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The Effect of Preoperative Weight Loss before Gastric Bypass: A Systematic Review

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Journal of Obesity
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Abstract and Figures

. Many insurance companies require obese patients to lose weight prior to gastric bypass. From a previous study by the same authors, preoperative weight at surgery is strongly predictive of weight loss up to one year after surgery. This review aims to determine whether preoperative weight loss is also correlated with weight loss up to one year after surgery. Methods . Of the 186 results screened using PubMed, 12 studies were identified. A meta-analysis was performed to further classify studies (A class, B class, regression, and rejected). Results . Of all 12 studies, one met the criteria for A class, six were B class, four were regression, and one was rejected. Six studies supported our hypothesis, five were inconclusive, and no study refuted. Conclusions . Preoperative weight loss is additive to postsurgery weight loss as predicted from the weight at the time of surgery.
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Hindawi Publishing Corporation
Journal of Obesity
Volume 2012, Article ID 867540, 7 pages
doi:10.1155/2012/867540
Review A rticle
The Effect of Preoperative Weight Loss before Gastric Bypass:
ASystematicReview
Deepak K. Kadeli,
1
John P. Sczepaniak,
1, 2
Kavita Kumar,
1
Christie Youssef,
1
Arash Mahdavi,
2
and Milton Owens
2
1
John Sczepaniak Medical Enter prises, 6871 Eberhart Street, San Diego, CA 92115, USA
2
Coastal Center for Obesity, 2617 East Chapman Avenue, Suite 307, Orange, CA 92869, USA
Correspondence should be addressed to Deepak K. Kadeli, kadelideepak@gmail.com
Received 1 November 2011; Accepted 10 April 2012
Academic Editor: Natan Zundel
Copyright © 2012 Deepak K. Kadeli et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction i n any medium, provided the original work is properly
cited.
Background. Many insurance companies require obese patients to lose weight prior to gastric bypass. From a previous study by the
same authors, preoperative weight at surgery is strongly predictive of weight loss up to one year after surgery. T his review aims to
determine whether preoperative weight loss is also correlated with weight loss up to one year after surgery. Methods. Of the 186
results screened using PubMed, 12 studies were identified. A meta-analysis was performed to further classify studies (A class, B
class, regression, and rejected). Results. Of all 12 studies, one met the criteria for A class, six were B class, four were regression,
and one was rejected. Six studies supported our hypothesis, five were inconclusive, and no study refuted. Conclusions.Preoperative
weight loss is additive to postsurgery weight loss as predicted from the weight at the time of surgery.
1. Introduction
According to the latest statistics, one out of every three
adults (33.8%) in US is obese. Additionally, the rate of
morbid obesity is 5.7% in adults [1]. Bariatric surgery is
averyeective intervention for the morbidly obese. More
than 220,000 people underwent some form of bariatric
surgery in 2008 [2]. Age, gender, race, height, initial body
weight, postoperative behaviors, type of operation, and
surgeon have been reported to aect weight loss following
surgery. However, no consideration of factors impacting
weight loss outcomes would be complete without attention
to the importance of preoperative weight loss. Although
the California Department of Managed Care explicitly states
that “there is no literature presented by any authority that
mandated weight loss, once a patient has been identified
as a candidate for bariatric surgery, is indicated, yet the
majority of insurance payers continue to require prolonged
dietar y eorts as a prerequisite to surgical treatment [3].
A reduction in the size of the liver after four weeks of
dieting and an increase in ease of surgical exposure are well
documented [4, 5]. The impact on overall weight loss is less
clear. Numerous papers dealing with the subject provide an
array of experimental models that make a comparison of
results dicult. Our paper evaluates the existing publications
and separates them into four groups for comparison.
In a previous publication, we showed that weight loss in
the first year after gastric bypass is a p ercent of initial body
weight [6]. The following review attempts to determine the
eect of short-term preoperative weight loss on weight loss
following surgery and the eect of initial body weig ht.
2. Methods
The study was done using PubMed search for those papers
which dealt with aspects of preoperative weight loss before
bariatric surgery. The search terms used were (“preoperative
weight loss” or “pre-operative weight loss” or “preoperative
weight”or“pre-operativeweight)and(gastricbypass
(meSH) or bariatric surgery” (meSH) or “obesity surgery”
or “weight reduction surgery” or “predicting”).
Each abstract was analyzed to include only those studies
which satisfied all set criteria. Criteria for abst ract review
2 Journal of Obesity
were as follows. All studies reviewed were from a peer-
reviewed source and published either in English or Span-
ish. Studies were required to have one of the following
designs: randomized control trials, case control studies, or
series/cohort studies. Additionally, the majority of study
participants had to be greater than 18 years old. Accepted
abstracts included both open and laparoscopic cases.
Articles were obtained for the remaining abstracts and
were further analyzed. Each article was expected to have
more than ten patients in each group of study (preoperative
weight loss versus weight gain) or >20 patients in a regression
analysis. Information on pre/post-operation weight loss had
to be available for article selection. Papers were also excluded
that did not stratify the data such that gastric bypass
weight loss results were separated from alternate weight loss
procedures such as gastric banding or sleeve gastrectomy
(Figure 1). The selected studies were further searched for
their references to identify more papers pertaining to our
study.
