Data presented at a recent meeting of the American Geriatrics Society suggests that even small increases in prescription copayment costs have dramatic effects on the number of people who take their medications as prescribed.

Dr. Jalpa Doshi and colleagues from the University of Pennsylvania looked at data from the Veterans Affairs Medical Association (VA) covering prescription and office visit information since 2002, when the VA instituted a $5 increase in the required copayment rate for 30 day prescriptions. After discovering trends that seemed to suggest that fewer patients were taking their medicines as prescribed, the team focused their research on the 24 months prior to the rate increase and the 24 months immediately following the rate increase.

When compared to "category 1" veterans (who have no out of pocket fees for any medical services), all patients who experienced the increase had a declining rate in appropriate medication use after the $5 increase. Even more, the decrease was directly related to the increased cost, even though the actual cost was small. Overall, in the group of patients who had their copay rise by $5, the number of people taking their medications as prescribed fell by about 20%.

The researchers emphasize the importance of proper medication use and have used their study to urge government officials to more carefully consider the outcomes of price increases in the future.