The prevalence of chronic health conditions among colorectal cancer cases and controls and their impact on case survival.

Abstract

This study describes the interview-reported prevalence of hypertension, heart disease, stroke, diabetes, and respiratory disease in a population-based cohort of Black or White colon cancer cases (n = 2931), rectum cancer cases (n = 1304), and controls (n = 3749) in Metropolitan Detroit. Two-thirds of all newly diagnosed colorectal cancer cases and controls were found to have at least one, and nearly one-third of all subjects to have two or more, of these conditions. Hypertension and heart disease ranked as respectively, the first and second leading conditions for every group of age, race, gender, and subject type except White male colorectal cancer cases aged seventy-five and older; in this subset of the population, heart disease ranked as the most prevalent condition. Overall, respiratory disease, whose prevalence is followed by diabetes and stroke, represented the third most frequent of these chronic conditions. Case-control differences in the prevalence of each condition are reported and the associations of each condition with age, race, gender, pack-years of smoking, years of education, work status, and subject type are evaluated in multivariate analyses. With few exceptions, most notably diabetes and hypertension, the prevalence of chronic health conditions among colorectal cancer cases did not differ from that reported by controls. The influence of each condition on all-cause mortality is assessed in both case groups through proportional hazards models adjusted for race, age at cancer diagnosis, stage of the cancer at diagnosis, pack-years of smoking, and years of education. Diabetes, heart disease, and stroke each adversely influenced survival in both colon and rectum cancer cases. Respiratory disease also was an independent predictor of survival among those with colon cancer (relative hazard for respiratory disease = 1.27, 95% confidence interval: 1.10, 1.46). These results illustrate that in addition to commonly considered variables such as gender, race, age at cancer diagnosis, and cancer stage, the survival of colon and rectum cancer patients may be influenced by comorbidity as well as smoking history and socioeconomic status. The implications of this research and directions for future studies are discussed.