OBJECTIVES:Diabetes mellitus is an important chronic disease with a growing prevalence that absorbs an ever increasing investment of resources. This study described the prevalence and the cost of diabetic care using sampling claim data from the National Health Insurance Program in Taiwan. METHODS:Five-year (1997~2001) random sampling claimed database were prepared by the National Health Research Institute, Taiwan, R.O.C. The database contains 200,000 individuals' longitudinal medical claim data (0.9% Taiwan population), including outpatient and inpatient care records. Patients with the ICD-9-CM code of 250 in their primary diagnosis column were used in the analysis. RESULTS:The prevalence rate of diagnosed diabetes patients from 1997 to 2001 was 2.42%, 2.57%, 2.61%, 2.67% and 2.74%, respectively. This rate increased 12.8% in 5 years. The average total direct medical cost per patient per year increased 18%, from 10,479 NTD in 1997 to 12,811 NTD in 2001.The average number of outpatient visit increased from 7.4 in 1997 to 7.8 times in 2001. The average cost of outpatient care per patient per year increased 27%, from 7,680 NTD in 1997 to 10,016 NTD in 2001. The average inpatient care cost per hospitalization increased 60%, from 29,908 NTD in1997 to 48,071 NTD in 2001. Finally, the average total drug cost increased 31%, from 5,487 NTD in 1997 to 7,209 NTD in 2001. All costs did not adjust for inflation. CONCLUSION:The direct medical cost for diabetes care increased rapidly in these 5 years, the rate increased faster then the prevalence rate. The rate of drug cost increased more then that of the total medical cost. Although the representative of that sampling data needs verification, the preliminary data indicate that outpatient expenditure increased significantly. The appropriateness of resource utilization and quality of diabetes care need more stringent management.