Prevalence and secular trends of excess body weight and impact on outcomes after myocardial infarction in the community.

OBJECTIVES: To determine the trends in the prevalence of overweight and obese individuals among patients with myocardial infarction (MI), and to assess the association between weight and outcomes after MI.
DESIGN: Population-based cohort study.
METHODS: MIs occurring in Olmsted County, MN, between 1979 and 1998 were validated using standardized criteria. Clinical characteristics and outcomes were ascertained from community medical records. The prevalence and trends of excess weight and its association with outcomes were analyzed.
RESULTS: Sixty-four percent of the 2,277 subjects with incident MI were overweight or obese. The prevalence of overweight/obese patients increased from 58% in the period from 1979 to 1983, to 72% in the period from 1994 to 1998 (p < 0.001), while the prevalence of class 3 obesity (body mass index >or= 40) increased from 0.6 to 4.4%. Overweight and obese patients were more likely to have diabetes, hypertension, familial coronary disease, and hyperlipidemia than persons with normal weight but less likely to have comorbidities (obstructive lung disease, heart failure, cancer, renal failure, and stroke) [all p values < 0.05]. When compared to patients with normal weight, after adjusting for age and other confounders, overweight and obese patients had a lower mortality (risk ratio [RR], 0.84; 95% confidence interval [CI], 0.73 to 0.96 for overweight; and RR, 0.85; 95% CI, 0.72 to 1.02 for obese) and a similar risk of cardiac events.
CONCLUSION: The prevalence of overweight and obese individuals among patients with MI is high and increased over time. Despite a higher prevalence of other cardiovascular risk factors among patients with excess weight, these patients did not experience worse outcomes, underscoring the need to further study the paradoxical relation between weight and post-MI outcomes.