Use of Health Maintenance Organization Data Bases to Study Pharmacy Resource Usage in Diabetes Mellitus

OBJECTIVE: To evaluate use of medications by patients with diabetes. RESEARCH DESIGN AND METHODS: We analyzed the computerized pharmacy data base of a large health maintenance organization to evaluate cost impact and patterns of usage for all pharmacy products by a defined population of diabetic patients. RESULTS: Diabetic patients received 31.2 dispenses/yr compared with 11.5 for control patients. Total pharmacy costs were threefold higher for diabetic patients ($621 vs. 207/yr) and accounted for approximately 17% of their total health-care costs. Products specifically for the care of diabetes averaged $175/yr or approximately 4.5% of their total health-care costs: 57% received an oral hypoglycemic agent, 34% received insulin, and 6% received both. Cardiovascular drugs accounted for 29% of total costs. There was increased use of most classes of medication by patients with diabetes. CONCLUSIONS: Health maintenance organization management data bases, particularly those storing pharmacy dispensing data, provide useful information on the impact of chronic disease. People with diabetes receive a greater number of most types of medication with a greater overall cost than do nondiabetic people. Previous studies have underestimated the contribution of pharmacy purchases to the costs of caring for a diabetic population.