Health insurance plans have substantially increased the costs that plan members have to pay for prescription drugs. For patients suffering from chronic diseases, large increases in cost-sharing may reduce use of medications that are essential to control their disease, suggests a new study. It found that people with diabetes decreased their use of oral hypoglycemic (OH) medications when their share of medication costs increased by more than $10 for a 30-day supply. Over time, adults with type 2 diabetes, who typically use OH medication, require increases in their OH average daily dose or addition of other hypoglycemic agents such as insulin to achieve good blood-sugar control and avoid complications from diabetes.
Researchers, supported by the Agency for Healthcare Research and Quality's Centers for Education and Research on Therapeutics (CERTs) program (HS10391), analyzed membership, benefit, and pharmacy dispensing data from five managed care organizations. They compared 13,110 12-month episodes of OH use and a medication cost-sharing increase with 13,110 episodes with no increase during 6 months prior to and 6 months after a cost-sharing increase.
Researchers found that 6 months after an increase of more than $10 for a 30-day supply of medication, the OH average daily dose was 18.5 percent less than what would have been expected based on the OH average daily dose before the cost-sharing increase. However, established episodes of OH use with small cost-sharing increases ($1 to $6 per 30-day supply) and no cost-sharing increases had uninterrupted trends in rising OH average daily dose.
See "Effect of increased cost-sharing on oral hypoglycemic use in five managed care organizations: How much is too much?" by Douglas W. Roblin, Ph.D., Richard Platt, M.D., M.Sc., Michael J. Goodman, Ph.D., and others, in the October 2005 Medical Care 43(10), pp. 951-959.