Risk of Spondyloarthritis in Patients With Inflammatory Bowel Disease Receiving Treatment With Biologics or Janus Kinase Inhibitors.

Abstract

To detect spondyloarthritis (SpA) and evaluate risk factors in patients with inflammatory bowel disease (IBD) during biologic or Janus kinase inhibitor (JAKi) treatment. This was a retrospective cohort study of patients with IBD receiving biologics or JAKi, excluding prior SpA cases. We identified patients who developed musculoskeletal (MSK) symptoms during IBD treatment. SpA was diagnosed after a clinical evaluation by a rheumatologist alongside imaging analysis of conventional radiographs and HLA-B27 determination. Magnetic resonance imaging of the sacroiliac joints was performed only in cases where the conventional radiograph was inconclusive. Of 1649 patients with IBD receiving biologic or JAKi treatment (Crohn disease: 1335; ulcerative colitis [UC]: 314), 96 (5.8%) were excluded due to a prior SpA diagnosis. Among the remaining 1553 patients, 106 (6.8%) developed MSK symptoms during IBD treatment, and 30 (1.9%) were diagnosed with SpA (axial: 20; peripheral: 10) during the follow-up (median 5.2 [IQR 3.4-7.5] years). Risk factors for SpA in these patients included a partial Mayo score for UC at the time of onset of MSK symptoms (hazard ratio [HR] 1.57; <i>P</i> = 0.03) and HLA-B27 positivity (HR 3.70; <i>P</i> = 0.004). As well as IBD treatment, 23/30 (77%) patients with SpA used nonsteroidal antiinflammatory drugs (NSAIDs). IBD disease activity did not worsen during treatment, regardless of NSAID use. During a median follow-up of 5.2 years, 6.8% of patients with IBD undergoing biologic or JAKi treatment developed MSK symptoms, with one-third subsequently diagnosed with SpA. HLA-B27 positivity and higher UC disease activity were associated with an increased risk of SpA.