Phenotypes of Chronic Overlapping Pain Multimorbidity in Rheumatology: A Population‐Based Claims Study

OBJECTIVE: This study aims to characterize the burden and distinct patterns of chronic overlapping pain conditions (COPCs) multimorbidity in adults with autoimmune rheumatic diseases (ARDs). METHODS: We analyzed 2008-2021 data from the Merative MarketScan Commercial Claims and Encounters Database, identifying 149,742 patients with ARD (ankylosing spondylitis, psoriatic arthritis, rheumatoid arthritis, Sjögren's disease, systemic lupus erythematosus, systemic sclerosis) using ICD-9/10-CM codes. We assessed COPC (e.g., fibromyalgia, chronic low back pain, migraine, irritable bowel syndrome, chronic fatigue syndrome, temporomandibular disorders, and pelvic pain conditions) prevalence, multimorbidity patterns, and pairwise co-occurrence frequencies, calculating observed/expected ratios and odds ratios. RESULTS: Of 149,742 ARD patients, 57.5% had ≥1 COPC, with 22.7% experiencing multiple conditions. Chronic low back pain (41.4%) and fibromyalgia (21.1%) were most prevalent. Women and individuals aged 31-50 showed the highest COPC prevalence. Many COPC pairs co-occurred more frequently than expected by chance (e.g., fibromyalgia and chronic low back pain: observed/expected ratio 1.35; migraine and chronic low back pain: 1.42). Strongly associated dyads included urologic chronic pelvic pain and vulvodynia (OR 10.46). CONCLUSION: A substantial burden and distinct multimorbidity patterns of COPCs exist among ARD patients, suggesting shared pathophysiological mechanisms. Routine COPC screening and targeted non-opioid multimodal interventions, especially for common dyads, are crucial for improved pain management and reducing opioid-related risks in this population.