Incidence and prevalence of hidradenitis suppurativa across spondyloarthritis-related diseases: cohort study using electronic health records

Objective To describe the recorded prevalence and incidence of HS across pathologically related diseases within the spondyloarthritis (SpA) family, namely psoriatic arthritis (PsA), psoriasis, axial spondyloarthritis (axSpA), uveitis, Crohn’s disease, ulcerative colitis, and, for context, rheumatoid arthritis (RA). Methods We conducted a retrospective cohort study using electronic health records data between June 2006 and June 2026. ICD codes were used to define populations of SpA-related diseases and RA. We estimated recorded baseline prevalence and crude incidence of HS, then separately performed 1:1 propensity-score matched comparisons of each disease with healthcare controls, matching for age, sex, BMI and comorbidities. Results The disease populations ranged from 55,407 to 429,647 individuals. Recorded HS prevalence was highest in psoriasis (0.65%), PsA (0.52%) and Crohn’s disease (0.47%). Crude incidence was highest in Crohn’s (187.4 per 100,000 person-years) and PsA (134.1 per 100,000 person-years). After matching, incidence was higher than in controls for PsA (incidence rate ratio [IRR] 1.63, 95% CI 1.41-1.88), Crohn’s disease (2.02, 1.85-2.20), and ulcerative colitis (1.17, 1.04-1.32). Incidence was lower than controls in axSpA and RA. Conclusions This study highlights a significant epidemiological association between HS and PsA and Crohn’s disease. Clinicians providing care to these patient groups should consider enquiring about HS symptoms, although overall incidence rates are low. Further research is needed into the shared pathophysiology of HS and psoriatic disease.