Association between hidradenitis suppurativa and new-onset inflammatory arthritis: a retrospective population-based cohort study

Abstract Hidradenitis Suppurativa (HS) is a chronic inflammatory skin disease associated with systemic comorbidities. Emerging evidence suggests an associated risk of inflammatory arthritis in HS patients, but the timing of disease onset remains unclear. To assess the risk of developing new-onset psoriatic arthritis (PsA), rheumatoid arthritis (RA), ankylosing spondylitis (AS), and gout in HS patients at various time points post-HS diagnosis. This retrospective cohort study utilized the TriNetX database. Patients diagnosed with HS and without HS were identified. Patients with prior arthritis diagnoses were excluded. Propensity score matching was performed to control for various confounding variables. The risk of developing new-onset inflammatory arthritis was assessed with risk ratios (RR) and 95% confidence intervals (CIs). After matching, 53,989 patients were included in each cohort. At 3 months post-HS diagnosis, HS patients had an associated increased risk for PsA (RR 3.71, 95%CI 1.84-7.45), RA (RR 4.88 95%CI 2.80-8.59), AS (RR 3.45, 95%CI 1.65–7.80), and gout (RR 3.12, 95%CI 1.78-5.48). Risks remained elevated but declined over time. Retrospective design and lack of HS severity staging (Hurley classification). HS patients have an associated increased risk of developing new-onset inflammatory arthritis, particularly PsA, RA, AS, and gout post-HS diagnosis.