Insurance Status, Comorbidity Level, and Survival Among Colorectal Cancer Patients Age 18 to 64 Years in the National Cancer Data Base From 2003 to 2005

Abstract

PurposePrevious analyses have found that insurance status is a strong predictor of survival among patients with colorectal cancer aged 18 to 64 years. We investigated whether differences in comorbidity level may account in part for the association between insurance status and survival.MethodsWe used 2003 to 2005 data from the National Cancer Data Base, a national hospital-based cancer registry, to examine the relationship between baseline characteristics and overall survival at 1 year among 64,304 white and black patients with colorectal cancer. In race-specific analyses, we used Cox proportional hazards models to assess 1-year survival by insurance status, controlling first for age, stage, facility type, and neighborhood education level and income, and then further controlling for comorbidity level.ResultsComorbidity level was lowest among those with private insurance, higher for those who were uninsured or insured by Medicaid, and highest for those insured by Medicare. Survival at 1 year was significantly poorer for patients without private insurance, even after adjusting for important covariates. In these multivariate models, risk of death at 1 year was approximately 50% to 90% higher for white and black patients without private insurance. Further adjustment for number of comorbidities had only a modest impact on the association between insurance status and survival. In multivariate analyses, patients with ≥ three comorbid conditions had approximately 40% to 50% higher risk of death at 1 year.ConclusionAmong white and black patients aged 18 to 64 years, differences in comorbidity level do not account for the association between insurance status and survival in patients with colorectal cancer.