The selected studies were divided into dierent classes:
class A, class B, and regression studies. The classification was
based on the patient’s weight at initial consultation and the
weight at surgery. Both class A and class B studies grouped
patients into two follow-up cohorts, one that lost weight and
the other that did not.
In class A studies, the weight loss and weight gain
groups both had the same mean weight at initial consultation
but dierent at the time they went for surgery. This is
demonstrated in Figure 2 by using two groups with five
hypothetical patients in each group. Both groups initially
begin with similar mean weights and dier directly prior to
surgery with dierent average weights (confidence interval
95%).
2.1. Class A Study Supporting/Refuting Criteria. Studies were
deemed to support our hypothesis if both groups of patients
had a persistent statistical dierence in the average weight
within the first 12 months, and the mean weight values did
not crossover in this time fr a me. Refuting studies would
have crossing over of the means (e.g., the weight loss group
having a higher mean weight after surgery at six months
than the weight gain group). Inconclusive studies lacked 50%
followup during the first year or proper notation to elicit a
definitive conclusion.
In class B studies weight loss and weight gain groups had
dierent mean weights (P<0.05) at initial consultation but
similar means at the time of surgery. This is demonstrated
in Figure 3 by using two groups with five hypothetical
patients in each who begin with dierent weights at initial
consultation but eventually enter the surgery with similar
mean weights.
2.2. Class B Study Supporting/Refuting Criteria. Studies were
deemed to support our hypothesis if both groups of patients
did not have any statistical dierence in their mean weight for
the first 12 months. Refuting studies would have a statistically
dierent dierences between the weight loss and weight gain
group. Inconclusive studies lacked 50% followup during the
first year or proper notation to elicit a definitive conclusion.
2.3. Regression Studies. Regression studies do not have to
utilize groups of patients and may look at preoperative
weight loss as a variable. In regression studies the patients
are no longer grouped into weight loss/gain groups or
dieters/nondieters g roups. The focus is on individual per-
formance of each patient. The following concept has been
explained by using six hypothetical patients who undergo
gastric bypass surgery (P1, P2, P3, P4, P5, and P6). Each
of these hypothetical patients had dierent amounts of
preoperative weight loss with the exception of one patient
who did not lose or gain weight.
Thepreoperativeweightlossisconsideredtobeacon-
tinuous variable and can be plotted on the x-axis (Figure 4).
The outcome is also a continuous variable percent of initial
weight loss, plotted on y-axis (Figure 5)foraperiodofone
year after surgery. For explanation and standardization, we
use percent of initial weight at surgery as the outcome for
y-axis.
2.4. Regression Study Supporting/Refuting Criteria. Regres-
sion studies were judged based on the variables included and
the results reported by the authors. Analysis was hampered
due to absence of data or modeling protocol. Inconclusive
studies were defined as <50% followup or too complex for us
to interpret without additional input from the author.
Classification of studies was required to define criteria
needed to support and refute our hypothesis.
A flow chart used to arrive at the chosen classification is
provided in Figure 5.
3. Results
3.1. Class A Studies. The study by Solomon et al. [7]and
Alami et al. [19] was a randomized control trial conducted
at Stanford Medical University. The study was done for a
year comparing postoperative weights between two groups,
one which lost weight preoperatively and other which gained
weight. The statistical dierence between both groups was
maintained up to 3 months. At one year, the patients in
both arms of the study showed no dierence in excess weight
loss. But when patients were divided according to those who
had lost at least five percent of their excess body weight
preoperatively, the one-year results for excess weight loss
were much lower for the weight-loss group. This class-A
study shows that weight loss is a percent of initial b ody
weight at the time of surgery (Table 1).
3.2. Class B Studies. In the study by Martin e t al. [8], the
subjects were divided into dieters and nondieters. Here,
also the data show that weight loss after surgery is a
percent of body weight at the time of surgery. The only
statistically significant dierence in mean weight between
the two groups was at initial presentation (Tab le 2 ). The
studybyStilletal.[9] was done at Geisinger Medical
Center in Danville, Pennsylvania. This study was considered
Journal of Obesity 3
MeSH results in Pubmed search for preoperative
122 search results were further
reviewed for the criteria
46 full text articles
were analyzed
12 were
chosen
76 abstracts were excluded as they did not
meet one of the above criteria
34 articles were excluded as they did not fulfill
added requirements
weight loss—186 titles and abstracts found
64 abstracts excluded—unrelated topics
Figure 1: Diagram representing the inclusion and exclusion of PubMed search results.
Table 1: Class A studies.
Lead author Study design Group Patients Mean age (yr) Female (%) Results
Solomon [7]
RCT
WL 26 42.4 88.5%
Supportive
WG 35 44.9 80.0%
WL: weight loss; WG: weight gain; RCT: randomized controlled trial.
Mean
Mean
Mean
Mean
Initial weight at consultation Initial weight at surgery
Weight (kilograms)/BMI/percent excess weight
Figure 2: Example of Class A study. Graph showing ten hypothet-
ical patients in Class A study that have been divided into weight
loss (blue) and weight gain (red) groups. The weight loss group
was statistically dierent from the weight gain g roup at surgery.
Confidence Interval 95%.
inconclusive because its postoperative assessment was carried
out in percentages of patients meeting their weight loss goal
as opposed to actual weight values making analysis dicult.
