UK renal transplant outcomes in low and high BMI recipients: the need for a national policy.

Introduction: We assessed the effect of recipient body mass index (BMI) on the outcomes of renal transplantation and the management of obese patients with end-stage renal disease across the UK.

Methods: We analyzed data of 25539 adult renal transplants (2007-2016) from the UK Transplant Registry. Patients were divided in BMI groups [underweight: < 18.5, normal: 18.5-24.9 (reference group), overweight: 25-29.9, class I obese: 30-34.9, class II/III obese: ≥ 35]. We also conducted a national survey of all UK renal transplant centers on the influence of BMI on decisions regarding management of renal transplant candidates.

Results: BMI ≥ 25 was an independent risk factor for delayed graft function and primary non-function (p ≤ 0.001). Underweight (p = 0.001), class I obese (p = 0.017) and class II/III obese recipients (p < 0.001) had poorer graft survival, however, 5- and 10-year graft survival rates were good. Patient survival was shorter for underweight recipients (p < 0.001) and longer for overweight (p = 0.028) and class I obese recipients (p = 0.013). The national survey revealed significant variability among transplant centers in BMI threshold for listing patients on transplant waiting list and limited support with conservative or surgical procedures for weight control.

Conclusions: Obesity alone should not be a barrier for renal transplantation. A national strategy is required to give all patients equal chances in transplantation.