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Articles
www.thelancet.com Published online February 9, 2016 http://dx.doi.org/10.1016/S0140-6736(15)01223-4
1
Mortality of people with chronic fatigue syndrome:
a retrospective cohort study in England and Wales from the
South London and Maudsley NHS Foundation Trust
Biomedical Research Centre (SLaM BRC) Clinical Record
Interactive Search (CRIS) Register
Emmert Roberts, Simon Wessely, Trudie Chalder, Chin-Kuo Chang*, Matthew Hotopf*
Summary
Background Mortality associated with chronic fatigue syndrome is uncertain. We investigated mortality in individuals
diagnosed with chronic fatigue syndrome in secondary and tertiary care using data from the South London and
Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search
(CRIS) register.
Methods We calculated standardised mortality ratios (SMRs) for all-cause, suicide-specifi c, and cancer-specifi c
mortality for a 7-year observation period using the number of deaths observed in SLaM records compared with age-
specifi c and sex-specifi c mortality statistics for England and Wales. Study participants were included if they had had
contact with the chronic fatigue service (referral, discharge, or case note entry) and received a diagnosis of chronic
fatigue syndrome.
Findings We identifi ed 2147 cases of chronic fatigue syndrome from CRIS and 17 deaths from Jan 1, 2007, to Dec 31,
2013. 1533 patients were women of whom 11 died, and 614 were men of whom six died. There was no signifi cant
diff erence in age-standardised and sex-standardised mortality ratios (SMRs) for all-cause mortality (SMR 1·14, 95% CI
0·65–1·85; p=0·67) or cancer-specifi c mortality (1·39, 0·60–2·73; p=0·45) in patients with chronic fatigue syndrome
when compared with the general population in England and Wales. This remained the case when deaths from suicide
were removed from the analysis. There was a signifi cant increase in suicide-specifi c mortality (SMR 6·85, 95% CI
2·22–15·98; p=0·002).
Interpretation We did not note increased all-cause mortality in people with chronic fatigue syndrome, but our fi ndings
show a substantial increase in mortality from suicide. This highlights the need for clinicians to be aware of the
increased risk of completed suicide and to assess suicidality adequately in patients with chronic fatigue syndrome.
Funding National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley
NHS Foundation Trust and King’s College London.
Copyright © Roberts et al. Open Access article distributed under the terms of CC BY.
Introduction
Chronic fatigue syndrome is an illness characterised by
persistent or relapsing fatigue of a debilitating nature,
which is present for at least 6 months, in addition to at
least four symptoms from a range including memory
loss, poor concentration, joint pain, and tender glands.1,2
Patients with chronic fatigue syndrome usually have
extensive investigations to ensure any potential treatable
medical causes of fatigue are addressed. By defi nition, at
diagnosis, individuals with chronic fatigue syndrome are
free of prespecifi ed major medical and psychiatric
disorders leading to prolonged fatigue, and therefore
might be expected to have a mortality risk similar to, or
indeed lower than, the general population.1–3
Although claims have been made on the basis of small,
uncontrolled, clinical case series of higher overall death
risks for heart failure, cancer, and suicide in people with
chronic fatigue syndrome,4,5 a review of descriptive
studies that reported follow-up or outcome data from
patients with a primary diagnosis of chronic fatigue
syndrome showed no convincing evidence of increased
all-cause mortality or suicide-specifi c mortality.6
Specifi cally, only one study has compared the mortality
within a cohort of individuals with chronic fatigue
syndrome (n=641) with that of the general population,7
and reported no signifi cant increase in all-cause
mortality adjusted for sex, race, age, and calendar time
(standardised mortality ratio [SMR] 0·7, 95% CI 0·4–1·2;
14 deaths). Although the relative risk of suicide was
raised in this cohort (SMR 3·6, 95% CI 0·4–12·9;
two deaths), limited statistical power made it diffi cult to
draw conclusions about excess suicide risk in people
Published Online
February 9, 2016
http://dx.doi.org/10.1016/
S0140-6736(15)01223-4
See Online/Comment
http://dx.doi.org/10.1016/
S0140-6736(16)00270-1
*Authors contributed equally
Department of Psychological
Medicine, Institute of
Psychiatry, Psychology and
