Background <p>Rheumatoid arthritis (RA) is associated with excess cardiovascular morbidity and mortality, yet long-term U.S. mortality trends involving coexisting ischemic heart disease (IHD) and RA among older adults remain insufficiently characterized.</p> Methods <p>We performed ecological time-series analysis of the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) Multiple Cause of Death database for 1999–2023. Adults aged 65 years or older were included when both IHD (ICD-10 codes I20-I25) and RA (ICD-10 codes M05-M06) were recorded anywhere on the death certificate. Crude mortality rates (CMRs) and age-adjusted mortality rates (AAMRs) per 100,000 population were calculated, and Joinpoint regression was used to estimate annual percentage changes (APCs) and average annual percentage changes (AAPCs).</p> Results <p>A total of 50,457 deaths met study criteria. The overall AAMR declined from 7.06 per 100,000 in 1999 to 3.47 in 2016, followed by a modest increase to 3.60 in 2023 (AAPC, -2.53; 95% CI, -3.12 to -1.94). Females consistently had higher mortality than males (1999: 8.10 vs. 5.30; 2023: 3.92 vs. 3.15). Non-Hispanic White individuals had the highest average mortality burden among the analyzed racial and ethnic groups. Nonmetropolitan areas had higher mortality than metropolitan areas, the Midwest had the highest regional burden, and crude mortality increased sharply with age, peaking among adults aged 85 years or older.</p> Conclusions <p>Mortality involving coexisting IHD and RA among older U.S. adults declined substantially through the mid-2010s, followed by a later rebound, with persistent demographic and geographic disparities with persistent demographic and geographic disparities. Focused cardiovascular risk reduction, equitable access to rheumatology and cardiology care, and targeted public-health strategies may help reduce this burden.</p>