Measuring substantial reductions in functioning in patients with chronic fatigue syndrome

Abstract:

PURPOSE: All the major current case definitions for chronic fatigue syndrome (CFS) specify substantial reductions in previous levels of occupational, educational, social, or personal activities to meet criteria. Difficulties have been encountered in operationalizing ‘substantial reductions.’ For example, the Medical Outcomes Study Short Form-36 Health Survey (SF-36) has been used to determine whether individuals met the CFS disability criterion. However, previous methods of using the SF-36 have been prone to including people without substantial reductions in key areas of physical functioning when diagnosing CFS. This study sought to empirically identify the most appropriate SF-36 subscales for measuring substantial reductions in patients with CFS.

METHOD: The SF-36 was administered to two samples of patients with CFS: one recruited from tertiary care and the other a community-based sample; as well as a non-fatigued control group. Receiver operating characteristics were used to determine the optimal cutoff scores for identifying patients with CFS.

RESULTS: The SF-36 Role-Emotional subscale had the worst sensitivity and specificity, whereas the Vitality, Role-Physical, and Social Functioning subscales had the best sensitivity and specificity.

CONCLUSION: Based on the evidence from this study, the potential criteria for defining substantial reductions in functioning and diagnosing CFS is provided.

© 2011 Informa UK, Ltd.

 

Source: Jason L, Brown M, Evans M, Anderson V, Lerch A, Brown A, Hunnell J, Porter N. Measuring substantial reductions in functioning in patients with chronic fatigue syndrome. Disabil Rehabil. 2011;33(7):589-98. doi: 10.3109/09638288.2010.503256. Epub 2010 Jul 9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3170036/ (Full article)

 

Employment status in chronic fatigue syndrome. A cross-sectional study examining the value of exercise testing and self-reported measures for the assessment of employment status

Abstract:

OBJECTIVE: To examine the value of exercise testing and self-reported disability for the assessment of employment status in patients with chronic fatigue syndrome.

DESIGN: Cross-sectional observational study.

SETTING: A university-based chronic fatigue clinic.

SUBJECTS: Fifty-four consecutive, Flemish, employed (not self-employed) chronic fatigue syndrome patients (49/54 female).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Participants were questioned about their current and premorbid employment status, filled in the Chronic Fatigue Syndrome Activities and Participation Questionnaire (CFS-APQ), the Medical Outcomes Short Form 36 Health Status Survey (SF-36), and performed a maximal exercise test on a bicycle ergometer with continuous monitoring of cardiorespiratory variables.

RESULTS: A significant association was observed between the current employment rate and two SF-36 subscales (i.e., role limitations due to physical functioning and social functioning; rho = 0.39 and 0.35 respectively) (n = 54). Analysing only the female chronic fatigue syndrome patients (n = 49), the current employment rate correlated significantly with the peak workload (rho = 0.38).

CONCLUSIONS: The associations between either exercise testing or self-reported disability and employment status are too weak to predict employment status.

 

Source: Nijs J, Van de Putte K, Louckx F, De Meirleir K. Employment status in chronic fatigue syndrome. A cross-sectional study examining the value of exercise testing and self-reported measures for the assessment of employment status. Clin Rehabil. 2005 Dec;19(8):895-9. http://www.ncbi.nlm.nih.gov/pubmed/16323389

 

A pilot randomized controlled trial of dexamphetamine in patients with chronic fatigue syndrome

Abstract:

This study determined whether dexamphetamine improved symptoms and quality of life in patients with chronic fatigue syndrome. The setting was a specialized clinic within a tertiary referral hospital. This was a 6-week parallel-group, placebo-controlled trial with random allocation. There was a 2-week dose-adjustment phase and a 4-week stable treatment period. Outcome measures were the Fatigue Severity Scale, the Medical Outcomes Study 36-item Short-Form Health Survey, and two patient-determined outcomes. Ten patients were randomly assigned to dexamphetamine, and 10 were assigned to placebo. Fatigue Severity Scale scores improved in nine of 10 dexamphetamine and four of 10 placebo patients. The change in mean score was statistically significant. There were large but statistically nonsignificant changes in scores for the Short-Form Health Survey domains vitality and physical functioning. Dexamphetamine may be useful in the management of chronic fatigue syndrome; a larger and longer trial is justified by these results.

