The impact of morbid obesity on hospital length of stay in kidney transplant recipients

Objectives: Obesity is often associated with higher hospital costs because of longer length of stay (LOS) but this has not been well studied in the kidney transplant population. Therefore, we used national data to compare LOS in select groups of morbidly obese and normal weight recipients after kidney transplant. Design: This study was a retrospective analysis of the Organ Procurement and Transplant Network/United Network for Organ Sharing database. Subjects: The study sample consisted of 42,787 morbidly obese (body mass index 35-40kg/m²) and normal weight (body mass index 18.5-24.9kg/m²) who underwent primary kidney-only transplantation between 2000 and2008. Main Outcome Measures: Morbidly obese and normal-weight subgroups were crudely evaluated for prolonged LOS (>7days). Logistic regression modeling compared LOS in morbidly obese and normal-weight subgroups with varying characteristics and determined predictors of prolonged LOS. Results: All morbidly obese subgroups had significantly higher crude rates of prolonged LOS (P<.05). However, no significant differences in prolonged LOS were seen between any of the morbidly obese or normal-weight subgroups in multivariate analysis. Morbid obesity was an independent predictor of prolonged LOS (P<.001) but not a stronger predictor than that of being African American, having coronary artery disease, diabetes mellitus, or peripheral vascular disease, being 50 to 80years of age, having a previous transplant or poor functional status. Receiving a deceased-donor transplant and being dialysis dependent >4years were significantly better predictors of prolonged LOS compared with morbid obesity (P<.05). Conclusions: Some morbidly obese populations have LOS rates that are not significantly different than many commonly transplanted normal weight populations, and the impact morbid obesity has on LOS is not different than many other factors often seen in kidney transplant recipients; therefore, morbid obesity alone should not be a financial consideration in kidney transplant.