Fibromyalgia Frequently Misdiagnosed, Study Says

Agreement between clinical diagnosis and criteria-based diagnosis of fibromyalgia is only fair, according to a study published in Arthritis Care & Research. Investigators compared clinician diagnosis with published criteria to identify possible diagnostic misclassification of the disease.

In a university clinic, 497 patients completed the Multidimensional Health Assessment Questionnaire (MD-HAQ) and the 2010 American College of Rheumatology (ACR) preliminary diagnostic criteria for fibromyalgia questionnaire. Patients were then evaluated by rheumatology staff.

A total of 121 (24.3%) patients met ACR criteria for fibromyalgia and 104 (20.9%) received a clinician diagnosis of fibromyalgia. The agreement between clinical- and criteria-based diagnosis was 79.2%. However, clinicians were unable to identify 60 (49.6%) criteria-positive patients and misidentified 43 (11.4%) criteria-negative patients.

In a subset of 88 patients with rheumatoid arthritis, the kappa value was 0.32, indicating slight to fair agreement. More abnormal MD-HAQ scores were associated with higher polysymptomatic distress scores and criteria-based diagnosis.

“There is considerable disagreement between ICD clinical diagnosis and criteria-based diagnosis of fibromyalgia, calling into question ICD-based studies,” the investigators concluded. “Fibromyalgia criteria were easy to use, but problems regarding clinician bias, meaning of a fibromyalgia diagnosis, and the validity of physician diagnosis were substantial.”

Reference

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.