Neuroscience, King’s College
London, Weston Education
Centre, London, UK
(E Roberts MRCP,
Prof S Wessely FMedSci,
Prof T Chalder PhD,
Prof M Hotopf PhD); and
Department of Psychological
Medicine, Institute of
Psychiatry, Psychology and
Neuroscience, King’s College
London, Denmark Hill, London,
UK (C-K Chang PhD)
Correspondence to:
Dr Emmert Roberts, South
London and Maudsley NHS
Foundation Trust, Department of
Psychological Medicine, Institute
of Psychiatry, Psychology and
Neuroscience, King’s College
London, London SE5 9RJ, UK
emmert.roberts@kcl.ac.uk
or
Dr Chin-Kuo Chang, Department
of Psychological Medicine,
Institute of Psychiatry, Psychology
and Neuroscience, King’s College
London, Denmark Hill,
London SE5 8AF, UK
chin-kuo.chang@kcl.ac.uk
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with chronic fatigue syndrome. By contrast, anecdotal
accounts in various internet and patient forums
repeatedly report increased all-cause mortality.8,9
Mortality associated with chronic fatigue syndrome
remains uncertain, and larger studies are needed to
further address the issue of chronic fatigue syndrome as
a risk factor for all-cause and specifi c causes of mortality.
Therefore, we investigated a retrospective cohort
consisting of people diagnosed with chronic fatigue
syndrome, using data from the national research and
treatment service for chronic fatigue at the South London
and Maudsley NHS Foundation Trust (SLaM) and King’s
College London Hospital (KCH).
Method
Setting and study population
The cohort of patients assessed in this study was
assimilated from the Clinical Record Interactive
Search (CRIS),10 a case register system that provides
de-identifi ed information from electronic clinical
records relating to secondary and tertiary mental health
care services across SLaM. SLaM is a National Health
Service (NHS) mental health trust that provides
secondary mental health care to a population of roughly
1·3 million residents of four London boroughs
(Lambeth, Southwark, Lewisham, and Croydon), and
additionally in collaboration with King’s College Hospital
(KCH), provides a single secondary and tertiary care
national referral service for individuals with suspected
chronic fatigue syndrome, accepting referrals from
general practitioners, general and specialist physicians,
occupational physicians, con sultant psychiatrists, and
community mental health teams. As is the system in the
NHS in England and Wales, all referrals need to be
approved by the local clinical commissioning groups
before they can be seen at the service.
Electronic clinical records have been used
comprehensively across all SLaM services since 2006.
CRIS was established in 2008 to allow searching and
retrieval of full but de-identifi ed clinical information for
research purposes with a permission of secondary data
analysis, approved by the Oxfordshire Research Ethics
Committee C (reference 08/H0606/71+5).10
The chronic fatigue syndrome service follows a
routine assessment procedure, in which all patients
undergo medical screening to exclude detectable
organic illness, including a minimum of physical
examination, urinalysis, full blood count, urea and
electrolytes, thyroid function tests, liver function tests,
tissue transglutaminase, and erythrocyte sedimentation
rate. Patients were interviewed with a semi-structured
diagnostic interview to establish whether they had
fatigue and whether they met the 1994 case defi nition
or Oxford criteria for chronic fatigue syndrome.1,11,12
Additionally, we had information about whether
patients fulfi lled chronic fatigue syndrome criteria as
defi ned by the National Institute of Health and Care
Excellence (NICE).13 Patients with the 1994 case
Research in context
Evidence before this study
We searched Embase, MEDLINE, and PsycINFO for all studies
published from database inception to April 1, 2015, using the
following search terms: [“mortalit*” and (“chronic fatigue
syndrome” or “chronic-fatigue syndrome” or “CFS” or
“post-viral fatigue syndrome” or “post viral fatigue syndrome”
or “CFS/ME” or “ME/CFS” or “myalgic encephalomyelitis” or
“myalgic encephalomyelopathy”)]. We initially assessed the
titles and abstracts identifi ed by the search and excluded
articles that were deemed not relevant. We reviewed the full
text of the remaining articles for inclusion, and all relevant
references were checked for additional citations. We included
studies that compared mortality in individuals with chronic
fatigue syndrome with that of controls without the disorder.
