title: Disparities in colon cancer screening in the Medicare population.
abstract: BACKGROUND
  Colorectal cancer is the third most common cancer in the United States, but the rate of screening remains low. Since 2001, Medicare has provided coverage of colonoscopy for colorectal cancer screening in individuals at average risk, but little is known about the effect of this coverage on screening or disparities in screening practices.
  
  
  METHODS
  We examined the Medicare physician/supplier billing claims file for New York, Florida, and Illinois for the years 2002 and 2003. Using a previously employed algorithm, we identified the rates of colorectal screening tests in individuals at average risk. We performed multivariate logistic regression analysis to calculate the effects of sex, racial/ethnic, and socioeconomic characteristics on screening. We also looked for interactions between socioeconomic and demographic variables.
  
  
  RESULTS
  A total of 596 470 Medicare beneficiaries were included in the study. Approximately 18.3% of the population had undergone a screening colon test during the study period. Nonwhite persons were less likely to be screened for colorectal cancer than were white persons (relative risk [RR], 0.52; 95% confidence interval [CI], 0.50-0.53). The lowest RR of screening colonoscopy in women compared with men was in the oldest age group and the highest income tertile (RR for whites, 0.64; 95% CI, 0.59-0.70). Higher income level was associated with screening colonoscopy in white patients (men: RR, 1.19; 95% CI, 1.14-1.25; women: RR, 1.09; 95% CI, 1.05-1.15) but not in nonwhite patients (men: RR, 0.97; 95% CI, 0.78-1.22; women: RR, 0.94; 95% CI, 0.78-1.14).
  
  
  CONCLUSIONS
  Despite the expansion of Medicare coverage for colorectal cancer screening, there still remain significant disparities between sex and racial/ethnic groups in screening practices.
authors.affiliation: Department of Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Schellhase
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Sparapani
authors.forename: Purushottam W
authors.initials: PW
authors.lastname: Laud
authors.forename: Joan M
authors.initials: JM
authors.lastname: Neuner
mesh_terms: D000367:Age Factors; D000368:Aged; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000208:ethnology; D003938:Diagnostic Techniques, Digestive System / Q000706:statistics & numerical data*; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D005431:Florida; D006801:Humans; D007087:Illinois; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data*; D006278:Medicare / Q000706:statistics & numerical data*; D009518:New York; D012737:Sex Factors; D012959:Socioeconomic Factors; D044465:White People / Q000706:statistics & numerical data*