A recent study of the effect of copayments on patient adherence to their medication regimens found that lower copayments led to a statistically significant improvement in patients taking their heart-disease, diabetes, and high-cholesterol drugs.

The 12-month study by researchers at Harvard and the University of Michigan and funded by GlaxoSmithKline and Pfizer investigated the impact on medication adherence of reducing prescription copayments for employees of a leading service industry company that also offered disease management programs. Copayment rates for generic medications were reduced from $5 to $0; copayments for branded drugs were reduced by 50%. A similar employer with identical disease management offerings but stable copayments served as the control group.

The difference in medication use between chronically ill patients at the 2 companies was sizable—even though all the employees in the study were also enrolled in special programs designed to help them take control of their diseases. Just by cutting a few dollars off the copay, the study suggests, employers could increase the chances that employees with chronic illnesses will take certain preventive medicines.

"These results bolster the idea that health insurance benefits should be designed in ways that produce the most per health care dollar spent," noted senior study author Mark Fendrick, MD.

The study is published in the January/February 2008 issue of Health Affairs. For more, information, visit www.med.umich.edu.