Medicare's reimbursement policy was changed in 1998 to provide coverage for screening colonoscopies for patients with increased colon cancer risk.
The reimbursement policy was further expanded in 2001 to cover screening colonoscopies for all individuals.
Dr Cary Gross and colleagues from Connecticut determined whether the Medicare reimbursement policy changes were associated with an increase in either colonoscopy use or early stage colon cancer diagnosis.
Patients in the Surveillance, Epidemiology, and End Results Medicare linked database who were 67 years of age and older, and had a primary diagnosis of colon cancer during 1992 and 2002.
In addition, a group of Medicare beneficiaries who resided in Surveillance, Epidemiology, and End Results areas but who were not diagnosed with cancer were evaluated.
The researchers used multivariate Poisson regression to assess trends in colonoscopy and sigmoidoscopy use among Medicare beneficiaries without cancer.
|Early stage diagnosis increased from 23% in Period 1 to 26% in both Period 2|
|Journal of the American Medical Association|
Among the patients with cancer, stage 1 was classified as early vs all other.
Time was categorized as Period 1, which included no screening coverage from 1992 to 1997.
Period 2 included limited coverage from 1998 and 2001, and Period 3 was a universal coverage from 2001 to 2002.
The researchers used a multivariate logistic regression was used to assess temporal trends in stage at diagnosis; an interaction term between tumor site and time was included.
Colonoscopy use increased from an average rate of 285 per 100,000 per quarter in Period 1 to 889.
The team observed that colonoscopy use increased at a rate of 1919 per 100,000 per quarter in Periods 2, and 3, respectively.
During the study period, the researchers diagnosed 44,924 eligible patients with colorectal cancer.
The proportion of patients diagnosed at an early stage increased from 23% in Period 1 to 26% in both Period 2 and Period 3.
The research team found that changes in Medicare coverage were strongly associated with early stage at diagnosis for patients with proximal colon lesions.
However, the team observed a weak association, if any at all, for patients with distal colon lesions.
Dr Gross' team concludes, “Expansion of Medicare reimbursement to cover colon cancer screening was associated with an increased use of colonoscopy for Medicare beneficiaries, and for those who were diagnosed with colon cancer, an increased probability of being diagnosed at an early stage.”
“The selective effect of the coverage change on proximal colon lesions suggests that increased use of whole-colon screening modalities such as colonoscopy may have played a pivotal role.”