Early mortality after acute myocardial infarction: observational study in Yamagata, 1993-1995

Although considerable information is available regarding the prognosis after acute myocardial infarction (AMI) in Western populations, little is known about the fate of Japanese subjects after AMI. The purpose of this study was to assess short-term mortality and factors influencing it after AMI in Japan. From April 1993 to December 1995, 1,014 patients with AMI from 41 hospitals in Yamagata Prefecture were registered by cardiologists for the prospective survey. Among patients who died within 28 days after the onset of AMI, immediate causes of death were examined and the clinical profiles of these subjects were compared with those of patients that survived. Early death occurred in 184 patients (short-term mortality 18%). Patients who died were significantly older than survivors (76.1+/-9.4 vs 67.6+/-11.8 years, p<0.01). They were also more likely to be women (50% vs 31%, p<0.01), to have had hypertension (64% vs 54%, p<0.05), diabetes mellitus (29% vs 20%, p<0.02), prior MI (17% vs 12%, p<0.05), or Killip class III or IV disease (63% vs 15%, p<0.01), and were significantly less likely to be current smokers (26% vs 45%, p<0.01) or to have been treated with reperfusion therapy (27% vs 63%, p<0.01). Multivariate logistic analysis demonstrated that independent predictors of early death were Killip class III or IV and advanced age. Reperfusion therapy was a negative predictor of death. Patients who died had arrived at hospital earlier than patients who survived. Mortality as a result of heart failure, cardiac rupture, or arrhythmia fell exponentially after the onset of AMI. Thus, the predictors of short-term mortality were similar to those reported in Western populations. More deaths occurred just after the onset of disease, suggesting that early therapy is important in reducing short-term mortality.