Body Mass Index and Postoperative Complications in Kidney Transplant Recipients

Background: There is a growing number of overweight and obese patients receiving kidney transplants, despite elevated body mass index (BMI) being associated with postoperative complications. Understanding associations between BMI and complications would allow more objectivity when recommending patients for transplantation or otherwise.

Methods: We analysed a retrospective cohort of 508 adult patients who received primary kidney grafts at a single centre in South Australia, 2002-2009, using hospital records and Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) data. Complications within 1 year of transplantation were classified into: surgical, wound, urological, delayed graft function, early nephrectomy and admission to intensive care unit (ICU).

Results: Overall, 62% of transplant recipients had a BMI above 25 kg/m(2) at transplant. Higher BMI was associated with an increased risk of wound complications (P < 0.001), early nephrectomy (P = 0.002) and delayed graft function (P = 0.03), but not associated with surgical or urological complications, or ICU admission. These associations were stronger for Indigenous Australians than other patients, especially for surgical complications. There was no BMI value above which risks of complications increase substantially.

Conclusion:   Delayed graft function is an important determinant of patient outcomes. Wound complications can be serious, and are more common in patients with higher BMI. This may justify the use of elevated BMI as a contraindication for transplantation, although no obvious cut-off value exists. Investigations into other measures of body fat composition and distribution are warranted.