Type 2 diabetes: incremental medical care costs during the first 8 years after diagnosis.

OBJECTIVE: To describe and analyze the time course of medical care costs caused by type 2 diabetes, from the time of diagnosis through the first 8 postdiagnostic years. RESEARCH DESIGN AND METHODS: From electronic health maintenance organization (HMO) records, we ascertained the ongoing medical care costs for all members with type 2 diabetes who were newly diagnosed between 1988 and 1995. To isolate incremental costs (costs caused by the diagnosis of diabetes), we subtracted the costs of individually matched HMO members without diabetes from costs of members with diabetes. RESULTS: The economic burden of diabetes is immediately apparent from the time of diagnosis. In year 1, total medical costs were 2. 1 times higher for patients with diabetes compared with those without diabetes. Diabetes-associated incremental costs (type 2 diabetic costs minus matched costs for people without diabetes) averaged 2, 257 per type 2 diabetic patient per year during the first 8 postdiagnostic years. Annual incremental costs varied relatively little over the period but were higher during years 1, 7, and 8 because of higher-cost hospitalizations for causes other than diabetes or its complications. CONCLUSIONS: For the first 8 years after diabetes diagnosis, patients with type 2 diabetes incurred substantially higher costs than matched nondiabetic patients, but those high costs remained largely flat. Once the growth in costs due to general aging is controlled for, it appears that diabetic complications do not increase incremental costs as early as is commonly believed. Additional research is needed to better understand how diabetes and its diagnosis affect medical care costs over longer periods of time.