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.

Management of comorbidities, including healthy lifestyle coaching, at diagnosis and into survivorship is an important component of cancer care.