OP0076 Risk of developing additional immune mediated manifestations for patients with systemic arthritides

Abstract

Background: Patients with the systemic arthritides ankylosing spondylitis [AS], psoriatic arthritis [PsA], rheumatoid arthritis [RA] may develop additional, nonmusculoskeletal immune mediated manifestations (nms-IMMs). Objective(s): To compare the risk of developing nms-IMMs between patients with and without an existing AS, PsA, or RA. Method(s): Risk for nms-IMMs was estimated in the MarketScan Commercial Claims and Encounters database (1/2006-9/2015) for case patients with AS, PsA, RA (the "systemic arthritides"). Up to 1,000 controls were matched with replacement by age, sex, state of residence and insurance type to case patients aged 18-64. The systemic arthritides ("cases") were identified by ICD-9 diagnosis codes on >=2 medical claims >=30 days apart. A case patient's earliest nms-IMM claim was designated as the index date for the case and all matched controls. Onset of 6 nms-IMDs was identified by the first post-index claim: celiac disease [CE], hidradenitis suppurativa [HS], inflammatory bowel disease [IBD], lupus [SLE], psoriasis [PsO], uveitis [UV]; some of these are well-known manifestations of seronegative spondylarthropathies, like PsA and AS; some are not. All subjects had continuous health plan enrollment for >=365 days before and after index date. Cumulative incidence of nms-IMMs was assessed at 5 years. Their risk was analyzed with stratified Cox proportional hazards models. Standard errors were adjusted for clustering by case-control match group. Result(s): Among 117,794 cases, mean age was 49 years and 71% were female. Mean number of matched controls per case was 664. Across the 3 initial cohorts of patients with AS, PsA, or RA, median follow-up ranged 939-972 days for cases and 931-950 days for controls. Among case patients, 5-year cumulative incidence of any nms-IMM occurrence was 17.5% for AS, 41.8% for PsA, and 14.4% for RA. Patients with nms-IMMs had significantly higher risk than matched controls of developing each, any 1, or any 2 of the 6 manifestations (P