Ali et al. [10] had 351 subjects who were divided into 4
groups based on the percent EWL (excess weight loss). At
surgery, no significant dierences were found among the 4
groups in total body weight and BMI or EBW except for a
BMI dierence in group 1 and 3. At 6 and 12 months, no
significant dierence was found in the total body weight or
Mean
Mean
Mean
Mean
Initial weight at consultaion Initial weight at surgery
Weight (kilograms)/BMI/percent excess weight
Figure 3: Example of class B study. Graph showing ten hypothetical
patients in class B study who have been divided into weight
loss (blue) and weight gain (red) groups. The weight loss group
was statistically dierent from the weight gain group at initial
consultation.
Confidence interval 95%.
BMI among the 4 groups indicating again that weight loss is
a function of weight at the time of surgery (Ta bl e 2).
The study by Fujioka et al. [11] divided the patients
into two groups based on whether patients lost or gained
weight preoperatively. Both groups had similar mean weights
at surgery. When these patients were followed after surgery,
no significant dierences in the mean EWL were found at
any follow-up point in the first 12 months thus supporting
our hypothesis. Harnishs et al. [12] study also had similar
structure and findings to that of Fujioka (Table 2 ).
4 Journal of Obesity
Table 2: Class B studies.
Lead author Study design Group Patients Mean age Female (%) Results
Martin [8]
Prospective
WL (dieters) 47 40.2 74.5%
Supportive
WG (nondiet) 53 38.8 92.5%
Still [9]
Prospective
5–10% EBWL 67 43 77.6%
Inconclusive
5% EBWL 86 43 74.4%
0–5% EBWG 137 43 78.8%
>5% EBWG 169 45 79.9%
Ali [10]
Retrospective
WL > 10% TBW 23 42.7 73.9%
Supportive
WL 5–10% TBW 102 43 87.3%
WL 0–5% TBW 135 42.8 95.5%
WG % TBW 91 42.1 96.7%
Fujioka [11]
Retrospective
WL (>0 lbs) 55 49 80.0%
Supportive
WG (<0 lbs) 66 48 86.4%
Harnisch [12]
Retrospective
WL (
10 lbs) 88 44 84.1%
Supportive
WG (
10 lbs) 115 41.4 85.2%
Huerta [13]
Retrospective
WL 15 50 33.3%
Inconclusive
WG (non-WL) 25 50 28.0%
WL: weight loss; WG: weight gain; EBW: excess body weight; TBW: total body weight.
P1
P2
y
=
1x +0.38
P3
P4
P5
P6
Percentage weight Loss (based on IW at surgery)
Percent IW loss before surgery (based on IW at surgery)
5 101520
55
60
50
45
40
35
Figure 4: Example of regression. Study includes six hypothetical
patientswholostweightpreoperatively.Thepreoperativeweight
loss is graphed against their complete program weight loss (from
initial consultation to one year after operation).
TheBclassstudybyHuertaetal.[13] was considered
inconclusive as the followup was less than 50% during the
first year and only had postoperative data for the second and
fourth years after surgery.
3.3. Regression Studies. The study by Alger-Mayer et al.
[16], which was done at Albany, NY, was analyzed using
regression. Even though the year 3 and 4 results supported
our hypothesis, the results were considered inconclusive
because the paper lacked postoperative data in the first year
after gastric bypass.
ThestudybyJantzetal.[14] was inconclusive because
they were not looking at immediate preoperative weight loss.
Carlin et al. [17] published a paper that changed weight
loss requirements based on the initial BMI. Those individuals
that had BMI greater than 60 had to lose more than those
that were less than 50 kg/m
2
. Thus, the study was considered
inconclusive due to diculty interpreting the methodology.
The study by Alvarado et al. [15] identified a 1.8%
increase in the % EWL one year after gastric bypass w ith each
1% total body weight lost preoperatively. This retrospective
study was considered supportive due to the positive eect
preoperative weight loss would have on postoperative weight
loss in the absence of controlling for initial weig h t at surgery.
Results are summarized in Ta bl e 3.
3.4. Rejected Studies. The study by Riess et al. [18]was
rejected as a study because the weight loss group and the
weight gain group had statistically significant dierence in
mean weight at both initial consultation and the time before
surgery. The dierence was preserved postoperatively (see
Table 4).
4. Discussion
Our study found that weight at the time of surgery, rather
than the amount of weight lost preoperatively, determines
the weight loss outcome postoperatively. Stated dierently,
weight at a given time period after surgery is the same
percent of initial body weight independent of starting weight.
For example, if a patient weighs 160 kg at the time of
surgery, he will weigh approximately 62% of that at one
year after surgery or 100 kg. If he lost 22.5 kg preoperatively
Journal of Obesity 5
Class-A study
Rejected
No
Class B study
No
No No
Regression study
Selected study
Are the groups of patients similar mean
weight at the time before operation?
Are the groups of patients similar
mean weight at initial consultation?
Are the groups of patients similar mean
weight at the time before operation?
Are the patients divided into
WL and WG groups?
Yes
Yes Yes
Yes
Figure 5: Flow chart depicting the classification of the selected studies into Class A, B, and regression studies. WL: weight loss; WG: weight
gain.
Table 3: Regression studies.
