were included in the analyses. But
these results are mainly based on one large study with about 600 participants that was judged to be of high quality, and the fact that
most of the other studies excluded from analysis indirectly (e.g. via successful withdrawal of blood pressure reducing drugs) further
underline these effects, gives confidence in the obtained results.
2Long-term effects of weight-reducing diets in hypertensive patients (Review)
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B A C K G R O U N D
Description of the condition
Hypertension is a chronic condition associated with an increased
risk of cardiovascular mortality and morbidity. High blood pres-
sure is estimated to lead to over 7 mill ion deaths each year, about
13% of the total deaths world wide (
WHO 2002). Lowering blood
pressure levels in hy pertensive patients has been shown to be an
effective means of reducing cardiovascular morbidity and mortal-
ity (
Turnbull 2003, Staessen 2005).
Consistently, epidemiological investigations have found an asso-
ciation between high blood pressure and different lifestyle factors,
excess body weight among them (
Kenchaiah 2002, Wilson 2002,
Yusuf 2004, Woodward 2005, Wannamethee 1996). This assump-
tion was also supported by some recently published systematic
reviews of randomised controlled trials showing that weight loss
intervention resulted in lower blood pressure (
Dickinson 2006,
Horvath 2008, Aucott 2005). In addition, high body weight is also
associated with increased cardiovascular complications(
Kenchaiah
2002
, Wilson 2002). However, the obser vation that certain vari-
ables (e.g. excess body weight, high blood pressure) are quantita-
tively related to more cardiovascular events does not necessarily
mean that lowering these variables will automatically reduce the
number of cardiovascular events. This may be due to the fact that
the variable in question (e.g. overweight) has no impact on aetio-
logical pathways or that the damage to the cardiovascular system
is already established and is only poorly or no longer reversible.
It could also be the case that the treatment is effective and does
lower cardiovascular events by reducing the risk factor, but at the
same time increases cardiovascular or other risks through a differ-
ent mechanism. To prove the e ffectiveness of an intervention, a
randomised controlled trial is required, f or which, ideally, a pro-
tocol should have been published prospectively. Numerous inter-
ventions that have bee n recommended on the basis of associations
found in e pidemiological studies eventually failed to show any
beneficial effect and sometimes even did harm in subsequent ran-
domised controlled trials. E.g. a large dietary intervention study of
8.1 years duration in 48835 obese postmenopausal women (40%
having hypertension) resulted in only a modest reduction in di-
astolic blood pressure and no significant reduction of any cardio-
vascular outcomes (
Howard 2006).
Nevertheless, weight reduction is recommended in major guide-
lines as a first step inter vention in the therapy of hypertensive pa-
tients (
ESH-ESC 2007, WHO 2005, JNC 2003, NICE 2006,
CHEP 2008). Body weight may be reduced by non-pharmaco-
logical, pharmacological or invasive interventions. A recently pub-
lished Cochrane review (
Siebenhofer 2009) of pharmacological
interventions for weight reduction showed that orlistat reduced
blood pressure and sibutramine increased blood pressure. As of
March 2007, there were no randomised controlled trials testing
the effect of invasive interventions in patients with elevated blood
pressure (
IQWiG 2006, Horvath 2008).
The aim of this systematic review is to evaluate the potential bene-
ficial and harmful long-term effects for hypertensive patients who
intend to reduce their body weight with non-pharmacological di-
etary interventions.
Description of the intervention
This review covers dietary inter ventions (duration of at least 24
weeks) that aim to reduce body weight (e.g. dietary counselling,
caloric restrictions, reduction in fat intake). Other interventions
such as exercise or other non-drug approaches such as stress re-
duction techniques are not included.
How the intervention m ight work
Non-pharmacological dietary obser vations in hypertensive pa-
tients have suggested a positive association between body weight
and blood pressure. One therefore might hypothesize that dietary
intervention with the aim of reducing body weight would reduce
blood pressure and adverse cardiovascular events in hypertensive
patients.
Why i t is important to do this review
For overweight patients with established hypertension, it is com-
monly recommended that blood pressure should first be man-
aged by non-pharmacological interventions, including weight re-
duction (ESH-ESC 2007, WHO 2005, JNC 2003, NICE 2006,
CHEP 2008). Since dietary interventions might support the ef-
forts of patients to reduce body weight, it is important for the
physician to be informed about the efficacy and potential harms
of diets before recommending them.
Recently published reviews and meta-analyses have shown that
non-pharmacological weight reducing interventions (
Horvath
2008
, IQWiG 2006) lead to reduction in blood pressure. None
of these reviews provided data to give a clear answer as to whether
the risk of mortality or cardiovascular morbidity can be lowered
by long-term weight loss dietary interventions.
Therefore, there is a need to update the previous reviews and in
particular the
Horvath 2008 review.
O B J E C T I V E S
Primary objectives
To assess the long-term e ffects of weight-reducing diets in hyper-
tensive patients on
all cause mortality
3Long-term effects of weight-reducing diets in hypertensive patients (Review)
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cardiovascular morbidity
adverse events (including total serious adverse events,
withdrawal due to adverse events and total non-serious adverse
events)
Secondary objectives
change from baseline in systolic blood pressure
change from baseline in diastolic blood pressure
body weight reduction
M E T H O D S
Criteria for considering studies for this review
Types of studies
We included randomised controlled trials of at least 24 weeks du-
ration that compare weight reducing dietary interventions to no
dietary intervention in adult patients with primary hypertension.
Any additional pharmacological or non-pharmacological co-inter-
vention must have been administered to all randomised patients
and must not have been significantly different for the treatment
and control groups at baseline or during the duration of the trial.
For example: A randomised trial with exercise plus diet versus
no treatment was not included. A trial in which all randomised
patients exercised and the only difference was weight reducing
diet versus no treatment or placebo would have met the inclusion
criteria.
Types of participants
Men and non-pregnant women 18 years old with essential hy-
pertension (defined as baseline systolic blood pressure of at least
140 mm Hg and/or baseline diastolic blood pressure of at least 90
mm Hg or patients on antihypertensive treatment) were included.
Types of interventions
Dietary intervention with the intention to reduce body weight in
comparison with no dietary intervention to reduce body weight.
Types of outcome measures
Primary outcomes
The primary outcomes were total mortality, cardiovascular mor-
bidity and adverse events (including total serious adverse events,
withdrawal due to adverse e vents and total non-serious adverse
events).
Secondary outcomes
Secondary outcomes were the change from baseline in systolic and
diastolic blood pressure and in body weight.
Search methods for identification of stud ies
Electronic searches
The Database of Abstracts of Reviews of Effectiveness (DARE)
and the Cochrane Database of Systematic Reviews were searched
for related reviews.
English language databases, including MEDLINE (1966-Novem-
ber 2010) and EMBASE (1988-November 2010) and the
Cochrane Central Register of Controlled Trials (Ovid EBM-
CCTR, 4th Quarter, 2010) electronic databases were searched to
identify relevant randomised controlled trials. A combination of
subject headings and text words relating to hypertension, diet and
overweight / weight reduction was used for this search. No l an-
guage restrictions were applied to the searches.
The MEDLINE search strategy (Appendix 1) was translated into
EMBASE (
Appendix 2) and Cochrane CENTRAL (Appendix 3)
using the appropriate controlled vocabulary as applicable.
Searching other resources
1. Reference lists of all papers and relevant reviews identified
2. Authors of relevant papers were contacted regarding any
further published or unpublished work
3. Authors of trials reporting incomplete information were
contacted to provide the missing information
Data c ollection and an alysis
Selection of studies
Two authors independently screened the title and abstract of each
reference identified by the search and applied the inclusion cri-
teria. In case of disagreement between the two authors, the full
article was obtained and inspected independently by the two au-
thors. A third author resolved disagreements. If a resolution of
the disagreement was not possible, the article was added to those
awaiting assessment” and the authors of th e study were contacted
for clarification. After receiving the authors replies, articles were
re-assessed.
4Long-term effects of weight-reducing diets in hypertensive patients (Review)
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Data extraction and management
Two independent authors using a standardized data extraction
form extracted data from each included study. Differences in data
extraction were resolved by consensus, referring back to the origi-
nal ar ticle. If necessary, information was sought from the authors
of the primary studies. The foll owing data were extracted, checked
and recorded:
General information included the sponsor of the trial
(specified, known or unknown) and country of publication.
All characteristics of the trial, participants, interventions
and outcome measures were summarized as reported in the
publication.
