All-Cause and Disease-Specific Mortality Among U.S. Adults Living With Co-Existing Cancer and Atherosclerotic Cardiovascular Disease

BACKGROUND: Despite increasing evidence on the bi-directional association between cancer and atherosclerotic cardiovascular disease (ASCVD), less is known about differences in mortality among individuals with co-existing diseases. OBJECTIVE: We examined all-cause and disease-specific mortality among U.S. adults living with cancer, ASCVD, and co-existing cancer and ASCVD. METHODS: Among adults aged ≥18 years in the National Health Interview Survey (2005-2018) linked to the National Death Index (through December 31, 2019), we estimated multivariable-adjusted HRs (aHRs) and 95% CIs using Cox proportional hazards models. Mortality outcomes were compared across individuals with cancer alone, ASCVD alone, and co-existing conditions, relative to those with neither condition. RESULTS: Among 388,632 individuals, 1.3% had co-existing cancer and ASCVD, representing approximately 3.0 million U.S. adults annually. Over a mean follow-up of 7.2 years, co-existing disease was associated with the highest all-cause mortality (aHR, 2.45 [95% CI: 2.23-2.70]), exceeding ASCVD alone (aHR, 1.93 [1.82-2.04]) and cancer alone (aHR, 1.90 [1.77-2.04]). Co-existing disease was associated with elevated risks of both cancer mortality (aHR, 4.18 [3.48-5.03]) and cardiovascular mortality (aHR, 2.73 [2.30-3.24]). Among those living with co-existing diseases, older age (≥75 years) (aHR, 6.02 [1.97-18.37]), diabetes (aHR, 1.23 [1.03-1.46]), and current/former smoking status (aHR, 1.26 [1.07-1.49]) were associated with increased hazards of all-cause mortality. CONCLUSIONS: Among community-dwelling U.S. adults living with cancer and/or ASCVD, co-existing disease was associated with substantially higher mortality. These findings highlight the elevated burden of mortality among individuals with co-existing cancer and ASCVD and underscore the importance of integrated cardio-oncology care.