Abstract 15575: In Patients With Diabetes Mellitus, Obesity is Associated to an Increased Risk of Cardiovascular Events but, Paradoxically, to a Lower Mortality (>100,000 Patient Years Follow-Up)
Background: Obesity is a key trigger for insulin resistance leading to type-2 diabetes mellitus (T2DM). However, recent evidence suggests that obese patients with T2DM may have lower morbidity and mortality compared to patients of normal weight. These reports are limited by statistical power and confounders. We investigated the relationship between Body Mass Index (BMI), mortality and cardiovascular (CV) morbidity in a long-term large cohort of patients with T2DM.
Methods: Between 1995 and 2011, weight (BMI), blood pressure, dyslipidemia, smoking and comorbidities was collected in patients with T2DM without known CV disease. Total mortality and hospital admissions for acute coronary syndrome (ACS), cerebrovascular accidents (CVA) and heart failure (HF) were gathered. Subjects were divided according to BMI quartiles. Kaplan Meier and Cox-Regression analysis were. Sensitivity analysis was performed accounting for cancer.
Results: In total, 10,568 patients (54% men, mean age 61±14 years) were enrolled and followed for a mean of 10±4 years. The risk of ACS was smallest in the lowest BMI quartile and increased with higher BMI quartiles (BMI 32 HR 1.39; p=0.001). This was true also for the risk of HF hospitalization (BMI >32 HR 1.36; p=0.01). However, the risk of CVA was not significantly different across the BMI groups (p=NS).
Although the risk of cardiovascular events was greater with higher BMI, paradoxically overweight and obesity conferred a beneficial effect over all-cause mortality. When we divided our population in age tertiles, this obesity paradox held true in the elderly (>68 years old) (BMI 28-31 HR 0.75; p<0.0001), but not in the young patients (<57 years old) (BMI 29-35 HR 1.54; p=0.02).
Sensitivity analysis did not significantly change any of the above results.
Conclusions: In this analysis, in patients with T2DM, although being overweight was associated with an increased risk of CV events, higher BMIs were associated with a survival benefit, especially in older patients. Thin T2DM patients may have a more severe metabolic disorder than patients in whom insulin resistance is primarily due to obesity.
- © 2013 by American Heart Association, Inc.