The search process identifi ed 121 unique records. We assessed
three full text articles for eligibility and included one study
comparing the mortality of individuals with chronic fatigue
syndrome with that of a general population control. The results
suggested no increased all-cause or suicide-specifi c mortality in
641 individuals with chronic fatigue syndrome (standardised
mortality ratios [SMRs] 0·7, 95% CI 0·4–1·2 and 3·6, 0·4–12·9,
respectively); however, the study was limited by its small
sample size, with both all-cause and suicide-specifi c mortality
outcomes receiving a GRADE rating of very low quality
evidence. As such whether chronic fatigue syndrome is
associated with a diff ering mortality compared with the general
population remains unknown.
Added value of this study
We report the largest study of mortality in patients with chronic
fatigue syndrome available so far, with 2147 individuals
diagnosed with chronic fatigue syndrome. Our fi ndings showed
that although the overall and cancer-specifi c mortality of patients
with chronic fatigue syndrome was not signifi cantly diff erent to
that of the general population, we noted an increased risk of
completed suicide in patients with chronic fatigue syndrome
when compared with a population control. Individuals with a
diagnosis of chronic fatigue syndrome and a lifetime diagnosis of
depression might be at increased risk of completed suicide.
Implications of all the available evidence
The evidence highlights the need for clinicians to be aware of
the increased risk of completed suicide and to assess suicidality
adequately in patients with chronic fatigue syndrome. Future
studies should focus on identifi cation of protective measures
that can reduce suicide-related mortality in patients with
chronic fatigue syndrome.
Articles
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defi nition-specifi ed exclusionary psychiatric disorders
and also somatisation disorder (DSM-IV) were excluded
from this study. For this study we adopted the most
inclusive criteria, and thus included all patients with a
clinical diagnosis of chronic fatigue syndrome. A
subsample of 755 patients had full diagnostic criteria
applied prospectively of which 65% met Oxford criteria,
58% the 1994 case defi nition criteria, and 88% NICE
criteria. All patients in this sample met at least
one criterion. All were clinic attendees referred within
the UK NHS and have been shown to be a representative
sample of patients with chronic fatigue syndrome
in secondary and tertiary care, similar to those in
Australia, the USA, Scotland, England, and
Northern Ireland.14–16
Study participants were included if they had had
contact with the chronic fatigue service (referral,
discharge, or case note entry) and received a diagnosis
of chronic fatigue syndrome from Jan 1, 2007, to
Dec 31, 2013.
Anyone who was active as a patient with chronic
fatigue syndrome or newly diagnosed as a patient with
chronic fatigue syndrome at any point of this period was
followed up until their death or the end of the
observation period. The diagnosis was ascertained from
having received the prespecifi ed clinic code for a chronic
fatigue syndrome diagnosis, which was the ICD-10 code
for neurasthenia (F48.0) in structured fi elds within
CRIS, and was supplemented by a bespoke natural
language processing application developed at SLaM
using General Architecture for Text Engineering (GATE)
software, which extracts and returns diagnostic
statements from open-text fi elds of the source electronic
health records.17 We emphasise that we do not use the
category or criteria for neurasthenia in either our
clinical or research practice—it is just a computer code
imposed by our data or fi nancial management systems
that run across the trust and which are based on
the ICD-10.
