Cardiovascular disease as a contributing cause of cancer mortality: A population-based analysis of United States death certificate data (1999–2020)

BACKGROUND Emerging evidence suggests a complex bidirectional relationship between cardiovascular disease (CVD) and cancer. However, population-level data characterizing the burden of cardiovascular comorbidities at the time of cancer-attributable death remains limited. We analyzed the association between the presence of cardiovascular disease on death certificates and cancer mortality patterns across demographic groups using national mortality data from 1999 to 2020. METHODS Using CDC WONDER multiple cause-of-death data, we analyzed records of adults ≥ 18 years with cancer as the underlying cause of death. CVD comorbidity was defined as any cardiovascular condition (ICD-10 I00-I99) listed as a contributing cause. We calculated age-adjusted mortality rates (AAMR) per 100,000 population and rate ratios, stratified by demographics and cancer types. RESULTS Among 13,847,293 cancer deaths, 4521,847 (32.6 %) had cardiovascular disease listed as a contributing cause. The overall AAMR for cancer deaths with CVD was 47.75 per 100,000 (95 % CI: 47.66-47.85). Males showed higher rates than females (62.26 vs 37.22 per 100,000, rate ratio 1.67). Non-Hispanic Black populations had the highest burden (57.10 per 100,000), while Asian/Pacific Islander populations had the lowest (30.80 per 100,000). For lung cancer, mortality rates were substantially higher when CVD was present, with rate ratios ranging from 1.70 to 2.43; however, this association is likely attributable to profound unmeasured confounding by shared risk factors such as smoking. CONCLUSIONS Cardiovascular disease is listed as a contributing factor in nearly one-third of all cancer deaths, with distinct demographic patterns. These findings highlight the significant burden of cardiovascular comorbidities documented on death certificates at the end of life for cancer patients.