Supplementary Material for: Increased healthcare utilization in hidradenitis suppurativa and arthritis: a propensity score-matched analysis from a hospital-based cohort

Hidradenitis suppurativa (HS) has been linked to arthritis, but large real-world analyses remain limited. This study evaluated the prevalence, risk, and clinical impact of arthritis in patients with HS, focusing on healthcare use.
A retrospective multicenter cohort was assembled using the TriNetX network. Adults with HS (n = 226,047) were compared with matched controls without HS (n = 12,286,573). Arthritis prevalence, 5-year incidence, and healthcare utilization were assessed after 1:1 propensity score matching.
Arthritis prevalence was higher in the HS group (6.22% vs. 5.66%). Over five years, HS patients had an increased risk of developing arthritis (2.22% vs. 1.73%; RR 1.29, 95% CI: 1.23–1.34). Within the HS cohort, those with arthritis showed greater use of systemic therapies, including TNF inhibitors (27% vs. 6%) and interleukin inhibitors (12% vs. 2%). They also had more outpatient visits, emergency visits, and hospitalizations across 1-, 3-, and 5-year periods.
Findings should be interpreted considering the limitations of administrative datasets, including potential misclassification and underreporting. Overall, HS is associated with a higher risk of arthritis, and patients with both conditions exhibit substantially increased healthcare use.