There may be substantial disparity between diagnoses of fibromyalgia based on criteria vs International Classification of Diseases standards, according to a study published in Arthritis Care & Research.
A total of 497 consecutive patients attending a university rheumatology clinic were asked to complete the Multidimensional Health Assessment Questionnaire, the 2010 American College of Rheumatology preliminary diagnostic criteria for fibromyalgia (including the 2011 modification for self-report).
In this cohort, 24.3% of the patients were considered to satisfy the criteria for fibromyalgia, and 20.9% were given a fibromyalgia diagnosis by a clinician, based on International Classification of Diseases criteria, corresponding to 79.2% agreement between criteria and clinicians (κ, 0.41). Physicians failed to diagnose fibromyalgia in 60 patients (49.6%) deemed to have fibromyalgia according to criteria, and incorrectly diagnosed fibromyalgia in 43 criteria-negative patients (11.4%). Of patients clinically diagnosed with fibromyalgia, 58.7% were found to satisfy criteria for the disease, and of 393 patients not diagnosed with fibromyalgia by physicians, 15.3% were found to satisfy the criteria, a rate that the researchers considered to be clinically significant.
In a subset of 88 patients with rheumatoid arthritis, the clinicians and criteria agreed in 84.1% of cases (fair agreement; κ, 0.32). Of 13 patients with rheumatoid arthritis and criteria-positive fibromyalgia, only 5 (38.5%) were diagnosed by clinicians.
Women and those with more symptoms (but fewer pain areas) were found to be less likely to satisfy fibromyalgia criteria than to be diagnosed for the condition by a clinician.
Study limitations include the study setting in a rheumatology clinic, where disagreement between criteria-based and clinician diagnosis may have been less severe than in a primary care setting.
“It is likely that misdiagnosis [of fibromyalgia] is a public health problem and one that can lead to overdiagnosis and overtreatment, as well as to inappropriate treatment of individuals not recognized to have fibromyalgia symptoms,” noted the study authors.
Wolfe F, Schmukler J, Jamal S, et al. Diagnosis of fibromyalgia: disagreement between fibromyalgia criteria and clinician-based fibromyalgia diagnosis in a university clinic. Arthritis Care Res. 2019;71(3):343-351.