ABSTRACT
OBJECTIVES: Previous studies have shown that kidney transplant recipients with a high body mass index (BMI) have inferior graft and patient outcomes compared to patients with a lower BMI. We hypothesized that there would be secular improvements in outcomes among high BMI recipients. We used data from the United Network for Organ Sharing (UNOS) to determine whether obesity affects patient and graft outcomes following kidney transplantation in the modern immunosuppressive era. METHODS: The study sample consisted of 69,749 recipients from 1987 to 1999 and 197,986 recipients from 2000 to 2016. BMI values were categorized into 11 tiers: below 18 kg/m2, from 18 to 36 kg/m2 at 2 kg/m2-unit increments, and above 36 kg/m2. We created multivariate models to evaluate the independent effect of BMI on graft and patient outcomes, adjusting for factors known to affect graft success and patient survival. RESULTS: Overall graft and patient survival has improved for all BMI categories. Cox regression modeling hazard ratios showed that the relative risk for graft loss, patient death, and patient death with a functioning graft in the modern immunosuppressive era (2000 to 2016) has significantly decreased compared to the earlier era (1987 to 1999), especially for living kidney transplant recipients. CONCLUSIONS: The relative risk of graft failure and patient death with increasing BMI has appreciably decreased in the modern immunosuppressive era, especially for living donor transplant recipients. Withholding transplantation from patients with higher BMIs may no longer be justifiable on grounds of worse clinical outcomes.
