Association Between Urolithiasis and Hidradenitis Suppurativa: A Retrospective Cohort Study

BACKGROUND/AIM: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder associated with systemic comorbidities. Its potential link with urolithiasis, a common urological disease, remains unclear. PATIENTS AND METHODS: We conducted a multicenter, retrospective cohort study using the TriNetX US Collaborative Network. Adults ≥18 years with HS diagnoses and more than two visits between 2005 and 2018 were identified and matched 1:1 with non-HS controls using propensity scores. Patients with prior urolithiasis or malignancy were excluded. The final analytic cohort included 79,567 patients with HS and 79,567 controls. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated. Sensitivity analyses applied alternative definitions, wash-out periods, and follow-up durations. Comparator groups included psoriasis, rosacea, and androgenic alopecia. Stratified analyses were performed by age and sex. RESULTS: HS was associated with an increased risk of urolithiasis in 15-year follow-up (HR=1.334, 95% CI=1.260-1.413). This association persisted across sensitivity analyses. Comparisons with psoriasis, rosacea, and androgenic alopecia also demonstrated significantly elevated risks (HRs ranging from 1.247 to 1.296). Stratified analyses showed consistent results in both sexes (males: HR=1.340, 95% CI=1.202-1.493; females: HR=1.326, 95% CI=1.214-1.417) and age groups (18-64 years: HR=1.317, 95% CI=1.237-1.402; ≥65 years: HR=1.308, 95% CI=1.160-1.475). Site-specific analyses demonstrated increased risks for renal, ureteric, and lower urinary tract calculi. CONCLUSION: HS is associated with elevated risk of urolithiasis, consistent across analytic models and subgroups. These findings highlight the existence of overlapping inflammatory pathways and underscore the importance of renal monitoring in HS management.