The JSIC nationwide database for cost analysis of percutaneous transluminal coronary angioplasty (PTCA) in Japan. Part 2: Multivariate analysis of initial in-hospital charge and the inter-hospital difference

Background: When the inter-hospital difference in treatment process is larger than the difference of the patients' attribute case-mix, the complete compliance with treatment guideline should be given higher priority than DRG/PPS (Diagnosis Related Groups/Prospective Payment System) in terms of health care policy. Objective: The magnitude of inter-hospital statistical difference among factors contributing to variability in the in-hospital charge for initial coronary angioplasty (PTCA) was determined for the first time by multivariate analysis. Methods: Thirty seven institutions have constructed a database with a total of 1,914 patients including 50 consecutive PTCA cases from each hospital. Patients were divided into two groups, 675 cases with acute myocardial infarction (AMI) and a non-AMI group of 1,239 patients. Partial R square (R: correlation coefficient) was used as an assessment parameter comparing each factor. Inter-hospital differencs were divided into two aspects: hospital characteristics as a structural factor, and hospital code as the treatment process including operator characteristics but excluding hospital characteristics. Results: Partial R-square for hospital code was as high as 20% in the AMI group, while it was as low as 4% in non-AMI group. Conclusion: PTCA treatment for AMI patient should adhere strictly to the guideline, while in-hospital chargs for non-AMI should be reimbursed under the DRG/PPS.