 

Source: Olson LG, Ambrogetti A, Sutherland DC. A pilot randomized controlled trial of dexamphetamine in patients with chronic fatigue syndrome. Psychosomatics. 2003 Jan-Feb;44(1):38-43. http://www.ncbi.nlm.nih.gov/pubmed/12515836

 

Psychological correlates of functional status in chronic fatigue syndrome

Abstract:

BACKGROUND: The present study was designed to test a cognitive model of impairment in chronic fatigue syndrome (CFS) in which disability is a function of severity of fatigue and depressive symptoms, generalized somatic symptom attributions and generalized illness worry.

METHODS: We compared 45 CFS and 40 multiple sclerosis (MS) outpatients on measures of functional ability, fatigue severity, depressive symptoms, somatic symptom attribution and illness worry.

RESULTS: The results confirmed previous findings of lower levels of functional status and greater fatigue among CFS patients compared to a group of patients with MS. Fatigue severity was found to be a significant predictor of physical functioning but not of psychosocial functioning in both groups. In CFS, when level of fatigue was controlled, making more somatic attributions was associated with worse physical functioning, and both illness worry and depressive symptoms were associated with worse psychosocial functioning.

CONCLUSIONS: Our findings support the role of depression and illness cognitions in disability in CFS sufferers. Different cognitive factors account for physical and psychosocial disability in CFS and MS. The SF-36 may be sensitive to symptom attributions, suggesting caution in its interpretation when used with patients with ill-defined medical conditions.

 

Source: Taillefer SS, Kirmayer LJ, Robbins JM, Lasry JC. Psychological correlates of functional status in chronic fatigue syndrome. J Psychosom Res. 2002 Dec;53(6):1097-106. http://www.ncbi.nlm.nih.gov/pubmed/12479992

 

Health and functional status of twins with chronic regional and widespread pain

Erratum in: J Rheumatol. 2002 Dec;29(12):2667. Buchwald, Dedra [corrected to Buchwald, Debra].

 

Abstract:

OBJECTIVE: To examine the independent effects of chronic regional and widespread pain syndromes on health and functional status after accounting for comorbid chronic fatigue using a co-twin control design.

METHODS: We identified 95 twin pairs discordant for pain in which one twin had chronic regional or widespread pain and the other denied chronic pain. Demographic data, functional and psychological status, health behaviors, and symptoms based on the 1994 criteria for chronic fatigue syndrome (CFS) were assessed by questionnaire. Psychiatric diagnoses were based on structured interview. Random effects regression modeling estimated associations between chronic regional and widespread pain and each health measure with and without adjustment for CFS.

RESULTS: Significant differences (p </= 0.05) were found within twin pairs discordant for chronic regional and widespread pain, for general health perception, and physical and mental health functioning as measured by summary scores from the Short Form-36. In addition, differences were observed within pain discordant pairs in psychological distress as measured by the General Health Questionnaire as well as the number of psychiatric diagnoses. Adjustment for CFS eliminated the association between chronic pain and mental health, but the association between chronic pain and poor general health, physical functioning, and sleep quality persisted (p </= 0.01). Only the intra-pair difference in physical functioning distinguished twins with regional vs widespread pain (p </= 0.05).

CONCLUSION: Both chronic regional and widespread pain exact debilitating effects on perceived general health, physical functioning, and sleep quality independent of CFS. However, the psychological and psychiatric influence of chronic pain appears closely tied to CFS. Research should examine the additive role of CFS-like illnesses in patients with chronic pain, and its influence on treatment and outcome.

 

Source: Aaron LA, Arguelles LM, Ashton S, Belcourt M, Herrell R, Goldberg J, Smith WR, Buchwald D. Health and functional status of twins with chronic regional and widespread pain. J Rheumatol. 2002 Nov;29(11):2426-34. http://www.ncbi.nlm.nih.gov/pubmed/12415604

 

Immunological variables mediate cognitive dysfunction in gulf war veterans but not civilians with chronic fatigue syndrome

Abstract:

We explored the relationship between a set of immunological variables and a set of cognitive and functional status measures and a diagnosis of chronic fatigue syndrome (CFS) in civilians and veterans using various regression and factor analytic methods.

