Background Fibromyalgia (FM) is prevalent in patients with chronic inflammatory rheumatic diseases (CIRd), where it hampers diagnosis and activity assessment. No tool for screening FM associated with CIRd has ever been evaluated. The Fibromyalgia Rapid Screening Tool (FiRST) is a brief and simple self-complete questionnaire that has been validated for screening FM in patients with diffuse chronic pain.
Objectives The purpose of this study was to evaluate how well FiRST performs on screening for FM associated with CIRd.
Methods This single-center cross-sectional study was conducted between September 2014 and April 2015 on all patients with chronic pain presenting for rheumatoid arthritis (RA), spondyloarthritis (SpA), and connective tissue disease (Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), scleroderma (Scl), myositis). Diagnosis of FM was based on ACR–90 classification criteria (to minimize interfering overlap between rheumatic disease-related pain and FM-related pain) and expert opinion.
Results The population included 605 patients: 279 RA, 271 SpA (52 psoriatic arthritis, 126 radiographic axial SpA, 64 non-radiographic axial SpA, 29 peripheral SpA), 57 connective tissue disease. In total, 51 patients had FM meeting the ACR–90 criteria, and 93 patients were given a diagnosis of FM by the expert. When tested against the ACR–90 classification criteria, FiRST demonstrated a sensitivity of 74.5%, a specificity of 80.4%, a positive predictive value of 26.6% and a negative predictive value of 97.1%. Specificity was significantly weaker in the connective tissue disease group (RA: 84.4%, SpA: 80.2%, connective tissue disease: 59.6%; p<0.001). When tested against expert opinion, FiRST demonstrated a sensitivity of 75.8%, a specificity of 85.1%, a positive predictive value of 48.3% and a negative predictive value of 95%. FiRST underperformed on sensitivity in the SpA group compared to the connective tissue disease group (66% vs 94.4%; p=0.004). Performances varied according to item in the self-complete questionnaire.
Conclusions The FiRST self-questionnaire performs less well in inflammatory rheumatic diseases than in primary fibromyalgia, but nevertheless it remains a simple and rapid tool to help rheumatologist and general practitioner detects fibromyalgia associated with inflammatory rheumatic disease.
Disclosure of Interest None declared