The aim of this research was to find out the costs of diabetes, as research in a prospective cohort study looking into the development of diabetic complications followed by treatment intervention by a medical institution. The research compared the changes in medical costs by following-up on the treatment details of diagnosed diabetes for the last 10 years in a university hospital.

The research used data of outpatient, inpatient, pharmaceutical and total medical costs, from 1996 to 2005, of individual patients who were diagnosed with diabetic patients, to analyze the outpatient and inpatient total medical cost changes over the years.

After antidiabetic drug, in the case of outpatient treatment, pharmaceutical costs increased on average by about 25,000 won a month for diabetic patients without complications and by 35,000 won for diabetic patients with microvascular complications. Outpatient medical costs were affected after drug treatment by as much of an increase as created by the pharmaceutical costs. The total medical costs, that is the sum of inpatient and outpatient costs, decreased by 30~40% compared to that before drug treatment. In the case of total medical cost, MI or ESRD cost 2~3 times more in pharmaceutical costs than before the development of complications. The total medical costs of diabetic patients with CVA, MI and ESRD complications increased in the first year after development of the complication, and this was followed by a decrease in the next year, showing a tendency to remain constant with no increase or decrease over subsequent years. This means that the total medical costs of patients with complications remain continuously large throughout the life of the diagnosed patient.

For diabetic patients, pharmaceutical costs are the most important factor in determining outpatient medical costs.