Characteristics of the trial comprised the study design,
duration of the trial, method of randomisation, allocation
concealment, blinding (patients, people administering
treatment, outcome assessors) and testing of blinding. The
characteristics of randomised patients at baseline were reported
and the similarity of groups at baseline was checked.
Characteristics of participants are summarized in the
“Table of included studies and comprised the number of
participants in each group, how the participants were selected
(random), the exclusion criteria used and the general
characteristics (e.g. age, gender, nationality, ethnicity).
Relevant information regarding duration of
intervention, the length of follow-up (in months), and the types
of dietary weight-reducing interventions.
Data of outcome measures concerning total mortality,
cardiovascular morbidity (including stroke, myocardial
infarction, sudden death, heart f ailure, etc), total serious adverse
events, withdrawals due to adverse effects, total non-serious
adverse events, mean change from baseline in systolic and
diastolic blood pressure as wel l as change in body weight.
Assessment of risk of bias in included studies
Trials meeting the inclusion criteria were assessed independently
by two authors to evaluate methodological quality. Any differences
in opinion were resolved by discussion with a third author. All
trials meeting th e inclusion criteria were assessed using the “Risk of
bias assessment tool (
COCHRANE 2008) under the categories
adequate sequence generation, allocation concealment, blinding,
incomplete outcome data, selective reporting, and other biases.
Important numerical data such as screened, eligible and ran-
domised patients as well as intention-to-treat (ITT) and per-pro-
tocol (PP) population were e valuated carefully. Attrition rates, for
example drop-outs, losses to follow-up and withdrawals, were in-
vestigated. Issues of missing data, ITT and PP were critically ap-
praised and compared to specifications for primary outcome pa-
rameters and power calculation.
Measures of treatment effect
Relative risk with 95% confidence interval was used for dichoto-
mous variables such as total mortality, cardiovascular morbid-
ity, total withdrawals, and withdrawals due to adverse effects.
Weighted mean difference (WMD) was calculated for the mean
change in systolic as well as diastolic blood pressure and body
weight between the groups. If the standard deviation of the mean
change was not explicitly given in th e study it was calculated from
confidence intervals and standard error of the mean or estimated
from p-values.
The position of the patient during BP measurement may affect
the BP lowering effect. When measurements are reported for more
than one position, the order of preference was: 1) sitting; 2) stand-
ing; and 3) supine. (
Musini 2009)
Dealing with missing data
If necessary, authors of trials reporting incomplete information
were contacted to provide missing information.
Assessment of heterogeneity
Heterogeneity was assessed using Higgins I
2
. In the case of sub-
stantial heterogeneity (I
2
>50%), we planned to perform sensitivity
and subgroup analyses for the following items: study quality, per-
protocol vs. ITT analyses, sex, age, body mass index, concomitant
diseases, ethnicity, blood pressure at baseline, blood pressure goals,
concomitant antihypertensive therapy and socioeconomic status.
Assessment of reporting biases
Publication bias and small study effects in general were tested using
the funnel plot or other corrective analytical methods depending
on the number of clinical trials included in the systematic review.
Data synthesis
Data were summarised statistically if they were available, suffi-
ciently similar and of adequate quality. Data synthesis and anal-
yses were done using the Cochrane Review Manager software,
RevMan 5. Statistical analysis was performed according to the sta-
tistical guidelines referenced in the Cochrane Handbook for Sys-
tematic Reviews of Interventions (
COCHRANE 2008). Fixed ef-
fects models were used for the meta-analyses. In case of moderate
or larger heterogeneity as measured by Higgins I
2
random eff ects
model were used and presented.
Subgroup ana lysis and investigation of heterogeneity
If appropriate, subgroup analyses were performed. Heterogenity
among participants could be related to e.g. sex, age, body mass
index, concomitant diseases, ethnicity, blood pressure at baseline,
blood pressure goals, concomitant antihypertensive therapy and
socioeconomic status.
5Long-term effects of weight-reducing diets in hypertensive patients (Review)
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Sensitivity analysis
If appropriate, robustness of results was tested using several sensi-
tivity analyses (e.g. study quality or per-protocol vs. ITT analyses,
studies with large drop-out rates and losses to follow-up).
R E S U L T S
Description of studies
See:
Characteristics of included studies; Characteristics of excluded
studies.
Results of the search
The search in the electronic databases yielded 7669 records, of
which 3159 could be excluded as duplicates. Of the remaining
4510 publications, 4436 were excluded by consensus as not rele-
vant to the question under study on the basis of their abstracts. In
addition one study was identified among the references of a report
of the Institute for Quality and Efficiency in Health Care (
IQWiG
2006
) and two furth er articles were found in the reference lists
of included trials and relevant reviews, resulting in 77 articles for
further examination. After screening the full texts of these publica-
tions, 30 articles on eight studies finally met the inclusion criteria
(see Figure 1 for details of the QUOROM [QUality Of Reporting
Of Meta- analyses] statement).
6Long-term effects of weight-reducing diets in hypertensive patients (Review)
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Figure 1.
7Long-term effects of weight-reducing diets in hypertensive patients (Review)
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Page 9
Included studies
Details of the characteristics of the included studies are given in
the “Characteristics of included studies table. The following gives
a brief overview of the comparisons between dietary interventions
with an intention to reduce body weight in comparison to no
dietary interventions to reduce body weight.
All 8 included studies (
DISH 1985, Cohen 1991, Croft 1986,
Jalkanen 1991, ODES 1995, TAIM 1992, TONE 1998, Ruvolo
1994) had a parallel and open design, and three of them had a fac-
torial design (
TAIM 1992, TONE 1998, ODES 1995). Four stud-
ies were performed as single centre trials (
Cohen1991, Croft 1986,
ODES 1995, Ruvolo 1994) and three (Cohen 1991, Jalkanen
1991
, Ruvolo 1994) did not mention any industrial sponsoring.
Participants and duration
The included studies involved a total of 2100 hypertensive partic-
ipants with a mean age of 45 to 66 years, a baseline systolic BP of
128 to 178 mm Hg and a baseline diastolic BP of 72 to 107 mm
Hg. Mean treatment duration was 6 to 36 months.
Interventions
In all studies patients received either a dietary intervention with
the aim of reducing body weight or no dietary interventions to
reduce body weight.
Outcomes
Primary outcomes
Only one study (
TONE 1998) included th e occurrence of clinical
cardiovascular disease complications during follow-up as a pre-
defined outcome. In two studies (
TONE 1998, DISH 1985),
adverse events were reported.
Secondary outcomes
Except for three studies (
TONE 1998, Cohen 1991, DISH 1985),
all described the mean change in systolic and diastolic blood pres-
sure. Mean ch ange in body weight was described in all but one
study (
TONE 1998).
Excluded studies
The main reason for exclusion was a lack of (sufficient) results for
the hypertensive subgroup in studies including normotensive as
well as hypertensive patients. Some studies were excluded because
they were not randomised controlled trials, did not include pa-
tients with essential hypertension, did not aim for weight reduc-
tion or examined a combined intervention, provided only an in-
appropriate control inter vention or different accompanying ther-
apies, had a duration of intervention less th an 24 weeks, or full
text was not available. Two studies (
Haynes 1984, Curzio 1989)
were excluded after personal communication. Both studies were
performed in the 1980s and for neither of them were electronic
records and/or hard copies still available to further clarify whether
the studies were suitable f or inclusion in our review. Reasons for
excluding each trial are listed in the “Characteristics of excluded
studies table.
Risk of bias in included studies
For details see the “Risk of bias tables in the section “Character-
istics of included studies”. The following gives a brief overview.
Allocation
Only two studies reported the method of randomisation (
TONE
1998
, TAIM 1992) and both of them had a factorial design. Only
one study (
TAIM 1992) described the method of concealment.
One study performed a cluster randomised trial in family prac-
tices (
Cohen 1991), but without providing any information on
allocation.
Blinding
All included trials had an open design in terms of patients and
study personnel. In one study (
TONE 1998), an independent
committee masked to inter vention assignment evaluated the e nd-
points. In another study (
TAIM 1992), blood pressure endpoint
assessment was blinded in only one out of three clinical centres
due to logistical and budgetary considerations.
