To describe the prevalence and characteristics of fibromyalgia (FM) in patients with underlying rheumatic disease, and to compare it by three different measures.
We studied 546 patients with chronic rheumatic diseases who attended our rheumatology clinic. If patients answered all of a screening questionnaire with yes, then we considered patients to be having widespread pain as assessed by the fibromyalgia impact questionnaire (FIQ), widespread pain index (WPI), and symptom severity (SS). A physician administered the tender point (TP) exam and clinician's judgment of FM. We collected demographics, clinical and laboratory features.
One hundred and sixty-four (30.0%) patients among 546 cases had a further exam. The male-to-female count was 25 : 139. The mean age was 49.7 years, disease duration 3.7 years, TP counts 4.2, FIQ score 47.0 and WPI with SS score was 11.1. We classified 17 patients (10.4%) with concomitant FM with widespread pain by tender point exam, 56 patients (34.2%) by WPI with SS, and 36 patients (22.0%) by a clinician's judgment. A total of 70.6% (n = 12) of those classified as FM by 1990 American College of Rheumatology (ACR) criteria wee categorized as FM by clinician's judgment, while 33.3% by clinician's judgment were classified by 1990 ACR criteria.
We found a 10.4~34.2% prevalence of concomitant FM in the patients with chronic widespread pain. The 1990 ACR criteria were the most restrictive except for SLE. Although The 2010 ACR criteria had a wide spectrum, it can be used for FM diagnosis even in the patient with underlying rheumatic diseases.