To determine the specificity and sensitivity of the Modified 2010 American College of Rheumatology (ACR) Diagnostic Criteria for Fibromyalgia (given as a self-administered questionnaire) in clinical practice.
A cohort of patients with widespread pain, referred by primary care physicians to rheumatologists, completed the questionnaire for the Modified ACR 2010 criteria. Prior to completion of the questionnaire, patients were diagnosed by at least 1 rheumatologist as either having fibromyalgia (FM) or not having FM, using the rheumatologist's clinical assessment as the gold standard for diagnosis of FM. The Modified ACR 2010 criteria were then applied to determine whether a diagnosis of FM was satisfied by the criteria. Sensitivity and specificity were determined, using the rheumatologist's clinical assessment as the gold standard. A score ≥ 12 on the Modified ACR 2010 criteria questionnaire was also tested as the criterion to satisfy a diagnosis of FM, and subsequently to determine sensitivity and specificity. We examined the effect of using a cutoff score ≥ 13, as previous research indicated that this may be a more useful cutoff value.
A total of 451 subjects completed the questionnaire: 174 with an a priori diagnosis of FM by a rheumatologist and 277 with widespread pain who did not have an a priori clinical diagnosis of FM by a rheumatologist. The Modified ACR 2010 criteria were satisfied by 90.2% of patients with an a priori diagnosis of FM, and by 10.5% of subjects who had widespread pain, but were not diagnosed with FM when previously assessed by a rheumatologist. Thus, sensitivity and specificity are 90.2% and 89.5%, respectively, using the Modified ACR 2010 criteria. A score ≥ 12 on the Modified ACR 2010 criteria was observed in 97.4% of patients with an a priori diagnosis of FM, and 14.8% of subjects who had widespread pain, but were not diagnosed with FM when previously assessed by a rheumatologist. Thus, the sensitivity and specificity are 97.4% and 85.2%, respectively, using a cutoff score ≥ 12. Using a score of ≥ 13, however, the sensitivity was 93.1% and the specificity was 91.7%.
The Modified ACR 2010 criteria questionnaire can be used in primary care as a tool to assist physicians in the diagnosis of FM with high specificity and sensitivity. Calculating the total score on a Modified ACR 2010 criteria questionnaire, and setting the value of ≥ 13 as the cutoff for a diagnosis of FM appears to be the most effective approach. The Modified ACR 2010 criteria may reduce the need for rheumatology referral simply for the diagnosis of FM.