Category: Methodology

Minimum data elements for research reports on CFS

Abstract:

Chronic fatigue syndrome (CFS) is a debilitating condition that has received increasing attention from researchers in the past decade. However, it has become difficult to compare data collected in different laboratories due to the variability in basic information regarding descriptions of sampling methods, patient characteristics, and clinical assessments. The issue of variability in CFS research was recently highlighted at the NIH’s 2011 State of the Knowledge of CFS meeting prompting researchers to consider the critical information that should be included in CFS research reports.

To address this problem, we present our consensus on the minimum data elements that should be included in all CFS research reports, along with additional elements that are currently being evaluated in specific research studies that show promise as important patient descriptors for subgrouping of CFS. These recommendations are intended to improve the consistency of reported methods and the interpretability of reported results. Adherence to minimum standards and increased reporting consistency will allow for better comparisons among published CFS articles, provide guidance for future research and foster the generation of knowledge that can directly benefit the patient.

Copyright © 2012 Elsevier Inc. All rights reserved.

 

Source: Jason LA, Unger ER, Dimitrakoff JD, Fagin AP, Houghton M, Cook DB, Marshall GD Jr, Klimas N, Snell C. Minimum data elements for research reports on CFS. Brain Behav Immun. 2012 Mar;26(3):401-6. doi: 10.1016/j.bbi.2012.01.014. Epub 2012 Jan 28. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4643273/ (Full article)

 

Validation of the three-factor model of the PSQI in a large sample of chronic fatigue syndrome (CFS) patients

Abstract:

OBJECTIVE: To evaluate whether a 3-factor model of the Pittsburgh Sleep Quality Index (PSQI) scale would fit the constellation of sleep disturbances in patients with a diagnosis of chronic fatigue syndrome (CFS).

METHODS: Consecutive CFS patients filled out the PSQI. Scores from this self-report questionnaire were examined with exploratory and confirmatory factor analysis (CFA).

RESULTS: 413 CFS patients were included for analysis in this study. CFA showed that the 7 PSQI component scores clustered into the 3 factors reported by Cole et al. (2006), i.e. Sleep Efficiency, Perceived Sleep Quality and Daily Disturbances. In contrast with the single-factor and all 2-factor models, all factor loadings were significant, and all goodness-of-fit values were acceptable.

CONCLUSION: In CFS, the PSQI operates as a 3-factor scoring model as initially seen in healthy and depressed older adults. The separation into 3 discrete factors suggests the limited usefulness of the global PSQI as a single factor for the assessment of subjective sleep quality, as also evidenced by a low Cronbach’s alpha (0.64) in this patient sample.

Copyright © 2011 Elsevier Inc. All rights reserved.

 

Source: Mariman A, Vogelaers D, Hanoulle I, Delesie L, Tobback E, Pevernagie D. Validation of the three-factor model of the PSQI in a large sample of chronic fatigue syndrome (CFS) patients. J Psychosom Res. 2012 Feb;72(2):111-3. doi: 10.1016/j.jpsychores.2011.11.004. Epub 2011 Dec 22. https://www.ncbi.nlm.nih.gov/pubmed/22281451

 

Factor analysis of the Beck Depression Inventory-II with patients with chronic fatigue syndrome

Abstract:

This study examined the properties of the Beck Depression Inventory-II (BDI-II) in a sample of 111 patients with chronic fatigue syndrome (CFS). Exploratory factor analysis identified two factors. The mean score for the Somatic-Affective factor was significantly higher than the Cognitive factor. Convergent and discriminant validity were assessed for BDI-II total score, the two factor scores, and the BDI for Primary Care (BDI-PC). The BDI-PC and Cognitive factor demonstrated superior validity. Results suggest patients endorse BDI-II somatic items that overlap with CFS symptoms at a high rate. Factor scores should be evaluated separately, or the BDI-PC should be utilized with this population.