Lead author Study design Patients Mean age Operation type Female (%) Results
Jantz [14] Retrospective 384 43.3 LRYGB 82.5 Inconclusive
Alvarado [15] Retrospective 90 42 LRYGB 90 Supportive
Sharon Alger
[16]
Prospective 150 45.3 RYGB
80 Inconclusive
Carlin [17] Retrospective 295 45 LRYGB 88.8 Inconclusive
LRYGB: laparoscopic roux-en-y gastric bypass;
RYGB: Roux en Y Gastric Bypass. the roux-en-y gastric bypass was an open procedure.
and weighed 136 kg at the time of surgery, he would weigh
62% of his initial body weight or 81.5 kg . His overall
weight loss would be 13.5 kg greater for having lost 22.5 kg
preoperatively. Since weight loss following gastric bypass
tends to be negligible after one year, this probably represents
a real gain. In this paper, we have detailed two classes of
studies, A and B. Combining review data with previous
work by Sczepaniak et al. [6], it is possible to create visual
representation of both studies. Class A and class B studies are
shown in Figures 2 and 3, respectively. Both groups changed
in mean weight at initial consultation, one group gaining
weight and the other losing weight. Preoperative weight gain
and loss were arbitrarily set for explanation purposes. In a B
class study it is observed that the means of both the weight
loss and weight gain groups is not dierent for the first year.
With regards to regression study, in the six hypothetical
patients, the relationship to preoperative weight loss can now
be clearly seen from Figure 6. The more preoperative percent
initial body weight loss (based on initial weight at surgery),
the more the percent total body weight loss (calculated from
6 Journal of Obesity
36812
Percent initial weight at surgery
120
110
100
90
80
70
60
62%
P2
P4
P3
P5
P6
P1
Time after operation (months)
Consultation Surgery
Figure 6: Hypothetical regression model. This model demonstrates
the eect of preoperative weight loss in gastric bypass patients.
Table 4: Rejected Studies
Lead
author
Study design Group Patients Age
Female
(%)
Riess et
al. [18]
Retrospective
WL 74 43.4 70.3%
WG
(non-WL)
279 42.7 86.4%
WL: weight loss; WG: weight gain.
subtract ing percent total body weight at initial consultation
from achieved percent total body weight after surgery), see
Figure 6.
From the graph on the hypothetical patients in Figure 4,
it is now possible to see the benefit of losing preoperative
weight on an individual level.
Our study has only dealt with studies having gastric
bypass surgeries, but the preoperative weight loss might have
a similar role in sleeve gastrectomy and sleeve plication (also
current methods for weight reduction).
Losing weight leads to b etter outcomes because a patient
entering surgery with a lower weight than someone entering
surgery without weight loss will have more weig ht loss in
total.
5. Conclusion
Our review of the literature supports the idea that weight
loss after surgery for gastric bypass, and by extension other
procedures as well, is a percent of initial body weight.
Moreover, the literature is generally supportive of the idea
that short-term preoperative weight loss is additive, that is,
increases the total amount of weight lost.
Conflict of Interests
The authors have no commercial associations that might be
a conflict of interest in relation to this paper.
Acknowledgments
TheauthorsaregratefultoSanDiegoUniversity,CA;St.
George’s University Grenada, WI; Amit Kulkarni, MBBS—
Mayo Clinic, Rochester; Adel Youssef MD, Gastroenterology
Clinic,Warren, OH. They would also like to thank the many
others who made this work possible.
References
[1] Centers for disease control and prevention, “Data from the
National Health and Examination Survey (NHANES), 2007-
2008.
[2] American society for Metabolic and Bariatric Surgery Statis-
tics, 2008.
[3] Department of Managed Healthcare, California, http://www
.dmhc.ca.gov.
[4] D. Edholm, J. Kullberg, A. Haenni et al., “Preoperative 4-week
low-calorie diet reduces liver volume and intrahepatic fat,
and facilitates laparoscopic gastric bypass in morbidly obese,
Obesity Surgery, vol. 21, no. 3, pp. 345–350, 2011.
[5] M. C. Lewis, M. L. Phillips, J. P. Slavotinek, L. Kow, C. H.
Thompson, and J. Toouli, “Change in liver size and fat content
after treatment with Optifast very low calorie diet, Obesity
Surgery, vol. 16, no. 6, pp. 697–701, 2006.
[6] John P. Sczepaniak, Milton L. Owens, William Garner et al.,
A SimplerMethod for PredictingWeight Loss in the First Year
after Roux-en-Y Gastr ic Bypass, Journal of Obesity, vol. 2012,
Article ID 195251, 5 pages, 2012.
[7] H. Solomon, G. Y. Liu, R. Alami, J. Morton, and M. J. Curet,
“Benefits to patients choosing preoperative weight loss in
gastric bypass surgery: new results of a randomized trial,
Journal of the American College of Surgeons, vol. 208, no. 2, pp.
241–245, 2009.
[8] L. F. Martin, T. L. Tan, P. A. Holmes, D. A. Becker, J. Horn, and
E. O. Bixler, “Can morbidly obese patients safely lose weight
preoperatively?” The American Journal of Surgery, vol. 169, no.
2, pp. 245–253, 1995.
