Medicare recipients may choose to skip mammograms due to small co-pay. Source: Baptist Health South Florida

Relatively small co-payments by Medicare managed plans were associated with significantly lower mammography rates among women who should undergo screening mammography according to accepted clinical guidelines, according to a new study in the Jan. 23 issue of the New England Journal of Medicine.

Amal N. Trivedi, MD, of Brown University in Providence, R.I., and colleagues, examined the policies that increase patients' share of healthcare expenses, decreasing the use of discretionary health services but also may reduce the use of important preventive care, such as mammography.

The researchers reviewed coverage for mammography within 174 Medicare-managed care plans from 2001 through 2004.

Among 550,082 individual-level observations for 366,475 women between the ages of 65 and 69 years, they compared rates of biennial breast cancer screening in plans requiring cost sharing for mammography with screening rates in plans with full coverage. The researchers also performed a longitudinal analysis of screening rates in plans that changed from full coverage to cost sharing for mammography as compared with rates in matched control plans that did not institute cost sharing.

The authors noted the number of plans with cost sharing for mammography, which was defined as requiring a copayment of more than $10 or coinsurance of more than 10 percent for screening mammography, increased from three in 2001 (representing 0.5 percent of women) to 21 in 2004 (11.4 percent of women).

Triveldi and colleagues reported that the biennial screening rates were 8.3 percentage points lower in cost-sharing plans than in plans with full coverage, a difference that persisted in adjusted analyses. They found that the effect of cost sharing was magnified among women residing in areas of lower income or educational levels. Screening rates decreased by 5.5 percentage points in plans that instituted cost sharing and increased by 3.4 percentage points in matched control plans that retained full coverage, the researchers said.

Cost sharing disproportionately affected vulnerable population groups including black women and those living in areas of lower income or educational levels, the authors wrote.

In an accompanying editorial, Peter B. Bach, MD, of Memorial Sloan-Kettering in New York, said that the findings of the study raise a challenging health policy question: “How, if at all, should cost sharing be incorporated into the design of health insurance?”

Trivedi and colleagues suggested that cost sharing should be waived for mammography among Medicare enrollees.