Trends and Inequalities in mortality from ischemic heart disease in adult patients with colorectal cancer: A population-based retrospective study in the United States from 1999 to 2020

Background Ischemic heart disease (IHD) ranks as one of the primary causes of non-cancer mortality in patients with colorectal cancer (CRC). However, population studies examining long-term mortality trends and disparities among various adult populations in the United States remain relatively scarce. Methods This study employed death certificate data from the CDC WONDER spanning 1999 to 2020 to identify adult patients (≥ 25 years old) in the United States who died from colorectal cancer (CRC; ICD-10: C18-C20) as the primary cause of death due to ischemic heart disease (IHD; ICD-10: I20-I25). Age-adjusted mortality rates (AAMRs) and annual percentage changes (APCs) were calculated, and stratified analyses were performed based on gender, age, race, and geographical location. Results Consensus identified 43,395 cases of IHD-related deaths among CRC patients. From 1999 to 2020, the overall AAMR exhibited a significant downward trend, with an average annual percentage change (AAPC) of -8.26 from 2002 to 2016 (p < 0.001), and it appeared to stabilize after 2016. Subgroup analysis indicated notable population differences: the AAMR in men consistently surpassed that in women. The AAMR was highest among the elderly population (aged 65 and above) at 4.36, while it was lower in the middle-aged group at 0.18. In terms of racial and ethnic stratification, non-Hispanic blacks/African Americans recorded the highest AAMR at 0.98. Additionally, the AAMR in the northeastern region was 1.24, exceeding that of other regions. Furthermore, the AAMR in non-urban areas was 0.994, which was higher than the 0.896 observed in urban areas. Conclusion Despite a decline in the overall mortality rate associated with IHD among CRC patients over the past 20 years, notable disparities persist across gender, age, race/ethnicity, and geographical location. These observations underscore the necessity for targeted public health interventions and the strategic allocation of medical resources to mitigate these health inequalities. Special emphasis should be placed on high-risk populations, including men, the elderly, non-Hispanic blacks/African Americans, and individuals residing in rural areas.