Effect of donor body mass index on the outcome of donation after cardiac death kidneys: how big is too big?

Donor Body Mass Index as a Risk Factor for Delayed Onset of Graft Function

Delayed graft function continues to pose a significant challenge to clinicians in the context of kidney transplantation. The objective of this retrospective, 5-year analysis is to identify the parameters of beating heart donors and those of recipients that affect the delayed development of graft function. The monitored group was composed of 152 beating heart donors and 179 recipients. Delayed graft function was identified in 32 (17%) patients. The predictor for development of delayed graft function was the body mass index of the donor (odds ratio: 1.1473; 95% confidence interval [CI]: 1.0017-1.3140; P = .0472), and the independent risk factors were donor body mass index 30 to 34.9 kg/m² (hazard ratio [HR]: 6.0215; 95% CI: 1.4188-25.556; P = .0149), donor body mass index ≥35 kg/m² (HR: 13.5484; 95% CI: 1.4575-125.938; P = .0220), and abuse of alcohol in the donor's history (HR: 1.779; 95% CI: 1.0679-2.964; P = .0270).

Kidney Transplant Outcomes in the Super Obese: A National Study From the UNOS Dataset

BACKGROUND

We evaluated outcomes of super-obese patients (BMI > 50) undergoing kidney transplantation in the US.

METHODS

We performed a review of 190 super-obese patients undergoing kidney transplantation from 1988 through 2013 using the UNOS dataset.

RESULTS

Super-obese patients had a mean age of 45.7 years (21-75 years) and 111 (58.4 %) were female. The mean BMI of the super-obese group was 56 (range 50.0-74.2). A subgroup analysis demonstrated that patients with BMI > 50 had worse survival compared to any other BMI class. The 30-day perioperative mortality and length of stay was 3.7 % and 10.09 days compared to 0.8 % and 7.34 days in nonsuper-obese group. On multivariable analysis, BMI > 50 was an independent predictor of 30-day mortality, with a 4.6-fold increased risk of perioperative death. BMI > 50 increased the risk of delayed graft function and the length of stay by twofold. The multivariable analysis of survival showed a 78 % increased risk of death in this group. Overall patient survival for super-obese transplant recipients at 1, 3, and 5 years was 88, 82, and 76 %, compared to 96, 91, 86 % on patients transplanted with BMI < 50. A propensity score adjusted analysis further demonstrates significant worse survival rates in super-obese patients undergoing kidney transplantation.

CONCLUSION

Super-obese patients had prolonged LOS and worse DGF rates. Perioperative mortality was increased 4.6-fold compared to patients with BMI < 50. In a subgroup analysis, super-obese patients who underwent kidney transplantation had significantly worse graft and patient survival compared to underweight, normal weight, and obesity class I, II, and III (BMI 40-50) patients.