 

Source: Brown M, Kaplan C, Jason L. Factor analysis of the Beck Depression Inventory-II with patients with chronic fatigue syndrome. J Health Psychol. 2012 Sep;17(6):799-808. doi: 10.1177/1359105311424470. Epub 2011 Nov 21. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655435/ (Full article)

 

Fatigue Scales and Chronic Fatigue Syndrome: Issues of Sensitivity and Specificity

Abstract:

Few studies have explored issues of sensitivity and specificity for using the fatigue construct to identify patients meeting chronic fatigue syndrome (CFS) criteria. In this article, we examine the sensitivity and specificity of several fatigue scales that have attempted to define severe fatigue within CFS. Using Receiver Operating Characteristic (ROC) curve analysis, we found most scales and sub-scales had either significant specificity and/or sensitivity problems.

However, the post-exertional subscale of the ME/CFS Fatigue Types Questionnaire (Jason, Jessen, et al., 2009) was the most promising in terms of specificity and sensitivity. Among the more traditional fatigue scales, Krupp, LaRocca, Muir-Nash, and Steinberg’s (1989) Fatigue Severity Scale had the best ability to differentiate CFS from healthy controls. Selecting questions, scales and cut off points to measure fatigue must be done with extreme care in order to successfully identify CFS cases.

 

Source: Jason LA, Evans M, Brown M, Porter N, Brown A, Hunnell J, Anderson V, Lerch A. Fatigue Scales and Chronic Fatigue Syndrome: Issues of Sensitivity and Specificity. Disabil Stud Q. 2011 Winter;31(1). Pii: 1375. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181109/ (Full article)

 

Measuring disability in patients with chronic fatigue syndrome: reliability and validity of the Work and Social Adjustment Scale

Abstract:

BACKGROUND: Disability is a defining feature of chronic conditions, and it is an increasingly used measure of therapy effectiveness. The Work and Social Adjustment Scale (WSAS) is a simple and clear measure of disability. Although the scale is widely used, no study has yet investigated its psychometric properties in patients with chronic fatigue syndrome (CFS).

METHODS: Data from two samples of patients were used, one from a multicenter randomized controlled clinical trial of treatments for CFS (n =639) and the other from a clinic that specializes in CFS (n=384). All patients completed the WSAS as well as other measures.

RESULTS: Internal consistency and the Spearman-Brown split-half coefficient values indicated that the scale is reliable. CFS patients who had comorbid diagnoses of depression, anxiety or fibromyalgia had higher WSAS scores. High levels of disability were associated with high number of physical symptoms, severe fatigue, depression, anxiety, poor sleep quality and poor physical fitness, with correlation coefficients ranging between 0.41 and 0.11. Lower scores on the WSAS were modestly associated with better physical functioning as well as higher levels of physical capacity as assessed by a walking test. Sensitivity to change was evaluated in a subgroup of patients who had undergone a course of cognitive behavioral therapy. Disability significantly decreased after therapy and remained stable at follow-ups.

CONCLUSION: The WSAS is a reliable and valid assessment tool for disability in patients with CFS.

Copyright © 2011 Elsevier Inc. All rights reserved.

 

Source: Cella M, 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. 2011 Sep;71(3):124-8. doi: 10.1016/j.jpsychores.2011.02.009. Epub 2011 Apr 3. https://www.ncbi.nlm.nih.gov/pubmed/21843745

 

Multi-source synthesis of data to inform health policy

Abstract:

OBJECTIVES: To propose a new method for comparing and integrating original qualitative data with systematic reviews of quantitative and qualitative studies, demonstrated by a study of the psychosocial needs of chronic fatigue syndrome (CFS) sufferers in Québec.

METHODS: A systematic literature review was performed across various databases for English and French language studies, on the psychosocial aspects of CFS. Qualitative, quantitative, and mixed method studies published between January 1994 and July 2008 were included. Unpublished literature and reference lists of included studies were also searched. Themes identified in the literature were used to guide semi-structured interviews with seventeen CFS-sufferers, mostly recruited from a large specialist practice in Montreal. Interviews were transcribed verbatim and validated by a research assistant. Transcripts were coded using the identified themes. New codes were created when new issues arose. All themes were subsequently synthesized into overall categories using a constant comparative method.

