Intermediate Renal Outcomes, Kidney Failure, and Mortality in Obese Kidney Donors

Abstract

BackgroundObesity is associated with the two archetypal kidney disease risk factors: hypertension and diabetes. Concerns that the effects of diabetes and hypertension in obese kidney donors might be magnified in their remaining kidney have led to the exclusion of many obese candidates from kidney donation.MethodsWe compared mortality, diabetes, hypertension, proteinuria, reduced eGFR and its trajectory, and the development of kidney failure in 8583 kidney donors, according to body mass index (BMI). The study included 6822 individuals with a BMI of <30 kg/m2, 1338 with a BMI of 30–34.9 kg/m2, and 423 with a BMI of ≥35 kg/m2. We used Cox regression models, adjusting for baseline covariates only, and models adjusting for postdonation diabetes, hypertension, and kidney failure as time-varying covariates.ResultsObese donors were more likely than nonobese donors to develop diabetes, hypertension, and proteinuria. The increase in eGFR in obese versus nonobese donors was significantly higher in the first 10 years (3.5 ml/min per 1.73m2 per year versus 2.4 ml/min per 1.73m2 per year; P<0.001), but comparable thereafter. At a mean±SD follow-up of 19.3±10.3 years after donation, 31 (0.5%) nonobese and 12 (0.7%) obese donors developed ESKD. Of the 12 patients with ESKD in obese donors, 10 occurred in 1445 White donors who were related to the recipient (0.9%). Risk of death in obese donors was not significantly increased compared with nonobese donors.ConclusionsObesity in kidney donors, as in nondonors, is associated with increased risk of developing diabetes and hypertension. The absolute risk of ESKD is small and the risk of death is comparable to that of nonobese donors.

Living Kidney Donation, Obesity, and Dietary Change: Investing in Those Who Give the “Gift of Life”

“…Multiple studies in LKDs [43][44][45] report mortality risk as similar to matched healthy nondonors, but these studies were not risk-stratified by BMI. Ibrahim et al 46 reported comparable mortality risk with nonobese donors. In a study of 119,769 living donors in the United States, the cumulative incidence of long-term mortality at 20 years postdonation for obese donors was 304.3 per 10,000 donors compared to 208.9 per 10,000 among nonobese donors.…”

“…There is a higher incidence of proteinuria in obese LKDs compared to nonobese LKDs, reported in different studies to range between 17.8% to 44% versus 13-17%. 46,50,51 Studies with short-term follow up of obese donors reported no differences in GFR compared to nonobese donors. 40,52,53 Two single-center studies reported no significant differences in eGFR of obese LKDs compared to nonobese LKDs, and the risk of ESRD was 0.7% in obese versus nonobese LKDs.…”

“…40,52,53 Two single-center studies reported no significant differences in eGFR of obese LKDs compared to nonobese LKDs, and the risk of ESRD was 0.7% in obese versus nonobese LKDs. 46,54 Locke et al 47 demonstrated in a study of 119,769 donors that the estimated risk of development of ESRD after LKD is higher in obese donors compared to not obese donors, but the absolute risk remains low (0.93% in obese donors versus 0.39% in nonobese donors) at 20 years after donation. They also found with each 1 kg/m 2 increase in BMI .27 kg/m 2 , there was a 7% increase in ESRD risk, suggesting that overweight status presents a risk for ESRD postdonation.…”

“…Multiple single-center studies found that obese LKDs had a higher risk of developing hypertension, and they developed this earlier compared to nonobese LKDs, with one study reporting 41.6% of obese patients developed hypertension at 6.8 6 1.5 years postdonation. 46,50,[54][55][56] A study of 8,951 donors at 3 US centers from 1963 to 2007 reported a steady increase over time in the median values of fasting glucose at donation. 24 Multiple studies have shown that obese donors are at higher risk of developing diabetes mellitus (DM) compared to nonobese donors.…”

Diabetes-free survival among living kidney donors and non-donors with obesity: A longitudinal cohort study

“…While LKDs with obesity have become more prevalent-nearly 25% of LKDs nationally have obesity, the long-term safety of donation in this population is unknown [14][15][16]. Our understanding of the impact of kidney donation on lifetime ESKD development-the guiding principle of donor selection-remains limited as most studies report mean follow-up of 20 years or less [17][18][19]. Given the concern for kidney disease development or progression in the setting of diabetes and uninephrectomy [20][21][22], the need to evaluate intermediate outcomes of ESKD, such as diabetes development among LKDs with obesity, is critical to guide donation practices and prioritize LKD safety.…”