Mortality trends involving colon cancer and atrial fibrillation in the United States,1999-2023: A CDC WONDER analysis.

e24021 Background: Colon cancer is a leading cause of cancer-related mortality in the United States, while atrial fibrillation (AF) is prevalent among older, medically complex patients. AF may complicate cancer management through shared risk factors, treatment-related cardio toxicity, and competing mortality risks. However national long-term mortality trends involving colon cancer and AF remain poorly defined. Methods: U.S. mortality data was analyzed from 1999-2023 using the CDC WONDER database. Deaths involving colon cancer (ICD-10: C18) and AF (ICD-10: I48) were identified. Age-adjusted mortality rates were stratified by ten-year age group, sex, race, census region, place of death and urbanization. Joinpoint regression assessed temporal trends for ten-year age group, sex, census region, and urbanization, reporting annual percentage change (APC) and average annual percentage change (AAPC). Race and place of death were analyzed descriptively. Results: Overall mortality involving colon cancer and AF accelerated around 2015-2016. The steepest increases occurred in adults aged 55-64, with deaths rising (APC 2.6%) annually from (1999-2016), followed by post-2016 acceleration of (APC 12.2% per year), resulting in an upward trend (AAPC 5.3%, p < 0.001). Adults aged 65-74 also showed post-2015 increases (APC 6.7% per year).Trends among older age groups were more gradual. Post-2016 increases in mortality were observed for both males and females (APC 4-5% per year), indicating no sex-specific differences.The Southern U.S. showed acceleration compared to other regions (AAPC 2.5%, p < 0.001). Urbanization analysis (1999-2020) showed increasing mortality in nonmetropolitan areas (AAPC 2.3%, p < 0.001). Deaths predominated among white individuals and in inpatient hospital settings. Conclusions: Mortality involving colon cancer and AF has risen substantially in the U.S. since 2016, shifting towards middle-aged adults and nonmetropolitan populations. This highlights a widening "cardio-oncology" gap underscoring the need for earlier risk recognition, improved cancer screening, integrated care, and targeted resource allocation in high-burden regions.