Comorbidities in relation to fatality of first myocardial infarction

Abstract

Introduction: Present knowledge concerning potential associations between comorbidities and the fatality of a first myocardial infarction (MI) is limited.

Aim: To identify comorbidities in 45-70-year-old individuals who suffered a first MI and died within 7 days in Stockholm County from 1992-1994. In addition, to assess how each of the comorbidities identified, as well as the number of hospitalizations during the 10-year period prior to the MI, was associated with MI fatality.

Methods: The data collected on our inception cohort of 1984 first MI, of which 524 were fatal within 7 days, were primarily self-reported, proxy-reported by questionnaire and/or extracted from comprehensive national registers. Comorbidities among fatal cases with a prevalence >2% were identified. Risk ratios (with 95% confidence intervals) for the association of MI fatality with number of prior hospitalizations and specific comorbidities were calculated using binomial regression with log link. A structured review of autopsy reports on fatal cases was performed in order to identify additional indicators of comorbidities.

Results: After adjusting for sex, age and disposable income, the number of previous hospitalizations was associated with 7-day MI fatality. Of the comorbidities identified as prevalent in fatal cases, the following were associated with 7-day fatality in crude analysis: epilepsy, heart failure, stroke, alcoholism, cancer, renal diseases, asthma, psychiatric diseases, diabetes, and rheumatoid arthritis. Indicators of comorbidities identified from autopsy data included a silent MI, severe atherosclerosis of the abdominal aorta, and hepatic steatosis. Adjustments for sex and age (although not possible for epilepsy and alcoholism), did not substantially alter results.

Conclusions: Our current findings indicate that in connection with a first MI, particular attention should be paid to those with repeated prior hospitalizations and/or epilepsy, heart failure, stroke, alcoholism, cancer, renal diseases, asthma, psychiatric diseases, diabetes and rheumatoid arthritis.

Keywords: Comorbidity; Fatality; Myocardial infarction.