Incomplete outcome data
In one study, the description of the outcome data was complete
because Cohen (Cohen 1991) had no losses to follow-up. In DISH
(
DISH 1985), no withdrawals were reported for the endpoint suc-
cess of withdrawal from antihypertensive medication, butconcern-
ing body weight at follow-up, between 13% and 23% of values are
missing. In Jalkanen and Ruvolo (
Jalkanen 1991, Ruvolo 1994),
only 1 to 2 patients were missing, but no reason for withdrawal was
given. In TAIM and ODES (
TAIM 1992, ODES 1995), study
withdrawals were only reported for the whole study population
and no ITT analysis was per formed. In TONE (
TONE 1998),
numbers of withdrawals and reasons are missing, but 96% - 99%
of par ticipants were included at the follow-up analysis.
Selective reporting
There is a risk of selective reporting bias in 1 study where post-
hoc analyses of blood pressure were cal cul ated and results were not
reported for all predefined outcomes (
ODES 1995).
8Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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Other potential sources of bias
In all except one study (
TONE 1998), other potential sources
of bias could be identified. One study (
Cohen 1991) f eatured
stratified randomisation of investigators instead of patients, with
very small cl uster size. In another study (
DISH 1985), patients
were randomised before consent was obtained and in two studies
(
Cohen 1991, TAIM 1992), treatment in the intervention group
seemed to be more intensive. For further details please see the
“Risk of bias table and
Figure 2 and Figure 3.
Figure 2. Risk of bias graph: review a uthors’ judgements about each risk of bias item presented as
percentages across all included studies.
9Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 11
Figure 3. Risk of bias summary: review authors’ judgements about each risk of bias item for each included
study.
10Long-term effects of weight-reducing diets in hypertensive patients (Review)
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Page 12
Effects of interventions
Primary outcomes
Mortality
None of the studies was designed to evaluate the effects on mor-
tality of weight loss diet vs. no diet.
Cardiovascular morbidity
Only one study (TONE 1998) evaluated the effects of dietary
weight loss vs. no dietary intervention on a combined end point,
including cardiovascular complications. After 30 months, the haz-
ard ratio for patients in the dietary group to reach the combined
end point, consisting of the necessity of reinstating antihyper-
tensive therapy and severe cardiovascular complications, was 0.70
(95% confidence interval [CI], 0.57 to 0.87) compared with pa-
tients in the usual care group.
Adverse events
None of the studies evaluated the endpoint adverse event as de-
signed in our protocol (includingtotal serious adverse e vents, with-
drawal due to adverse events and total non-serious adverse events).
In TONE (
TONE 1998), adverse events were classified by type
(primary cardiovascular events) and time of occurrence before,
during or after attempted antihypertensive drug withdrawals.
However, no usable results were reported for the obese subgroups
with and without dietary interventions. In DISH (
DISH 1985),
adverse events were reported as withdrawals due to the need to
resume antihypertensive medication; this was the case in 40.5%
in the intervention group and 64.7% in the control group (p=
0.0015).
Secondary outcomes
For details on secondary outcome data, see Table 1, Table 2 and
Table 3. Due to between-study variability, results from random
effects models are presented in the following analyses.
Changes in systolic blood pressure
Five studies investigating the effects of dietary vs. no dietary in-
tervention could not be included in the meta-analysis for systolic
blood pressure. In two studies (
DISH 1985, TONE 1998), suc-
cessful withdrawal from antihypertensives was the primary out-
come. In another study (
Cohen 1991), only the mean blood pres-
sure change was reported, and in the studies of Ruvolo and Jalka-
nen (
Ruvolo 1994, Jalkanen 1991) estimators for variance and p-
values for the change in systolic blood pressure are missing. There-
fore, only three studies remained for analysis, in case of the TAIM
study (
TAIM 1992), the overall SD presented for the combined
analyses could be used for the meta-analysis. There was a signifi-
cant reduction of SBP with a WMD of -4.5 mm Hg (95% CI: -
7.2 to -1.8) in favour of dietary intervention. The test of hetero-
geneity gave a p-value of 0.3 and Higgins I
2
indicated only low
heterogeneity between studies (I
2
= 21%) (see Analysis 1.1, Figure
4
). Differences in study quality could not explain heterogeneity.
No plausible explanation for heterogeneity could be deduced from
differences in study design, study duration, sample sizes, interven-
tions or characteristics of included patients.
Figure 4. Forest plot of comparison: 1 Weight reducing diet versus no weight reducing diet, outcome: 1.1
Change in systolic blood pressure from baseline to endpoint [mm Hg].
Changes in diastolic blood pressure
Five studies investigating the effects of dietary vs. no dietary in-
tervention could not be included in the meta-analysis for diastolic
blood pressure. In two studies (
DISH 1985, TONE 1998), suc-
cessful withdrawal from antihypertensives was the primary out-
come. In another study (
Cohen 1991), only the mean blood pres-
sure change was reported, and the study of Jalkanen and Ruvolo
11Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 13
(Jalkanen 1991, Ruvolo 1994) does not include an estimator for
variance and p-values for the change in diastolic blood pressure.
Therefore, only three studies remained for analysis, in case of the
TAIM study (
TAIM 1992), the SDs presented for the subgroup
(atenolol, chlorthalidone, placebo) analyses could be used for the
meta-analysis. There was a significant reduction of DBP with a
WMD of -3.2 mm Hg (95% CI: -4.8 to -1.5) in favour of dietary
intervention. The test of heterogeneity gave a p-value of 0.2 ( I
2
= 35%) (see
Analysis 1.2, Figure 5). Differences in study qual-
ity could not e xpl ain heterogeneity. No plausible explanation for
heterogeneity could be deduced from differences in study design,
study duration, sample sizes, interventions or characteristics of in-
cluded patients.
Figure 5. Forest plot of comparison: 1 Weight reducing diet versus no weight reducing diet, outcome: 1.2
Change in diastolic blood pressure from baseline to endpoint [mm Hg].
Body weight
Only three studies investigating the effects of dietary vs. no di-
etary intervention could not be included in the meta-analysis for
body weight. In two studies (
ODES 1995, TONE 1998), no val-
ues for changes in body weight were presented and in the study
of Ruvolo (
Ruvolo 1994), an estimator for variance and p-values
for the change in body weight is missing. Therefore, five studies
remained for analysis. In the TAIM study (
TAIM 1992), the SDs
presented for the subgroup (atenolol, chlorthalidone and placebo)
analyses could be used. Dietary intervention was f ound to lower
body weight significantly more effectivel y with a WMD of -4.0
kg (95% CI: -4.8 to -3.2) in favour of dietary intervention. The
test of heterogeneity gave a p-value of 0.2 (I
2
= 34%) (see
Analysis
1.3
, Figure 6). Differences in study quality could not explain het-
erogeneity. No plausible explanation for heter ogeneity could be
deduced from differences in study design, study duration, sample
sizes, interventions or characteristics of included patients.
Figure 6. Forest plot of comparison: 1 Weight reducing diet versus no weight reducing diet, outcome: 1.3
Change in body weight from baseline to endpoint [kg].
12Long-term effects of weight-reducing diets in hypertensive patients (Review)
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Page 14
Heterogeneity
See appropriate statements in the outcomes section.
Subgroup analyses
Not performed due to lack of data.
Sensitivity analyses
Not performed due to lack of data.
Publication and small study bias
A clear interpretation of the funnel plot was not possible, which
we mainly attributed to the relatively small number of included
studies.
D I S C U S S I O N
Summary of main results
This systematic review attempted to determine the long-term ef-
fects of weight loss through dietary interventions on patient rel-
evant endpoints, namely death, cardiovascular complications and
adverse events, in the antihypertensive therapy of patients with
essential hypertension, but we found that no randomised con-
trolled trials are currently available that were designed to answer
this question. We identified eight relevant trials that intended to
reduce body weight (e.g. dietary counselling, caloric restrictions,
reduction in fat intake) vs. no dietary interventions. We found
that of the eight included studies, only two were judged as having
minor deficiencies of study quality (
TONE 1998, TAIM 1992).
Only one study (
TONE 1998) reported on cardiovascular com-
plications as part of a combined primary outcome - consisting
of the necessity of reinstating antihypertensive therapy and severe
cardiovascular complications - that was in favour of the dietary
intervention group. No valuable information on possible adverse
effects was reported in any publications on the relevant trials. The
meta-analyses showed that patients under dietary therapy could
reduce th eir systolic and diastolic blood pressure and body weight
levels statistically significantly more than patients in the control
groups.
