Is big bad or bearable? Long-term renal transplant outcomes in obese recipients

The global obesity epidemic has implications for kidney transplantation. There are conflicting reports regarding the impact of obesity on long-term post-transplant outcomes.

To explore the impact of body mass index (BMI) on long-term outcomes after kidney transplantation.

The association between BMI and cardiovascular disease, cancer, post-transplant diabetes mellitus, graft and recipient survival was investigated in recipients who had been transplanted at least ten years previously.

All consecutive adult renal transplant recipients who received first, deceased donor, transplants between 1986 and 2005 in Northern Ireland were followed-up until 2016.

A total of 328 patients were eligible. Of them, 96 were overweight with a BMI 25.0-29.9 kg/m2, and 56 were obese with a BMI exceeding 29.9 kg/m2. Median follow-up time was 16.7 years. In multivariate analysis recipient BMI was associated with the development of post-transplant diabetes mellitus (P=0.003), but not with new cardiovascular disease (P=0.78). Cancer was less common in recipients with a higher BMI (hazard ratio (HR) 0.58, P < 0.001). BMI at the time of transplantation did not significantly influence graft (P=0.28) or recipient survival (P=0.13).

Increased BMI at time of transplantation is associated with an increased risk of post-transplant diabetes mellitus but not new cardiovascular disease or malignancy. Long-term graft and recipient survival is not impacted. Potential recipients should not be excluded from transplantation solely on the basis of obesity, rather it should be considered as one part of an individualized risk stratification, based on comorbidity and considering the risk of death on maintenance dialysis.