Mental health, frequency of healthcare visits, and colorectal cancer screening

Background: Research regarding the association between mental health and colorectal cancer (CRC) screening has produced mixed results. Variations may be explained by methodology, including whether potential confounders such as frequency of healthcare visits are considered. Objective: We examined the association between mental health and CRC screening, before and after controlling for demographics, comorbidities, and outpatient visit frequency. Design: Observational study based on a retrospective cohort. Subjects: A total of 855 veterans receiving care at a Veterans Affairs Medical Center. Measures: Medical record data were used to assess CRC screening rates and mental health status (number of diagnoses and the presence of depression, anxiety, posttraumatic stress disorder, substance, or psychotic disorders). Logistic regression was used to estimate the association between mental health diagnoses and CRC screening, before and after controlling for covariates. Results: Bivariate analyses suggested that CRC screening rates were higher for patients with a history of one or more mental health diagnoses (57% vs. 47%, P < 0.01). However, adjusting for timing of mental health diagnosis and outpatient visit frequency resulted in significant negative associations between CRC screening and all measures of mental health except posttraumatic stress disorder. Conclusions: Estimates of the association between mental health and CRC screening that do not adjust for outpatient visit frequency may be misleading. Veterans with mental health diagnoses were significantly less likely to be screened for CRC than their counterparts with no mental health diagnoses and an equal number of outpatient visits.