Our approach emphasized the extraction of a few distinct factors in order to limit statistical problems associated with doing large numbers of multiple comparisons. This approach led to our finding cytokine data grouping into type 1 and type 2 clusters. A type 2 cluster plus a T and B cell factor predicted CFS caseness for Gulf War veterans but not for civilians with CFS. When a cognitive variable, reaction time, was added into the model, both immunological factors lost statistical significance; this indicates that the cognitive variable reaction time moderated the effects of the immunological factors in predicting patient status.

We did a similar analysis on the roles of the immunological and cognitive variables in functional status using SF-36 data. Higher levels of these same two immunological factors predicted poorer general health as well as poorer physical and social functioning in Gulf War veterans but not in civilians with CFS. When the reaction time factor was added, only the lymphocyte factor remained significant. This implies that lymphocytes are directly related to functional status in Gulf War veterans with CFS, but the Th2 factor produces its effect on functional status via changes in cognitive abilities.

Copyright 2002 S. Karger AG, Basel

 

Source: Brimacombe M, Zhang Q, Lange G, Natelson B. Immunological variables mediate cognitive dysfunction in gulf war veterans but not civilians with chronic fatigue syndrome. Neuroimmunomodulation. 2002-2003;10(2):93-100. http://www.ncbi.nlm.nih.gov/pubmed/12372983

 

Health-related quality of life in patients with chronic fatigue syndrome: an international study

Abstract:

OBJECTIVE: Chronic fatigue syndrome (CFS) has been reported worldwide. Our objectives were to determine if patients from different countries have similar profiles of impairments.

METHODS: Health-related quality of life (HRQoL) was assessed in 740 CFS patients in the US, 82 in the UK, and 65 in Germany using the eight subscales of the Short-Form General Health Survey (SF-36). To examine the internal structure, factor analyses were performed.

RESULTS: Overall, there was a remarkable similarity in HRQoL among all CFS patients, regardless of location. Patients scored two to three standard deviations below normal on six subscales and one standard deviation below normal on the other two subscales. Factor analysis suggested a two-factor model where the same six subscales constitute the first factor and the two others the second factor.

CONCLUSION: HRQoL is poor in CFS patients from three countries. This study is a first step towards conducting further comparative cross-cultural and international studies.

 

Source: Hardt J, Buchwald D, Wilks D, Sharpe M, Nix WA, Egle UT. Health-related quality of life in patients with chronic fatigue syndrome: an international study. J Psychosom Res. 2001 Aug;51(2):431-4. http://www.ncbi.nlm.nih.gov/pubmed/11516765

 

Relationship of brain MRI abnormalities and physical functional status in chronic fatigue syndrome

Abstract:

Chronic Fatigue Syndrome (CFS) is an unexplained illness that is characterized by severe fatigue. Some have suggested that CFS is a “functional somatic syndrome” in which symptoms of fatigue are inappropriately attributed to a serious illness. However, brain magnetic resonance imaging (MRI) data suggest that there may be an organic abnormality associated with CFS.

To understand further the significance of brain MRI abnormalities, we examined the relationship between MRI identified brain abnormalities and self-reported physical functional status in 48 subjects with CFS who underwent brain MR imaging and completed the Medical Outcomes Study SF-36. Brain MR images were examined for the presence of abnormalities based on 5 general categories previously shown to be sensitive to differentiating CFS patients from healthy controls.

There were significant negative relationships between the presence of brain abnormalities and both the physical functioning (PF) (rho=-.31, p=.03), and physical component summary PCS (rho=-.32, p=.03) subscales of the SF-36. CFS patients with MRI identified brain abnormalities scored significantly lower on both PF (t(1,46) =2.3, p=.026) and the PCS (t(1,41) =2.4, p=.02) than CFS subjects without an identified brain abnormality. When adjusted for age differences only the PF analysis remained significant. However, the effect sizes for both analyses were large indicating meaningful differences in perceived functional status between the groups.

