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Title: Fatigue and psychosocial variables in autoimmune rheumatic disease and chronic
fatigue syndrome: a cross-sectional comparison.
Running head: Running title: Fatigue in autoimmune rheumatic diseases and CFS.
Abstract
Objective
Fatigue is common in autoimmune rheumatic diseases (ARD). This study compared
symptom-related cognitions, beliefs, behaviours, quality of sleep, lack of acceptance and
distress in participants with ARD such as rheumatoid arthritis(RA), spondyloarthropathy
(SpA), and connective tissue disease (CTD), and participants with chronic fatigue syndrome
(CFS).
Methods
303 participants with RA, SpA, CTD and CFS completed questionnaire measures of fatigue,
social adjustment, cognitive-behavioural responses, lack of acceptance, distress and quality of
sleep. The RA, SpA and CTD groups were first compared with each other. They were then
combined into one group and compared with the CFS group.
Results
There were no statistically significant differences between the RA, SpA or CTD groups for
any of the measures. The CFS group were more fatigued, reported more distress and sleep
disturbance and had worse social adjustment than the ARD group after adjustment for age
and illness duration. After adjustment for fatigue, age, and illness duration, the CFS group
scored more highly on lack of acceptance and avoidance/resting behaviour while the ARD
group showed significantly higher levels of catastrophising, damage beliefs, and symptom
focusing than the CFS group.
1
Conclusion
Fatigue in rheumatic diseases may be perpetuated by similar underlying transdiagnostic
processes. The ARD and CFS groups showed similarities but also key differences in their
responses to symptoms. Specific aspects of treatment may need to be tailored towards each
group. For example, lack of acceptance and avoidance behaviour may be particularly
important in perpetuating fatigue in CFS.
Key words: fatigue, rheumatology, transdiagnostic, cognitive behavioural responses,
acceptance.
Highlights
Patients with ARD show similar cognitive-behavioural responses.
Transdiagnostic treatment approaches may be beneficial for fatigue in ARD.
Lack of acceptance is associated with fatigue severity in CFS and ARD.
2
Introduction
Transdiagnostic theory proposes that heterogeneous illnesses share similar underlying
emotional, cognitive and behavioural processes, and that the same treatment can be used
across different diagnoses[1, 2]. This approach can be applied to fatigue in chronic illnesses.
Fatigue is common in the general population, with 18.3% of the general population reporting
substantial fatigue for six months or longer [3]. It is a significant feature of CFS (Chronic
Fatigue syndrome). Fatigue is also a ubiquitous symptom of many chronic diseases [4],
including ARD (autoimmune rheumatic diseases). From a transdiagnostic perspective, the
cognitive and behavioural responses to fatigue may be similar across different rheumatic
diseases and CFS, and may respond to similar treatment approaches regardless of the specific
diagnosis.
CFS is characterised by long-standing fatigue and includes physical and mental symptoms
such as muscle pain and concentration difficulties, which can impact on physical and social
functioning [5, 6]. Moreover, patients often report sleep disturbance and distress [7-10]. In
ARD such as rheumatoid arthritis (RA), seronegative spondyloarthropathies (SpA) and
connective tissue diseases (CTD), fatigue is a pervasive symptom which affects every day
functioning, and has been associated with decreased quality of life and increased disease
burden[11-19]. Fatigue often persists even after disease activity has been managed with
disease-modifying medication[20].
There is some evidence that fatigue in ARD could be associated with cognitive and
behavioural factors. For example, cognitive factors such as self-efficacy and pain
catastrophizing have been shown to correlate with fatigue and distress in both SLE (systemic
lupus erythematosus) [21] and Sjögren's syndrome[22]. In RA a systematic review of
3
psychological correlates of fatigue [23]found evidence that RA-related unhelpful cognitions
such as lower arthritis self-efficacy were associated with higher levels of fatigue [24, 25].
Similarly, research suggests that fatigue in CFS may also be maintained by a complex
interplay of cognitive, behavioural and physiological factors. According to the cognitive-
behavioural model of fatigue in CFS, unhelpful beliefs about physical activity can perpetuate
fatigue severity, and an individual may reduce or avoid certain activities for fear of
worsening symptoms. This can lead to a vicious cycle of negative beliefs about activity,
avoidance of activity, prolonged rest, and worsening symptoms, along with a reinforced
belief that activity is harmful [26, 27]. This model is supported by Petrie et al’s finding that
catastrophic beliefs were associated with worse fatigue and functioning in patients with CFS
[28]. Another view is that lack of acceptance, or a desire to control symptoms, may cause
distress and impaired functioning. Research suggests that a lack of acceptance of symptoms is
associated with higher levels of fatigue and disability, and in turn higher levels of acceptance
are associated with better psychological well-being [29, 30].
