Prevalence of diagnosed idiopathic hypersomnia among adults in the United States 2019–2023: analysis of healthcare claims

Study Objectives: National prevalence estimates for idiopathic hypersomnia (IH) are difficult to obtain. This study estimated the diagnosed IH prevalence among US adults. Methods: Symphony Integrated Dataverse claims (01/2015-12/2023) were analyzed. Eligible patients were aged ≥18 years with at least one medical/prescription claim in the year of interest (2019-2023) and prior year. IH was defined by ≥1 medical claim with an IH diagnosis code. Prevalence was estimated among all eligible patients in two ways: annual (IH diagnoses during year of interest) and all-time (IH diagnoses looking back all-time in the database from 2015 through year of interest). Age- and sex-adjusted prevalence estimates were also calculated using the US Census Bureau. Results: Over 179, 182, 193, 205, and 198 million adults were assessed for diagnosed IH prevalence in each respective year 2019-2023. Unweighted annual prevalence of diagnosed IH from 2019 to 2023 was 12.1, 11.1, 11.0, 10.5, and 11.1 per 100 000 persons, respectively. Unweighted all-time lookback prevalence of diagnosed IH from 2019 to 2023 was 32.7, 37.3, 40.6, 43.3, and 49.0 per 100 000 persons, respectively. From 2019 to 2023, estimated standardized numbers of US adults diagnosed with IH were 30 563, 27 975, 27 859, 26 624, and 28 754 based on annual prevalence, and 82 027, 93 768, 101 766, 107 763, and 124 905 based on all-time prevalence. Conclusions: Annual prevalence estimates (i.e. proportions of individuals with diagnosed IH during each year of interest) remained consistent across the follow-up period, ranging from 10.5 to 12.1 per 100 000 persons, signifying the rarity of the diagnosis.