Declining yet persistent asthma mortality among U.S. adults aged 65 years and older (1999-2020).

Background: Asthma in older adults (≥65 years) represents a growing yet understudied public health burden. Comprehensive spatiotemporal trends and future projections of asthma mortality in this population remain incompletely characterized. This study aimed to characterize the temporal, demographic, and geographic patterns of asthma mortality among U.S. adults aged ≥65 years, project future mortality trends through 2030, and evaluate state-level disparities relative to an empirical mortality frontier. Methods: Using the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) Underlying Cause of Death data from 1999 to 2020, we examined asthma mortality (ICD-10 J45-J46) among U.S. adults aged ≥65 years. Age-adjusted mortality rates (AAMRs) per 100,000 population were calculated. Joinpoint regression was used to characterize temporal changes and estimate annual percent changes (APCs). A non-seasonal ARIMA model was used to project mortality through 2030. State-level ecological associations with the Socio-demographic Index (SDI) and variation relative to an SDI-conditioned LOESS mortality frontier were evaluated. Results: Between 1999 and 2020, 38,101 asthma-related deaths occurred among adults aged ≥65 years, yielding an overall AAMR of 4.14 (95% CI, 4.09-4.18) per 100,000 population. Mortality declined by 54.5%, from 7.01 per 100,000 in 1999 to 3.19 per 100,000 in 2020. In the overall population, the decline slowed after 2010 (APC, -5.751% during 1999-2010 and -2.194% during 2010-2020). Sex-specific patterns differed: the female decline slowed after 2010, whereas the male decline slowed after 2008 and ceased after 2016. Women had a higher pooled AAMR than men (4.94 vs. 2.91 per 100,000), although the absolute difference between annual sex-specific rates decreased over time. Substantial geographic and racial/ethnic variation persisted. Overall AAMR point estimates were projected to range from 3.02 to 3.46 per 100,000 during 2021-2030. The LOESS-based frontier analysis showed considerable state-level variation in the distance between observed mortality and the empirical mortality benchmark. Conclusion: Although asthma mortality among U.S. adults aged ≥65 years declined substantially between 1999 and 2020, the decline slowed after 2010, and marked demographic and geographic disparities persisted. These population-level patterns identify groups and regions that may benefit from enhanced surveillance and further investigation. Because the analyses were based on aggregated observational data, the reported associations should not be interpreted as evidence of individual-level or state-level causal relationships.