Mortality identifi cation
The analysis outcome is mortality over a 7-year
observation window (2007–13, the at-risk period). In
each NHS trust, a list of deceased people is obtained on
a monthly basis from the “Service User Death Report”
of “the Spine”, maintained by NHS Care Records
Service.18 Therefore, the date of death of each deceased
patient ever served by SLaM is recorded. Further routine
checking occurs for details, including the cause of
death, which were retrieved from the diagnosis (1a) in
death certifi cate via linkage with nationwide data from
the UK Offi ce of National Statistics, and classifi ed by
code of the 10th edition of the WHO International
Classifi cation of Diseases (ICD-10). ICD-10 codes for
cause of death were searched and ascribed to malignant
neoplasm (ICD-10 codes: C00-97), suicide (ICD-10
codes: X60-84), or other causes.
Covariates in analysis
Date of birth, sex, and ethnic origin were routinely
recorded in NHS medical records. For the classifi cation
of age bands, the index date was set as July 1, 2010 (ie, the
mid-point of the at-risk period), or at death, whichever
came fi rst, to defi ne age. Ethnic group was divided
into four categories: white, black, Asian, and mixed,
unknown, or other. Presence of a lifetime diagnosis of
depression was defi ned as having had a recorded
depressive episode (ICD-10 code: F32.x) or recurrent
depressive disorder (F33.x). Multiple deprivation score
(or the indices of multiple deprivation), a measure of
socioeconomic status developed by the UK Offi ce of
National Statistics, which combines various indicators to
include a range of economic, social, and housing
dimensions into one deprivation score for each small
area in the UK, was also available for analysis.19
Statistical analysis
SMRs were calculated for the cohort of patients with
chronic fatigue syndrome during the 7-year observation
period, using number of deaths observed in SLaM
records as the numerator. The denominator was the
expected number of deaths, estimated by 5-year age
bands, and sex-specifi c mortality rates for the England
and Wales population in 2011 multiplied by the weighting
of average person-years in the at-risk period experienced
by chronic fatigue syndrome patients in each age and
sex category.20 We also did stratifi ed analyses of SMRs by
splitting the target population into groups for ethnic
category, presence or absence of a lifetime diagnosis of
depression, and tertiles of multiple deprivation scores.
Focusing on suicide-related mortality of particular
interest, we adapted competing risk regression, a
modifi ed Cox modelling method developed by Fine and
Gray21 for univariate and multivariate analysis, with
suicide-specifi c deaths as the target events and other
causes of death as competing outcomes. Subhazard
ratios and their 95% CIs were thus generated with the
existence of lifetime diagnosis of depression as the
major exposure of interest. This time-to-event analysis
method accounts for the fact that cohort members are
subject to various potential competing causes of death,
which might occur ahead of the specifi c cause of interest.
The main purpose of the modifi cation of the Cox model
was to discriminate censoring between deaths from
other causes and end of follow-up or loss to follow-up to
have a better estimation of relative risk on the specifi c
event of interest (suicide-specifi c mortality) within the
chronic fatigue syndrome cohort. We regarded age and
sex as potential confounders in the multivariate analysis.
Tertile of multiple deprivation score and ethnic origin
were too extreme (because no one died in some smaller
categories) to be imputed as potential confounders in
multivariate analysis. All analyses were done by
STATA SE (version 12) and the signifi cance level was
set as 0·05.
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Role of the funding source
The funders had no role in study design; in the collection,
analysis, or interpretation of data; in the writing of the
report; or in the decision to submit the paper for
publication. ER and C-KC had full access to all the data
in the study and all authors had fi nal responsibility for
the decision to submit for publication.
Results
We identifi ed 2147 cases of chronic fatigue syndrome in
CRIS with 17 deaths. Of them, 1533 patients were women
of whom 11 died, and 614 were men of whom six died.
Eight deaths were from malignant neoplasm, fi ve from
suicide, and four from other causes.
