Abstract
BACKGROUND: There were racial disparities in treatment and mortality among patients with colorectal cancer, but few studies incorporated information on hypertension and diabetes and their treatment status. PATIENTS AND METHODS: The study identified 101,250 patients from Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database in the United States who were diagnosed with colorectal cancer at age ≥65 years between 2007 and 2015 with follow-up to December 2016. RESULTS: There were substantial racial and ethnic disparities in the prevalence of hypertension and diabetes in patients with colorectal cancer, in receiving chemotherapy and radiation therapy, and in receiving antihypertensive and antidiabetic treatment. Racial disparities in receiving these therapies remained significant in this large cohort of Medicare beneficiaries after stratifications by private health insurance status at the time of cancer diagnosis and by tumor stage. Non-Hispanic black patients had a significantly higher risk of all-cause mortality (hazard ratio: 1.07, 95% CI: 1.04-1.10), which remained significantly higher (1.05, 1.02-1.08) after adjusting for patient sociodemographics, tumor factors, comorbidity and treatments as compared to non-Hispanic white patients. The adjusted risk of colorectal cancer-specific mortality was also significantly higher (1.08, 1.04-1.12) between black and white patients. CONCLUSIONS: There were substantial racial disparities in prevalence of hypertension and diabetes in men and women diagnosed with colorectal cancer and in receipt of chemotherapy, radiation therapy, antihypertensive and antidiabetic treatment. Black patients with colorectal cancer had a significantly higher risk of all-cause mortality and colorectal cancer-specific mortality than whites, even after adjusting for sociodemographic characteristics, tumor factors, comorbidity scores, and treatments.