Is the obesity paradox present in left ventricular assist device recipients? A BMI-based analysis

While body mass index (BMI) is a known determinant of cardiovascular outcomes, its impact on patients undergoing left ventricular assist device (LVAD) implantation remains unclear. This study aimed to evaluate the association between BMI and in-hospital outcomes in LVAD recipients. We conducted a retrospective, cross-sectional analysis using the National Inpatient Sample (2016-2020), identifying adult hospitalizations for LVAD implantation. Patients were categorized into six BMI groups. Outcomes assessed included in-hospital mortality, acute stroke, pump thrombosis, LVAD infection, length of stay (LOS), and hospital costs. Multivariable logistic regression adjusted for demographic, clinical, and hospital-level confounders, to estimate adjusted odds ratios (ORs) and beta (β) coefficients. Among 25,250 weighted admissions, 29.3% were females, with a median age of 63 years (IQR: 52-71). Class III obesity (BMI ≥40 kg/m2) accounted for the largest proportion (32.1%). The highest mortality rate was observed in the underweight group (6.7%), and class III obesity (5.8%) groups, while the lowest rate was noted in the class II obesity group (2.5%). Overall, a reverse J-shaped relationship between BMI and in-hospital mortality was observed. Compared to normal BMI, Class I (OR: 2.46; p=0.038), Class II (OR: 3.73; p=0.017), and Class III obesity (OR: 6.80; p<0.001) were significantly associated with increased odds of in-hospital mortality. Class III obesity was also associated with significantly prolonged LOS (β: 7.07 days; p=0.002) and higher hospital costs (β: $208,791.5; p=0.001). Overweight patients (BMI 25-29.9 kg/m2) had significantly lower odds of acute stroke (OR: 0.40; p=0.030), while no BMI group showed a significant association with pump thrombosis and LVAD infection. Higher BMI, particularly Class III obesity, is independently associated with increased mortality, length of stay, and hospital costs in LVAD recipients. These findings challenge the obesity paradox and underscore the need for refined risk stratification in this population.