Background: Poorer survival in cancer patients with vs. without comorbidity has been reported for various cancer sites. For patients with colorectal cancer (CRC), limited data are available so far.
Methods: Patients with CRC diagnosed between 2010 and 2018 were identified in a health claims database covering 20% of the German population. We assessed the prevalence of comorbidities at cancer diagnosis and categorized the patients into the groups: 'none', 'somatic only', 'mental only' or 'both' types of comorbidities. Hazard ratios (HR, with 95% confidence intervals) for five-year overall survival were estimated by Cox proportional hazard models, adjusted for age, sex and stage at diagnosis (advanced vs. non-advanced).
Results: We included 92,991 patients (females: 49.1%, median age: 72 years) with a median follow-up of 30 months. The proportions assigned to the groups 'none', 'somatic only', 'mental only' or 'both' were 24.7%, 65.5%, 1.4% and 8.4%. Overall, 32.8% of the patients died during follow-up. Compared to patients without comorbidities ('none'), the adjusted HR regarding death from any cause was 1.11 (95% CI: 1.07-1.14) in the group 'somatic only', 1.74 (95% CI: 1.58-1.92) in the group 'mental only' and 1.92 (95% CI: 1.84-2.00) in the group 'both'. For patients with 'mental only' comorbidities, the adjusted HR was higher in males than in females (HR = 2.19, 95% CI: 1.88-2.55 vs. HR = 1.55, 95% CI: 1.37-1.75).
Conclusions: Our results suggest that patients with CRC and with mental comorbidities, particularly males, have a markedly lower overall survival compared to those without any or only somatic comorbidities.
Keywords: Colorectal cancer; comorbidity; mental health; risk factors; survival.