[9]C.D.Still,P.Benotti,G.C.Woodetal.,“Outcomesof
preoperative weight loss in high-risk patients undergoing
gastric bypass surgery, Archives of Surgery, vol. 142, no. 10,
pp. 994–998, 2007.
[10] M. R. Ali, S. Baucom-Pro, G. A. Broderick-Villa et al.,
“Weight loss before gastric bypass: feasibility and eect on
postoperative weig ht loss and weight loss maintenance,
Surgery for Obesity and Related Diseases, vol. 3, no. 5, pp. 515–
520, 2007.
[11] K. Fujioka, E. Yan, H. J. Wang, and Z. Li, “Evaluating preopera-
tive weight loss, binge eating disorder, and sexual abuse history
on Roux-en-Y gastric bypass outcome, Surgery for Obesity
and Related Diseases, vol. 4, no. 2, pp. 137–143, 2008.
[12] M. C. Harnisch, D. D. Portenier, A. D. Pryor, R. Prince-
Petersen, J. P. Grant, and E. J. DeMaria, “Preoperative weight
gain does not predict failure of weight loss or co-morbidity
resolution of laparoscopic Roux-en-Y gastric bypass for
morbid obesity, Surgery for Obesity and Related Diseases, vol.
4, no. 3, pp. 445–450, 2008.
[13] S. Huerta, S. Dredar, E. Hayden et al., “Preoperative weight
loss decreases the operative time of gastr ic bypass at a veterans
administration hospital, Obesity Surgery,vol.18,no.5,pp.
508–512, 2008.
[14] E. J. Jantz, C. J. Larson, M. A. Mathiason, K. J. Kallies, and S.
N. Kothari, “Number of weight loss attempts and maximum
Journal of Obesity 7
weight loss before Roux-en-Y laparoscopic gastric bypass
surgery are not predictive of postoperative weight loss,
Surgery for Obesity and Related Diseases, vol. 5, no. 2, pp. 208–
211, 2009.
[15] R. Alvarado, R. S. Alami, G. Hsu et al., The impact of preop-
erative weight loss in patients undergoing laparoscopic Roux-
en-Y gastric bypass, Obesity Surgery, vol. 15, no. 9, pp. 1282–
1286, 2005.
[16] S. Alger-Mayer, J. M. Polimeni, and M. Malone, “Preoperative
weight loss as a predictor of long-term success following Roux-
en-Y gastric bypass, Obesity Surgery, vol. 18, no. 7, pp. 772–
775, 2008.
[17] A. M. Carlin, E. A. O’Connor, J. A. Genaw, and S. Kawar,
“Preoperative weight loss is not a predictor of postoperative
weight loss after laparoscopic Roux-en-Y gastric bypass,
Surgery for Obesity and Related Diseases, vol. 4, no. 4, pp. 481–
485, 2008.
[18] K. P. Riess, M. T. Baker, P. J. Lambert, M. A. Mathiason,
andS.N.Kothari,“Eectofpreoperativeweightlosson
laparoscopic gastric bypass outcomes, SurgeryforObesityand
Related Diseases, vol. 4, no. 6, pp. 704–708, 2008.
[19] R. S. Alami, J. M. Morton, R. Schuster et al., “Is there a benefit
to preoperative weight loss in gastric bypass patients? A
prospective randomized trial, Surgery for Obesity and Related
Diseases, vol. 3, no. 2, pp. 141–145, 2007.
... The most recent bariatric guidelines [14,15] and literature [24,[29][30][31][32][33] are in favour of energy-restricted diets to achieve rapid preoperative weight reduction. However, there is significant heterogeneity in the type of energy-restricted dietary regimes being prescribed [34]. ...
... A striking feature about the literature in this area is an increase in the number of publications of RCTs since 2014, probably due to the growing recognition that preoperative weight loss may optimise some perioperative outcomes [30,32,33,51]. ...
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Objective A preoperative very low-calorie diet (VLCD) is a common method to reduce weight before bariatric surgery. However, patient compliance and acceptability are not always known. The aim of this study is to evaluate the effectiveness, compliance, and acceptability of our regimen in a metropolitan academic quaternary care center. Methods Patients with a BMI < 50 kg/m² and a BMI ≥ 50 kg/m² were instructed to be on a liquid VLCD for 1 week and 2 weeks, respectively. The primary outcome was the amount of weight loss. Secondary outcomes were patient compliance and acceptability of either regimen using a questionnaire for hunger, satisfaction, desire, and deviation for solids. Results The study included 128 patients. Ninety-four patients were in the BMI < 50 kg/m² group, and 34 patients were in the BMI ≥ 50 kg/m² group. The BMI ≥ 50 kg/m² group had a greater percentage of total weight loss (mean ± SD) than that of the BMI < 50 kg/m² group without statistical differences (4.4 ± 1.3% vs. 3.8 ± 1.6%, p = 0.072). There were no statistical differences between the groups in terms of hunger, satisfaction with a liquid diet, or satisfaction of eating over drinking. However, hunger sensation (median [IQR]) tended to be higher in the BMI < 50 kg/m² group than that in the BMI ≥ 50 kg/m² group (2 [2] vs. 2 [2, 3]; p = 0.06). There was no statistical difference in the percentage of patient compliance between the groups (75.5% [n = 71] vs. 61.8% [n = 21], p = 0.18). Conclusions Preoperative liquid VLCD provided a modest amount of weight loss and showed a high rate of patient compliance and acceptability.
