Exploratory study into the relationship between the symptoms of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) and fibromyalgia (FM) using a quasiexperimental design

Abstract:

Objective: To explore the relationship between symptoms of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) and fibromyalgia (FM). The hypothesis predicated that there would be no significant differences between the group’s symptom experience.

Design: A quasiexperimental design. Structural equation modelling (SEM) and invariance testing.

Participants: Males (M) and females (F) >16 with a confirmed diagnosis of CFS/ME or FM by a general practitioner or specialist. CFS/ME (n=101, F: n=86, M: n=15, mean (M) age M=45.5 years). FM (n=107, F: n=95, M: n=12, M=47.2 years).

Outcome measures: Diagnostic criteria: the American Centers for Disease Control and Prevention (CDC) for CFS/ME and the American College of Rheumatology (ACR) criteria for FM. Additional symptom questionnaires measuring: pain, sleep quality, fatigue, quality of life, anxiety and depression, locus of control and self-esteem.

Results: Invariance was confirmed with the exception of the American CDC Symptom Inventory, Fibromyalgia Impact Questionnaire and Hospital Anxiety and Depression Scale (p<0.05) based on five questions. Consequently, it was erroneous to conclude differences. Therefore, the Syndrome Model was created. SEM could not have tested the ACR previously, as it comprised a single data point. Thus, it was combined with these three questionnaires, increasing the data points, to create this new measurable model. Results confirmed no significant differences between groups (p=0.07 (p<0.05)).

Conclusion: Participants responded in a similar manner to the questionnaire, confirming the same symptom experience. It is important to consider this in context with differing criteria and management guidelines, as this may influence diagnosis and the trajectory of patient’s management. With the biomedical cause currently unclear, it is the symptom experience and the impact on quality of life that is important. These findings are meaningful for patients, clinicians and policy development and support the requirement for future research.

Source: Mckay PG, Walker H, Martin CR, Fleming M. Exploratory study into the relationship between the symptoms of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) and fibromyalgia (FM) using a quasiexperimental design. BMJ Open. 2021 Feb 1;11(2):e041947. doi: 10.1136/bmjopen-2020-041947. PMID: 33526500. https://bmjopen.bmj.com/content/11/2/e041947.long (Full text)

Systematic Review of Primary Outcome Measurements for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) in Randomized Controlled Trials

Abstract:

Background: Due to its unknown etiology, the objective diagnosis and therapeutics of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) are still challenging. Generally, the patient-reported outcome (PRO) is the major strategy driving treatment response because the patient is the most important judge of whether changes are meaningful.

Methods: In order to determine the overall characteristics of the main outcome measurement applied in clinical trials for CFS/ME, we systematically surveyed the literature using two electronic databases, PubMed and the Cochrane Library, throughout June 2020. We analyzed randomized controlled trials (RCTs) for CFS/ME focusing especially on main measurements.

Results: Fifty-two RCTs out of a total 540 searched were selected according to eligibility criteria. Thirty-one RCTs (59.6%) used single primary outcome and others adapted ≥2 kinds of measurements. In total, 15 PRO-derived tools were adapted (50 RCTs; 96.2%) along with two behavioral measurements for adolescents (4 RCTs; 7.7%). The 36-item Short Form Health Survey (SF-36; 16 RCTs), Checklist Individual Strength (CIS; 14 RCTs), and Chalder Fatigue Questionnaire (CFQ; 11 RCTs) were most frequently used as the main outcomes. Since the first RCT in 1996, Clinical Global Impression (CGI) and SF-36 have been dominantly used each in the first and following decade (26.1% and 28.6%, respectively), while both CIS and Multidimensional Fatigue Inventory (MFI) have been the preferred instruments (21.4% each) in recent years (2016 to 2020).

Conclusions: This review comprehensively provides the choice pattern of the assessment tools for interventions in RCTs for CFS/ME. Our data would be helpful practically in the design of clinical studies for CFS/ME-related therapeutic development.

Source: Kim DY, Lee JS, Son CG. Systematic Review of Primary Outcome Measurements for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) in Randomized Controlled Trials. J Clin Med. 2020 Oct 28;9(11):E3463. doi: 10.3390/jcm9113463. PMID: 33126460. https://pubmed.ncbi.nlm.nih.gov/33126460/

Paediatric patients with myalgic encephalomyelitis/chronic fatigue syndrome value understanding and help to move on with their lives

Abstract:

AIM: The aim of this study was to document qualitative questionnaire feedback regarding management from a cohort observational study of young people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

METHODS: Between 1991 and 2009, 784 paediatric patients, age 6-18 years, were diagnosed with ME/CFS following referral to a specialised clinic at the Royal Children’s Hospital, Melbourne. Over a 14-year period, feedback was requested on up to seven occasions. Management included the following: symptom management and a self-management lifestyle plan that included social, educational, physical and a pleasurable activity outside of home. They adjusted it by severity of illness, stage of education, family circumstances and life interests.

