Evaluation of the inclusive payment system based on the diagnosis procedure combination with respect to cataract operations in Japan------A comparison of lengths of hospital stay and medical payments among hospitals

Following the recommendations of a report submitted by the Central Social Insurance Medical Council concerning the 2002 revision of the Medical Service Fee Schedule, a new inclu-sive payment system, which is based on the Diagnosis Procedure Combination (DPC) sys-tem, was introduced in 82 special functioning hospitals in Japan, effective beginning in April 2003. Since April 2004, the system has been gradually extended to general hospitals that satisfy certain prerequisites. In this paper, the new inclusive payment system is analyzed. Data pertaining to 1,225 patients, who were hospital-ized for cataract diseases and underwent lens operations from July 2004 to September 2005, are used. The lengths of hospital stay and medical payments among hospitals are com-pared. Even after eliminating the influence of patient characteristics, there are large differ-ences among hospitals in average lengths of hospital stay and DPC-based inclusive pay-ments. The highest average inclusive payment is 3.5 times as high as the lowest payment. On the other hand, there are relatively small differ-ences in non-inclusive payments based on the conventional fee-for-service system—the larg-est deviation from the average of all hospitals is approximately 10%. Thus, although payments based on the DPC account for only one-third of the total medical payments for this disease, the major differences in medical payments among hospitals are caused by differences in their DPC-based inclusive payments. The results of the study strongly suggest that revisions of the payment system in Japan are necessary for the efficient use of medical resources in the future.