Etiologies and predictors of readmission among obese and morbidly obese patients admitted with heart failure.

The relationship between severity of obesity and outcomes in heart failure (HF) has long been under debate. We studied index HF admissions from the 2013-14 National Readmission Database. Admissions were separated into three weight-based categories: non-obese (Non-Ob), obese (Ob), and morbidly obese (Morbid-Ob) to analyze hospital mortality and readmission at 30 days and 6 months. We investigated etiologies and predictors of 30-day readmission among these weight categories. We studied a total of 578,213 patients of whom 3.0% died during index hospitalization (Non-Ob 3.3% vs. Ob 1.9% vs. Morbid-Ob 1.9%; p < 0.01). Non-Ob comprised 79.5%, Ob 9.9%, and Morbid-Ob 10.6% of patients. Morbid-Ob patients were the youngest among age categories and more likely to be female. In-hospital mortality during readmission at 30 days and 6 months was significantly lower among Morbid-Ob and Ob compared with Non-Ob patients (all p < 0.01). Thirty-day readmission among Morbid-Ob was lower than Non-Ob and higher than Ob patients (19.6% vs. 20.5% vs. 18.6%, respectively; p < 0.01). Morbid-Ob patients were less likely to be readmitted for cardiovascular etiologies compared with both Ob and Non-Ob (45.0% vs. 50.3% vs. 50.6%; p < 0.01). Multivariable regression analysis revealed that Ob (adjusted odds ratio 0.84, 95% confidence intervals 0.82-0.86) and Morbid-Ob (aOR 0.83, 95% CI 0.81-0.85) were independently associated with lower 30-day readmission. Readmission at 6 months was highest among Morbid-Ob followed by Non-Ob and Ob (51.1% vs. 50.2% vs. 49.1%, p < 0.01). Morbid-Ob and Ob patients experience lower in-hospital mortality during index HF admission and during readmission with 30 days or 6 months compared with Non-Ob. Morbid-Ob patients experience greater readmission at 6 months despite the lower rate at 30 days post discharge. Morbid-Ob patients are most likely to be readmitted for non-cardiovascular causes.