Right Regional Variations in Medical Expenditure and Hospitalization Days for Heart Attack Patients in Japan: Evidence from the Tokai Acute Myocardial Study (TAMIS) by

The use of percutaneous transluminal coronary angioplasty (PTCA), a costly high-tech treatment for patients with acute myocardial infarction (AMI), is much more frequent in Japan than in other developed countries, resulting in large medical expenditure. Using chart-based data from the Tokai Acute Myocardial Infarction Study (TAMIS) and exploiting regional variations, we explore what factors explain the intensive use of PTCA in Japan, employing propensity score matching to estimate the average treatment effects on hospital expenditure and hospital days. We find that the probability of receiving high-tech treatment is affected by a patient’s characteristics as well as the density of medical resources in a region. Moreover, once heterogeneity between treated and non-treated patients is adjusted for, medical expenditure is higher for treated patients while there are no significant differences in hospitalization days. Our findings imply that the higher medical costs resulting from high-tech treatments are not associated with better outcomes and that the frequent use of high-tech treatments is economically motivated. JEL classification: I11