Prevalence of Fibromyalgia and Widespread Pain in Psoriatic Arthritis: Association With Disease Severity Assessment in a Large US Registry

The classic conception of pain etiology in rheumatologic disease is nociceptive pain-tissue injury and inflammation signaling through peripheral and central nerve fibers. But this can be mixed with other pain etiologies, including nociplastic, which is augmented pain experience due to central sensitization. The pain of fibromyalgia (FM) is nociplastic, occurs in 10% to 30% of patients with rheumatologic disease, and its presence can influence disease severity assessment. The objective of our study was to (1) ascertain the prevalence of FM and widespread pain (WP) in the CorEvitas psoriatic arthritis (PsA) registry as assessed by the Widespread Pain Index (WPI) and Symptom Severity Scale (SSS) questionnaires; (2) characterize the demographic and clinical factors associated with FM and WP; and (3) ascertain the association of FM and WP on the Clinical Disease Activity in Psoriatic Arthritis (cDAPSA) score and other disease activity measures.