We know of only one study to date which has compared the illness-related cognitions of
patients with CFS and those with a rheumatic disease. Moss-Morris and
Chalder[31]compared illness-related cognitions of RA patients with cognitions of patients
with CFS, and found that the patients with CFS had more negative illness beliefs than
patients with RA as well as more negative beliefs about the course and prognosis of their
illness. This may be due to differences in the way that CFS and RA are defined and
diagnosed. For example, rheumatoid arthritis includes objective manifestations of disease
such as joint swelling or damage as well as subjective symptoms such as pain, whereas the
diagnosis of chronic fatigue syndrome relies largely on subjective self-reports of
symptomatology [31]. Patients with CFS report experiencing stigma and scepticism from
4
health professionals, and difficulties with obtaining a diagnosis [32, 33]. Therefore their
experiences may differ from those of RA patients.
In this paper, we suggest that the processes that maintain fatigue in the context of CFS, which
is defined by fatigue, may be similar to the processes that perpetuate fatigue in chronic
diseases such as autoimmune rheumatic diseases (ARD). The purpose of the current study
was to examine the levels of fatigue, disability, distress and sleep problems in participants
with ARD such as RA, CTD and SpA. We also sought to examine the symptom-related
cognitive and behavioural responses of these participants. We hypothesised that there would
be no differences between the three ARD groups on the cognitive and behavioural responses
subscales. Another aim of the study was to compare the fatigue, cognitions and behaviours of
participants with CFS and a heterogeneous group of participants with ARD. It was
hypothesised that the CFS group would show higher levels of fatigue and disability than the
ARD group. Also, given the previous research showing differences between participants with
CFS and RA in terms of illness-related cognitions [31], we hypothesised that participants
with CFS would show more extreme cognitive behavioural responses and a higher lack of
acceptance than participants with ARD.
Methods
Participants and procedure
This cross-sectional questionnaire study compared the questionnaire data of participants with
rheumatoid arthritis (RA), seronegative spondyloarthropathies (SpA) and connective tissue
diseases (CTD). These ARD groups were subsequently compared with a group of participants
with CFS. Data was collected in accordance with the ethical principles of the Declaration of
Helsinki. Data collection for the participants with ARD was approved by the London
5
Dulwich Research Ethics Committee; REC reference number: 10/H0808/135. Collection of
data from the CFS patients was approved by the audit committee of the South London and
Maudsley NHS Foundation Trust. Data collection took place from November 2011 to March
2013.
Autoimmune rheumatic disease groups
Participants with ARD were recruited consecutively from outpatient rheumatology clinics.
They were approached by a rheumatologist or a researcher and invited to participate in the
study. Participants gave written, informed consent. Participants with ARD completed
questionnaires at an outpatient appointment with a rheumatologist. Questionnaires were
completed in the waiting room of the hospital or in the participant’s home. Patients were
diagnosed by a rheumatologist in accordance with accepted diagnostic or classification
criteria, where appropriate [34-39].
Participants were subsequently grouped into three broad categories according to their
clinician-verified diagnosis. The categories were: Rheumatoid Arthritis (RA), Seronegative
Spondyloarthropathy (SpA) and Connective tissue disease (CTD). The SpA group included
the following diagnoses (in order of prevalence): psoriatic arthritis, seronegative
spondyloarthritis (unspecified), enteropathic arthritis, ankylosing spondylitis and reactive
arthritis. The CTD group included the following diagnoses (in order of prevalence):
connective tissue disease (unspecified), systematic lupus erythematosus, myositis, vasculitis,
Behçet's disease and Sjögren's syndrome. Participants were excluded from the analysis if they
did not have a clinician-verified diagnosis, or if their diagnosis did not fit into the categories
of RA, SpA or CTD. Subsequently, participants in the RA, SpA and CTD groups were
combined to form a group of ARD in order to be compared with the CFS group.
6
Chronic Fatigue Syndrome group
Participants with CFS were recruited consecutively from a specialist outpatient clinic for
chronic fatigue syndrome. A medical assessment was undertaken in accordance with NICE
Guidelines[40] to confirm a diagnosis of CFS and rule out other causes of fatigue.
Participants were excluded from the analysis if they did not have a diagnosis of CFS or if
they had a comorbid illness which may account for the fatigue (e.g. bipolar disorder).
Participants completed questionnaires after the specialist assessment by a clinician and prior
to starting treatment for CFS.
Questionnaires
All participants completed questionnaires including the following:
Chalder Fatigue Questionnaire[41, 42]
This is an 11-item scale which measures physical and mental fatigue. It has been validated in
fatigue and CFS. Scores on the 11 items can be summed to calculate a fatigue score out of 33.
A higher score is associated with greater levels of fatigue. It is reliable and valid. Reliability
in this sample, as measured using Cronbach’s alpha, was 0.93 and 0.92 for the CFS and ARD
groups respectively.
