Abstract Body (Do not enter title and authors here): Introduction: The incidence of Heart Failure (HF) has increased as the US population ages, with Chronic Renal Failure (CRF) being a common comorbidity and risk factor for mortality. This study aims to identify annual, gender, race, and geographical trends in CRF-related mortality in patients with HF for older adults.

Methods: We used ICD-10 (International Classification of Diseases 10th Revision) codes to retrospectively analyze death certificate data from the Centers for Disease Control and Prevention Wide-Ranging OnLine Data for Epidemiologic Research (CDC WONDER) database between 1999-2020 for patients ≥65 years old with concomitant HF and CRF. Age-adjusted mortality rates (AAMRs) per 100,000 people and Annual Percentage Change (APCs) and their respective 95% Confidence Intervals (CI) were also calculated for patient data grouped according to year, gender, race, and geography.

Results: From 1999-2020, 425,854 deaths occurred from CRF and HF in patients ≥ 65 years. The overall AAMR was 46.1 (95% CI: 46 to 46.3), with the APC from 1999-2020 being 2.96 (95% CI: 1.84 to 4.32). Males reported higher AAMRs than females (overall AAMRs: 62.1 vs 36.2). Stratifying data by race revealed NH (Non-Hispanic) Black or African American to have the highest AAMR (62.2) followed by NH American Indian or Alaska Native (52.5), NH White (45.5) and Hispanic or Latino (37.2), with the NH Asian or Pacific Islander race having the lowest AAMR (30). According to the census region, the highest AAMRs were reported in the Midwest (54.3), followed by the West (45.1) and South (43.4), with the lowest AAMRs in the Northeast (42.3). Furthermore, Non-Metropolitan areas revealed higher AAMRs when compared to Metropolitan areas (54.4 vs 43.3). The states in the top 90^th percentile were Indiana, Kentucky, Minnesota, North Dakota, and West Virginia. They had AAMRs nearly double those in the bottom 10th percentile, such as Arizona, Hawaii, Nevada, and New Mexico.

Conclusion: Trends in CRF- and HF-related mortality in older adults have varied from 1999-2020, with the highest AAMRs being reported in men, NH Black or African Americans, Non-Metropolitan areas, and in the Midwest. Strategies to target precipitating events are necessary alongside further investigations to explain the trend variations.