Which symptoms best distinguish fibromyalgia patients from those with other chronic pain disorders?

Rationale, aims and objectives: The primary purpose of this study was to test both classic and novel FM pain and non-pain symptoms to determine their practical efficacy in aiding clinicians to distinguish FM pain from other chronic pain disorders. Methods: 158 pain patients from two primary care clinics were evaluated with history, physical exam, chart review, and a questionnaire containing 26 exploratory symptoms (10 from the Symptom Impact Questionnaire (SIQR) and 16 from the FM literature)). The symptoms were rated on a 0-10 VAS for severity by those patients reporting pain over the past week. Somers' D and mean severity differences between FM and chronic pain patients without FM were used to rank the discriminatory and diagnostic contributions of symptoms. Results: Fifty patients (14.2%) carried a chart diagnosis of FM, 108 (30.7%) had pain but not FM, and 192 (54.5%) who had neither pain nor FM. Comparing means between the two pain groups, the 5 best differentiating symptoms (all, P <.0001) were: a persistent deep aching over most of my body, poor balance (7.4 vs 3.1), environmental sensitivity (6.8 vs 3.0), tenderness to touch (6.8 vs 3.6) and pain after exercise (8.1 vs 4.1). Notably, VAS pain though significantly higher for FM was least discriminatory (6.5 vs 5.1, P <.001). The five best symptoms generated a ROC = 0.85 and Somers' D = 0.69, an accuracy of 81%, and an odd's ratio of 14.4. Conclusions: Our results herein suggest that clinicians may be well-served to consider symptoms in addition to those contained in current diagnostic criteria when recognizing FM in their chronic pain patients.