Two studies (TONE 1998, DISH 1985) did not aim for blood
pressure reduction, but used successful withdrawal of antihyper-
tensive medication as primary outcomes. In DISH (
DISH 1985),
about 35% of the participants in the control group and about
60% in the intervention group remained without antihyperten-
sive medication after 56 weeks. In TONE (
TONE 1998), 93%
of the patients in the weight loss group and 87% in the control
group could stop antihypertensive treatment. In the salt lowered
groups, 93% of both the dietary weight loss intervention and the
usual care group could be successfully taken off medication. Even
though successful withdrawal of antihyper tensive treatment was
not included as a chosen outcome in our review, it further under-
scores the success of dietary weight loss interventions for reducing
blood pressure.
In conclusion, in patients with essential hypertension, therapy
with dietary interventions to reduce body weight resulted in re-
ductions in BP and body weight. A reduction in body weight of
approximately 4 kg was necessary to achieve a reduction of approx-
imately 4.5 mm Hg systolic blood pressure and of approximately
3.2 mm Hg diastolic blood pressure. However, the fact that only
a part of the studies could be included in the analyses weakens
the conclusiveness of these results. None of the studies provided
data to answer the question whether the risk of mortal ity or other
patient relevant endpoints can be lowered by weight reduction.
Overall completeness and applicab ility of
evidence
We searched in three electronic databases until November 22,
2010 and we searched the reference lists of included trials and
relevant systematic reviews and meta-analyses. Each study’s quality
was assessed and the results were summarized. The results of this
review can therefore be taken to be complete and applicable. For
full information, please see details in the relevant sections.
While the se results show that dietary interventions may be a help-
ful option in the antihypertensive therapy of overweight hyperten-
sive patients, major questions still remain. One point raised by a
co-author (Brian Haynes), who was contacted for further clarifica-
tion of whether his paper was relevant for inclusion in the trial was
whether any effect on blood pressure lowering persists when the
patient’s per iod of active weight loss ends. His clinical impression is
that when weight loss stops (even if the weight loss is maintained?
), the blood pressure goes back up. However, as we could identify
no long-term follow-up trials for our review, the long-term effects
of weight loss on blood pressure found in this review are uncer-
tain. Indirect evidence from this assumption can be derived from
the Swedish Obese Subject Study (
Sjostrom 2004), where partici-
pants successfully reduced their body weight by me ans of bariatric
surgery. This study showed that the post-surgical blood pressure
reduction was still present 2 years after surgery but increased again
to baseline values after 10 years, despite continued weight loss.
Secondly, it can be asked whether patients with higher or lower
blood pressure or higher or lower body weight at baseline might
benefit in a different way from dietary intervention aiming to re-
duce body weight. It can, however, be assumed that in patients
with moderate to severe hypertension, the potential benefit on
blood pressure might be greater than in patients with mild hyper-
tension; in any case, no correlation could be identified from the
13Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 15
included studies.
Quality of the evidence
Of the e ight studies included in our analyses, only two (
TONE
1998
, TAIM 1992) were judged as having only minor deficiencies
of quality. Therefore, the beneficial effects shown reflect some
degree of uncertainty. Full details are provided in the “Risk of bias
tables in the section “Characteristics of included studies”.
Potential biases in the review process
A major l imitation of this review is that because of the lack of in-
formation in the included studies, no conclusions on the effects of
the different dietary weight-loss interventions on patient relevant
long-term outcomes can be drawn.
The results on blood pressure could also be considered uncertain,
because only data from three studies were included in the analyses.
These results are mainly based on the
TAIM 1992 study, which
was judged to have a low risk of bias and contributed more than
70% of all patients to the meta-analyses. In addition, two of the
trials that did not report results on blood pressure showed a re-
duction of antihypertensive medication as an indirect measure of
blood pressure, which supports the findings of our meta-analyses.
Also, inclusion of the remaining studies from which data on blood
pressure was available but were not sufficient would probably not
have changed the results because all these studies were small and
were rated as having a high risk of bias.
The findings on body weight may also be regarded as uncertain
because only results from five studieswere available for the analysis.
But again, the
TAIM 1992 study had the highest weight in the
analysis. Results are supported by results from the
ODES 1995
study, which did not report on body weight but found BMI to be
reduced to a greater extent among participants in the intervention
groups.
Agreements and disagreemen ts with other
studies or reviews
There are only a few published systematic reviews on long-term ef-
fects of weight-reducing drugs in patients with hypertension. One
systematic review, “Long-term effects of weight-reducing drugs in
hypertensive patients”, published by Aucott(
Aucott 2005) reached
the same conclusion, i.e. that only short-term trials were available.
The authors also warned, “that extrapolation of short-term blood
pressure changes with weight loss to the longer term is potentially
misleading. The weight/hypertension relationship is complex and
needs well-conducted studies with long-term follow-up to examine
the effects of weight loss on hypertension outcomes”. In addition,
we were also involved in the preparation of the scientific report on
the evaluation of the benefits and harms of non-drug treatment
strategies in patients with essential hypertension (
IQWiG 2006)
and published a paper on this topic in 2008 (
Horvath 2008).
Since our last search for dietary interventions performed on June
12, 2006 (
IQWiG 2006, Horvath 2008), no new trials could be
identified dealing with our research question. We can therefore say
with confidence that our findings are in agreement with recently
published reviews and studies.
A U T H O R S C O N C L U S I O N S
Implications for practice
Although trials on dietary interventions in patients with elevated
blood pressure demonstrated statistically significant decreases in
weight loss and blood pressure these findings are subject to a high
risk of selective reporting bias. Furthermore the available RCT
evidence provides no data on the effect of dietary interventions on
mortality and morbidity. In addition, no valuable information on
adverse events was reported in any of the included trials.
Implications for research
Long-term trials assessing the effect of dietary interventions to
reduce body weight on mortality, morbidity and adverse events
in patients with elevated blood pressure are needed. Long-term
follow-up data are also needed to determine the long-term effects
of weight reducing diets on blood pressure.
A C K N O W L E D G E M E N T S
We would like to thank Eva Matyas, Nicole Pignitter and Anika
Maas for reviewing the data and Eugenia Lamont for final editing
of the manuscript.
14Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 16
R E F E R E N C E S
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Anderssen S, Holme I, Urdal P, Hjermann I. Diet and
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pressure in mild hypertensives: the Oslo Diet and
Exercise Study (ODES). Blood pressure 1995;4(6):343–9.
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I. Improved carbohydrate metabolism after physical
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Merethe H, Anderssen Sigmund A, Drevon Christian
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Anderssen S, Holme I, Urdal P, Hjermann I. Diet and
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Exercise Study (ODES). Blood pressure 1995;4(6):343–9.
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Anderssen SA, Hjermann I, Urdal P, Torjesen PA, Holme
I. Improved carbohydrate metabolism after physical
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”atherothrombogenic syndrome’. Oslo Diet and Exercise
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Jacobs David R Jr, Sluik Diewertje, Rokling-Andersen
Merethe H, Anderssen Sigmund A, Drevon Christian
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The American journal of clinical nutrition 2009;89:509–17.
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Torjesen PA, Birkeland KI, Anderssen SA, Hjermann I,
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Urdal P, Haaland A, Hjermann I, Gjesdal K, Christian
C, Sorensen M, et al.The Oslo Diet and Exercise Study
(ODES): Design and objectives. Controlled c li ni cal trials
1993;14 (3):229–43.
ODES 1995 with exercise {published data only}
Anderssen S, Holme I, Urdal P, Hjermann I. Diet and
exercise interv ention have favourable effects on blood
pressure in mild hypertensives: the Oslo Diet and
Exercise Study (ODES). Blood pressure 1995;4(6):343–9.
[PUBMED: 8746601]
Anderssen SA, Hjermann I, Urdal P, Torjesen PA, Holme
I. Improved carbohydrate metabolism after physical
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“atherothrombogenic syndrome’. Oslo Diet and Exercise
Study (ODES). A randomized trial. Journal of internal
medici ne 1996;240(4):203–9. [P UBMED: 8918511]
Jacobs David R Jr, Sluik Diewertje, Rokling-Andersen
Merethe H, Anderssen Sigmund A, Drevon Christian
A. Association of 1-y changes in diet pattern with
cardiovascular disease risk factors and adipokines: results
15Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 17
from the 1-y randomized Oslo Diet and Exercise Study.
The American journal of clinical nutrition 2009;89:509–17.
