Supplementary Material for: Low Utilization of the Dermatology Ambulatory Encounter among Patients with Hidradenitis Suppurativa: A Population-Based Retrospective Cohort Analysis in the USA

Background: There are limited data evaluating the utilization of dermatologists for the care of patients with hidradenitis suppurativa. Objective: To determine the utilization of the dermatology ambulatory encounter among hidradenitis suppurativa patients, and to evaluate whether utilization varies by insurance status. Methods: This was a retrospective cohort analysis in an adult population sample of 42,030 hidradenitis suppurativa patients with either private or public health insurance who were identified by a validated scheme using SNOMED-CT terminology. The primary outcome was a dichotomous variable defined as having at least 1 ambulatory encounter with a dermatologist over a 3-year period. Results: Overall, 21.8% (9,170/42,020) of the hidradenitis suppurativa patients had at least 1 ambulatory encounter with a dermatologist. This proportion did not significantly vary between patients with private insurance (22%), Medicaid (21.6%), and Medicare (21.7%). Conclusion: Utilization of the ambulatory dermatology encounter among patients with hidradenitis suppurativa is low in the USA. Factors other than insurance status influence this level of utilization.