Deaths involving chronic obstructive pulmonary disease and cardiac arrest in older US adults, 1999–2023

National long-term trends and disparities in deaths in which both chronic obstructive pulmonary disease (COPD) and cardiac arrest are recorded on death certificates are not well characterized. We used CDC WONDER Multiple Cause of Death data (1999-2023) to identify US adults aged ≥ 65 years whose death certificates listed both COPD (ICD-10 J41-J44) and cardiac arrest (I46) as underlying or contributing causes. Age-adjusted mortality rates (AAMRs) were stratified by sex, race/ethnicity, region, and urbanization; the urbanization analysis was limited to 1999 to 2020 because those data were not available after 2020. Trends were analyzed using annual percentage changes (APCs) with 95% confidence intervals (CIs); P < .05 was considered statistically significant. Among 7,18,280 deaths involving concurrent coding of COPD and cardiac arrest, AAMRs declined from 86.4 in 1999 to 52.5 in 2023. A significant decrease occurred from 1999 to 2006 (APC: -2.87; P = .01), followed by a plateau and a further decline from 2021 to 2023 (APC: -4.77; P < .001). Older men exhibited higher AAMRs than older women (86.8 vs 55.2). Non-Hispanic (NH) White individuals had the highest mortality (69.7), followed by NH Black/African American (64.3) and Hispanic/Latino (60.7) populations. The West region reported the highest AAMR (98.9). During 1999 to 2020, nonmetropolitan residents had higher AAMRs than metropolitan residents (70.8 vs 67.9). Population-level mortality records involving both COPD and cardiac arrest declined overall but remained heterogeneous across demographic and geographic strata. These findings describe concurrent coding on death certificates and do not establish that COPD increases the risk of cardiac arrest or causes the observed deaths.