Type 2 diabetes: Incremental medical care costs during the 8 years preceding diagnosis

OBJECTIVE - To describe and analyze medical care costs for the 8 years prec eding a diagnosis of type 2 diabetes. RESEARCH DESIGN AND METHODS - From electronic records of a large group-mode l health maintenance organization (HMO), we ascertained the medical care co sts preceding diagnosis for all members with type 2 diabetes who were newly diagnosed between 1988 and 1995. To isolate incremental costs (costs cause d by the future diagnosis of diabetes), we subtracted the costs of individu ally age- and sex-matched HMO members without impending diabetes from the c osts of members who were destined to receive this diagnosis. We also compar ed these prediagnosis costs with the first 3 years of postdiagnosis costs. RESULTS - An economic burden from impending diabetes is apparent for at lea st 8 years before diagnosis, beginning with costs for outpatient and pharma cy services. Diabetes-associated incremental costs (costs of type 2 diabeti c patients minus matched costs of nondiabetic patients) averaged $1,205 per type 2 diabetic patient per year during the first eight prediagnostic year s, including $1,913 each year for the 3 years preceding diagnosis. In the y ear immediately preceding diagnosis, incremental costs were equivalent to t hose observed in the second and third years after diagnosis. CONCLUSIONS - Incremental costs of diabetes begin at least 8 years before d iagnosis and grow at an accelerating rare as diagnosis approaches and immed iately after diagnosis. These incremental costs span the full range of medi cal services. Furthermore, the majority of these costs are for conditions n ot normally associated with diabetes or its complications.