Trends in Colorectal Cancer Testing Among Medicare Subpopulations

Background: In 1998, Medicare initiated universal coverage for colorectal cancer (CRC) screening via fecal occult blood testing (FOBT) and sigmoidoscopy. In mid-2001, universal coverage was advanced to screening colonoscopy. This study sought to determine whether trends in CRC testing differed among racial/ethnic, age, or gender subgroups of the Medicare population. Methods: In 2006, claims from 1995 to 2003 were analyzed for annual 5% random samples of fee-for-service Medicare enrollees living in Surveillance, Epidemiology, and End Results (SEER) regions to calculate the annual, age-standardized percentages of subjects who received FOBT, sigmoidoscopy, or colonoscopy. Logistic regression then modeled trends in annual test use within racial/ethnic, age, and gender subgroups across three Medicare coverage periods (precoverage [1995-1997]; limited coverage [1998-mid-2001]; and full coverage [mid-2001-2003]). Results: The annual use of FOBT and sigmoidoscopy declined from 1995 to 2003 in all racial/ethnic groups, but the relative decline in sigmoidoscopy use was greater among whites compared to nonwhites. In contrast, colonoscopy use increased substantially in all racial/ethnic groups. However, relative to the precoverage period among whites, the full-coverage period was associated with significantly greater colonoscopy use among whites (OR=2.14; 95% CI=2.09, 2.19) than blacks (OR=1.86; 95% CI=1.75, 1.96); Asian/Pacific Islanders (OR=1.73; 95% CI=1.62, 1.86); or Hispanics (OR=1.65; 95% CI=1.49, 1.81). The use of colonoscopy during the full-coverage period was also differentially greater among enrollees aged <80 years. CRC testing trends were similar among male and female enrollees. Conclusions: Colonoscopy is supplanting sigmoidoscopy as a CRC test among Medicare enrollees, while FOBT use is in decline. The transition from sigmoidoscopy to colonoscopy has occurred more quickly among white than nonwhite Medicare enrollees.