[PUBMED: 19116328]
Torjesen PA, Birkeland KI, Anderssen SA, Hjermann I,
Holme I, Urdal P. Lifestyle changes may reverse development
of the insulin resistance syndrome. The Oslo Diet and
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Urdal P, Haaland A, Hjermann I, Gjesdal K, Christian
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[PUBMED: 1736933]
Wylie-Rosett J, Wassertheil-Smoller S, Blaufox MD,
Davis BR, Langford HG, Oberman A, et al.Trial of
antihypertensive intervention and management: greater
efficacy with weight reduction than with a sodium-
potassium intervention. Journal of the Americ an Dietetic
Association 1993;93(4):408–15. [PUBMED: 8454808]
TAIM 1992 atenolol {published data only}
Blaufox MD, L ee HB, Davis B, Oberman A, Wassertheil-
Smoller S, Langford H . Renin predicts diastolic blood
pressure response to nonpharmacologic and pharmacologic
therapy. JAMA : the journal of the American Medical
Association 1992;267(9):1221–5. [PUBMED: 1538559]
Davis BR, Blaufox MD, Hawkins CM, Langford HG,
Oberman A, Swencionis C, et al.Trial of antihypertensive
interventions and management. Design, methods, and
selected baseline results. Controlled clinical trials 1989;10
(1):11–30. [PUBMED: 2649308]
Davis BR, Blaufox MD, Oberman A, Wassertheil-Smoller
S, Zimbaldi N, Cutler JA, et al.Reduction in long-term
antihypertensive medication requirements. Effects of weight
reduction by dietary intervention in overweight persons
with mild hypertension. Archives of internal medicine 1993;
153(15):1773–82. [PUBMED: 8333814]
Davis BR, Oberman A, Blaufox MD, Wassertheil-
Smoller S, Hawkins CM, Cutler JA, et al.Effect of
antihypertensive therapy on weight loss. The Trial of
Antihypertensive Interventions and Management Research
Group. Hypertension 1992;19(4):393–9. [PUBMED:
1555871]
Davis BR, Oberman A, Blaufox MD, Wassertheil-Smoller
S, Zimbald i N, Kirchner K, et al.La ck of effectiveness
of a low-sodium/high-potassium diet in reducing
16Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 18
antihypertensive medication requirements in overweight
persons with mild hypertension. TAIM Research Group.
Trial of Antihypertensive Interventions and Management.
American journal of hypertension 1994;7(10 Pt 1):926–32.
[PUBMED: 7826557]
Langford HG, Davis BR, Blaufox D, Oberman A,
Wassertheil-Smoller S, H a wkins M, et al.Effect of drug and
diet treatment of mild hypertension on diastolic blood
pressure. The TAIM Research Group. Hypertension 1991;
17(2):210–7. [PUBMED: 1671380]
Oberman A, Was sertheil-Smoller S, Langford HG, Blaufox
MD, Da vis BR, Blaszkowski T, et al.Pharmacologic and
nutritional treatment of mild hypertension: changes in
cardiovascular risk status. Annals of internal medicine 1990;
112(2):89–95. [PUBMED: 1967210]
Wassertheil-Smoller S, Blaufox M D, Da vis B R, Kirchner
K, Langford H G, Oberman A. The trial of antihypertensive
interventions and management (TAIM). Nieren- und
Hochdruckkrankheiten 1994;23 (SUPPL. 1):S22–7.
Wassertheil-Smoller S, Blaufox MD, Oberman AS,
Langford HG, Davis BR, Wylie-Rosett J. The Trial of
Antihypertensive Interventions and Management (TAIM)
study. Adequate weight loss, alone and combined with drug
therapy in the treatment of mild hypertension. Archives
of internal medicine 1992;152(1):131–6. [PUBMED:
1728908]
Wassertheil-Smoller S, Davis BR, Oberman A. The TAIM
Study: Sex-Race differences in effects of diet and drugs on
cardiovascular risk. Cardiovascular Risk Factors 1991;1(7):
427–35.
Wassertheil-Smoller S, Oberman A, Blaufox MD, Davis B,
Langford H. The Trial of Antihypertensive Interventions
and Management (TAIM) Study. Final results with regard
to blood pressure, cardiovascular risk, and quality of
life. American journal of hypertension 1992;5(1):37–44.
[PUBMED: 1736933]
Wylie-Rosett J, Wassertheil-Smoller S, Blaufox MD,
Davis BR, Langford HG, Oberman A, et al.Trial of
antihypertensive intervention and management: greater
efficacy with weight reduction than with a sodium-
potassium intervention. Journal of the Americ an Dietetic
Association 1993;93(4):408–15. [PUBMED: 8454808]
TAIM 1992 chlorthalidone {published data only}
Blaufox MD, L ee HB, Davis B, Oberman A, Wassertheil-
Smoller S, Langford H . Renin predicts diastolic blood
pressure response to nonpharmacologic and pharmacologic
therapy. JAMA : the journal of the American Medical
Association 1992;267(9):1221–5. [PUBMED: 1538559]
Davis BR, Blaufox MD, Hawkins CM, Langford HG,
Oberman A, Swencionis C, et al.Trial of antihypertensive
interventions and management. Design, methods, and
selected baseline results. Controlled clinical trials 1989;10
(1):11–30. [PUBMED: 2649308]
Davis BR, Blaufox MD, Oberman A, Wassertheil-Smoller
S, Zimbaldi N, Cutler JA, et al.Reduction in long-term
antihypertensive medication requirements. Effects of weight
reduction by dietary intervention in overweight persons
with mild hypertension. Archives of internal medicine 1993;
153(15):1773–82. [PUBMED: 8333814]
Davis BR, Oberman A, Blaufox MD, Wassertheil-
Smoller S, Hawkins CM, Cutler JA, et al.Effect of
antihypertensive therapy on weight loss. The Trial of
Antihypertensive Interventions and Management Research
Group. Hypertension 1992;19(4):393–9. [PUBMED:
1555871]
Davis BR, Oberman A, Blaufox MD, Wassertheil-Smoller
S, Zimbald i N, Kirchner K, et al.La ck of effectiveness
of a low-sodium/high-potassium diet in reducing
antihypertensive medication requirements in overweight
persons with mild hypertension. TAIM Research Group.
Trial of Antihypertensive Interventions and Management.
American journal of hypertension 1994;7(10 Pt 1):926–32.
[PUBMED: 7826557]
Langford HG, Davis BR, Blaufox D, Oberman A,
Wassertheil-Smoller S, H a wkins M, et al.Effect of drug and
diet treatment of mild hypertension on diastolic blood
pressure. The TAIM Research Group. Hypertension 1991;
17(2):210–7. [PUBMED: 1671380]
Oberman A, Was sertheil-Smoller S, Langford HG, Blaufox
MD, Da vis BR, Blaszkowski T, et al.Pharmacologic and
nutritional treatment of mild hypertension: changes in
cardiovascular risk status. Annals of internal medicine 1990;
112(2):89–95. [PUBMED: 1967210]
Wassertheil-Smoller S, Blaufox M D, Da vis B R, Kirchner
K, Langford H G, Oberman A. The trial of antihypertensive
interventions and management (TAIM). Nieren- und
Hochdruckkrankheiten 1994;23 (SUPPL. 1):S22–7.
Wassertheil-Smoller S, Blaufox MD, Oberman AS,
Langford HG, Davis BR, Wylie-Rosett J. The Trial of
Antihypertensive Interventions and Management (TAIM)
study. Adequate weight loss, alone and combined with drug
therapy in the treatment of mild hypertension. Archives
of internal medicine 1992;152(1):131–6. [PUBMED:
1728908]
Wassertheil-Smoller S, Davis BR, Oberman A. The TAIM
Study: Sex-Race differences in effects of diet and drugs on
cardiovascular risk. Cardiovascular Risk Factors 1991;1(7):
427–35.
Wassertheil-Smoller S, Oberman A, Blaufox MD, Davis B,
Langford H. The Trial of Antihypertensive Interventions
and Management (TAIM) Study. Final results with regard
to blood pressure, cardiovascular risk, and quality of
life. American journal of hypertension 1992;5(1):37–44.