There was no signifi cant diff erence in age-
standardised and sex-standardised mortality ratios for
all-cause mortality (SMR 1·14; 95% CI 0·5–1·85;
p=0·67) or cancer-related mortality (1·39; 0·60–2·73;
p=0·45). This remained the case when stratifi ed by sex,
and when those deaths from external causes were
removed from the analysis. However, there was a
signifi cant increase in suicide mortality with an SMR of
6·85 (95% CI 2·22–15·98; p=0·002; table 1). Although
the suicide-specifi c SMR was signifi cantly increased
compared with the general population, if there had been
two fewer deaths by suicide, this result would have been
non-signifi cant, although the eff ect size (SMR>4) would
still be indicative of a strong eff ect. Table 1 shows
detailed SMRs for the study cohort.
1583 patients were white, 93 black, 48 Asian, and
423 other, mixed or unknown ethnic origin (table 2).
One patient who died from cancer had a missing
ethnicity value and was excluded from the analysis. All
other patients who died were white. When restricted to
only include white patients, there remained no
signifi cant diff erence in age-standardised SMR for all-
cause mortality (SMR 1·44, 95% CI 0·82–2·34; p=0·20)
or cancer-specifi c mortality (1·09, 0·36–2·55; p=0·96;
table 1). Suicide-specifi c mortality remained signifi cantly
elevated (9·12, 2·96–21·27; p<0·0001).
When stratifi ed by lifetime diagnosis of depression,
216 patients had a recorded lifetime diagnosis of F32.x or
F33.x. Four (26%) of 17 patients who died had a lifetime
diagnosis of depression, for two of whom the cause of
death was suicide. No signifi cance was identifi ed for all-
cause (SMR 2·44, 95% CI 0·66–6·24; p=0·17), suicide-
specifi c (3·06, 0·37–11·07; p=0·28), or cancer-specifi c
mortality (0·22, 0·01–1·22; p=0·11) by the presence of
lifetime diagnosis of depression.
The mean multiple deprivation score (MDS) was 22·4%
(SD 12·4), suggesting that the average patient in our cohort
lived in less deprived areas than 78% of the UK population.
64 (3%) of 2147 patients had missing MDS values of whom
one died from suicide and was excluded from the analysis.
There was no signifi cant diff erence in age-standardised
All-cause mortality Suicide-related mortality Cancer-related mortality
Observed
deaths
SMR 95% CI p value Observed
deaths
SMR 95% CI p value Observed
deaths
SMR 95% CI p value
All (n=2147) 17 1·14 0·65–1·85 0·67 5 6·85 2·22–15·98 0·002* 8 1·39 0·60–2·73 0·45
Men 6 1·14 0·42–2·48 0·86 2 4·83 0·58–17·44 0·13 2 1·15 0·14–4·16 1·00
Women 11 1·14 0·55–2·10 0·75 3 9·49 1·96–27·75 0·009* 6 1·49 0·55–3·24 0·44
White† 16 1·44 0·82–2·34 0·20 5 9·12 2·96–21·27 <0·0001* 7 1·09 0·36–2·55 0·96
With lifetime depression
diagnosis
4 2·44 0·66–6·24 0·17 2 3·06 0·37–11·07 0·28 1 0·22 0·01–1·22 0·11
Without lifetime depression
diagnosis
13 1·05 0·56–1·79 0·94 3 4·57 0·94–13·36 0·06 7 1·37 0·55–2·82 0·51
Lower MDS tertile‡ 6 1·34 0·49–2·92 0·58 2 8·96 1·08–32·35 0·04* 2 1·08 0·13–3·90 1·00
Middle MDS tertile‡ 8 1·78 0·77–3·51 0·17 2 8·75 1·06–31·61 0·045* 5 2·67 0·87–6·23 0·08
Upper MDS tertile‡ 2 0·44 0·05–1·60 0·34 0 ·· ·· ·· 1 0·55 0·01–3·08 1·00
SMR=standardised mortality ratio. MDS=multiple deprivation score. *p<0·05. †All the patients who died were white. ‡Tertile of MDS (or the indices of multiple deprivation) a measure of socioeconomic status
developed by the UK Offi ce of National Statistics that combines various indicators to include a range of economic, social, and housing dimensions into one deprivation score. 64 patients had missing MDS values
of whom one died from suicide and was excluded from the analysis.
