Contemporary Trends in the Nationwide Incidence of Primary Intracerebral Hemorrhage

Background: We report contemporary trends in nationwide incidence of intracerebral hemorrhage (ICH) across demographic and regional strata over a 15-year period. Methods: Utilizing the Nationwide Inpatient Sample (2004-2018) and US Census Bureau data, we calculated ICH incidence rates for age, race/ethnicity, sex, and hospital region sub-cohorts across 5 consecutive 3-year periods (2004-2006 to 2016-2018). We fit Poisson and log binomial regression models to evaluate demographic and regional differences in ICH incidence and trends in prevalence of hypertension and past/current anticoagulant use among hospitalized ICH patients. Results: Overall, the annual incidence rate (95% CI) of ICH per 100 000 was 23.15 (23.10-23.20). The 3-year incidence of ICH (per 100 000) increased from 62.79 in 2004 to 2006 to 78.86 in 2016 to 2018 (adjusted incidence rate ratio, CI: 1.11 [1.02-1.20]), coinciding with increased 3-year prevalence of hypertension and anticoagulant use among hospitalized ICH patients (adjusted risk ratio, CI: hypertension - 1.16 [1.15-1.17]; anticoagulant use - 2.30 [2.14-2.47]). We found a significant age-time interaction, whereby ICH incidence increased significantly faster among those aged 18 to 44 years (adjusted incidence rate ratio, CI: 1.10 [1.05-1.14]) and 45 to 64 years (adjusted incidence rate ratio, CI: 1.08 [1.03-1.13]), relative to those aged ≥75 years. Conclusions: Rising ICH incidence among young and middle-aged Americans warrants ICH prevention strategies targeting these economically productive age groups.