Hidradenitis Suppurativa in the United States: Insights From the National Inpatient Sample (2008-2017) on Contemporary Trends in Demographics, Hospitalization Rates, Chronic Comorbid Conditions, and Mortality.

Background Hidradenitis suppurativa (HS) is a clinical condition characterized by the formation of painful lumps under the skin. It often affects intertriginous areas like armpits and groin. There is a paucity of contemporary data on patient and hospital-level characteristics of HS in the United States. Methods We analyzed the Nationwide Inpatient Sample (NIS) for retrospective analysis to calculate the frequency and yearly rates of HS hospitalizations, demographic variations, rates of comorbidities, and length of stay. Results The rate of hospitalizations with HS as a primary diagnosis increased from 7.9 per 100,000 all-cause hospitalizations in 2008 to 11.6 per 100,000 all-cause hospitalizations in 2017 (p < 0.0001). The mean age ± standard error of hospitalized patients was 39.5 ± 0.2 years. The age group of 18-34 years was the most affected. Women showed a higher preponderance of the disease than men (56.6% vs. 43.5%, p < 0.0001). The Black race was the most affected out of all the racial groups (59.9%). Most hospitalizations were in large, urban teaching hospitals. Hypertension (34.9%), skin and subcutaneous tissue infections (26.5%), and diabetes mellitus (25.9%) were the most common comorbidities. Out of the total hospitalizations with HS, 12.7% were found to have a major or extreme loss of function and 3.5% were at a major or extreme likelihood of dying. Conclusions HS disproportionately affects young adults, women, and Black patients. A significant proportion of these patients are at a major risk of major loss of bodily function or death. Prospective studies are needed to identify the risk factors for hospitalizations in these patient populations and devise appropriate prevention and treatment strategies.