RESULTS: Questionnaires were returned from 626 (80%) with 44% providing feedback more than once. They reported that their management plan allowed them to regain control over their lives. They cited early diagnosis, empathetic, informed physicians, self-management strategies and educational liaison as helping them to function and remain socially engaged. Ongoing support, particularly assistance to navigate the education system, was essential for general well-being and ability to cope.

CONCLUSION: Young people valued regaining the control over their lives that was lost through illness, support to maintain social contacts and assistance to achieve educational and/or life goals.

© 2019 The Authors. Acta Paediatrica published by John Wiley & Sons Ltd on behalf of Foundation Acta Paediatrica.

Source: Rowe K. Paediatric patients with myalgic encephalomyelitis/chronic fatigue syndrome value understanding and help to move on with their lives. Acta Paediatr. 2019 Dec 18. doi: 10.1111/apa.15054. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31854020

Psychometric properties of the PROMIS® Fatigue Short Form 7a among adults with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

PURPOSE: To evaluate the psychometric properties of the Patient-Reported Outcome Measurement Information System® Fatigue Short Form 7a (PROMIS F-SF) among people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

METHODS: Analyses were conducted using data from the Multi-Site Clinical Assessment of ME/CFS study, which recruited participants from seven ME/CFS specialty clinics across the US. Baseline and follow-up data from ME/CFS participants and healthy controls were used. Ceiling/Floor effects, internal consistency reliability, differential item functioning (DIF), known-groups validity, and responsiveness were examined.

RESULTS: The final sample comprised 549 ME/CFS participants at baseline, 386 of whom also had follow-up. At baseline, the sample mean of PROMIS F-SF T-score was 68.6 (US general population mean T-score of 50 and standard deviation of 10). The PROMIS F-SF demonstrated good internal consistency reliability (Cronbach’s α = 0.84) and minimal floor/ceiling effects. No DIF was detected by age or sex for any item. This instrument also showed good known-groups validity with medium-to-large effect sizes (η2 = 0.08-0.69), with a monotonic increase of the fatigue T-score across ME/CFS participant groups with low, medium, and high functional impairment as measured by three different variables (p < 0.01), and with significantly higher fatigue T-scores among ME/CFS participants than healthy controls (p < 0.0001). Acceptable responsiveness was found with small-to-medium effect sizes (Guyatt’s Responsiveness Statistic = 0.28-0.54).

CONCLUSIONS: Study findings support the reliability and validity of PROMIS F-SF as a measure of fatigue for ME/CFS and lend support to the drug development tool submission for qualifying this measure to evaluate therapeutic effect in ME/CFS clinical trials.

Source: Yang M, Keller S, Lin JS. Psychometric properties of the PROMIS® Fatigue Short Form 7a among adults with myalgic encephalomyelitis/chronic fatigue syndrome. Qual Life Res. 2019 Sep 10. doi: 10.1007/s11136-019-02289-4. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31506915

Symptom frequency and development of a generic functional disorder symptom scale suitable for use in studies of patients with irritable bowel syndrome, fibromyalgia syndrome or chronic fatigue syndrome

Abstract:

OBJECTIVES: To describe the extent to which irritable bowel syndrome (IBS), fibromyalgia syndrome (FMS), and chronic fatigue syndrome (CFS) exhibit symptom overlap, and to validate a patient-derived, generic symptom questionnaire.

METHODS: A patient-derived 61-item symptom-frequency questionnaire was completed by participants recruited through IBS, FMS and CFS self-help websites. Principal axis factor analysis with oblimin rotation was performed separately for those reporting an IBS, FMS or CFS diagnosis.

RESULTS: Questionnaires were completed by 1751 participants of whom 851 reported more than one of the three diagnoses. Stomach pain on at least a weekly basis was reported by 79% of IBS, 52% of FMS, and 43% of CFS single diagnosis participants. Pain increasing the day after activity was reported by 32% of IBS, 94% of FMS, and 85% of CFS single diagnosis participants. Waking still tired at least once weekly was reported by 75% of IBS, 97% of FMS, and 95% of CFS single diagnosis participants. Exploratory factor analysis produced consistent results across all three diagnostic groups, the 61 items loading on 12 correlated factors with a single higher order factor on which all items loaded. Frequency analysis led to the rejection of one item (cold sores on or near lips), and freeform reporting by participants of additional symptoms identified an additional five, namely, restless legs, hair loss/brittle hair/thinning, dizziness/balance problems, blurred vision and urination problems.