Table 1: Age-standardised and sex-standardised mortality ratios of all-cause, suicide-related, and cancer-related mortality in patients with chronic fatigue syndrome, compared with the
general population in England and Wales in 2011
All patients with chronic
fatigue syndrome (n=2147)
Patients with chronic fatigue
syndrome who died (n=17)
Mean age (years) 39·1 48·3
Women 1533 11
Men 614 6
White 1583 16
Black 93 0
Asian 48 0
Mixed, other, or unknown 423 1
Documented lifetime
diagnosis of depression
216 4
Table 2: Baseline characteristics
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and sex-standardised SMRs for all-cause or cancer-related
mortality in any tertile of the MDS. Suicide-specifi c
mortality remained signifi cantly increased in the lower
(SMR 8·96, 95% CI 1·08–32·35; p=0·04) and middle
(8·75, 1·06–31·61; p=0·045) MDS tertile. There were no
deaths from suicide in the upper MDS tertile (table 1).
With regards to the outcomes of competing risk
regression using the signifi cantly increased suicide-
related mortality as the specifi c event of interest,
univariate analyses showed that women with chronic
fatigue syndrome had a highly raised but not signifi cant
relative risk of death from suicide-specifi c causes
(subhazard ratio 2·57; 95% CI 0·37–17·89; p=0·34).
Patients with a lifetime diagnosis of depression had a
high risk of dying from suicide (subhazard ratio 9·57;
95% CI 1·34–68·13; p=0·02). The result remained
signifi cant when age and sex were controlled as
confounders (9·61, 1·44–64·21; p=0·02; table 3).
Discussion
Although the all-cause and cancer-specifi c mortality of
patients with chronic fatigue syndrome in specialist care
was not signifi cantly diff erent to that of the general
population, the risk of suicide was higher. This is the fi rst
study to show a specifi c increased risk of suicide in a
population of patients with chronic fatigue syndrome
compared with the general population; however, if there
had been two fewer deaths by suicide, this risk would not
be signifi cantly increased.22
There are limitations to our data including that, despite
being the largest study of mortality in chronic fatigue
syndrome available so far, the sample size is still modest.
The all-cause mortality gave an estimation of SMR close
to 1, and the study had insuffi cient statistical power to
identify such a small eff ect size with a wide confi dence
interval. The SMR for suicide is greatly increased and
although the estimate is imprecise, it is highly unlikely
that the result is due to chance. The modest sample size
limited our ability to explore other cause-specifi c
mortality, or the eff ect of chronic fatigue syndrome on
mortality in subgroups of patients. In view of the
observational nature of the study design, and the limited
number of confounders measured and controlled, it is
possible that the fi ndings are a result of confounding.
For example, because we relied on population mortality
rates, we were unable to control for smoking, BMI, and a
range of chronic diseases that might aff ect mortality risk.
Although the joint chronic fatigue syndrome service
off ered by SLaM and KCH is a national referral service,
more than 80% of patients in the cohort were resident in
the south of England, and as such national mortality
statistics may not be representative of this region.
However, previous work to establish sensitivity between
mortality in “England and Wales” and London concluded
there was no signifi cant diff erence between the mortality
estimates.18 We also accept that the cohort is quite
young and it might, at least theoretically, be possible that
diff erential mortality rates could have emerged after the
7-year observation window.
Patients concerned by ongoing fatigue symptoms might
not wish to be referred to mental health services or be
assessed by a psychiatrist. Reasons for this are
multifactorial but include the perceived stigma of
psychological and rehabilitation treatment, and some
patients’ views that the cause of their symptoms is
biological precludes any form of psychological treatment.
Because the referral pathway for this centre includes a full
assessment including a psychiatric evaluation, an
argument could be made that cases referred to the joint
SLaM and KCH service may not be representative of
chronic fatigue syndrome cases seen in secondary and
tertiary care, and may include a referral bias, favouring
patients with more severe chronic fatigue syndrome,
psychiatric comorbidity, and higher socioeconomic status.
