[Prognosis predictor of chronic-stage acute myocardial infarction]

An investigation of acute myocardial infarction (AMI) was performed in Obihiro City, Hokkaido from October 1.1990 to March 31.1996. Based on the recorded cases, we conducted an investigation on the progress of 194 survivors by questionnaires, and we investigated the factors affecting long-term prognosis of AMI. The mean follow-up period was 1.62 years. The mean age at onset and frequency of hypertension were higher in women than in men. On the other hand, a larger percentage of men smoked and drank alcohol. Kaplan-Meier analysis showed that survival was strongly influenced by aging, drinking, prior history of AMI or stroke, renal dysfunction, cardiac failure and early rehabilitation. Using Cox's hazard model, it was found that mortality risk increases 1) by 1.5 times for an increase of 10 years in age (2.6-times higher for people over 65 years old), 2) by 2.5 times for people with a history of AMI or stroke, 3) by 4.6 times for people with renal dysfunction, and 4) by 5.7 times for people with cardiac failure of Killip class III or IV. On the other hand, it was found that mortality risk decreases 1) by 0.3 times for people who drink alcohol, 2) by 0.1 times for people who have undergone PTCA, and 3) by 0.3 times for people who have undergone rehabilitation. The mortality risk is high for people who do not drink alcohol and those who have not undergone rehabilitation using Cox's hazard model adjusted all those factors. In conclusion, prognostic predictor in chronic-stage acute myocardial infarction are aging, drinking, prior history of AMI or stroke, renal dysfunction, cardiac failure, early rehabilitation, and PTCA. The results also indicated that, regardless of the historical and clinical characteristics, early rehabilitation is very important to increase the probability of long-term survival.