Obesity: An Independent Predictor of Morbidity and Graft Loss after Kidney Transplantation

Abstract

<b><i>Background:</i></b> There is conflicting information on current medical and surgical complications associated with high body mass index (BMI) after kidney transplantation. <b><i>Methods:</i></b> In a single-center observational study, we analyzed the 5-year outcomes of all consecutive primary kidney transplant recipients between 2010 and 2015 based on BMI at the time of transplant. <b><i>Results:</i></b> There were 1,467 patients included in this study, distributed in the following groups based on BMI: underweight (<i>n</i> = 32, 2.2%), normal (<i>n</i> = 407, 27.7%), overweight (<i>n</i> = 477, 32.5%), grade I obesity (<i>n</i> = 387, 26.4%), grade II obesity (<i>n</i> = 155, 10.6%), and grade III obesity (<i>n</i> = 9, 0.6%). Obesity was associated with an increased incidence of delayed graft function (<i>p</i> = 0.008), length of stay (LOS, <i>p</i> = 0.03), 30-day surgical re-exploration (<i>p</i> = 0.02), and hospital readmission (<i>p</i> < 0.0001). Obesity was also associated with higher 1-year serum creatinine (<i>p</i> = 0.03) and increased 5-year incidence of cardiac events (<i>p</i> < 0.0001) and congestive heart failure (<i>p</i> < 0.0001). Multivariable Cox regression analyses determined grade III obesity (HR = 5.84, 95% CI: 1.40–24.36, <i>p</i> = 0.01), LOS >4 days (HR = 1.94, 95% CI: 1.19–3.18, <i>p</i> = 0.008), hospital readmission (HR = 2.25, 95% CI: 1.20–4.22, <i>p</i> = 0.01), 1-year serum creatinine >1.5 (HR = 1.95, 95% CI: 1.20–3.18, <i>p</i> = 0.007), and proteinuria (UPC) >1 g/g (HR = 1.85, 95% CI: 1.06–3.24, <i>p</i> = 0.03) as independent predictors of death-censored graft failure. <b><i>Conclusion:</i></b> In the current era of renal transplant care, obesity is common, and high BMI remains associated with significant medical and surgical complications after transplant.