Trends in Colorectal Cancer Testing Among Medicare Subpopulations
published online 11 July 2008.
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.
aDepartment of Family and Community Medicine, Sacramento, California
bUniversity of California Davis Cancer Center, Sacramento, California
cDepartment of Public Health Sciences, University of California Davis, Sacramento, California
dDepartment of Sociology, University of Utah, Salt Lake City, Utah
eDepartment of Family Medicine, University of Washington, Seattle, Washington
Address correspondence and reprint requests to: Joshua J. Fenton, MD, MPH, Department of Family and Community Medicine, University of California Davis, 4860 Y Street, Suite 2300, Sacramento CA 95817.
ABSTRACT