Cognitive Behavioural Responses Questionnaire[8, 43, 44]
The cognitive and behavioural responses questionnaire (CBRQ) is a measure of beliefs about
symptoms and behavioural responses to symptoms. It was developed specifically to examine
unhelpful symptom-related beliefs and coping behaviour, for example, avoidance of activity,
symptom focusing, catastrophic thoughts about symptoms, and embarrassment about
symptoms. This questionnaire has been shown to be reliable and valid in patients with CFS
7
and multiple sclerosis [8, 43, 44]. The questionnaire consists of seven subscales. There are
five subscales which measure cognitive responses (fear avoidance, symptom focusing,
catastrophizing, embarrassment avoidance, damage beliefs). There are also two subscales
which measure behavioural responses (avoidance/resting behaviour and all-or-nothing
behaviour). Participants are presented with a series of statements which they are asked to rate
on a scale of 0 (strongly disagree) to 4 (strongly agree). Totals are calculated for each
subscale. Higher scores indicate more extreme beliefs or behavioural responses. Examples of
items from these subscales can be seen in table A1 in the appendix. Examination of internal
consistency showed that the acceptance measure and the subscales of the CBRQ were reliable
in both the CFS and ARD groups (see Table A2 in appendix).
Work and Social adjustment Scale[45, 46]
This is a five-item scale which measures social functioning and social adjustment. Each item
has a maximum score of 8 and the five items summed can give a maximum total score of 40.
A higher score indicates worse social adjustment. It has good reliability and is valid in
patients with CFS [46]. Cronbach’s alpha for the CFS and ARD groups were 0.88 and 0.95
respectively.
Jenkins sleep questionnaire [47]
The Jenkins sleep questionnaire is a measure of sleep disturbance. Four items are combined
to create a total out of 40. A higher score indicates worse sleep disturbance. Cronbach’s alpha
for the CFS and ARD groups were 0.75 and 0.84 respectively.
Hospital Anxiety and Depression Scale [48]
This is a measure of mood, with subscales for anxiety and depression. There are fourteen
items, with seven items for anxiety and seven items for depression. Higher scores indicate 8
more severe anxiety or depression. The scale is reliable and valid. For anxiety, Cronbach’s
alpha for the CFS and ARD groups were 0.88 and 0.86 respectively. For depression,
Cronbach’s alpha for the CFS and ARD groups were 0.85 and 0.86 respectively.
Fatigue acceptance questionnaire [30, 49, 50])
This is a measure of lack of acceptance of fatigue. It is adapted from the pain willingness
subscale of the Chronic Pain Acceptance Questionnaire[49]. In each item, the word pain was
substituted by fatigue. It consists of nine items, which are listed in table A3 in the
supplementary material. Each item is scored on a scale of 0 (never true) to 6 (always true).
The nine items of the scale are summed to create a total score. A higher score indicates a
greater lack of acceptance and less willingness to be in direct confrontation with fatigue
symptoms. Cronbach’s alpha for the CFS and ARD groups were 0.79 and 0.95 respectively.
Statistical analysis
Data were analysed using version 21 of the Statistical Package for the Social Sciences [51].
Examination of the residuals indicated that parametric statistics were appropriate for this
analysis.
For the main analyses, missing data were pro-rated. Therefore if 25% or less of the items
were missing for each scale, a prorated total was calculated which substituted the missing
items with the mean of the remaining items of the scale for the same individual.
Analysis of Covariance (ANCOVA) was used to compare the three ARD illness groups on
CBRQ, fatigue, social adjustment, anxiety, depression, quality of sleep and lack of
acceptance while taking into account the effect of age and illness duration.
9
As previously mentioned, the three ARD groups were combined into one group (ARD) and
compared with the CFS group. Separate one-way ANCOVA analyses were carried out for
fatigue, social adjustment, anxiety, depression, quality of sleep, lack of acceptance and each
of the CBRQ subscales. Age and illness duration were added as covariates, and estimated
marginal means and standard errors were computed.
In order to assess for the potential impact of fatigue, the ANCOVA analyses were repeated
with the inclusion of fatigue as a covariate in addition to the other covariates of age and
illness duration. Bivariate correlations were also carried out in order to assess the relationship
between fatigue and each of the CBRQ subscales as well as lack of acceptance. Bivariate
correlations were also performed to investigate relationships between social adjustment and
CBRQ as well as acceptance. Differences between the correlations were assessed using the
Fisher’s r to Z transformation [52, 53].
10
Results
Demographics
A total of 303 participants were included in the final analysis. The demographic
characteristics of study participants are shown in table 1.
[Insert table 1 here]
Of 232 patients from the rheumatology clinic who were assessed for eligibility for the study,
70 were excluded because they did not have a clinician-verified diagnosis of a disease that
could be classified under the groups of RA, CTD, or SpA. Therefore 162 rheumatology
patients were included in the final analysis. In this group, 56 patients had a diagnosis of RA,
69 had a diagnosis of CTD, and 37 had a diagnosis of SpA.
151 patients from the CFS clinic were assessed for inclusion in the study. Ten of these were
excluded because they did not have a clinician-verified diagnosis of CFS. 141 CFS patients
were included in the final analysis. Patients self-reports of their symptoms indicated that 141
(100%) met NICE[40] criteria for CFS, 87(61.7%) met Oxford criteria for CFS, and 70
(49.6%) met CDC criteria for CFS.
ANCOVA analyses
Table 2 shows the results of one-way ANCOVA analyses comparing the three ARD groups
for all of the questionnaire measures. There were no statistically significant differences
between the groups for any of the measures and the differences between the mean scores
were very small.