... The results of these three behavioral studies parallel the more extensively researched link between pre-treatment weight change and post-surgical weight loss in bariatric surgery. Analyses that have statistically combined study results (Kadeli et al., 2012;Livhits et al., 2012) suggest that weight loss before surgery results in greater total losses from the start of the pre-surgical program, but does not impact post-surgical weight loss. It would be useful to examine whether individuals who engage in selfdirected dieting also experience weight fluctuations between forming the intention to lose weight and beginning to make dietary changes. ...
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Background: Many participants experience clinically significant fluctuations in weight before beginning a behavioral weight loss program. Pre-treatment weight gain, often referred to as the “last supper” effect, may limit total weight loss from the time of the pre-treatment screening visit and could be an indicator that a participant will respond poorly to behavioral intervention. Methods: Data were from the weight loss phase of a two-phase weight loss maintenance trial, in which 178 participants with obesity (screening BMI = 40.5 ± 6.0 kg/m², 87.6% female; 71.3% black) were provided with a 14 week lifestyle intervention that included a meal replacement diet. Participants were categorized as having gained >1.15%, remained weight stable, or lost >1.15% of initial weight between the pre-treatment screening visit and the first treatment session (48.7 ± 29.4 days). We first examined whether the weight change groups differed in baseline eating characteristics (e.g., emotional eating, self-regulation, craving frequency) using one-way ANCOVAs. Linear mixed models were then used to compare weight change groups on total weight loss from the screening visit to week 14 and in-treatment weight loss from weeks 1 to 14. Results: Nearly half of the sample (48.9%) gained >1.15% of initial weight during the pre-treatment period (+2.5 ± 1.2%); 41.0% remained weight stable (+0.2 ± 0.6%); and 10.1% lost >1.15% of initial weight (-2.2 ± 0.9%). There were no significant differences between the groups in baseline eating characteristics. As measured from the screening weight, the weight-gain group had a lower total loss of 6.8%, compared to 7.8% in the weight stable group (p = 0.02) and 9.0% in the weight-loss group (p = 0.003). The weight-gain group lost more weight in the first 4 weeks of treatment, but in-treatment losses did not differ among the groups at week 14. Conclusion: Pre-treatment weight gain was not an indicator of a poor response to a behavioral weight loss intervention and was associated with greater weight loss early in treatment. However, weight gain during the pre-treatment period may limit the total weight loss that participants achieve from the time that they first enroll in a weight loss program.
... Univariate analyses suggest that patients with a less favorable starting point have a smaller chance of reaching 50%EWL postoperatively. In this regard, our data are largely in agreement with those reported in a meta-analysis by Kadeli et al. [35]. In our study, we found a positive correlation between prediet weight and weight loss following diet, as measured by absolute weight loss in kilograms. ...
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Preoperative weight loss (PWL), defined as weight loss which is required and mandated before bariatric surgery will be scheduled, has been mandated by some bariatric programs due to a perceived benefit on post-operative outcomes, as well as by various insurance companies as a requirement for preauthorization approval. PWL can restrict access to bariatric surgery and can lead to increased attrition rates among patients who may otherwise greatly benefit from the procedure. There is a paucity of strong evidence to support mandated PWL. Additionally, mandated PWL does not equate to predictable post-operative weight loss as most patients have struggled their entire lives with medical weight management. The data are scant but show no difference in resolution of comorbid conditions with PWL. The data are conflicting regarding the effect of PWL on postoperative weight loss outcomes, and there is no difference in 30-day morbidity with PWL. Therefore, the authors agree with consensus guidelines that there is not enough data to recommend PWL to improve bariatric surgery outcomes.
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The aim of this study was to explore changes in liver volume and intrahepatic fat in morbidly obese patients during 4 weeks of low-calorie diet (LCD) before surgery and to investigate if these changes would facilitate the following laparoscopic gastric bypass. Fifteen female patients (121.3 kg, BMI 42.9) were treated preoperatively in an open study with LCD (800-1,100 kcal/day) during 4 weeks. Liver volume and fat content were assessed by magnetic resonance imaging and spectroscopy before and after the LCD treatment. Liver appearance and the complexity of the surgery were scored at the operation. Eighteen control patients (114.4 kg, BMI 40.8), without LCD were scored similarly. Average weight loss in the LCD group was 7.5 kg, giving a mean weight of 113.9 kg at surgery. Liver volume decreased by 12% (p < 0.001) and intrahepatic fat by 40% (p < 0.001). According to the preoperative scoring, the size of the left liver lobe, sharpness of the liver edge, and exposure of the hiatal region were improved in the LCD group compared to the controls (all p < 0.05). The overall complexity of the surgery was perceived lower in the LCD group (p < 0.05), due to improved exposure and reduced psychological stress (both p < 0.05). Four weeks of preoperative LCD resulted in a significant decrease in liver volume and intrahepatic fat content, and facilitated the subsequent laparoscopic gastric bypass as scored by the surgeon.
