Age-related hospitalization and mortality rates for acute myocardial infarction: The 1969-82 vs. the 1990-94 period

To evaluate how the population aging process influences the incidence and prognosis of acute myocardial infarction (AMI) we compared the age-related hospitalization and mortality rates obsenmd in our Intensive Care Unit (ICU) in the 1939--82 period (2056 patients, pts) with that of the 1990-94 period (546 pts). Pts were divided into four age-groups - A: < 65, B: 65-74, C: 75-84 and D: > 85. In the 1930-94 pedod hospitalization rates significantly increased in elder groups (p < 0.0001, Figure) while mortality decreased in all groups, the reduction being signiticative for pts aged 65-74 and 75-84 (A:from 12.0 to 8.0% ~OR: 0.63, CI 0.36-1.11, NS- B:from 35.0 to 10.7% OR: 0.22, CI 0.13-0.37, p < 0.0001; C: from 42.0 to 25.2%--OR: 0,46, CI 0.31-0.71, p = 0.0003; D: from 50,0 to 31.4% -- OR: 0.46, Ch 0.18-1.15, NS). In the 1990--94 pts age remained a strong prognostic factor, the relative risk (RR) of mortality growing from 1.38 (t3 vs. A, NS) to 3.88 (C vs. A, p< 0.0001) and finally to 5.29 (D vs. A, p < 0.0001). Due to the absence of age-limited treatment criteria, we built a logistic regression model to verify the influence of the most important clinical factors on prognosis. Age (RR = 1.57, p = 0.014), pre-existing left ventricular failure (RR = 6.69, p < 0.0001), the need for mechanical ventilation (RR = 8.78, p < 0.0001) and total parenteral nutrition (RR = 5.86, p = 0.094) were associated with in-hospital death. In conclusion, despite the great reduction in mortality observed in elderly pts, age still represents a negative prognostic factor. The growing incidence of AMI in aged pts compel us to a more and more intensive treatment, so to reduce mortality and post-myocardial infarction disability.