11
[Insert table 2 here]
Subsequently, pairwise group comparisons were carried out between the ARD and CFS
groups for each of the measures (see table 3). The CFS group were significantly more
fatigued and had worse social adjustment than the ARD group. The CFS group also had more
sleep and mood problems and a higher lack of acceptance. In addition, the CFS group scored
significantly higher than the ARD group for fear avoidance, embarrassment avoidance, all or
nothing behaviour, and avoidance resting behaviour.
[Insert table 3 here]
The ANCOVA analyses were repeated with fatigue as covariate in addition to age and illness
duration. As seen in Table 4, after adjusting for fatigue, age and illness duration, the CFS
patients still had worse social adjustment and higher lack of acceptance than the ARD
patients. The CFS patients also showed more avoidance/resting behaviour than the ARD
patients. However the difference between the groups for fear avoidance beliefs, anxiety,
depression, embarrassment avoidance and all or nothing behaviour became non-significant.
Also, after this additional adjustment for fatigue, significantly higher levels of
catastrophising, symptom focusing and damage beliefs were seen in the ARD group.
[Insert table 4 here]
Correlation analyses
As seen in Table 5, for the CFS patients, fatigue was correlated with fear avoidance,
catastrophizing, embarrassment avoidance, all or nothing behaviour, avoidance resting
behaviour and lack of acceptance. The correlation coefficients ranged between 0.12 and 0.38.
In the ARD group, fatigue was correlated with all of the CBRQ subscales, with lack of
acceptance and catastrophizing showing the strongest associations with fatigue. Overall the 12
ARD group showed stronger correlations between fatigue and the CBRQ subscale, with
correlation coefficients ranging between .38 and .53. The associations were most pronounced
for fear avoidance, catastrophizing, damage beliefs, symptom focusing, and lack of
acceptance. Similarly, as seen in Table 6, the ARD group showed stronger associations
between social adjustment and the CBRQ subscales as well as lack of acceptance. These
associations were all significantly higher than the CFS group with the exception of all or
nothing behaviour. In the ARD group, lack of acceptance showed the strongest association
with both fatigue and social adjustment.
[Insert tables 5 and 6 here]
Discussion
Summary of findings
This study investigated the symptom-related beliefs and behavioural responses of participants
with ARD such as RA, CTD and SpA, and participants with CFS.
To our knowledge, this is the first study to measure these psychological constructs in a
sample of people with varied rheumatological diagnoses and to show that the results were
similar regardless of the specific diagnosis.
As hypothesised, results showed that the three ARD groups did not differ from each other for
fatigue, social adjustment, sleep, mood, lack of acceptance, or any of the cognitive-
behavioural responses to symptoms. This suggests that patients with heterogeneous diagnoses
of rheumatic disease report similar levels of fatigue, work and social adjustment, sleep
problems, anxiety and depression. They also appear to respond to symptoms similarly.
13
The findings also showed that there were cross cutting concerns in ARD illness groups and
CFS. For example both groups showed statistically significant associations between fatigue
and symptom-related cognitions and behaviours. This finding requires further exploration,
but it may indicate that there are similar underlying processes which are maintaining fatigue
in CFS and ARD, but to differing degrees. Long-term fatigue in both illnesses could be
perpetuated by cognitions such as fear avoidance beliefs and avoidance behaviour.
The groups also showed some differences. In line with hypotheses, participants in the CFS
group reported more fatigue, worse social adjustment, and higher levels of sleep disturbance,
anxiety and depression than the ARD group when adjusting for age and illness duration. In
addition, the CFS group had significantly higher scores than the ARD group for fear
avoidance beliefs, embarrassment avoidance beliefs, all or nothing behaviour, avoidance
resting behaviour and lack of acceptance. When fatigue was added as an additional covariate
to the ANCOVA analysis, the difference between the two groups for avoidance behaviour,
social adjustment and lack of acceptance remained. However, in contrast to hypotheses, the
ARD group showed higher levels of catastrophising, damage beliefs, and symptom focusing
than the CFS group. Also, after this additional adjustment for fatigue there was no longer a
significant difference between groups for anxiety, depression, fear avoidance, embarrassment
avoidance and all or nothing behaviour.
Another key difference between the groups was that the ARD group showed stronger
associations between fatigue severity and symptom-related beliefs and behaviours than the
CFS group. These findings may indicate that fatigue plays a more important role in the
symptom-related cognitions of the ARD group compared to the CFS group. The correlations
between cognitive-behavioural responses and social adjustment were also higher in the ARD
14
group than in the CFS group, suggesting that beliefs need to be targeted in the context of
treatment for fatigue.
Findings in the context of previous literature
In support of previous literature [11, 16, 54] this study confirmed that fatigue is prevalent in
ARD such as RA, SpA and CTD.
