Flat-sum payment systems for treatment costs, such as the Diagnosis Procedure Combination (DPC) system, are now being introduced in medical institutions. Owing to the introduction of such payment systems, hospital pharmacists are now required to be more actively involved in the selection of drugs through the provision of appropriate drug information including that on cost effectiveness. In Japan, however, very few pharmacoeconomic evaluations by hospital pharmacists have been reported to date. In view of this, we conducted a pharmacoeconomic evaluation of HMG-CoA reductase inhibitors using information that hospital pharmacists can obtain comparatively easily.
Referring to an analytical method reported in Britain, we investigated the amounts of four kinds of HMG-CoA reductase inhibitors, Pravastatin, Simvastatin, Fluvastatin, and Atorvastatin, used for each strength in the target medical institutions. Responders to treatment was defined as patients whose lipid values (low density lipoprotein cholesterol and total cholesterol) improved to the level suggested in the 2002 edition of the Japan Atherosclerosis Society Guidelines for Diagnosis and Treatment of Atherosclerotic Cardiovascular Diseases. Based on this, we calculated response rates for the present investigation and other clinical studies conducted in Japan. Drug treatment costs were estimated based on the volume of the drugs administered and the drug prices listed in the National Health Insurance price list.
The results of the current investigation showed that cost effectiveness was highest for atorvastatin followed by simvastatin, fluvastatin, and pravastatin. In addition, they indicated that based on treatment data available in their hospitals, hospital pharmacists are able to make practical pharmacoeconomic evaluations of drugs that reflect the actual practice of treatment.
