Extent and impact of obesity in patients with diabetes and acute myocardial infarction - experience from a national cohort

Abstract Background Elevated body mass index (BMI) has an adverse effect on cardiovascular riskfactors where diabetes and coronary artery disease increases with obesity. However, less in known about the prevalence and the grades of obesity in a diabetes population with acute myocardial infarction (AMI) and the impact on prognosis. Further, for the moment there is a shortage of access to cardioprotective weight loss medications as Glucagon Like Peptide Receptor Agonists (GLP-1 RA). Purpose To explore features and grades of obesity in patients with diabetes and AMI and impact on outcome in a national perspective. Methods All patients with diabetes and AMI admitted for coronary angiography in Sweden the years 2010-2021 were included. Information on BMI was collected at the time of angiography and grouped into obesity categories: low BMI (<18.5 kg/m2), normal BMI (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), obesity grade 1 (30.0-34.9 kg/m2), obesity grade 2 (35.0-39.9 kg/m2) and obesity grade 3 (≥40.0 kg/m2). Information on baseline characteristics and outcome was collected from national registries. Mortality was followed until March 2022. Restricted cubic spline analysis of association between continuous BMI and age-adjusted mortality was performed where normal BMI served as a reference with Hazard Ratio (HR) 1.0. Results Of 19 378 patients with diabetes, 67% were men and 46% suffered a STEMI. Normal BMI was present in 21%, overweight in 41%, obesity grade 1 in 25%, obesity grade 2 in 9% and obesity grade 3 in 3% (Figure 1). Age was decreasing with grade of obesity (72 years in normal BMI vs. 62 years in obesity grade 3, p<0.001). Hypertension and hyperlipidaemia were more common in patients with more severe obesity than in those with normal BMI (67% vs. 80%, p<0.001, and 44% vs. 50%, p<0.001, in normal BMI and obesity grade 3 respectively) while a higher proportion of those with normal BMI had suffered a previous MI (10% vs. 6% in obesity grade 3, p<0.001) and a previous stroke (10% vs. 5% in obesity grade 3, p<0.001). In patients with normal BMI STEMI was more common (51% vs. 39%, p<0.001) than in those with obesity grade 3. In patients with obesity grade 3 GLP-1 RA was used in 14% compared to 4% in those with normal BMI. Figure 2 depicts age-adjusted HR and 95% Confidence Interval for mortality for different BMI levels with a U-shaped pattern illustrating that associated mortality risk is higher when obesity is present especially grade 2 and 3. Conclusion Obesity is common affecting around one third of patients with diabetes and AMI and impacts survival. This strengthens that after AMI use of effective weight loss cardioprotective treatment should be prioritised in patients with diabetes and obesity especially if severe.