The effect of comorbidities on outcomes in colorectal cancer survivors: a population-based cohort study
To examine the prevalence of comorbidities and the association of these comorbidities with demographics, tumor characteristics, treatments received, overall survival, and causes of death in a population-based cohort of colorectal cancer (CRC) patients.
Adult patients with stage I–III CRC diagnosed between 2004 and 2015 were included. Comorbidities were captured using Charlson comorbidity index. Causes of death were categorized using International Classification of Diseases, tenth revision codes. Patients were categorized into five mutually exclusive comorbid groups (cardiovascular disease alone, diabetes alone, cardiovascular disease plus diabetes, other comorbidities, or no comorbidities). Data were analyzed using descriptive statistics, Kaplan-Meier survival analyses, and Cox proportional hazards models.
There were 12,265 patients. Mean follow-up was 3.8 years. Approximately one third of patients had a least one comorbidity, with cardiovascular disease and diabetes being most common. There were statistically significant differences across comorbid groups on treatments received and overall survival. Those with comorbidity had lower odds of treatment and greater risk of death than those with no comorbidity. Those with cardiovascular disease plus diabetes fared the worst for prognosis (median overall survival 3.3 [2.8–3.7] years; adjusted HR for death, 2.27, 95% CI 2.0–2.6, p < .001). Cardiovascular disease was the most common cause of non-CRC death.
CRC patients with comorbidity received curative intent treatment less frequently and experienced worse outcomes than patients with no comorbidity. Cardiovascular disease was the most common cause of non-cancer death.
Implications for Cancer Survivors
Management of comorbidities, including healthy lifestyle coaching, at diagnosis and into survivorship is an important component of cancer care.
KeywordsColorectal Cancer Survival Comorbidities Population Cohort Study Cause of Death
Colleen Cuthbert: conceptualization, formal analysis, and writing, reviewing, and editing. Brenda Hemmelgarn: conceptualization, formal analysis, and writing, reviewing, and editing. Yuan Xu: data abstraction, reviewing, and editing. Winson Cheung: conceptualization, formal analysis, and writing, reviewing, and editing.
Dr. Cuthbert has postdoctoral salary support through the University of Calgary, Cumming School of Medicine Arnie Charbonneau Cancer Institute and O’Brien Institute for Public Health and the Canadian Institutes of Health Research. No additional funding was obtained for this study.
Compliance with ethical standards
This study received approval from the Health Research Ethics Board of Alberta (HREBA.CC-17-0034-REN1). Study findings are reported according to Strengthening of the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.
Conflict of interest
The authors declare that they have no conflict of interest.
Research involving human subjects
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required.
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