Colorectal cancer screening in the elderly population: disparities by dual Medicare-Medicaid enrollment status

Health Serv Res. 2006 Dec;41(6):2136-54. doi: 10.1111/j.1475-6773.2006.00585.x.


Objectives: To assess the disparities in colorectal cancer (CRC) screening between elderly dual Medicare-Medicaid enrollees (or duals), the most vulnerable subgroup of the Medicare population, and nonduals.

Data sources/study setting: The 1999 Medicare Denominator File, the Medicare Outpatient Standard Analytic Files, and Physician Supplier Part B files. In addition, the 1998 Area Resource File was used as a source for county-level attributes.

Data collection/extraction methods: CRC screening procedures for 1999-fecal occult blood test (FOBT), flexible sigmoidoscopy (FLEX), colonoscopy with FOBT and/or FLEX (COL-WFF), and colonoscopy only (COL-ONLY)-were extracted from claim records, using diagnostic and procedure codes. Duals (n = 2.5 million) and nonduals (n = 20.2 million) receiving their care through the fee-for-service system were identified from the Denominator file. Hierarchical logistic regression analysis was conducted to adjust for individual- and county-level characteristics.

Principal findings: Compared with nonduals, duals were disproportionately represented by female, older-old, and minority individuals (respectively 74.4 versus 58.5 percent; 19.3 versus 10.8 percent; 35.7 versus 8.0 percent), and CRC screening was significantly lower in duals than in nonduals (5.1 versus 12.2 percent for FOBT adjusted odds ratio [AOR]: 0.48, 95 percent confidence interval [CI]: 0.45-0.51); 0.7 versus 1.9 percent for FLEX, (AOR: 0.55, 95 percent CI: 0.49-0.61); 0.4 versus 0.8 percent for COL-WFF (AOR: 0.60, 95 percent CI: 0.54-0.67); and 1.8 versus 2.5 percent for COL-ONLY (AOR: 0.85, 95 percent CI: 0.80-0.89); p < .001 for all comparisons.

Conclusions: Duals are significantly less likely than nonduals to undergo CRC screening, even after adjusting for individual- and county-level covariates. Future studies should evaluate the contribution of comorbidity and low socioeconomic status to these disparities.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Algorithms
  • Colorectal Neoplasms / diagnosis*
  • Cross-Sectional Studies
  • Female
  • Health Services Research
  • Humans
  • Insurance Coverage / statistics & numerical data*
  • Logistic Models
  • Male
  • Mass Screening / methods
  • Mass Screening / statistics & numerical data*
  • Medicaid*
  • Medicare*
  • United States