Clinical investigations: acute ischemic heart disease
Obesity and the risk of death after acute myocardial infarction

https://doi.org/10.1016/j.ahj.2003.12.015Get rights and content

Abstract

Background

In the general population, obesity is associated with an increased risk of all-cause death. However, the importance of obesity in patients with established coronary heart disease is less well defined.

Methods

As part of the Determinants of Myocardial Infarction Onset Study, we performed a prospective cohort study of 1898 patients hospitalized with confirmed acute myocardial infarction between 1989 and 1994, with a median follow-up of 3.8 years. We assessed all-cause death through December 1995, using the National Death Index. We categorized patients according to WHO criteria for body mass index (BMI). We compared long-term death according to BMI (kg/m2) by using Cox proportional hazards regression.

Results

Of the 1898 eligible patients, 607 (32%) were normal weight (18.5 to 24.9 kg/m2), 832 (44%) were overweight (25.0 to 29.9 kg/m2), 331 (17%) were class I obese (30.0 to 34.9 kg/m2), and 128 (7%) were class II or more obese (≥35.0 kg/m2). A total of 311 patients died during follow-up. After adjustment for potentially confounding risk factors and excluding patients with noncardiac comorbidity, the risk for death appeared to increase linearly, with increasing BMI across all categories (P for trend = .08). The relative risk of death in all obese patients (≥30 kg/m2) was 1.46, compared with those with normal weight (95% CI, 0.98 to 2.17).

Conclusions

We found that BMI appeared to have a positive, graded relation with post–myocardial infarction death. Whether weight reduction and secondary prevention strategies would reverse this effect in obese population remains to be seen.

Section snippets

Methods

The Onset Study was conducted in 45 community hospitals and tertiary care medical centers in the United States. Between August 1989 and September 1994, 1935 patients (601 women and 1334 men) were interviewed at a median of 4 days after having an acute MI. Trained research interviewers identified eligible patients by reviewing coronary care unit admission logs and patient charts. Thus, our study does not include patients who died before hospitalization or did not go to a hospital with their

Results

The characteristics of the Onset Study participants have been previously reported.8Table Ishows characteristics of the patient population according to BMI category. The mean BMI ranged from 22.7 kg/m2 in patients in the normal weight category to 39.3 kg/m2 in obesity class II or higher. Higher BMI was associated with younger age, diabetes, and hypertension. Minorities also tended to be more likely to be obese (P = .07). Sex, abstention from alcohol, and presence of noncardiac comorbidities were

Discussion

In this multicenter, prospective study of early survivors of acute MI followed for an average of 3.8 years, we found that BMI had a positive, graded relation with post-MI death of borderline statistical significance. The association was most apparent among patients free of major noncardiac comorbid conditions at baseline. This association remained essentially similar after adjustment for sociodemographic and clinical characteristics.

Recent data from the 1999 to 2000 National Health and

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    Supported by grant HL-41016 (for the Determinants of Myocardial Infarction Onset Study) from the National Heart, Lung, and Blood Institute, Bethesda, Md, grant T32-HL07374-22 from the National Institutes of Health, Bethesda, Md, and grant 9630115N from the American Heart Association, Dallas, Tex.

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