Representation of patients in receipt of disability benefits among trials of therapy for fibromyalgia

Article type
Authors
Busse J1, Mulla S1, Bruno P2, Kirmayr K3, Avrahami D4, Riva J1, Ebrahim S1, Struijs P5, Brunarski D4, Burnie S4, LeBlanc F4, Coomes E6, Oyberman I1, Bala M7, Schandelmaier S8, Faulhaber M1, Montoya L6, Lopes L9, Makosso S1, Wang L1, Craigie S1, Khokhar R1, Chrispim P10, Silva S10, Lesniak W11, Mohiuddin M12, Agarwal A6, Thakor S13, Kaushal A1, Montori V14, Guyatt G1
1McMaster University, Canada
2University of Regina, Canada
3German Hospital, Argentina
4Canadian Memorial Chiropractic College, Canada
5Academic Medical Center, The Netherlands
6University of Toronto, Canada
7Polish Institute of Evidence-Based Medicine, Poland
8University Hospital, Basel, Switzerland
9University of Sorocaba, Brazil
10Escola Nacional de Saúde Pública, Brazil
11Jagiellonian University Medical College, Poland
12American Academy of Orthopaedic Surgeons, USA
13University of New England, USA
14Mayo Clinic, USA
Abstract
Background: Fibromyalgia is a syndrome characterized by chronic widespread pain for which no clear cause can be found. Approximately 2% of the general population in the USA, and 3% in Canada, suffers from fibromyalgia. Observational studies have found that 20% to 50% of people with fibromyalgia report that they are unable to work or that they can work only a few days per month, and 27% to 55% receive disability or social security payments. Despite the high proportion of patients with fibromyalgia that receive disability benefits, it is not known to what degree such patients are represented in clinical trials.
Objectives: To explore the degree to which patients in receipt of disability benefits are represented among trials of therapy for fibromyalgia.
Methods: We identified relevant randomized controlled trials, in any language, by a systematic search of CINAHL, EMBASE, MEDLINE, AHMED, HealthSTAR, PsychINFO, PapersFirst, ProceedingsFirst, and Cochrane Central Register of Controlled Trials (CENTRAL), from inception of the database to April 2011. Eligible trials met the following criteria: 1) random allocation of patients to an intervention or a control; 2) inclusion of patients presenting with fibromyalgia or a related condition. Teams of reviewers extracted data, independently and in duplicate from each eligible study, regarding whether patients receiving disability benefits had been enrolled.
Results: We identified 15,466 potentially eligible articles and retrieved 763 articles in full text; 292 articles proved eligible. We found that 47 of 292 trials (16%) explicitly considered disability benefit status; however, 58% (27 of 47) did so only as an exclusion criteria. Of the remaining 20 trials, 33% of patients enrolled (598 of 1788) were receiving disability benefits.
Conclusions: Most clinical trials exploring management of fibromyalgia do not explicitly report whether they enrolled patients in receipt of disability benefits. Of the minority that do, most use this feature as an exclusion criterion. The generalizability of treatment effects, reported by clinical trials of fibromyalgia, to patients receiving disability benefits is uncertain.