CONCLUSIONS: IBS, FMS and CFS are polysymptomatic spectrum disorders with a wide range of overlapping symptoms, many of which are unrelated to diagnostic criteria. Frequency analysis and factor analysis confirm the validity of using the same questionnaire across different diagnostic categories. The 65-item general symptom questionnaire (GSQ-65) is a valid generic symptom scale suitable for assessing the many different symptoms of people with IBS, FMS and CFS.

Source: Hyland ME, Bacon AM, Lanario JW, Davies AF. Symptom frequency and development of a generic functional disorder symptom scale suitable for use in studies of patients with irritable bowel syndrome, fibromyalgia syndrome or chronic fatigue syndrome. Chronic Dis Transl Med. 2019 Jun 24;5(2):129-138. doi: 10.1016/j.cdtm.2019.05.003. eCollection 2019 Jun. https://www.sciencedirect.com/science/article/pii/S2095882X18300987?via%3Dihub (Full article)

The Development of the DePaul Symptom Questionnaire: Original, Expanded, Brief, and Pediatric Versions

Abstract:

One of the key requirements of a reliable case definition is the use of standardized procedures for assessing symptoms. This article chronicles the development of the DePaul Symptom Questionnaire (DSQ) to assess symptoms of the major chronic fatigue syndrome (CFS) and myalgic encephalomyelitis (ME) case definitions.

The original questionnaire has been modified and expanded over time to more fully capture symptoms from various adult case definitions, and a brief as well as pediatric version have also been developed. The DSQ has demonstrated very good psychometric properties in terms of test-retest reliability and sensitivity/specificity, as well as construct, predictive, and discriminant validity. The DSQ allows for a clear characterization of a patient’s illness and allows scientists and clinicians to improve diagnostic reliability and validity when employing case definitions of ME and CFS.

Source: Jason LA, Sunnquist M. The Development of the DePaul Symptom Questionnaire: Original, Expanded, Brief, and Pediatric Versions. Front Pediatr. 2018 Nov 6;6:330. doi: 10.3389/fped.2018.00330. eCollection 2018.  https://www.ncbi.nlm.nih.gov/pubmed/30460215

Test-Retest Reliability of the DePaul Symptom Questionnaire

Abstract:

BACKGROUND: The DePaul Symptom Questionnaire (DSQ) was developed to provide a structured approach for collecting standardized symptomatology and health history information to allow researchers and clinicians to determine whether a patient meets the diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), myalgic encephalomyelitis (ME), and/or chronic fatigue syndrome (CFS).

PURPOSE: The purpose of this study was to examine the test-retest reliability of the DSQ.

METHODS: Test-retest reliability of the measure was examined with a sample of 26 adults self-identifying as having either ME/CFS, ME and/or CFS and 25 adults who did not self-identify as having these illnesses and were otherwise healthy controls.

RESULTS: Overall, the majority of items on the DSQ exhibited good to excellent test-retest reliability, with Pearson’s or kappa correlation coefficients that were 0.70 or higher.

CONCLUSIONS: Thus, the present study suggests that the DSQ is a reliable diagnostic measure that can provide a standardized way of examining illness constructs and symptomatology among patients who identify as having ME/CFS, ME and/or CFS.

 

Source: Jason LA, So S, Brown AA, Sunnquist M, Evans M. Test-Retest Reliability of the DePaul Symptom Questionnaire. Fatigue. 2015 Jan 1;3(1):16-32. Epub 2015 Jan 8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4788471/ (Full article)

 

Assessment of activity limitations and participation restrictions with persons with chronic fatigue syndrome: a systematic review

Abstract:

PURPOSE: To summarize measurement instruments used to evaluate activity limitations and participation restrictions in patients with chronic fatigue syndrome (CFS) and review the psychometric properties of these instruments.

METHOD: General information of all included measurement instruments was extracted. The methodological quality was evaluated using the COSMIN checklist. Results of the measurement properties were rated based on the quality criteria of Terwee et al. Finally, overall quality was defined per psychometric property and measurement instrument by use of the quality criteria by Schellingerhout et al.

RESULTS: A total of 68 articles were identified of which eight evaluated the psychometric properties of a measurement instrument assessing activity limitations and participation restrictions. One disease-specific and 37 generic measurement instruments were found. Limited evidence was found for the psychometric properties and clinical usability of these instruments. However, the CFS-activities and participation questionnaire (APQ) is a disease-specific instrument with moderate content and construct validity.

