Trends in Prevalence and Incidence of Alopecia Areata, Alopecia Totalis, and Alopecia Universalis Among Adults and Children in a US Employer-Sponsored Insured Population

Abstract

ImportanceAlopecia areata (AA) is characterized by nonscarring hair loss of the scalp, face, and/or body. Alopecia totalis (AT) and alopecia universalis (AU) involve complete loss of the scalp and body hair, respectively. The epidemiology of AA in the US remains unclear, having previously been extrapolated from older studies that were limited to specific geographic areas or clinical settings, or from self-reported data.ObjectiveTo estimate the annual prevalence and incidence of AA and AT and/or AU (AT/AU) in the US.Design, Setting, and ParticipantsThis retrospective, population-based cohort study was conducted from January 2016 to December 2019 and included enrollees in the IBM MarketScan Commercial Claims and Encounters and Medicare Supplemental databases and their dependents, with plan enrollment during each study calendar year and the year prior.ExposuresPrevalent cases were identified by 1 or more claims for AA or AT/AU (International Statistical Classification of Diseases, Tenth Revision, Clinical Modification [ICD-10-CM] codes L63.x, L63.0, L63.1) during each year of interest or the year prior. Incident cases were identified by 1 or more claims for AA or AT/AU during a specific year and no diagnosis the year prior.Main Outcomes and MeasuresAnnual incidence and prevalence rates were calculated and stratified by age, sex, and region. National employer-sponsored insurance population estimates were obtained using population-based weights.ResultsAmong eligible patients (2016: n = 18 368 [mean (SD) age, 40.6 (17.9) years; 12 295 women (66.9%)]; 2017: n = 14 372 [mean (SD) age, 39.6 (17.7) years; 9195 women (64.0%)]; 2018: n = 14 231 [mean (SD) age, 38.9 (17.3) years; 8998 women (63.2%)]; 2019: n = 13 455 [mean (SD) age, 39.1 (17.4) years; 8322 women (61.9%)]), AA prevalence increased from 0.199% (95% CI, 0.198%-0.200%) in 2016 to 0.222% (95% CI, 0.221%-0.223%) in 2019. Roughly 5% to 10% of prevalent and incident cases of AA were AT/AU. The prevalence of AT/AU increased from 0.012% (95% CI, 0.012%-0.013%) to 0.019% (95% CI, 0.018%-0.019%) from 2016 to 2019. Incidence of AA per 100 000 person-years ranged from 87.39 (95% CI, 86.84-87.96) in 2017 to 92.90 (95% CI, 92.35-93.45) in 2019. Incidence of AT/AU ranged from 7.09 (95% CI, 6.94-7.25) in 2017 to 8.92 (95% CI, 8.75-9.09) in 2016. Prevalence and incidence of AA and AT/AU were higher among female vs male individuals, adults vs children and adolescents, and in the Northeast vs other regions.Conclusions and RelevanceThe results of this cohort study suggest that these recent AA prevalence and incidence estimates could help improve current understanding of the disease burden. Further research is warranted to elucidate subpopulation differences and trends in AA in the broader US population.

Characterizing Epidemiology and Burden of Disease in Alopecia Areata—Making It Count

“…It is encouraging that Sy et al and Mostaghimi et al coalesced around similar prevalence estimates despite using different data sources. When using large-scale big data like aggregate EHR data and health care claims, it is critical to interrogate who is actually included and who is missing from such data sets to properly contextualize any epidemiologic estimates.…”

“…Sy et al and Mostaghimi et al take different methodological approaches, using big data to estimate the burden of AA. In a 1-year cross-section in 2019 using EHR data, Sy et al evaluated more than 1 million patients, with a total of 1812 cases of AA, and estimated the prevalence of AA to be 0.18% among adults and 0.10% among children and adolescents.…”

“…In a 1-year cross-section in 2019 using EHR data, Sy et al evaluated more than 1 million patients, with a total of 1812 cases of AA, and estimated the prevalence of AA to be 0.18% among adults and 0.10% among children and adolescents. Using claims data, Mostaghimi et al analyzed more than 13 000 affected patients per year for 4 years and described increasing prevalence of AA from 2016 to 2019, with prevalence reaching 0.22% in 2019.…”

“…Mostaghimi et al use the IBM Watson Marketscan claims database to characterize the burden of AA in the contemporary era. One of the important strengths of claims-based approaches for understanding disease burden is that they detect health care received in various settings.…”

“…In the last several years, studies of the National Alopecia Areata Foundation registry and the National Ambulatory Medical Care Survey database have characterized the population of patients with AA in the US as predominantly female and people of racial and ethnic minority groups, including Asian, Black, and Hispanic individuals. In this issue of JAMA Dermatology , the 2 studies by Sy et al and Mostaghimi et al undertake the task of estimating prevalence for AA and the racial and ethnic makeup of the AA population using novel claims-based and electronic health care record (EHR)–based methods.…”