RESULTS: The literature search yielded thirty-one papers: twenty-eight primary studies and three systematic reviews. Twelve themes were identified and synthesized into four overall problem categories, such as “Lack of professional recognition.” Interviews confirmed findings from the literature, but also revealed unidentified needs specific to CFS-sufferers in Québec. Policy recommendations were provided to address these needs.

CONCLUSIONS: Multi-Source Synthesis provides a systematic method for synthesizing data from original studies with literature findings, thereby broadening the knowledge base and the local relevance of decisions concerning specific patient populations.

 

Source: Pedersen VH, Dagenais P, Lehoux P. Multi-source synthesis of data to inform health policy. Int J Technol Assess Health Care. 2011 Jul;27(3):238-46. doi: 10.1017/S0266462311000213. Epub 2011 Jul 8. https://www.ncbi.nlm.nih.gov/pubmed/21736858

 

Reliability and validity of Short Form 36 Version 2 to measure health perceptions in a sub-group of individuals with fatigue

Abstract:

PURPOSE: To determine the validity and reliability of Short Form 36 Version 2 (SF36v2) in sub-groups of individuals with fatigue.

METHOD: Thirty subjects participated in this study, including n = 16 subjects who met case definition criteria for chronic fatigue syndrome (CFS) and n = 14 non-disabled sedentary matched control subjects. SF36v2 and Multidimensional Fatigue Inventory (MFI-20) were administered before two maximal cardiopulmonary exercise tests (CPETs) administered 24 h apart and an open-ended recovery questionnaire was administered 7 days after CPET challenge. The main outcome measures were self-reported time to recover to pre-challenge functional and symptom status, frequency of post-exertional symptoms and SF36v2 sub-scale scores.

RESULTS: Individuals with CFS demonstrated significantly lower SF36v2 and MFI-20 sub-scale scores prior to CPET. Between-group differences remained significant post-CPET, however, there were no significant group by test interaction effects. Subjects with CFS reported significantly more total symptoms (p < 0.001), as well as reports of fatigue (p < 0.001), neuroendocrine (p < 0.001), immune (p < 0.01), pain (p < 0.01) and sleep disturbance (p < 0.01) symptoms than control subjects as a result of CPET. Many symptom counts demonstrated significant relationships with SF36v2 sub-scale scores (p < 0.05). SF36v2 and MFI-20 sub-scale scores demonstrated significant correlations (p < 0.05). Various SF36v2 sub-scale scores demonstrated significant predictive validity to identify subjects who recovered from CPET challenge within 1 day and 7 days (p < 0.05). Potential floor effects were observed for both questionnaires for individuals with CFS.

CONCLUSION: Various sub-scales of SF36v2 demonstrated adequate reliability and validity for clinical and research applications. Adequacy of sensitivity to change of SF36v2 as a result of a fatiguing stressor should be the subject of additional study.

 

Source: Davenport TE, Stevens SR, Baroni K, Van Ness JM, Snell CR. Reliability and validity of Short Form 36 Version 2 to measure health perceptions in a sub-group of individuals with fatigue. Disabil Rehabil. 2011;33(25-26):2596-604. doi: 10.3109/09638288.2011.582925. Epub 2011 Jun 20. https://www.ncbi.nlm.nih.gov/pubmed/21682669

 

Quality and acceptability of patient-reported outcome measures used in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review

Abstract:

PURPOSE: To review the quality and acceptability of condition-specific, domain-specific and generic multi-item patient-reported outcome measures (PROMs) used in the assessment of adults with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME).

METHODS: Systematic literature searches were made to identify PROMs. Quality and acceptability was assessed against an appraisal framework, which captured evidence of both the thoroughness and results of evaluations: evidence of measurement (reliability, validity, responsiveness, interpretability, data quality/precision) and practical properties (feasibility, patient acceptability), and the extent of active patient involvement was sought.

