Overall and Subgroup Prevalence of Crohn Disease Among Patients With Hidradenitis Suppurativa A Population-Based Analysis in the United States

IMPORTANCE Limited evidence supports a link between hidradenitis suppurativa (HS) and Crohn disease (CD), and this relationship has not been established in the United States. OBJECTIVE To evaluate the prevalence of CD among patients with HS in the United States and to determine the strength of association between the 2 conditions. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional analysis of data from 51 340 patients with HS identified using electronic health records data in the Explorys multiple health system data analytics and research platform, which includes data from more than 50 million unique patients across all US census regions. MAIN OUTCOMES AND MEASURES Primary outcome was diagnosis of CD. RESULTS Of the 18 455 660 total population considered, 51 340 had HS (35 000 women). Of these patients with HS, 29 010 (56.5%) were aged 18 to 44 years; 17 580 (34,2%), 45 to 64 years; and 4750 (9.3%), 65 years or older. Prevalence of CD among patients with HS was 2.0% (1025/51 340), compared with 0.6% (113 360/18 404 260) among those without HS (P<.001). Prevalence of CD was greatest among patients with HS who were white (2.3%), aged 45 to 64 years (2.4%), nonobese (2.8%), and tobacco smokers (2.3%). In univariable and multivariable analyses, patients with HS had 3.29 (95% CI, 3.09-3.50) and 3.05 (95% CI, 2.87-3.25) times the odds of having CD, respectively, compared with patients without HS. Crohn disease was associated with HS across all patient subgroups. The association was strongest for men (OR, 3.61; 95% CI, 3.24-4.03), patients aged 45 to 64 years (OR, 3.49; 95% CI, 3.16-3.85), nonobese patients (OR, 4.09; 95% CI, 3.69-4.54), and nonsmokers (OR, 3.44; 95% CI, 3.10-3.82). CONCLUSIONS AND RELEVANCE These data suggest that patients with HS are at risk for CD. Gastrointestinal symptoms or signs suggestive of CD warrant additional evaluation by a gastroenterologist.