Analysis of patient claims data to determine the prevalence of hidradenitis suppurativa in the United States

Background Recent prevalence estimates for hidradenitis suppurativa (HS), a chronic inflammatory skin condition, are limited by timeliness, population size, and generalizability. Objective We sought to develop prevalence estimates for HS in the United States using large health care claims databases. Methods A retrospective analysis used PharMetrics Integrated Database to gather health care claims information for HS among patients with 12 or more months of continuous enrollment in a commercial health care plan throughout 2007. Included patients had: 1 or more diagnoses with International Classification of Diseases, Ninth Revision, Clinical Modification code 705.83 for HS during 2007 without a Current Procedural Terminology code for HS; 1 or more Current Procedural Terminology codes of 11450, 11451, 11462, 11463, 11470, or 11471 during 2007 without International Classification of Diseases, Ninth Revision, Clinical Modification code 705.83; or both. Age- and gender-specific prevalence projections were calculated. Results Among included patients (n = 7927), mean age (SD) was 38.2 (14.73) years, and 5834 (74%) were women. Most patients (n = 5205; 66%) were aged 30 to 64 years. The overall prevalence estimate was 0.053% (95% confidence interval 0.051-0.054). When adjusted for gender and age, prevalence rates were 0.052% and 0.051%, respectively. The most common procedures for HS were excision of skin and subcutaneous tissue axillary/inguinal simple or intermediate repair. Limitations Limitations were a health insured–only population; 12-month enrollment period for 2007; HS-specific procedural codes; and possible HS misclassifications. Conclusion We found a low rate of clinically detected HS (0.053%; approximately 146,000-162,000 patients in the United States in 2007), with affected persons almost 3 times as likely to be female and the highest prevalence in those aged 18 to 44 years.