These findings add to the previous findings of Moss-Morris and Chalder[31], who showed
that CFS patients had more negative illness beliefs and negative perceptions of illness
consequences compared to RA patients. In this study, CFS patients showed significantly
more avoidance behaviour than the ARD group, and the difference remained significant after
adjustment for fatigue severity. The literature suggests that avoidance may be used as a
coping strategy, with the aim of allowing the patient to exert some control over the
illness[26]. Although this strategy may be useful in terms of alleviating symptoms in the
short term, it may not be helpful in the long term. Avoidance behaviour may be related to
more extreme fear avoidance beliefs. On the other hand, it may also be a consequence of
more severe symptoms of fatigue. As previously mentioned, the diagnosis of CFS is made by
the exclusion of organic pathology, whereas most ARD have objective diagnostic features
such as swollen joints to confirm diagnosis. This gives patients more certainty [31].
However, some of the findings of this study also contrast with those of Moss-Morris and
Chalder [31]. For example, we found catastrophising and damage beliefs were significantly
higher in ARD patients after adjustment for fatigue as well as age and illness duration.
The findings of this study add to the literature in rheumatic disease by demonstrating a link
between fatigue and cognitions [23, 24, 55, 56]. Cognitive-behavioural models of fatigue
assume that a multifaceted and complex relationship exists between cognitions, behaviours
15
and symptoms, along with other psychosocial and biological factors, which all interact to
maintain fatigue in the long term. Similar factors may perpetuate the fatigue, whatever the
trigger or contribution of disease-related factors [23, 57, 58].
Given the emerging evidence that cognitive-behavioural interventions are effective for
reducing fatigue not only in CFS[44] but also RA[59] in addition to other illnesses such as
multiple sclerosis[60] and cancer [61], transdiagnostic interventions using similar principles
could be used for fatigue that occurs in many different types of rheumatic diseases, regardless
of the specific diagnosis.
Fatigue has an impact on quality of life and levels of occupational and social functioning in
rheumatic diseases, yet it often remains unaddressed. [16, 62]. The potential benefits for
treatment are manifold: an intervention for fatigue symptoms can potentially improve a
person’s functioning and participation in life.
Although there is evidence that CBT for rheumatic disease can lead to improvements in
fatigue [58, 59], most studies do not specify whether the improvement was clinically
significant or mention other important outcomes such as employment. Similarly, in the CFS
literature, there is a dearth of research about occupational outcomes in chronic fatigue
syndrome, and no consensus on how the outcomes are defined[63].
Clinical implications
As these results suggest that avoidance behaviour may be less marked in ARDs, a briefer
approach which targets specific cognitive processes such as lack of acceptance,
catastrophizing, symptom focusing and damage beliefs may be warranted. Specific attention
should be focused on damage beliefs and symptom focusing as these may vary in magnitude
during flare-ups. Interventions could be delivered by health professionals within an outpatient
16
clinic in the acute hospital setting or primary care. To our knowledge, the only CBT based
fatigue interventions so far have been tested on patients with RA [59, 64]and there is a dearth
of research on the effectiveness of CBT for other autoimmune rheumatic diseases.
The finding that CFS patients showed higher lack of acceptance than ARD patients, after key
demographic variables had been controlled for warrants discussion. In keeping with this
finding, our previous study of CFS patients showed that lack of acceptance changed
significantly after treatment with more conventional CBT where acceptance was not the main
focus [30]. There is emerging evidence however that newer, third wave therapies such as
ACT (acceptance and commitment therapy) can be effective for increasing acceptance in
individuals with chronic illnesses such as long-standing chronic pain[65]. This evidence and
the fact that lack of acceptance is problematic for people with CFS suggests that acceptance
should be targeted during treatment. There is a need for further research into the effectiveness
of these treatments for illnesses such as CFS.
Limitations
This study has some limitations which must be considered. For example, we included
covariates such as age and illness duration in our analysis, however, due to the observational
nature of this study, it was not possible to control for many other potential confounding
variables such as disease activity and medication usage. In addition, controlling for fatigue in
CFS is potentially problematic because it is the primary symptom of CFS.
The ANCOVA analyses showed no differences between the three ARD groups, and this was
interpreted as showing that the groups were similar. However, a more sophisticated statistical
method such as equivalence testing[66] is needed in order to establish whether the groups
were statistically equivalent to each other. Also, given that the groups were relatively small in
17
size, the study may have lacked power. Furthermore the analysis consisted of a number of
comparisons which may have increased the likelihood of type 1 error. This limitation should
be considered in future studies.
Conclusion
The results of this study suggest that although cognitive behavioural approaches may be
suitable for both CFS and ARD, there are specific variables that might need to be targeted in
each of the illnesses. For example, lack of acceptance and avoidance behaviour, which
appears to be important in CFS, could be addressed with acceptance and commitment therapy
which targets these processes specifically with valued based goals or mindfulness-based
treatment approaches.
Fatigue continues to be a debilitating symptom in ARD, yet it is inadequately addressed by
clinicians. Further research is needed into factors that maintain fatigue in ARD. This will
allow for transdiagnostic interventions to be developed and individualised to improve
symptoms, functioning, and quality of life.