These results demonstrate that the presence of brain abnormalities in CFS are significantly related to subjective reports of physical function and that CFS subjects with MRI brain abnormalities report being more physically impaired than those patients without brain abnormalities.

 

Source: Cook DB, Lange G, DeLuca J, Natelson BH. Relationship of brain MRI abnormalities and physical functional status in chronic fatigue syndrome. Int J Neurosci. 2001 Mar;107(1-2):1-6. http://www.ncbi.nlm.nih.gov/pubmed/11328679

 

Randomised controlled trial of patient education to encourage graded exercise in chronic fatigue syndrome

Abstract:

OBJECTIVE: To assess the efficacy of an educational intervention explaining symptoms to encourage graded exercise in patients with chronic fatigue syndrome.

DESIGN: Randomised controlled trial.

SETTING: Chronic fatigue clinic and infectious diseases outpatient clinic.

SUBJECTS: 148 consecutively referred patients fulfilling Oxford criteria for chronic fatigue syndrome.

INTERVENTIONS: Patients randomised to the control group received standardised medical care. Patients randomised to intervention received two individual treatment sessions and two telephone follow up calls, supported by a comprehensive educational pack, describing the role of disrupted physiological regulation in fatigue symptoms and encouraging home based graded exercise. The minimum intervention group had no further treatment, but the telephone intervention group received an additional seven follow up calls and the maximum intervention group an additional seven face to face sessions over four months.

MAIN OUTCOME MEASURE: A score of >/=25 or an increase of >/=10 on the SF-36 physical functioning subscale (range 10 to 30) 12 months after randomisation.

RESULTS: 21 patients dropped out, mainly from the intervention groups. Intention to treat analysis showed 79 (69%) of patients in the intervention groups achieved a satisfactory outcome in physical functioning compared with two (6%) of controls, who received standardised medical care (P<0.0001). Similar improvements were observed in fatigue, sleep, disability, and mood. No significant differences were found between the three intervention groups.

CONCLUSIONS: Treatment incorporating evidence based physiological explanations for symptoms was effective in encouraging self managed graded exercise. This resulted in substantial improvement compared with standardised medical care.

Comment in:

Patient education to encourage graded exercise in chronic fatigue syndrome. Trial has too many shortcomings. [BMJ. 2001]

ACP J Club. 2001 Sep-Oct;135(2):46.

 

Source: Powell P, Bentall RP, Nye FJ, Edwards RH. Randomised controlled trial of patient education to encourage graded exercise in chronic fatigue syndrome. BMJ. 2001 Feb 17;322(7283):387-90. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC26565/ (Full article)

Comparison of Euroqol EQ-5D and SF-36 in patients with chronic fatigue syndrome

Abstract:

The objective of the study was to compare the Euroqol EQ-5D (Euroqol) and short-form 36 (SF-36) health questionnaires in patients with chronic fatigue syndrome (CFS).

One hundred and twenty-seven outpatients referred to a hospital-based infectious disease clinic with a diagnosis of CFS were contacted by post and asked to complete both questionnaires. Additional data were determined from hospital casenotes. Eighty-five patients returned correctly completed questionnaires.

Euroqol health values and visual analogue scale (VAS) scores were strongly and significantly correlated with all dimensions of the SF-36, with the exception of physical limitation of role. SF-36 dimensions were in turn strongly and significantly correlated with each other, with the same exception.

Patients reported a high degree of physical disability and a moderate degree of emotional or psychological ill-health. The Euroqol elements dealing with mobility and self-care referred to inappropriately severe degrees of disability for these patients with CFS. Similarly some dimensions in the SF-36 were oversensitive and did not discriminate between patients with moderate or severe disability.

It was concluded that Euroqol scores correlated strongly with SF-36 scores and provided useful information about patients with CFS and that Euroqol would be a useful tool for the rapid assessment of health status in CFS. The current Euroqol instrument refers to inappropriately severe degrees of disability for patients with CFS and would need to be modified to be maximally useful in this situation.

 

Source: Myers C, Wilks D. Comparison of Euroqol EQ-5D and SF-36 in patients with chronic fatigue syndrome. Qual Life Res. 1999;8(1-2):9-16. http://www.ncbi.nlm.nih.gov/pubmed/10457734