Incidence of hidradenitis suppurativa in the United States: A sex- and age-adjusted population analysis

Background: The true incidence of hidradenitis suppurativa (HS) is unknown. Objective: To determine standardized incidence estimates for HS in the United States. Methods: We used a retrospective cohort analysis, including incident HS cases identified using electronic health records data for a demographically heterogeneous population-based sample of [48 million unique patients across all 4 census regions. We calculated standardized 1-and 10-year cumulative incidences for the overall population and for sex-, age-, and race-specific groups. Results: There were 5410 new HS diagnoses over a 1-year period, with an incidence of 11.4 (95% confidence interval [CI], 11.1-11.8) cases per 100,000 population. One-year incidence in women was 16.1 (95% CI, 15.5-16.6) per 100,000, more than twice that of men [6.8 (95% CI, 6.5-7.2) per 100,000; P < .0001]. Age groupespecific incidence was highest among patients 18 to 29 years of age [22.0 (95% CI, 21.0-23.2) per 100,000]. Incidence among African Americans [30.6 (95% CI, 29.1-32.2) per 100,000] was >2.5 times that of whites [11.7 (95% CI, 11.3-12.2) per 100,000; P < .0001]. The average annual overall incidence over 10 years was 8.6 (95% CI, 8.6-8.7) per 100,000 population. Limitations: The use of deidentified claims prevented validation for a larger case subset. Conclusion: HS incidence has increased over the past decade and disproportionately involves women, young adults, and African Americans.