18
Acknowledgements:
We would like to thank the patients who gave their time to take part in this study. We also
thank Ms Suzanne Roche, Ms Barbara Bowman, Dr Mary Burgess, Dr Antonia Dittner, Dr
Caroline Stokes, Ms Radka Chura, Mr Putu Khorisantono, Mr James Gwinnutt, Ms Fatma
Mehmet, and Ms Egli Ioannou for their assistance with gathering data for this study. We
would like to thank Dr Kimberley Goldsmith for statistical advice.
FM and TC receive salary support from the National Institute for Health Research (NIHR)
Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation
Trust and King’s College London. The views expressed in this article are those of the authors
and not necessarily those of the NIHR or the NHS.
References
[1] A. Harvey, Watkins E., Mansell W., Shafran R. Cognitive behavioural processes across psychological disorders: a transdiagnostic approach to research and treatment. .Oxford University Press, Oxford 2004.[2] D.H. Barlow, Allen L.B., Choate M.L. Toward a unified treatment for emotional disorders, Behav Ther. 35,(2)(2004) 205-30.[3] T. Pawlikowska, Chalder T., Hirsch S.R., Wallace P., Wright D.J., Wessely S.C. Population based study of fatigue and psychological distress, BMJ. 308,(6931)(1994) 763-6.[4] M.G. Swain. Fatigue in chronic disease, Clin Sci. 99,(1)(2000) 1-8.[5] K. Fukuda, Straus S.E., Hickie I., Sharpe M.C., Dobbins J.G., Komaroff A. The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group, Ann Intern Med. 121,(12)(1994) 953-9.[6] M.C. Sharpe, Archard L.C., Banatvala J.E., Borysiewicz L.K., Clare A.W., David A., et al. A report-chronic fatigue syndrome: guidelines for research, J R Soc Med. 84,(2)(1991) 118-21.[7] M. Fossey, Libman E., Bailes S., Baltzan M., Schondorf R., Amsel R., et al. Sleep Quality and Psychological Adjustment in Chronic Fatigue Syndrome, Journal of Behavioral Medicine. 27,(6)(2004) 581-605.[8] M. Cella, White P., Sharpe M., Chalder T. Cognitions, behaviours and co-morbid psychiatric diagnoses in patients with chronic fatigue syndrome, Psychol Med. 43,(02)(2013) 375-80.
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[9] K.A.M. Janssens, Zijlema W.L., Joustra M.L., Rosmalen G.M. Mood and Anxiety Disorders in Chronic Fatigue Syndrome, Fibromyalgia, and Irritable Bowel Syndrome: Results from the LifeLines Cohort Study, Psychosomatic medicine. 77(2015) 449-57.[10] L.A. Jason, Richman J.A., Rademaker A.W., Jordan K.M., Plioplys A.V., Taylor R.R., et al. A community-based study of chronic fatigue syndrome, Archives of internal medicine. 159,(18)(1999) 2129-37.[11] A. Schmeding, Schneider M. Fatigue, health-related quality of life and other patient-reported outcomes in systemic lupus erythematosus, Best Pract Res Clin Rheumatol. 27,(3)(2013) 363-75.[12] A. Van Tubergen, Coenen J., Landewé R., Spoorenberg A., Chorus A., Boonen A., et al. Assessment of fatigue in patients with ankylosing spondylitis: a psychometric analysis, Arthritis Rheum. 47,(1)(2002) 8-16.[13] C.D. Graham, Rose M.R., Grunfeld E.A., Kyle S.D., Weinman J. A systematic review of quality of life in adults with muscle disease, J Neurol. 258,(9)(2011) 1581-92.[14] B.L. Belza. Comparison of self-reported fatigue in rheumatoid arthritis and controls, J Rheumatol. 22,(4)(1995) 639-43.[15] H. Repping-Wuts, Uitterhoeve R., van Riel P., van Achterberg T. Fatigue as experienced by patients with rheumatoid arthritis (RA): a qualitative study, Int J Nurs Stud. 45,(7)(2008) 995-1002.[16] D. Da Costa, Zummer M., Fitzcharles M.A. Biopsychosocial determinants of physical and mental fatigue in patients with spondyloarthropathy, Rheumatol Int. 31,(4)(2011) 473-80.[17] Godaert GLR, Hartkamp R, Geenen R, Garssen A, Kruize AA, Bijlsma JWJ, et al. Fatigue in daily life in patients with primary sjögren's syndrome and systemic lupus erythematosus, Ann N Y Acad Sci. 966(2002) 320-6.[18] C. Tench, McCurdie I., White P., D'Cruz D. The prevalence and associations of fatigue in systemic lupus erythematosus, Rheumatology 39(2000) 1249-54.[19] R. Ramsey-Goldman, Rothrock N. Fatigue in systemic lupus erythematosus and rheumatoid arthritis, PM R. 2,(5)(2010) 384-92.[20] D. van Hoogmoed, Fransen J., Repping-Wuts H., Spee L., Bleijenberg G., van Riel P.L. The effect of anti-TNF-alpha vs. DMARDs on fatigue in rheumatoid arthritis patients, Scand J Rheumatol. 42,(1)(2013) 15-9.[21] T. Somers, Kurakula P., Criscone-Schreiber L., Keefe F., Clowse M. Self-Efficacy and pain catastrophising in systemic lupus erythematosus: relationship to pain, stiffness, fatigue, and psychological distress, Arthritis Care Res (Hoboken). 64,(9)(2012) 1334-40.[22] B. Segal, Pogatchnik B., Rhodus N., Sivils K.M., McElvain G., Solid C. Pain in primary sjögren’s syndrome: the role of catastrophizing and negative illness perceptions, Scand J Rheumatol. 