Longitudinal trends and influence of BMI mismatch in living kidney donors and their recipients

Abstract

Background and objectives Age and body mass index (BMI) of kidney donors and recipients affect kidney allograft outcomes. Moreover, while deceased donor and recipient body size mismatch have been reported to influence allograft outcomes, how BMI mismatch in living kidney donor–recipient pairs affect graft survival is not well defined. Design, setting, participants, and measurements We investigated trends in characteristics of 90,815 US. living kidney donors and their recipients between 1987 and 2008. Results Median ages of donors and their recipients have risen over time, and the proportion of living donors age ≥50 years increased from 11 to 25%. Median BMI of recipients increased from 22.6 to 26.6 kg/m2; median BMI of kidney donors for the past 5 years has been 26.4 kg/m2. Only 35% of living donor-recipient pairs were in the same BMI category (<25, 25–29.9, 30–34.9, or ≥35kg/m2). BMI mismatch where the living donor was three categories heavier than the recipient was associated with a significant adjusted risk for death-censored allograft loss (HR 2.31, 95% CI 1.05–5.08). Conclusions Living kidney donors are donating at more advanced ages, and the majority are overweight or obese in recent years. In summary: (1) previous longitudinal studies of living kidney donor outcomes may not be generalizable to recent donors, and studies of contemporary living kidney donor cohorts may be informative, (2) the majority of living donor–recipient pairs have BMI mismatch, and (3) extreme BMI mismatch where the living donor is heavier may confer an independent risk for allograft loss.

Living donor postnephrectomy kidney function and recipient graft loss: A dose-response relationship

“…Our findings identify post-donation eGFR as a novel but intuitive risk factor for graft loss, and reaffirm that older donor age and higher donor BMI are risk factors for graft loss (1–4). Our group previously identified that recipients of allografts from donors who develop ESRD had higher graft loss and mortality, supporting the hypothesis that subclinical kidney disease may exist at the time of donation (5).…”

“…In considering recipient outcomes following living donor kidney transplantation (LDKT), pre-donation donor risk factors of lower estimated glomerular filtration rate (eGFR), older age, and higher BMI have been associated with greater risk of recipient graft loss (1–4). Post-donation, development of end-stage renal disease (ESRD) in the donor is associated with increased risk of graft loss in the recipient (5).…”

A Risk Index for Living Donor Kidney Transplantation

“…A British registry-based study reported worse patient survival in LDKT recipients from older donors (24). Two prior studies of UNOS data reported increased risk to recipients of kidneys from African-American living donors (12, 25). Our results are consistent with these prior studies.…”

Rodent Transplant Medicine

“…In clinic, as the living donor is much heavier than recipient and BMI mismatch appears, the risk for kidney allograft will be increased (Lin et al 2011 ). In clinic, as the living donor is much heavier than recipient and BMI mismatch appears, the risk for kidney allograft will be increased (Lin et al 2011 ).…”