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Laparoscopic adjustable gastric banding (LAGB) requires surgical access to the gastroesophageal junction, which may be compromised by the enlarged, fatty liver that is frequently encountered in the obese. Liver size appears reduced and surgical access improved following preoperative weight loss with Optifast Very Low Calorie Diet (VLCD). The aim of this study was to assess the effects of 6 weeks Optifast VLCD on liver volume and fat content. 18 morbidly obese subjects underwent magnetic resonance imaging and spectroscopy to measure liver size and fat content before and after intensive treatment with Optifast VLCD for 6 weeks. All subjects completing 6 weeks Optifast VLCD lost weight. Body weight and BMI (median [interquartile range]) reduced from 119.7 [111.9-131.3] kg and 44 [40-51] kg/m(2) respectively, to 110.6 [98.0124.5] kg and 40 [36-47] kg/m(2), P<0.001. Median excess weight loss (EWL) was 15.1 [9.6-21.1]%. Baseline liver volume and fat content were related (r=0.633, P=0.005). After 6 weeks Optifast VLCD, there was a 14.7% reduction in mean liver volume (P<0.001) and a 43% reduction in mean liver fat (P=0.016). The change in liver volume was predicted by the change in the liver fat (r = 0.610, P=0.012). This study has demonstrated that a 6 week diet with Optifast VLCD results in significant related reductions in liver size and liver fat content. This suggests that the reduction in liver volume is due to loss of fat. The reduction in liver fat and volume likely accounts for the perceived improved operability in patients undergoing LAGB.
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Many insurance companies have mandated that bariatric surgery candidates already satisfying the National Institutes of Health criteria make an additional attempt at medically supervised weight loss. The objective of this study was to determine whether a correlation exists between the number of weight loss attempts (WLAs) or maximal preoperative weight loss (MWL) and the percentage of excess weight loss (%EWL) after laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery. The WLAs and MWL data were collected by bariatric medical record review. The postoperative %EWL was obtained by retrospective review of a prospectively enrolled bariatric database. Patients whose records contained 1 year of follow-up data and either the WLAs or MWL were included in the study. The data were analyzed using Pearson correlations and odds ratios. From September 2001 to 2006, 530 patients underwent LRYGB. Of these, 384 met the study criteria (82.6% were women). The mean WLAs was 4.3+/-1.8. The mean MWL was 46.6+/-31.2 lb (21.2+/-14.2 kg). At surgery, the mean patient age was 43.3+/-9.3 years, and the mean body mass index was 48.0+/-5.9 kg/m2. At 1 year after LRYGB, the mean body mass index was 30.2+/-5.0 kg/m2, and the mean %EWL was 72.3%+/-15.3%. Statistical analysis revealed no correlations between the %EWL at 1 year after LRYGB and the WLAs (R2=.011) or MWL (R2=.005). Neither the WLAs nor the MWL correlated with the %EWL at 1 year after LRYGB. Our results showed no evidence that the WLAs or MWL before surgery correlates with the %EWL in patients undergoing LRYGB.
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Requiring patients to lose weight before weight reduction surgery is controversial. The goal of this study was to determine whether preoperative weight loss affects laparoscopic Roux-en-Y gastric bypass surgery outcomes. The medical records of all laparoscopic Roux-en-Y gastric bypass patients from September 1, 2001 to March 31, 2005 were retrospectively reviewed in our prospective database. Depending on their habitus, patients were selectively required to lose >4.54 kg (10 lb) preoperatively (WL group). Their outcomes were compared with those of the patients not required to lose weight preoperatively (no-WL group). Statistical analysis was performed with the chi-square test and Student's t test for demographic data. Student's t test was used to assess the outcome data. P <.05 was considered significant. Of the 353 patients, 74 (21%) were in the WL group. The operative times in the WL group averaged 10 minutes longer than in the no-WL group (P = .022). The mean length of stay was not significantly different between the 2 groups. Of the 353 patients, 262 (74%) completed 1 year of follow-up. The mean net postoperative weight loss was not significantly different between the 2 groups. The no-WL patients had a greater percentage of excess postoperative weight loss than the WL group (74% versus 66%; P = .01). Net complications occurred less frequently in the WL group (P = .035). Preoperative weight loss did not decrease the operative times or the length of stay. Preoperative weight loss increased neither the mean net postoperative weight loss nor the percentage of excess postoperative weight loss at 1-year follow-up. However, the WL group had fewer net complications.
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Preoperative weight loss is often suggested as a means of reducing operative risk in obese patients requiring laparotomy but there are no large studies documenting that this is feasible or helpful. Although several commercial products are available that provide high levels of protein with low levels of carbohydrates in convenient liquid preparations, recommendations regarding the extent to which weight loss can be pursued preoperatively are not available. To determine whether it is practical and safe to have obese patients lose weight preoperatively. We asked 100 severely obese patients requesting gastric bypass surgery to diet before their operations. Seventy patients agreed to diet by consuming a 420 Kcal, 70 g protein liquid diet daily for at least 1 month. Forty-seven patients lost at least 7.5 kg (mean +/- SD 17.1 +/- 0.7). The patients who successfully lost weight preoperatively (dieters group) were significantly heavier than patients (nondieters group) who did not lose weight (251% +/- 45% of ideal body weight [IBW] versus 229% +/- 33% IBW, respectively; P < 0.01), had a significantly higher ratio of men to women, and had psychiatric evaluations and psychological test scores that suggested significantly more psychopathology. Other biosocial and medical characteristics were similar. Postoperatively, the dieters and nondieters had similar rates for morbidity. Dieters and nondieters had no differences in wound-healing complications, and subgroups who had collagen deposition measured experimentally had similar amounts of hydroxy-proline accumulation in their wounds. These results suggest that a preoperative diet program appeals more to certain subgroups of severely obese patients than to others. An aggressive preoperative weight loss program that encourages patients to lose an average of 17 kg is safe and can be accomplished practically using available commercial products.
