Long-Term Consequences of Complex Living Renal Donation: Is It Safe?

Donor obesity and weight gain after transplantation: two still overlooked threats to long-term graft survival

The effect of donor obesity on kidney transplantation success has long been an overlooked clinical research area. Even though there is no strict guideline in most countries prohibiting donation from obese individuals, most candidates with a body mass index >35-40 kg/m² are rejected due to concerns regarding long-term renal functional deterioration in the donor. The effects of excessive fat mass on renal function and allograft survival have been analysed by several longitudinal and follow-up studies. These studies have documented the deleterious effect on long-term graft outcomes of excessive body mass in living kidney donors and de novo obesity or pre-existing obesity worsening after transplantation on kidney outcomes. However, there is a paucity of clinical trials aimed at countering overweight and obesity in living and deceased kidney donors and in transplant patients. In this review we will briefly discuss the mechanism whereby fat excess induces adverse kidney outcomes and describe the effects on graft function and survival in living obese donors.

Hypertension and obesity in living kidney donors

Over the past few decades, the shortage in the kidney donor pool as compared to the increasing number of candidates on the kidney transplant waitlist led to loosening of kidney donors' acceptance criteria. Hypertension and obesity represent risk factors for chronic kidney disease, both in native kidneys and those in kidney transplant recipients. While great progress has been made in kidney transplantation from living donors to benefit the recipient survival and quality of life, progress has been slow to fully risk-characterize the donors. This review critically reassesses the current state of understanding regarding the risk of end-stage kidney disease in those donors with obesity, hypertension or both. Accurate risk assessment tools need to be developed urgently to fully understand the risk glomerular filtration rate compensation failure in the remaining kidney of the donors.