Abstract
Diagnosis Procedure Combinations (DPCs), which are American DRG-like units used for a Japanese new medical payment system, were introduced on April 1, 2003 for 82 hospitals providing advanced medical care. This study analyzed the distribution patterns of length of stay (LOS) of several DPCs and their influencing factors on LOS to establish hospital-wide quality management systems. The LOS distributions of two groups, malignant tumors of the liver and intrahepatic bile duct, and cataract and lens-related diseases, showed a wide range and were negatively skewed. While a given DPC seems a more homogeneous patient group because it is classified by use of procedures, comorbidity, and post-treatment clinical conditions, the LOS distribution still showed a wide range. Each DPC has four types of payment fees depending on the LOS. Approximately half of the patients showed LOS below the national average, which is desirable from a hospital financial management point of view. Differences in LOS for the same DPC could not always be explained by the clinical variables preliminarily collected for the new payment system. Therefore, data warehouse needs to be established, which includes clinical variables for risk adjustment as well as variables related to inpatient management systems.
