Inflammatory Bowel Disease and Interleukin-17 Inhibitors in Hidradenitis Suppurativa

Importance Interleukin (IL)-17 inhibitors have emerged as effective therapies for moderate to severe hidradenitis suppurativa (HS), but concerns remain regarding their potential association with inflammatory bowel disease (IBD). It is known that there is an increased risk of IBD in HS populations, but it remains unclear whether IL-17 inhibition increases the IBD risk or unmasks underlying disease. Objective To evaluate the incidence of IBD in patients with HS treated with IL-17 inhibitors and to compare IBD event rates between treatment and placebo groups. Data Sources PubMed, Embase, and the Cochrane CENTRAL were searched from inception through November 2025. Study Selection Randomized clinical trials (RCTs), nonrandomized studies, and case reports reporting IBD outcomes in patients with HS treated with IL-17 inhibitors were included. Of 1467 records identified, 24 studies met inclusion criteria (10 RCTs, 11 nonrandomized studies, and 3 case reports). Data Extraction and Synthesis Extracted variables included study design, IL-17 inhibitor, study duration, dosing regimen, sample size, patient age, sex, baseline personal or family history of IBD, new-onset IBD, relapse of preexisting IBD, IBD subtype and clinical features, and time to IBD onset. Main Outcomes and Measures Incidence of IBD event, defined as new-onset or worsening Crohn disease or ulcerative colitis during IL-17 inhibitor treatment in a patient with HS. For RCTs, pooled risk differences were calculated using a common effects Mantel-Haenszel model. For nonrandomized studies, a single group meta-analysis of proportions was performed to estimate pooled IBD incidence. Case reports were synthesized qualitatively. Results Across 10 RCTs, new-onset IBD occurred in 6 of 2572 patients treated with IL-17 inhibitors (0.23%) and in 0 of 1066 patients treated with placebo through week 16. There was no significant difference between groups (risk difference, 0.002; 95% CI, −0.003 to 0.007). In nonrandomized studies, 7 new-onset IBD events occurred among 469 patients (crude incidence, 1.49%), with a pooled incidence of 3.90% (95% CI, 2.30%-6.50%). Across randomized trials, long-term extension studies, and nonrandomized studies, 17 new-onset cases and 4 IBD flares were reported. Conclusions In this systematic review and meta-analysis, IBD events were rare. No significant increase in IBD risk was observed with IL-17 inhibitors, although low event rates and inconsistent reporting limited interpretation.