Dr. Virginia Chang, associate professor and interim chair of social and behavioral sciences at New York University College of Global Public Health has a new paper, Overweight or Obese BMI Is Associated With Earlier, But Not Later Survival After Common Acute Illnesses, published in the journal, BMC Geriatrics.
The paper includes the observational study of U.S. Health and Retirement Study (HRS) participants with federal health insurance (fee-for-service Medicare) coverage, hospitalized with congestive heart failure (N = 4287), pneumonia (N = 4182), or acute myocardial infarction (N = 2001), 1996 – 2012. Using cox proportional hazards models, the authors examined the association between overweight or obese BMI (BMI ≥ 25.0 kg/m2) and mortality to 5 years after hospital admission, adjusted for potential confounders measured at the same time as BMI, including age, race, sex, education, partnership status, income, wealth, and smoking status. Body mass index (BMI) was calculated from self-reported height and weight collected at the HRS survey prior to hospitalization (a median 1.1 year prior to hospitalization). The referent group was patients with a normal BMI (18.5 to < 25.0 kg/m2).
The results showed that patients were a median of 79 years old (IQR 71 – 85 years). The majority of patients were overweight or obese: 60.3 percent hospitalized for heart failure, 51.5 percent for pneumonia, and 61.6 percent for acute myocardial infarction. Overweight or obese BMI was associated with lower mortality at 1 year after hospitalization for congestive heart failure, pneumonia, and acute myocardial infarction — with adjusted hazard ratios of 0.68 (95 percent CI 0.59 – 0.79), 0.74 (95 percent CI: 0.64 – 0.84), and 0.65 (95 percent CI: 0.53 – 0.80), respectively. Among participants who lived to one year, however, subsequent survival was similar between patients with normal versus overweight/obese BMI.
In older Americans, overweight or obese BMI was associated with improved survival following hospitalization for congestive heart failure, pneumonia, and acute myocardial infarction. This association, however, is limited to the shorter-term. Conditional on surviving to one year, the authors did not observe a survival advantage associated with excess weight.