Incidence of new-onset depression after colorectal cancer diagnosis and associated mortality: a population-based cohort study
Vicki Cheng, Eric C Sayre, Jonathan M Loree, Sharlene Gill, Rachel A Murphy, Mary A De VeraObjectives
To examine the incidence of and factors associated with new-onset depression following colorectal cancer (CRC) diagnosis and its association with all-cause and CRC-specific mortality.
Design
Population-based retrospective cohort study using linked administrative health databases.
Setting
British Columbia, Canada.
Participants
Individuals diagnosed with CRC from 2010 to 2017 without a history of physician-recorded depression diagnoses in the 5 years preceding the CRC diagnosis.
Main outcome measures
New-onset depression following CRC diagnosis was identified using International Classification of Diseases (ICD)-9 and ICD-10 diagnostic codes. Cumulative incidence and incidence rates of new-onset depression were estimated, and factors associated with new-onset depression were examined using Cox proportional hazards models. Depression was modelled as a time-varying exposure in mortality analyses, with Cox proportional hazards models used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for all-cause and CRC-specific mortality.
Results
Among 13 986 patients with CRC (55.2% males, mean age 66.0), the 5-year cumulative incidence of new-onset depression among those without a history of depression was 6.63% following CRC diagnosis. Incidence rates were highest in the first year post-CRC diagnosis (3.54 per 100 person-years), indicating that new-onset depression was most common early after diagnosis. Factors associated with new-onset depression included female sex (HR 1.40 (95% CI 1.22 to 1.61)) and stage 4 disease (HR 1.77 (95% CI 1.34 to 2.33)). New-onset depression after CRC diagnosis was associated with 97% higher all-cause mortality (HR 1.97 (95% CI 1.74 to 2.23)) and 73% higher CRC-specific mortality (HR 1.73 (95% CI 1.48 to 2.03)).
Conclusions
The cumulative incidence of new-onset depression increased over time, with incidence rates highest in the first year following CRC diagnosis. New-onset depression after CRC diagnosis was associated with higher all-cause and CRC-specific mortality. Findings highlight the importance of early identification of patients at high risk for depression and consideration of longitudinal mental healthcare in CRC care.