CONCLUSION: The psychometric properties of the reviewed measurement instruments to evaluate activity limitations and participation restrictions are not sufficiently evaluated. Future research is needed to evaluate the psychometric properties of the measurement instruments, including the other properties of the CFS-APQ. If it is necessary to use a measurement instrument, the CFS-APQ is recommended.

IMPLICATIONS FOR REHABILITATION: Chronic fatigue syndrome (CFS). Chronic fatigue syndrome causes activity limitations and participation restrictions in one or more areas of life. Standardized, reliable and valid measurement instruments are necessary to identify these limitations and restrictions. Currently, no measurement instrument is sufficiently evaluated with persons with CFS. If a measurement instrument is needed to identify activity limitations and participation restrictions with persons with CFS, it is recommended to use the CFS-APQ in clinical practice and scientific research.

 

Source: Vergauwen K, Huijnen IP, Kos D, Van de Velde D, van Eupen I, Meeus M. Assessment of activity limitations and participation restrictions with persons with chronic fatigue syndrome: a systematic review. Disabil Rehabil. 2015;37(19):1706-16. doi: 10.3109/09638288.2014.978507. Epub 2014 Nov 3.https://www.ncbi.nlm.nih.gov/pubmed/25365699

 

Examining case definition criteria for chronic fatigue syndrome and myalgic encephalomyelitis

Abstract:

BACKGROUND: Considerable controversy has transpired regarding the core features of myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Current case definitions differ in the number and types of symptoms required. This ambiguity impedes the search for biological markers and effective treatments.

PURPOSE: This study sought to empirically operationalize symptom criteria and identify which symptoms best characterize the illness.

METHODS: Patients (n=236) and controls (n=86) completed the DePaul Symptom Questionnaire, rating the frequency and severity of 54 symptoms. Responses were compared to determine the threshold of frequency/severity ratings that best distinguished patients from controls. A Classification and Regression Tree (CART) algorithm was used to identify the combination of symptoms that most accurately classified patients and controls.

RESULTS: A third of controls met the symptom criteria of a common CFS case definition when just symptom presence was required; however, when frequency/severity requirements were raised, only 5% met criteria. Employing these higher frequency/severity requirements, the CART algorithm identified three symptoms that accurately classified 95.4% of participants as patient or control: fatigue/extreme tiredness, inability to focus on multiple things simultaneously, and experiencing a dead/heavy feeling after starting to exercise.

CONCLUSIONS: Minimum frequency/severity thresholds should be specified in symptom criteria to reduce the likelihood of misclassification. Future research should continue to seek empirical support of the core symptoms of ME and CFS to further progress the search for biological markers and treatments.

 

Source: Jason LA, Sunnquist M, Brown A, Evans M, Vernon SD, Furst J, Simonis V. Examining case definition criteria for chronic fatigue syndrome and myalgic encephalomyelitis. Fatigue. 2014 Jan 1;2(1):40-56. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3912876/ (Full article)

 

Validating a measure of myalgic encephalomyelitis/chronic fatigue syndrome symptomatology

Abstract:

OBJECTIVES: The present study sought to validate a comprehensive self-report measure of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) symptomatology to aid in clinical and research assessment.

METHOD: Exploratory factor analysis (EFA) was used to establish the underlying factor structure of the DePaul Symptom Questionnaire (DSQ) (Jason, Evans, et al., 2010) using a well-characterized sample of individuals (92.6% met the Fukuda et al. criteria (1994) and/or the Clinical Canadian Criteria (Carruthers et al., 2003)), and this structure was then tested on a less stringently recruited sample of individuals utilizing a confirmatory factor analysis (CFA). Convergent and discriminant validity of the DSQ were also examined utilizing alternative measures of symptomatology and functioning.

RESULTS: A 3-factor solution was found using EFA (Neuroendocrine, Autonomic & Immune Dysfunction; Neurological/Cognitive Dysfunction; Post-Exertional Malaise) and the fit of this factor structure was adequate for the second sample.

DISCUSSION: The DSQ is a valid measure of ME/CFS symptomatology. The emergent factors were consistent with previous literature on symptom clusters, and convergent and discriminant validity were established.

 

Source: Brown AA, Jason LA. Validating a measure of myalgic encephalomyelitis/chronic fatigue syndrome symptomatology. Fatigue. 2014;2(3):132-152. Epub 2014 Jul 23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4871625/ (Full article)