Pretransplant obesity: a weighty issue affecting transplant candidacy and outcomes

Because of the global increase in prevalence of obesity, many more overweight and obese individuals are undergoing evaluation for transplantation than in the past. Although obesity seems to provide a survival benefit in dialysis patients, obesity has traditionally been considered a contraindication for transplantation of most organs. It is theorized that obesity will contribute to worse transplant outcomes, including lower rates of graft and patient survival and higher rates of delayed graft function and infection. This review evaluates the available literature evaluating outcomes of obese patients with end-stage organ failure who undergo transplantation. Obesity seems to be associated with increased rates of wound infection after transplantation. However, other adverse transplant outcomes related to obesity seem to be dependent on the type of organ being transplanted and the degree of obesity. For example, a body mass index (BMI) of 30 kg/m(2) may reduce short-term survival in lung transplant recipients; however, obesity does not seem to confer an adverse effect on short- or long-term survival in liver transplant patients until a much higher BMI is reached (such as 35 or 40 kg/m(2)). Each transplant center must determine weight guidelines and criteria for identifying the level of obesity as a contraindication for transplantation. This must be based on organ type, each center's transplant and complication statistics, and available donor pools. Guidelines must also consider the morbidity and mortality risks of the obese patient with organ failure who does not receive a transplant.