Evaluation of Acute Myocardial Infarction In-hospital Mortality Using a Risk-adjustment Model Based on Japanese Administrative Data

Abstract

This study aimed to develop a new risk-adjustment method to assess acute myocardial infarction (AMI) in-hospital mortality. Risk-adjustment was based on variables obtained from administrative data from Japanese hospitals, and included factors such as age, gender, primary diagnosis and co-morbidity. The infarct location was determined using the criteria of the International Classification of Diseases (10th version). Potential co-morbidity risk factors for mortality were selected based on previous studies and their critical influence analysed to identify major co-morbidities. The remaining minor co-morbidities were then divided into two groups based on their medical implications. The major co-morbidities included shock, pneumonia, cancer and chronic renal failure. The two minor co-morbidity groups also demonstrated a substantial impact on mortality. The model was then used to assess clinical performance in the participating hospitals. Our model reliably employed the available data for the risk-adjustment of AMI mortality and provides a new approach to evaluating clinical performance.