NEW HAVEN, Conn. -- Older Americans are flocking to gastroenterologists to take advantage of Medicare's all-beneficiary coverage of colonoscopy screening, and that's paying off in earlier colon-cancer detection, a study here suggested.
NEW HAVEN, Conn., Dec. 20 -- Older Americans are flocking to gastroenterologists to take advantage of Medicare's all-beneficiary coverage of colonoscopy screening, and that's paying off in earlier colon-cancer detection, a study here suggested.
Colonoscopy use has increased by nearly sevenfold since the Medicare changed the rules in 2001 to cover all fee-for-service beneficiaries for screening, reported Cary P. Gross, M.D., of the Yale in the Dec. 20 issue of the Journal of the American Medical Association.
There has been a significant shift toward colon cancer being detected in the earliest stage, Dr. Gross and colleagues reported.
In an effort to see whether Medicare's reimbursement policy, changed in 1998 to cover screening of high-risk patients, and then in 2001 to cover all fee-for-service beneficiaries, was having the intended effect, the researchers analyzed Medicare data on colonoscopy use from 1991 through 2003.
To look for a shift in cancer stage at diagnosis, the researchers also examined data on nearly 45,000 individuals diagnosed with colon cancer during 1992 to 2002 from the Surveillance, Epidemiology, and End Results (SEER) Medicare-linked database
Colonoscopy use increased from an average rate of 285 per 100,000 beneficiaries before screening was covered to 889 per 100,000 after coverage was given to high-risk patients (P<0.001). Use rates increased further to 1,919 per 100,000 after coverage was extended to all (P<0.001), the study found.
The proportion of patients diagnosed with stage I disease also increased from 22.5% before coverage began to 25.5% after coverage was given to high-risk patients (P<0.001). That proportion rose further to 26.3% after reimbursement was extended to all (P<0.001), the study found.
The increase in the use of colonoscopy, compared with a simultaneous decrease in sigmoidoscopy, was manifested by the difference in lesion site diagnoses. The stage shift appeared statistically significant only for proximal lesions, not distal lesions.
For example, after screening coverage was extended to all, the adjusted odds ratio for diagnosis of colon cancer at stage I, compared with the period before coverage was available, was 1.10 (95% confidence interval=1.02 to 1.17; P=0.01) for proximal lesions. However, the odds ratio was 0.97 for distal lesions (95% CI=0.90 to 1.05; P=0.53).
"The selective effect of the coverage change on proximal colon lesions suggests that whole-colon screening modalities such as colonoscopy may have played a pivotal role," the authors said.
"This hypothesis is strongly supported by our finding that there was a significant increase in colonoscopy usage following each of the reimbursement changes, whereas sigmoidoscopy use actually decreased dramatically after the second policy change," they said.
Sigmoidoscopy use decreased from about 692 per 100,000 before the second policy change to about 268 per 100,000 afterward (95% CI=203 to 331), the study found.
The study also found that the policy changes did not affect HMO patients' probability of early-stage diagnosis, in contrast to their favorable effect on fee-for-service patients. "This suggests that the reimbursement change, which was directed toward fee-for-service beneficiaries, was directly associated with the change rather than national secular trends in clinical care," they wrote.
"Our finding that fee-for-service beneficiaries were actually more likely to be diagnosed at an early stage than HMO beneficiaries in the latter time period therefore represents a reversal of earlier findings and reinforces the importance of ensuring reimbursement for effective screening modalities," they continued.
"Our finding that new Medicare policies may have facilitated early diagnosis is encouraging and supports the institution and evaluation of other efforts to broaden the access to and use of screening tests in the older population," the authors concluded.
"Given that there are approximately 60,000 cases of colorectal cancer diagnosed annually among patients 65 years of age and older in the United States, even a 4% increase in the percentage of patients whose cancer is diagnosed at an early stage can have a substantial impact at the population level," they added.
In an accompanying editorial, Arden M. Morris, M.D., M.P.H, of the University of Michigan in Ann Arbor said, "Although there is no direct evidence that colonoscopy use increased due to policy change, it is intuitive that improving reimbursement of screening results in more screening."
He added, "Given the costs of universal screening, if rates of colonoscopy continue to increase without additional benefit in overall diagnosis of early stage disease, policy makers, health care organizations, and physicians may have to devise a feasible rationing plan for broader colon screening."