43,(3)(2014) 234-41.[23] F. Matcham, Ali S., Hotopf M., Chalder T. Psychological correlates of fatigue in rheumatoid arthritis: A systematic review, Clinical Psychology Review. 39(2015) 16-29.[24] J.H. Barlow, Cullen, L.A., Rowe, I.F. Educational preferences, psychological well-being and self-efficacy among people with rheumatoid arthritis, Patient Educ Couns. 46(2002) 11-9.[25] B.A. Huyser, Parker J.C., Thoreson R., Smarr K.L., Johnson J.C., Hoffman R. Predictors of subjective fatigue among individuals with rheumatoid arthritis, Arthritis Rheum. 41,(12)(1998) 2230-7.[26] C. Surawy, Hackmann A., Hawton K., Sharpe M. Chronic fatigue syndrome: a cognitive approach, Behav Res Ther. 33,(5)(1995) 535-44.[27] H. Knoop, Prins J.B., Moss-Morris R., Bleijenberg G. The central role of cognitive processes in the perpetuation of chronic fatigue syndrome, J Psychosom Res. 68,(5)(2010) 489-94.[28] K. Petrie, Moss-Morris R., Weinman J. The impact of catastrophic beliefs on functioning in chronic fatigue syndrome, J Psychosom Res. 39,(1)(1995) 31-7.
20
[29] S. Van Damme, Crombez G., Van Houdenhove B., Mariman A., Michielsen W. Well-being in patients with chronic fatigue syndrome: The role of acceptance, Journal of Psychosomatic Research. 61(2006) 595-9.[30] S.K. Brooks, Rimes K.A., Chalder T. The role of acceptance in chronic fatigue syndrome, Journal of Psychosomatic Research. 71,(6)(2011) 411-5.[31] R. Moss-Morris, Chalder T. Illness perceptions and levels of disability in patients with chronic fatigue syndrome and rheumatoid arthritis, J Psychosom Res. 55,(4)(2003) 305-8.[32] A. Dickson, Knussen C., Flowers P. Stigma and the delegitimation experience: An interpretative phenomenological analysis of people living with chronic fatigue syndrome, Psychology & Health. 22,(7)(2007) 851-67.[33] Picariello F, Ali S, Foubister C, Chalder T. It feels sometimes like my house has burnt down, but I can see the sky”: A qualitative study exploring patients’ views of CBT for Chronic Fatigue Syndrome., British Journal of Health Psychology (submitted ).[34] Bohan A, Peter JB. Polymyositis and dermatomyositis (first of two parts), N Engl J Med. 292(1975) 344-7.[35] A. Bohan, Peter J. Polymyositis and dermatomyositis (second of two parts), N Engl J Med. 292(1975) 403-7.[36] M. Dougados, van der Linden S., Juhlin R., Huitfeldt B., Amor B., Calin A., et al. The European Spondylarthropathy Study Group preliminary criteria for the classification of spondylarthropathy, Arthritis Rheum. 34,(10)(1991) 1218-27.[37] Aletaha D, Neogi T, Silman AJ, Funovits J, Felson DT, Bingham CO III, et al. Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative, Arthritis Rheum. 62(2010) 2569-81.[38] E.M. Tan, Cohen A.S., Fries J.F., Masi A.T., McShane D.J., Rothfield N.F., et al. The 1982 revised criteria for the classification of systemic lupus erythematosus, Arthritis Rheum. 25,(11)(1982) 1271-7.[39] W. Taylor, Gladman D., Helliwell P., Marchesoni A., Mease P., Mielants H. Classification criteria for psoriatic arthritis: development of new criteria from a large international study, Arthritis Rheum. 54,(8)(2006) 2665-73.[40] National Institute for Health and Care Excellence. Chronic fatigue syndrome/myalgic encephalomyelitis (or encephalopathy): Diagnosis and management of CFS/ME in adults and children. . London2007.[41] M. Cella, Chalder T. Measuring fatigue in clinical and community settings, Journal of psychosomatic research. 69,(1)(2010) 17-22.[42] T. Chalder, Berelowitz G., Pawlikowska T., Watts L., Wessely S., Wright D., et al. Development of a fatigue scale, Journal of psychosomatic research. 37,(2)(1993) 147-53.[43] T.N. Skerrett, Moss-Morris R. Fatigue and social impairment in multiple sclerosis: the role of patients' cognitive and behavioral responses to their symptoms, J Psychosom Res. 61,(5)(2006) 587-93.[44] D. Stahl, Rimes K.A., Chalder T. Mechanisms of change underlying the efficacy of cognitive behaviour therapy for chronic fatigue syndrome in a specialist clinic: a mediation analysis, Psychol Med. 44,(6)(2013) 1331-44.[45] J.C. Mundt, Marks I.M., Shear M.K., Greist J.H. The work and social adjustment scale: a simple measure of impairment in functioning, Br J Psychiatry. 180(2002) 461-4.[46] M. Cella, Sharpe M., Chalder T. Measuring disability in patients with chronic fatigue syndrome: reliability and validity of the work and social adjustment scale, J Psychosom Res. 71,(3)(2011) 124-8.[47] C.D. Jenkins, Stanton B.-A., Niemcryk S.J., Rose R.M. A scale for the estimation of sleep problems in clinical research, Journal of clinical epidemiology. 41,(4)(1988) 313-21.[48] A. Zigmond, Snaith R. The Hospital Anxiety and Depression Scale, Acta Psychiatrica Scandinavica. 67,(6)(1983) 361-70.