[PUBMED: 1736933]
Wylie-Rosett J, Wassertheil-Smoller S, Blaufox MD,
Davis BR, Langford HG, Oberman A, et al.Trial of
antihypertensive intervention and management: greater
efficacy with weight reduction than with a sodium-
potassium intervention. Journal of the Americ an Dietetic
Association 1993;93(4):408–15. [PUBMED: 8454808]
TAIM 1992 combined {published data only}
Blaufox MD, L ee HB, Davis B, Oberman A, Wassertheil-
Smoller S, Langford H . Renin predicts diastolic blood
pressure response to nonpharmacologic and pharmacologic
17Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 19
therapy. JAMA : the journal of the American Medical
Association 1992;267(9):1221–5. [PUBMED: 1538559]
Davis BR, Blaufox MD, Hawkins CM, Langford HG,
Oberman A, Swencionis C, et al.Trial of antihypertensive
interventions and management. Design, methods, and
selected baseline results. Controlled clinical trials 1989;10
(1):11–30. [PUBMED: 2649308]
Davis BR, Blaufox MD, Oberman A, Wassertheil-Smoller
S, Zimbaldi N, Cutler JA, et al.Reduction in long-term
antihypertensive medication requirements. Effects of weight
reduction by dietary intervention in overweight persons
with mild hypertension. Archives of internal medicine 1993;
153(15):1773–82. [PUBMED: 8333814]
Davis BR, Oberman A, Blaufox MD, Wassertheil-
Smoller S, Hawkins CM, Cutler JA, et al.Effect of
antihypertensive therapy on weight loss. The Trial of
Antihypertensive Interventions and Management Research
Group. Hypertension 1992;19(4):393–9. [PUBMED:
1555871]
Davis BR, Oberman A, Blaufox MD, Wassertheil-Smoller
S, Zimbald i N, Kirchner K, et al.La ck of effectiveness
of a low-sodium/high-potassium diet in reducing
antihypertensive medication requirements in overweight
persons with mild hypertension. TAIM Research Group.
Trial of Antihypertensive Interventions and Management.
American journal of hypertension 1994;7(10 Pt 1):926–32.
[PUBMED: 7826557]
Langford HG, Davis BR, Blaufox D, Oberman A,
Wassertheil-Smoller S, H a wkins M, et al.Effect of drug and
diet treatment of mild hypertension on diastolic blood
pressure. The TAIM Research Group. Hypertension 1991;
17(2):210–7. [PUBMED: 1671380]
Oberman A, Was sertheil-Smoller S, Langford HG, Blaufox
MD, Da vis BR, Blaszkowski T, et al.Pharmacologic and
nutritional treatment of mild hypertension: changes in
cardiovascular risk status. Annals of internal medicine 1990;
112(2):89–95. [PUBMED: 1967210]
Wassertheil-Smoller S, Blaufox M D, Da vis B R, Kirchner
K, Langford H G, Oberman A. The trial of antihypertensive
interventions and management (TAIM). Nieren- und
Hochdruckkrankheiten 1994;23 (SUPPL. 1):S22–7.
Wassertheil-Smoller S, Blaufox MD, Oberman AS,
Langford HG, Davis BR, Wylie-Rosett J. The Trial of
Antihypertensive Interventions and Management (TAIM)
study. Adequate weight loss, alone and combined with drug
therapy in the treatment of mild hypertension. Archives
of internal medicine 1992;152(1):131–6. [PUBMED:
1728908]
Wassertheil-Smoller S, Davis BR, Oberman A. The TAIM
Study: Sex-Race differences in effects of diet and drugs on
cardiovascular risk. Cardiovascular Risk Factors 1991;1(7):
427–35.
Wassertheil-Smoller S, Oberman A, Blaufox MD, Davis B,
Langford H. The Trial of Antihypertensive Interventions
and Management (TAIM) Study. Final results with regard
to blood pressure, cardiovascular risk, and quality of
life. American journal of hypertension 1992;5(1):37–44.
[PUBMED: 1736933]
Wylie-Rosett J, Wassertheil-Smoller S, Blaufox MD,
Davis BR, Langford HG, Oberman A, et al.Trial of
antihypertensive intervention and management: greater
efficacy with weight reduction than with a sodium-
potassium intervention. Journal of the Americ an Dietetic
Association 1993;93(4):408–15. [PUBMED: 8454808]
TAIM 1992 placebo {published data only}
Blaufox MD, L ee HB, Davis B, Oberman A, Wassertheil-
Smoller S, Langford H . Renin predicts diastolic blood
pressure response to nonpharmacologic and pharmacologic
therapy. JAMA : the journal of the American Medical
Association 1992;267(9):1221–5. [PUBMED: 1538559]
Davis BR, Blaufox MD, Hawkins CM, Langford HG,
Oberman A, Swencionis C, et al.Trial of antihypertensive
interventions and management. Design, methods, and
selected baseline results. Controlled clinical trials 1989;10
(1):11–30. [PUBMED: 2649308]
Davis BR, Blaufox MD, Oberman A, Wassertheil-Smoller
S, Zimbaldi N, Cutler JA, et al.Reduction in long-term
antihypertensive medication requirements. Effects of weight
reduction by dietary intervention in overweight persons
with mild hypertension. Archives of internal medicine 1993;
153(15):1773–82. [PUBMED: 8333814]
Davis BR, Oberman A, Blaufox MD, Wassertheil-
Smoller S, Hawkins CM, Cutler JA, et al.Effect of
antihypertensive therapy on weight loss. The Trial of
Antihypertensive Interventions and Management Research
Group. Hypertension 1992;19(4):393–9. [PUBMED:
1555871]
Davis BR, Oberman A, Blaufox MD, Wassertheil-Smoller
S, Zimbald i N, Kirchner K, et al.La ck of effectiveness
of a low-sodium/high-potassium diet in reducing
antihypertensive medication requirements in overweight
persons with mild hypertension. TAIM Research Group.
Trial of Antihypertensive Interventions and Management.
American journal of hypertension 1994;7(10 Pt 1):926–32.
[PUBMED: 7826557]
Langford HG, Davis BR, Blaufox D, Oberman A,
Wassertheil-Smoller S, H a wkins M, et al.Effect of drug and
diet treatment of mild hypertension on diastolic blood
pressure. The TAIM Research Group. Hypertension 1991;
17(2):210–7. [PUBMED: 1671380]
Oberman A, Was sertheil-Smoller S, Langford HG, Blaufox
MD, Da vis BR, Blaszkowski T, et al.Pharmacologic and
nutritional treatment of mild hypertension: changes in
cardiovascular risk status. Annals of internal medicine 1990;
112(2):89–95. [PUBMED: 1967210]
Wassertheil-Smoller S, Blaufox M D, Da vis B R, Kirchner
K, Langford H G, Oberman A. The trial of antihypertensive
interventions and management (TAIM). Nieren- und
Hochdruckkrankheiten 1994;23 (SUPPL. 1):S22–7.
Wassertheil-Smoller S, Blaufox MD, Oberman AS,
Langford HG, Davis BR, Wylie-Rosett J. The Trial of
Antihypertensive Interventions and Management (TAIM)
study. Adequate weight loss, alone and combined with drug
therapy in the treatment of mild hypertension. Archives
18Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 20
of internal medicine 1992;152(1):131–6. [PUBMED:
1728908]
Wassertheil-Smoller S, Davis BR, Oberman A. The TAIM
Study: Sex-Race differences in effects of diet and drugs on
cardiovascular risk. Cardiovascular Risk Factors 1991;1(7):
427–35.
Wassertheil-Smoller S, Oberman A, Blaufox MD, Davis B,
Langford H. The Trial of Antihypertensive Interventions
and Management (TAIM) Study. Final results with regard
to blood pressure, cardiovascular risk, and quality of
life. American journal of hypertension 1992;5(1):37–44.
[PUBMED: 1736933]
Wylie-Rosett J, Wassertheil-Smoller S, Blaufox MD,
Davis BR, Langford HG, Oberman A, et al.Trial of
antihypertensive intervention and management: greater
efficacy with weight reduction than with a sodium-
potassium intervention. Journal of the Americ an Dietetic
Association 1993;93(4):408–15. [PUBMED: 8454808]
TONE 1998 {published data only}
Appel LJ, Espeland M, Whelton PK, Dolecek T, Kumanyika
S, Applegate WB, et al.Trial of Nonpharmacologic
Intervention in the Elderly (TONE). Des ign and rationale
of a blood pressure control trial. Annals of epidemiology
1995;5(2):119–29. [PUBMED: 7795830]
Bahnson JL, Whelton PK, Appel LJ, Espeland MA, Wofford
JL, Rosen R, et al.Baseline characteristics of randomized
participants in the trial of nonpharmacologic intervention
in the elderly (TONE). Disease Management & Clinical
Outcomes 1997;1(2):61–8.
