Are there symptoms distinguishing fibromyalgia from chronic pain that are missing from the 2016 criteria?

Background: Fibromyalgia (FM) patients have a wide range of symptoms. Objectives: Herein we analysed 20 common symptoms to determine those that best discriminate between FM patients and chronic pain patients without FM (Chronic Pain). Methods: 352 patients (mean age 50+/16.3 years, 70% female) scheduled for a routine examination in two primary care practices were studied. 50 patients (14.2%) had FM (based on 1990 ACR) and 108 patients (30.7%) had Chronic Pain. All subjects completed a survey of 20 symptoms commonly found in FM patients – 10 were from the Symptom Impact Questionnaire (SIQR). Results: Table 1 presents the 20 symptoms ranked by magnitude of Somers’ D. This is a statistic that provides an estimate of predicting a diagnosis of fibromyalgia versus no fibromyalgia (OR: 1.87–8.00; p<0.001). The top 10 symptoms showed strong correlations with diagnosis (D=0.49 to 0.64) and large mean differences between the 2 groups (Means: 2.8–4.3). Notably, there was a 4.3 score difference in Persistent Deep Ache and only a 1.4 difference in SIQR Pain (p<0.001). Using a 4-point criterion as a clinical cut-off (0–10), symptoms best discriminating patients with FM from Chronic Pain were: Persistent Deep Aching (86% vs. 36%), Environmental Sensitivity (82% vs. 38%), Poor Balance (82% vs. 35%), Tenderness to Touch (84% vs. 39%) and Pain after exercise (96% vs. 54%). The symptoms of Pain, Unrefreshing Sleep, Muscle Stiffness and Low Energy were high in both groups, thus they are not good discriminators. Abstract SAT0718HPR – Table 1 Twenty common fibromyalgia symptoms ranked by Somers’ D. The top 10 symptoms are shaded. SIQR symptoms are italicised. Conclusions: In this sample from 2 primary care practices, Persistent Deep Aching, Tenderness to Touch, Environmental Sensitivity, Poor Balance and Pain after Exercise were the best discriminators between FM patients and patients with Chronic Pain. Notably: Depression, Headaches, Poor Memory and Irritable Bowel symptoms were weak discriminators; in fact, none of the top 10 discriminators appear in the 2016 Fibromyalgia Diagnostic Criteria. Disclosure of Interest: None declared DOI: 10.1136/annrheumdis-2018-eular.5741 Citation: Ann Rheum Dis, volume 77, supplement Suppl, year 2018, page A1821Session: HPR Measuring health (development and measurement properties of PROs, tests, devices)