Pro: Pretransplant weight loss: yes.

The obesity epidemic has not spared the population with renal failure. Obesity impacts prognosis after kidney transplantation, as markers of obesity are associated with worse outcomes (e.g. delayed graft function, graft failure, cardiovascular disease, costs) compared with ideal values in most studies. Obesity is also potentially modifiable. Kidney transplants are a scarce resource and the obligation to steward organs to good outcomes is inherent in transplant practice. Thus, it is appropriate to establish pretransplant weight loss targets and engage obese patients seeking transplantation in shared responsibility agreements to strive to reach goals. Nonetheless, important caveats may qualify the stringency of pretransplant weight loss requirements. Obese patients (who are otherwise healthy enough for transplant) may benefit from transplantation compared with long-term dialysis based on metrics such as improved long-term survival and lower cardiac risk. When optimal weight loss is difficult to achieve, factors in a given program's ability to extend the limits of obesity acceptable for safe and effective transplantation include expertise (e.g. surgical approaches and clinical management), tolerance for risk based on overall performance and tolerance for costs. More research is needed, including formal cost-effectiveness studies of transplantation in obese patients to determine if payers (e.g. Medicare) and society should be compensating programs for clinical and financial risks, and whether the risks are worth taking. To generate evidence to better guide management, prospective evaluations of the impact of intentional weight loss strategies in this population, including studies of dietary change, monitored exercise and bariatric surgery, are also urgently needed.