Fessler B. Sodium reduction a nd weight loss instead
of treatment with antihypertensive agents. [German].
Deutsche Apotheker Zeitung 1998;138(26):36–9.
Kostis JB, Wilson AC, Shindler DM, Cosgrove NM, Lacy
CR. Persistence of normotension after discontinuation
of lifestyle intervention in the trial of TONE. Trial of
Nonpharmacologic Interventions in the Elderly. American
journal of hypertension 2002;15(8):732–4. [PUBMED:
12160197]
Kumanyika SK, Espeland MA, Bahnson JL, Bottom JB,
Charleston JB, Folmar S, et al.Ethnic comparison of weight
loss in the Trial of Nonpharmacologic Interventions in the
Elderly. Obesity research 2002;10(2):96–106. [PUBMED:
11836455]
Whelton PK, Appel LJ, E speland MA, Applegate WB,
Ettinger WH Jr, Kostis JB, et al.Sodium reduction and
weight loss in the treatment of hypertension in older
persons: a randomized controlled trial of nonpharmacologic
interventions in the elderly (TONE). TONE Collaborative
Research Group. JAMA : the journal of the American Medical
Association 1998;279(11):839–46. [PUBMED: 9515998]
References to studies excluded from this review
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Evidence-Based Healthcare and Public Health. Advice
about diet and lifestyle does not reduce blood pressure in
people with hypertension. Evidence-Based Healthcare and
Public Health 2004;8 (6):348–9.
Andersen 1985 {published data only}
Andersen TR, Nielsen PE. Blood pressure lowering effect
of weight reduction. Scandinavian journal of clinical and
laboratory investigation. Supplementum 1985;176:7–14.
[PUBMED: 3864228]
Angelico 2009 {published data only}
Angelico F, Del Ben M, Pacella A, Carnevale R, Loffredo
L, Violi F. Low-fat, low-calorie, mediterranean-style diet
improves endothelial dysfunction in patients with the
metabolic syndrome. Journal of Diabetes 2009;Conference:
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Metabolic Syndrome Nice France. Conference Start:
20090401 Conference End: 20090404. Conference: 3rd
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Syndrome Nice France. Conference Start: 20090401
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(var.pagings). 1:A43.
Ard 2005 {published data only}
Ard JD, Svetkey LP. Diet and blood pressure: applying the
evidence to clinical practice. American heart journal 2005;
149(5):804–12. [PUBMED: 15894960]
Bao, 1999 {published data only}
Bao, D, Mori, T, Burke, V, et al.Dietary fish and weight
reduction improves multiple risk factors in overweight,
treated hypertensives. [abstract]. Australian & New Zealand
Journal of Medicine 1999;29:148.
Bartels 1974 {published data only}
Bartels RW, Bigalke C, Mollmann H, Schneeberger
W, Wessels F. Influence of various hunger-cures on the
behavior of body weight and blood pressure as well as on
relevant blood parameters [Der Einfluss unterschiedlicher
Fas tenkuren auf das Gewichts– und Blutdruckverhalten
sowie auf relevante metabolische Blutp a rameter]. Die
Medizinische Welt 1974;25(17):725–35. [PUBMED:
4421950]
Cakir 2006 {published data only}
Cakir H, Pinar R. Randomized controlled trial on lifestyle
modification in hypertensive patients. Western Journal of
Nursing Research 2006;28 (2):190–209.
Cambien 1986 {published data only}
Cambien F, Plouin Psmpggm, Dutemple C. [Comparative
study of a medical and a dietary intervention in overweight
hypertensive patients]. Archives des Maladies du Coeur et des
Vaisseaux 1986;79:1002.
Camhi 2010 {published data only}
Camhi S M, Stefanick M L, Katzmarzyk P T, Young D R.
Metabolic syndrome and changes in body fat from a low-
fat diet and/or exercise randomized controlled trial. Obesity
2010;18 (3):548–54.
Chen 2009 {published data only}
Chen L, Appel LJ, Loria C, Lin PH, Champagne CM,
Elmer PJ, et al.Reduction in consumption of sugar-
sweetened beverages is associated with weight loss: the
PREMIER trial. The American journal of c li ni cal nutrition
2009;89(5):1299–306. [PUBMED: 19339405]
19Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 21
Childress 2008 {published data only}
Childres s S, Brubaker P H, Amico L A, Nesbit B A,
Williams C M, Jack Rejeski W. Patterns of Physical Activity
Before and After An Exercise Intervention in Overweight/
Obese Older Adults With Cvd or the Metabolic Syndrome.
Journal of Cardiopulmonary Rehabilitation and Prevention
2008;28(4):268.
Coppell 2010 {published data only}
Coppell KJ, Kataoka M, Williams SM, Chisholm AW,
Vorgers SM, Mann JI. Nutritional intervention in patients
with type 2 diabetes who are hyperglycaemic despite
optimised drug treatment--Lifestyle Over and Above Drugs
in Diabetes (LOADD) study: randomised c ontrolled trial.
BMJ (Clinical research ed.) 2010;341:c3337. [PUBMED:
20647285]
Curzio 1989 {published data only}
Curzio JL, Kennedy SS, Elliott HL, Farish E, Barnes
JF, Howie CA, et al.Hypercholesterolaemia in treated
hypertensives: a controlled trial of intensive dietary advice.
Journal of hypertension. Supplement : official journal of the
International Society of Hypertension 1989;7(6):S254–5.
[PUBMED: 2698935]
Cutler 1997 {published data only}
Cutler J A, Stamler J. Chapter 1. Introduction and summary
of the dietary and nutritional methods and findings in the
Multiple Risk Factor Intervention Trial. American Journal of
Clinical Nutrition 1997;65 (1 SUPPL.):184S–90S.
De Mello 2008 {published data only}
De Mello V D F, Kolehmainen M, Pulkkinen L, Schwab
U, Mager U, Laaksonen D E, et al.Downregulation of
genes involved in NFB activation in peripheral blood
mononuclear cells after weight loss is associated with the
improvement of insulin sensitivity in individuals with the
metabolic syndrome: The GENOBIN study. Diabetologia
2008;51 (11):2060–7.
Fagerberg 1989 {published data only}
Fagerberg B, Berglund A, Berglund G, Wikstrand J,
Andersson OK. Food and health. Weight reduction and
decreased sodium chloride intake depress blood pressure
but not as much as drugs do [kost och halsa. Viktreduktion
och minskat koksaltintag sanker blodtrycket mindre
an lakemedel.]. Lakartidningen 1989;86(51):4522–4.
[PUBMED: 2689815]
Gillum 1983 {published data only}
Gillum RF, Prineas RJ, Jeffery RW, Jacobs DR, Elmer PJ,
Gomez O, et al.Nonpharmacologic therapy of hypertension:
the independent effects of weight reduction and sodium
restriction in overweight borderline hypertensive patients.
American heart journal 1983;105(1):128–33. [PUBMED:
6849226]
Hall 2003 {published data only}
Hall WD, Feng Z, George VA, Lewis CE, Oberman A,
Huber M, et al.Low-fat diet: effect on anthropometrics,
blood pressure, glucose, and insulin in older women.
Ethnicity & disease 2003;13(3):337–43. [PUBMED:
12894958]
Haynes 1984 {published data only}
Haynes RB, Harper AC, Costley SR, Johnston M, Logan
AG, Flanagan PT, et al.Fa ilure of weight reduction to reduce
mildly elevated blood pressure: a randomized trial. Journal
of hypertension 1984;2(5):535–9. [PUBMED: 6397541]
He 2000 {published data only}
He J, Whelton PK, Appel LJ, Charleston J, Klag MJ. Long-
term effects of weight loss and dietary sodium reduction on
incidence of hypertension. Hypertension 2000;35(2):544–9.
[PUBMED: 10679495]
Heshka 2003 {published data only}
Heshka S, Anderson J, Atkinson R, Gadde K M, Nanchahal
K. Commercial weight reduction programme reduces
weight more than self-help materials. Evidence-Based
Healthcare 2003;7 (4):179–81.
Heyden 1974 {published data only}
Heyden S, Hames CG. Diet therapy of elevated blood
pressure values in overweight persons. Hypertension-
intervention study: 1 year’s report from the Evans-
County (Ga.) study [Diatbehandlung erhohter
Blutd ruckwerte bei ubergewichtigen Personen.
