Prevalence of fibromyalgia varies with criteria applied

(HealthDay)—The prevalence of fibromyalgia varies with the different sets of the American College of Rheumatology (ACR) classification criteria, according to a study published in the February issue of Arthritis & Rheumatology.

Gareth T. Jones, Ph.D., from the University of Aberdeen in the United Kingdom, and colleagues examined the population prevalence of fibromyalgia and compared differences in prevalence using alternative criteria. Questionnaires were mailed to 4,600 adults in northeast Scotland, and 269 participants who had chronic widespread pain or met the modified 2010 criteria were invited to attend a research clinic. One hundred four attendees completed an additional questionnaire, underwent rheumatologic examination, and had their signs and symptoms classified according to the ACR 1990, 2010, and modified 2010 criteria.

The researchers found that 31 percent of the attendees met one or more set of fibromyalgia criteria. According to the ACR 1990, 2010, and modified 2010 criteria, the prevalence of fibromyalgia was 1.7, 1.2, and 5.4 percent, respectively. Of those meeting the respective criteria sets, the ratio of females to males was 13.7:1, 4.8:1, and 2.3:1, respectively.

"Prevalence is higher and a greater proportion of men are identified with the modified 2010 criteria as compared to the criteria sets requiring clinician input," the authors write. "This has important implications for the use of the new criteria, both in research and in clinical practice."