Primary care utilization and colorectal cancer outcomes among Medicare beneficiaries

Primary medical care may improve colorectal cancer (CRC) outcomes through increased use of CRC screening tests and earlier diagnosis. We examined the association between primary care utilization and CRC screening, stage at diagnosis, CRC mortality, and all-cause mortality.

We conducted a retrospective cohort study of patients, aged 67 to 85 years, diagnosed as having CRC between 1994 and 2005 in the Surveillance, Epidemiology, and End Results-Medicare-linked database. Association of the number of visits to primary care physicians (PCPs) in the 3- to 27-month period before the CRC diagnosis and CRC screening, early-stage diagnosis, CRC mortality, and all-cause mortality were examined using multivariable logistic regression and Cox proportional hazards models.

The odds of CRC screening and early-stage diagnosis increased with increasing number of PCP visits (P < .001 for trend). Compared with persons having 0 or 1 PCP visit, patients with 5 to 10 visits had increased odds of ever receiving CRC screening at least 3 months before diagnosis (adjusted odds ratio, 2.60; 95% CI, 2.48-2.72) and early-stage diagnosis (1.35; 1.29-1.42). Persons with 5 to 10 visits had 16% lower CRC mortality (adjusted hazard ratio [AHR], 0.84; 95% CI, 0.80-0.88) and 6% lower all-cause mortality (0.94; 0.91-0.97) compared with persons with 0 or 1 visit.

Medicare beneficiaries with CRC have better outcomes if they have greater utilization of primary care before diagnosis. Revitalization of primary care in the United States may help strengthen the national efforts to reduce the burden of CRC.