The rising incidence of colorectal cancer (CRC) and cardiovascular diseases, driven by aging populations and lifestyle changes, highlights congestive heart failure (CHF) as a critical comorbidity that significantly affects survival and treatment decisions in CRC patients. CHF not only affects survival outcomes but also complicates clinical decision-making. This study aims to investigate the impact of CHF on mortality among CRC survivors and explore potential factors of mortality.

This cohort study analyzed data from the Taiwan Cancer Registry and National Health Insurance Research Database. CRC patients aged 20 years or older (ICD-10-CM: C18–C20) who survived at least five years after diagnosis were included. After a 1:4 exact matching based on age, sex, and clinical stage, Cox regression was used to estimate mortality risk between CRC survivors with and without CHF.

A total of 535 CRC survivors with CHF and 2140 without CHF were enrolled in this study after matching. CRC survivors with CHF had a significantly higher overall mortality rate than those without CHF (36.64% vs. 15.23%, p < 0.001). After adjusting for potential confounders, CRC survivors with CHF had 1.93-folds risk of mortality (95% CI: 1.54–2.41, p < 0.001) compared to those without CHF. Subgroup analyses by sex, age, clinical stage, Charlson Comorbidity Index (CCI), and treatment types also show that CRC survivors with CHF had significantly higher mortality risk than those without CHF. The top three highest mortality risk ratios were observed in subgroups with a CCI score of 0 (AHR: 2.63, 95% CI: 1.08–6.39), age < 65 years (AHR: 1.87, 95% CI: 1.23–5.57), and advanced clinical stage (AHR: 2.03, 95% CI: 1.51–2.72).

CRC survivors with CHF demonstrated significantly higher overall mortality compared to those without CHF. This finding presented the prognostic impact of CHF in CRC survivors, so integrated care and early cardiovascular monitoring are essential to improve long-term outcomes.