Hypertonie–Interventionsstudie: 1–Jahres–Bericht aus der
Evans–County (Ga.)–Studie]. Die Medizinische Welt 1974;
25(49):2041–3. [PUBMED: 4444500]
Hsieh 2009 {published data only}
Hsieh YC, Hung CT, Lien LM, Bai CH, Chen WH, Yeh
CY, et al.A significant decrease in blood pressure through a
family-based nutrition health education programme among
community residents in Taiwan. Public health nutrition
2009;12(4):570–7. [PUBMED: 18561875]
Hyden 1973 {published data only}
Hyden S, Tyroler HA, Hames CG, Bartel A, Thompson
JW, Krishan I, et al.Diet treatment of obese hypertensives.
Clinical science and molecular medicine. Supplement 1973;45
Suppl 1:209s–12. [PUBMED: 4593567]
Jones 1999 {published data only}
Jones DW, Miller ME, Wofford MR, Anderson DC
Jr, Cameron ME, Willoughby DL, et al.The effect of
weight loss intervention on antihypertensive medication
requirements in the hypertension Optimal Treatment
(HOT) study. American journal of hypertension 1999;12(12
Pt 1-2):1175–80. [PUBMED: 10619579]
Karoff 1985 {published data only}
Karoff C, Zidek W, Lange-Ass chenfeldt H, Losse H, Vetter
H. Blood pressure and intracellular electrolytes during
weight reduction. Klinische Wochenschrift 1985;63 Suppl 3:
129–31. [PUBMED: 3999629]
Karvetti 1992 {published data only}
Karvetti RL, Hakala P. A seven-year follow-up of a weight
reduction programme in Finnish primary health care.
European journal of clinical nutriti on 1992;46(10):743–52.
[PUBMED: 1425528]
Katzel 1995 {published data only}
Katzel LI, Bleecker ER, Colman EG, Rogus EM, Sorkin
JD, Goldberg AP. Effects of weight loss vs aerobic exercise
training on risk fac tors for coronary disease in healthy, obese,
20Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 22
middle-aged and older men. A randomized controlled trial.
JAMA : the journal of the American Medical Association 1995;
274(24):1915–21. [PUBMED: 8568984]
Kawamura 1993 {published data only}
Kawamura M, Akasaka T, Kasatsuki T, Nakajima J,
Onodera S, Fujiwara T, et al.Blood pressure is reduced by
short-time calorie restriction in overweight hypertensive
women with a constant intake of sodium and potassium.
Journal of hypertension. Supplement : official journal of the
International Society of Hypertension 1993;11(5):S320–1.
[PUBMED: 8158405]
Kolehmainen 2008 {published data only}
Kolehmainen M, Salopuro T, Schwab U S , Kekalainen J,
Kallio P, Laaksonen D E, et al.Weight reduction modulates
expression of genes inv olved in extracellular matrix and
cell death: The GENOBIN study. International Journal of
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Korhonen 2003 {published data only}
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23Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 25
C H A R A C T E R I S T I C S O F S T U D I E S
Characteristics of included studies [ordered by study ID]
Cohen 1991
Methods DESIGN: parallel, cluster randomised, no information on blinding
DURATION: 12 months
NUMBER OF STUDY CENTRES: 1
COUNTRY OF PUBLICATION: USA
SPONSOR: -
Par ticipants WHO PA RTICIPATED: hypertensive and obese patients stratified by residents (resi-
dents not patients were randomised to intervention or control group)
SETTING: model family practice unit (Pittsburgh)
MAIN INCLUSION CRITERIA:
age 20-75 years; BMI 28 kg/m
2
(men); 27 kg/m
2
(women); systolic blood pressure
140 mm Hg, diastolic blood pressure 90 mm Hg in two or more readings
MAIN EXCLUSION CRITERIA:
not described in detail
NUMBER (educationally oriented intervention vs. standard consultation): 15 vs. 15
patients were randomised (10 vs. 8 physicians); 15 vs. 15 were analysed
GENERAL BASELINE CHARACTERISTICS (dietary intervention vs. no dietary in-
tervention):
MEAN AGE [YEARS]: 59 vs. 60
GENDER [% MALE]: 27 vs. 27
NATIONALITY: -
ETHNICITY: -
WEIGHT [kg]: 92 vs. 92
BODY MASS INDEX [kg/m2]: 34 vs. 34
SITTING SYSTOLIC BLOOD PRESSURE [mm Hg]: -
SITTING DIASTOLIC BLOOD PRESSURE [mm Hg]:-
MEAN ARTERIAL BLOOD PRESSURE [mm Hg]: 106 vs. 106
CO-MORBIDID CONDITIONS: obesity
ANTIHYPERTENSIVE TREATMENT: - (number of medications 1.6 vs. 1.2)
DURATION OF HYPERTENSION: -
SUBGROUP ANALYSES:
weight losers vs. weight gainer
Interventions LENGTH OF FOLLOW-UP: 12 months
DIETA RY INTERVENTION: physicians [n=10] were taught by a behavioural psychol-
ogist; the goal of the dietary advice was do reduce the caloric content of the diet without
radically changing the patients lifestyl e; monthly patients consultations and reviewing
diet history sheet; the suggested diets were not specifically intended to be salt reducing
NO DIETARY INTERVENTION: physicians [n=8] received no special instructions or
materials; the patients were continued to be treated with their usual care
Outcomes PRIMARY OUTCOMES:
1. MORTALITY: -
2. CARDIOVASCULAR MORBIDITY: -
3. ADVERSE EVENTS: -
24Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 26
Cohen 1991 (Continued)
SECONDARY OUTCOMES:
1. CHANGES IN SYSTOLIC BLOOD PRESSURE [mm Hg]: -
2. CHANGES IN DIASTOLIC BLOOD PRESSURE [mm Hg]: -
3. BODY WEIGHT [kg]:
Definition: body weight change from baseline to 6 month, from baseline to 12 month
and from 6 month to 12 month
ADDITIONAL OUTCOMES MEASURED IN THE STUDY:
1. Mean arte r ial blood pressure change in mm Hg
2. Change in number of antihypertensive medication
3. Number of visits
Notes
Risk of bias
Bias Authors’ judgement Support for judgement
Random sequence generation (selection
bias)
Unclear risk Comment: No details on generation se-
quence are provided
Quote: ”The residents were stratified by
residency year and randomly assigned to ei-
ther control or experimental groups. ... The
experimental or control status of a patient
was determined by the status of the physi-
cian, and great care was taken to avoid con-
tamination.
Allocation concealment (selection bias) Unclear risk Comment: Meth od of concealment is not
described
Blinding (performance bias and detection
bias)
All outcomes
High r isk Comments: No description of randomisa-
tion; since the physicians assigned into the
experimental group were taught about the
weight reducing programme, knowledge of
the allocation intervention was not pre-
vented during study
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk WITHDRAWALS: no withdrawals
REASONS / DESCRIPTIONS: -
Selective reporting (reporting bias) Unclear risk Comment: No primary and secondary out-
comes were defined.
Other bias High r isk Comments:
1. Lack of information of randomisation
2. Stratified randomisation of investigators
instead of patients with very small cluster
size
25Long-term effects of weight-reducing diets in hypertensive patients (Review)
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Page 27
Croft 1986
Methods DESIGN: parallel, randomised, no information on blinding
DURATION: 6 months
NUMBER OF STUDY CENTRES: 1
COUNTRY OF PUBLICATION: UK
SPONSOR: West Midlands Regional Research Committee; UK
Par ticipants WHO PARTICIPATED: newly diagnosed hypertensive and obese patients
SETTING: outpatient clinic (1 urban group practice)
MAIN INCLUSION CRITERIA:
age between 35 and 60 years; BMI >25 kg/m
2
; systolic blood pressure >140 mm Hg
and/or diastolic blood pressure >90 mm Hg in three measureme nts
MAIN EXCLUSION CRITERIA:
systolic blood pressure >200 mm Hg; diastolic blood pressure >114 mm Hg; previ-
ous antihypertensive medication; myocardial infarction or stroke within the previous 3
months; concurrent ser ious disease, conditions requiring diets or medication likely to
influence weight or blood pressure
NUMBER: 66 vs. 64 were randomised, 66 vs. 64 (last observation carried forward
analysis) / 47 vs. 50 were analysed per protocol (dietary intervention vs. no dietary
intervention)
GENERAL BASELINE CHARACTERISTICS (dietary intervention