RESULTS: A total of 11 CFS/ME-specific, 55 domain-specific and 11 generic measures were reviewed. With the exception of the generic SF-36, all measures had mostly limited evidence of measurement and/or practical properties. Patient involvement was poorly reported and often cursory.

CONCLUSIONS: The quality and acceptability of reviewed PROMs is limited, and recommendations for patient-reported assessment are difficult. Significant methodological and quality issues in PROM development/evaluation were identified by the appraisal framework, which must be addressed in future research. Clear discrepancies exist between what is measured in research and how patients define their experience of CFS/ME. Future PROM development/evaluation must seek to involve patients more collaboratively to measure outcomes of importance using relevant and credible methods of assessment.

 

Source: Haywood KL, Staniszewska S, Chapman S. Quality and acceptability of patient-reported outcome measures used in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review. Qual Life Res. 2012 Feb;21(1):35-52. doi: 10.1007/s11136-011-9921-8. Epub 2011 May 18. https://www.ncbi.nlm.nih.gov/pubmed/21590511

 

Classifying medication use in clinical research

Abstract:

BACKGROUND: Medication use data are usually collected in clinical research. Yet no standardized method for categorizing these exists, either for sample description or for the study of medication use as a variable.

OBJECTIVE: The present investigation was designed to develop a simple, empirically based classification scheme for medication use categorization.

METHOD: The authors used factor analysis to reduce the number of possible medication groupings. This permitted a pattern of medication usage to emerge that appeared to characterize specific clinical constellations. To illustrate the technique’s potential, the authors applied this classification system to samples where sleep disorders are prominent: chronic fatigue syndrome and sleep apnea.

RESULTS: The authors’ classification approach resulted in 5 factors that appear to cohere in a logical fashion. These were labeled Cardiovascular or Metabolic Syndrome Medication, Symptom Relief Medication, Psychotropic Medication, Preventative Medication, and Hormonal Medication.

CONCLUSIONS: The findings show that medication profile varies according to clinical sample. The medication profile for participants with sleep apnea reflects known comorbid conditions; the medication profile associated with chronic fatigue syndrome appears to reflect the common perception of this condition as a psychogenic disorder.

 

Source: Rizzo D, Creti L, Bailes S, Baltzan M, Grad R, Amsel R, Fichten CS, Libman E. Classifying medication use in clinical research. J Prim Care Community Health. 2011 Jan 1;2(1):26-32. doi: 10.1177/2150131910385843. Epub 2010 Oct 27. https://www.ncbi.nlm.nih.gov/pubmed/23804659

 

Measuring fatigue in clinical and community settings

Abstract:

OBJECTIVE: The Chalder Fatigue Scale (CFQ) is a widely used instrument to assess fatigue in both clinical and nonclinical settings. Psychometric properties of the scale and discriminative abilities were examined.

METHODS: A total of 361 patients with CFS and 1615 individuals in the community were assessed with the CFQ. Principal component analysis (PCA) was used to explore the structure of the scale. Receiver-operating characteristic curve (ROC) was used to investigate the discriminative properties.

RESULTS: Two components, physical and mental fatigue, were identified in the CFS patient group and in the general population samples. Area under the curve for ROC was .91. The fatigue scale effectively discriminates, at high scores, between CFS patients and the general population.

CONCLUSION: Physical and mental fatigue are clearly separable components of fatigue. The CFQ can discriminate reliably between clinical and nonclinical conditions.

Copyright (c) 2010 Elsevier Inc. All rights reserved.

 

Source: Cella M, Chalder T. Measuring fatigue in clinical and community settings. J Psychosom Res. 2010 Jul;69(1):17-22. doi: 10.1016/j.jpsychores.2009.10.007. Epub 2009 Dec 11. https://www.ncbi.nlm.nih.gov/pubmed/20630259