21
[49] L.M. McCracken, Vowles K.E., Eccleston C. Acceptance of chronic pain: component analysis and a revised assessment method, Pain. 107,(1–2)(2004) 159-66.[50] K.E. Vowles, McCracken L.M., McLeod C., Eccleston C. The Chronic Pain Acceptance Questionnaire: Confirmatory factor analysis and identification of patient subgroups, PAIN. 140,(2)(2008) 284-91.[51] C. IBM. IBM SPSS Statistics for Windows. 21.0 ed. Armonk, NY: IBM Corp; 2012.[52] F. RA. Frequency distribution of the values of the correlation coefficient in samples of an indefinitely large population., Biometrika Biometrika Trust 10,(4)(1915) 507-21.[53] F. RA. On the 'probable error' of a co-efficient of correlation deduced from a small sample, Metron. 1(1921) 3-32.[54] B.L. Belza, Henke C.J., Yelin E.H., Epstein W.V., Gilliss C.L. Correlates of fatigue in older adults with rheumatoid arthritis, Nurs Res. 42,(2)(1993) 93-9.[55] G.J. Treharne, Lyons A.C., Hale E.D., Goodchild C.E., Booth D.A., Kitas G.D. Predictors of fatigue over 1 year among people with rheumatoid arthritis, Psychol Health Med. 13,(4)(2008) 494-504.[56] Nicklin J, Cramp F., Kirwan J., Greenwood R, Urban M, Hewlett S. Measuring fatigue in rheumatoid arthritis: a cross-sectional study to evaluate the bristol rheumatoid arthritis fatigue multi-dimensional questionnaire, visual analog scales, and numerical rating scales, Arthritis Care Res (Hoboken). 62(2010) 1559-68.[57] S. Hewlett, Chalder T., Choy E., Cramp F., Davis B., Dures E., et al. Fatigue in rheumatoid arthritis: time for a conceptual model, Rheumatology. 50,(6)(2011) 1004-6.[58] E. Dures, Hewlett S. Cognitive-behavioural approaches to self-management in rheumatic disease, Nat Rev Rheumatol. 8,(1759-4804 (Electronic))(2012) 553-9.[59] A.W. Evers, Kraaimaat F.W., van Riel P.L., de Jong A.J. Tailored cognitive-behavioral therapy in early rheumatoid arthritis for patients at risk: a randomized controlled trial, Pain. 100,(1)(2002) 141-53.[60] K. van Kessel, Moss-Morris R., Willoughby E., Chalder T., Johnson M.H., Robinson E. A randomized controlled trial of cognitive behavior therapy for multiple sclerosis fatigue, Psychosomatic medicine. 70,(2)(2008) 205-13.[61] M.F.M. Gielissen, Verhagen C.A.H.H.V.M., Bleijenberg G. Cognitive behaviour therapy for fatigued cancer survivors: long-term follow-up, Br J Cancer. 97,(5)(2007) 612-8.[62] S. Hewlett, Cockshott Z., Byron M., Kitchen K., Tipler S., Pope D., et al. Patients' perceptions of fatigue in rheumatoid arthritis: overwhelming, uncontrollable, ignored, Arthritis Rheum. 53,(5)(2005) 697-702.[63] R. Cairns, Hotopf M. A systematic review describing the prognosis of chronic fatigue syndrome, Occupational Medicine. 55,(1)(2005) 20-31.[64] S. Hewlett, Ambler N., Almeida C., Cliss A., Hammond A., Kitchen K., et al. Self-management of fatigue in rheumatoid arthritis: a randomised controlled trial of group cognitive-behavioural therapy, Annals of the Rheumatic Diseases. 70,(6)(2011) 1060-7.[65] L.M. McCracken, Vowles K.E., Eccleston C. Acceptance-based treatment for persons with complex, long standing chronic pain: a preliminary analysis of tretament outcome in comparison to a waiting phase, Behav Res Ther. 43(2005) 1335-46.[66] J.L. Rogers, Howard K.I., Vessey J.T. Using significance tests to evaluate equivalence between two experimental groups, Psychol Bull. 113,(3)(1993) 553-65.
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