Analysis of yearly variations in drug expenditure for one patient using data warehouse in a hospital.

Medical expense has grown rapidly in Japan. It could be caused by the increase of the patient number and the increase of medical expense per patient. We studied the latter factor on drug expenditure from 1996 to 2002 using the prescription data stored in the data warehouse of one hospital. We found that the drug expenditure per patient had increased 1.32 times. The mean number of prescriptions per patient increased 1.23 times and the mean expenditure of one medicine increased 1.08 times. These results demonstrated that drug expenditure for one patient had gradually increased. This was caused by both the rise in the number of medicines taken by one patient and the rise in the prices of medicines. The data warehouse in the hospital was useful for the analysis of the trends in medical expenditure for one patient.