However, the study sample has previously been shown to
be typical of secondary and tertiary care cases in the UK
and internationally.15 We recognise the sample might not
be generalisable to primary-care or community-based
samples of patients with chronic fatigue syndrome,14,23 or
generalisable to health-care settings in which services are
not free to consumers. However, due to the no-cost setting,
we are more likely to capture a broad coverage of source
population when compared with insurance-based national
services, and only moderate to severe cases not seen by the
service would be those that can aff ord private medical care
in the UK. Because this study is restricted to patients aged
over 15 years the results cannot be extrapolated to children
with chronic fatigue syndrome. Finally, our results might
be aff ected by prevalence bias whereby cases known to a
service within a given time are dominated by those with
prolonged clinical courses; therefore, they cannot be taken
to generalise to incident cases.
Much research has been done to investigate the
association between chronic fatigue syndrome and
psychiatric disorder comorbidity. A signifi cant cross-
sectional and prospective association exists between
chronic fatigue syndrome and non-exclusionary psychiatric
disorder comorbidity,24–26 with depression and anxiety
disorders being strongly associated with chronic fatigue
syndrome. The incidence of detected comorbidity of
psychiatric disorder are similar to those seen elsewhere.27
Univariate analysis Multivariate analysis*
Subhazard
ratio
95% CI p value Subhazard
ratio
95% CI p value
Age 1·01 0·97–1·06 0·67 1·01 0·96–1·05 0·83
Sex 2·57 0·37–17·89 0·34 2·63 0·37–18·71 0·33
Lifetime diagnosis of
depression
9·57 1·34–68·13 0·02 9·61 1·44–64·21 0·02
*Age and sex were controlled as confounders in multivariate analysis.
Table 3: Univariate and multivariate analysis outcomes for risk factors of suicide mortality by competing
risk regressions in patients with chronic fatigue syndrome (n=2174)
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The lack of increase in all-cause mortality within the
chronic fatigue syndrome cohort compared with the
general population contrasts with that observed in most
psychiatric disorders, which show increased mortality
especially due to accidents, cancer, and cardiovascular
disease.18 The reasons for the normal all-cause mortality
may be that these patients might have good health
behaviours, an inherently smaller eff ect size, or that all-
cause mortality is confounded by the higher socioeconomic
status of the patient cohort.
Although the suicide-specifi c SMR is raised compared
with the general population, it is lower than for
psychiatric disorders including aff ective disorders,
personality disorders, and alcohol dependence reported
in other population-based studies.28
This study highlights the importance of adequate
assessment of mood and other psychiatric symptoms in
patients with chronic fatigue syndrome, because lifetime
diagnosis of depression is an independent risk factor for
increased risk of completed suicide in this population.
Although completed suicide was a rare event, the
fi ndings strengthen the case for robust psychiatric
assessment by mental health professionals when
managing individuals with chronic fatigue syndrome.
Contributors
ER contributed to the literature search, study question and design, data
collection, analysis, and interpretation, prepared the fi rst draft of the
report, and contributed to subsequent versions; SW and TC contributed
to data interpretation and drafting of the fi nal report; C-KC and MH
contributed to study design, data synthesis and analysis, and drafting of
the fi nal report. All authors approved the fi nal version.
Declaration of interests
ER, SW, C-KC, and MH declare no competing interests. TC received
funding from the Biomedical Research Centre during the conduct of the
study and receives royalties in relation to three self-help books.
Acknowledgments
We thank Hitesh Shetty for assistance with CRIS searches. This report
represents independent research funded by the National Institute for
Health Research (NIHR) Biomedical Research Centre at South London
and Maudsley NHS Foundation Trust and King’s College London, and a
joint infrastructure grant from Guy’s and St Thomas’ Charity and the
Maudsley Charity. The views expressed are those of the authors and not
necessarily those of the NHS, the NIHR, or the Department of Health.
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