Graft, patient outcomes in kidney recipients do not differ by obesity level

Long-term kidney transplant outcomes in patients with extreme obesity are similar to that in those with obesity, a study reports. This is despite an increased risk of delayed graft function likely unrelated to donor organ quality in the former.

The analysis, which applied mate-kidney models, used data from the Organ Procurement and Transplant Network/United Network of Organ Sharing database. It included a total of 44,560 adult recipients of first-time deceased donor kidney transplants, paired by donor.

Recipient body mass index (BMI) was categorized as follows: 18–25 kg/m² (n=12,446), >25–30 kg/m² (n=15,477), >30–35 kg/m² (obese; n=11,144), and >35 kg/m² (extremely obese; n=5,493). Outcomes were patient survival, graft survival, death-censored graft survival, delayed graft function, and length of stay.

The median follow-up was 3.9 years. In multivariable conditional logistic regression models, the odds of delayed graft function were lower in the first three BMI categories than in the extreme obesity category, with adjusted odds ratio of 0.42 (95 percent confidence interval [CI], 0.36­–0.48), 0.55 (95 percent CI, 0.48–0.62), 0.73 (95 percent CI, 0.64–0.83), respectively (p<0.001).

In terms of death-censored graft failure, the risk was lower for BMI ≤25 kg/m² (hazard ratio [HR], 0.66, 95 percent CI, 0.59–0.74; p<0.001) and BMI >25–30 kg/m² (HR, 0.79, 95 percent CI, 0.70–0.88; p<0.001), but not BMI >30–35 kg/m² (HR, 0.91, 95 percent CI, 0.861–1.02; p=0.09) than for extreme obesity.

Length of stay and patient survival did not differ by recipient BMI.

The findings support a flexible approach to kidney transplantation candidacy in candidates with extreme obesity.