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Laparoscopic Roux-en-Y gastric bypass (LRYGBP) is a widely performed bariatric operation. Preoperative factors that predict successful outcomes are currently being studied. The goal of this study was to determine if preoperative weight loss was associated with positive outcomes in patients undergoing LRYGBP. A retrospective analysis was performed of all patients undergoing LRYGBP at our institution between July 2002 (when a policy of preoperative weight loss was instituted) and August 2003. Outcome measures evaluated at 1 year postoperatively included percent excess weight loss (EWL) and correction of co-morbidities. Statistical analysis was performed by multiple linear regression. P<0.05 was considered significant. The study included 90 subjects. Initial BMI ranged from 35.4 to 63.1 (mean 48.1). Preoperative weight loss ranged from 0 to 23.8% (mean 7.25). At 12 months, postoperative EWL ranged from 40.4% to 110.9 % (mean 74.4%). Preoperative loss of 1% of initial weight correlated with an increase of 1.8% of postoperative EWL at 1 year. In addition, initial BMI correlated negatively with EWL, so that an increase of 1 unit of BMI correlated with a decrease of 1.34% of EWL. Finally, preoperative weight loss of >5% correlated significantly with shorter operative times by 36 minutes. Preoperative weight loss did not correlate with postoperative complications or correction of co-morbidities. Preoperative weight loss resulted in higher postoperative weight loss at 1 year and in shorter operative times with LRYGBP. No differences in correction of co-morbidities or complication rates were found with preoperative weight loss in this study. Preoperative weight loss should be encouraged in patients undergoing bariatric surgery.
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Roux-en-Y gastric bypass surgery is the leading surgical treatment of morbid obesity in the United States. The role of preoperative weight loss in gastric bypass surgery remains controversial. We performed a prospective randomized trial to determine whether preoperative weight loss results in better outcomes after laparoscopic gastric bypass. A total of 100 patients undergoing laparoscopic gastric bypass surgery from May 2004 to October 2005 were randomized preoperatively to either a weight loss group with a 10% weight loss requirement or a group that had no weight loss requirements. The patients were followed prospectively. The variables analyzed included perioperative complications, operative time, postoperative weight loss, and resolution of co-morbidities. Data were available for 26 patients in the weight loss group and 35 in the nonweight loss group. The 2 groups had similar preoperative characteristics, conversion and complication rates, and resolution of co-morbidities. The initial body mass index was 48.7 kg/m(2) and 49.3 kg/m(2) for the weight loss group and nonweight loss group, respectively (P = NS). The preoperative body mass index was 44.5 kg/m(2) and 50.7 kg/m(2) for the weight loss group and nonweight loss group, respectively (P = 0.0027). The operative time was 220.2 and 257.6 minutes for the 2 groups (P = 0.0084). The percentage of excess weight loss at 3 and 6 months for the weight loss group and nonweight loss group was 44.1% and 33.1% (P = 0.0267) and 53.9% and 50.9% (P = NS), respectively. The interval to surgery from the initial consultation was 5.4 months and 5.2 months for the 2 groups (P = NS). Preoperative weight loss before laparoscopic Roux-en-Y gastric bypass was associated with a decrease in the operating room time and an improved percentage of excess weight loss in the short term. Preoperative weight loss, however, did not affect the major complication or conversion rates, and its long-term effects were not apparent through this study. Also, preoperative weight loss did not have any bearing on the resolution of co-morbidities.
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This study was performed at a tertiary care university hospital. We hypothesized that weight loss before laparoscopic Roux-en-Y gastric bypass (LRYGB) is feasible, does not diminish the expected postoperative weight loss, and might enhance overall weight loss and maintenance. A population of 351 consecutive patients, who had undergone LRYGB, was divided into 4 groups depending on the percentage of body weight loss achieved before surgery (group 1, none or gain; group 2, <5%; group 3, 5-10%; and group 4, >10%). Data were collected regarding the demographics, body mass index (BMI) change, and excess weight loss and analyzed by analysis of variance and Fisher's exact test at the alpha = 0.05 level. All groups were demographically similar in age and were predominantly women. The maximal follow-up was 36 months. Groups 3 and 4 had significantly greater initial excess weight and BMI (P <.05) but these became similar after the preoperative weight loss. Most patients (74%) were able to lose weight before surgery, with 36% losing >5% body weight. Preoperative weight loss did not decrease the magnitude of the expected postoperative weight loss. Patients who lost weight preoperatively demonstrated more excess weight loss and BMI change (from their initial weight) that was sustained far into the postoperative period and reached statistical significance at several points (P <.05). The results of this study have demonstrated that obese patients are capable of losing weight before LRYGB and that this weight loss does not negatively affect their expected postoperative weight loss. Furthermore, preoperative weight loss combined with LRYGB might result in better long-term excess weight loss and BMI change than surgery alone.