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CONTEXT:Medicare's reimbursement policy was changed in 1998 to provide coverage forscreening colonoscopies for patients with increased colon cancer risk, andexpanded further in 2001 to cover screening colonoscopies for all individuals. OBJECTIVE:To determine whether the Medicare reimbursement policy changes were associatedwith an increase in either colonoscopy use or early stage colon cancerdiagnosis. DESIGN, SETTING, AND PARTICIPANTS: Patients in the Surveillance,Epidemiology, and End Results Medicare linked database who were 67 years of ageand older and had a primary diagnosis of colon cancer during 1992-2002, as wellas a group of Medicare beneficiaries who resided in Surveillance, Epidemiology,and End Results areas but who were not diagnosed with cancer. MAIN OUTCOMEMEASURES: Trends in colonoscopy and sigmoidoscopy use among Medicarebeneficiaries without cancer were assessed using multivariate Poissonregression. Among the patients with cancer, stage was classified as early(stage I) vs all other (stages II-IV). Time was categorized as period 1 (noscreening coverage, 1992-1997), period 2 (limited coverage, January 1998-June2001), and period 3 (universal coverage, July 2001-December 2002). Amultivariate logistic regression (outcome = early stage) was used to assesstemporal trends in stage at diagnosis; an interaction term between tumor siteand time was included. RESULTS: Colonoscopy use increased from an average rateof 285/100,000 per quarter in period 1 to 889 and 1919/100,000 per quarter inperiods 2 (P<.001) and 3 (P vs 2<.001), respectively. During the studyperiod, 44,924 eligible patients were diagnosed with colorectal cancer. Theproportion of patients diagnosed at an early stage increased from 22.5% inperiod 1 to 25.5% in period 2 and 26.3% in period 3 (P<.001 for eachpairwise comparison). The changes in Medicare coverage were strongly associatedwith early stage at diagnosis for patients with proximal colon lesions(adjusted relative risk period 2 vs 1, 1.19; 95% confidence interval,1.13-1.26; adjusted relative risk period 3 vs 2, 1.10; 95% confidence interval,1.02-1.17) but weakly associated, if at all, for patients with distal colonlesions (adjusted relative risk period 2 vs 1, 1.07; 95% confidence interval,1.01-1.13; adjusted relative risk period 3 vs 2, 0.97; 95% confidence interval,0.90-1.05). CONCLUSIONS: Expansion of Medicare reimbursement to cover coloncancer screening was associated with an increased use of colonoscopy forMedicare beneficiaries, and for those who were diagnosed with colon cancer, anincreased probability of being diagnosed at an early stage. The selectiveeffect of the coverage change on proximal colon lesions suggests that increaseduse of whole-colon screening modalities such as colonoscopy may have played apivotal role.
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