Outcomes of kidney donors with pre- and post-donation kidney stones

Outcomes of live renal donors with a history of nephrolithiasis; A systematic review

The clinical outcomes of kidney donors with a prior history of nephrolithiasis are poorly defined. We conducted a systematic review assessing the post-donation clinical outcomes of kidney donors with a history of nephrolithiasis. Electronic databases (Ovid and Embase) were searched between 1960 and 2021 using key terms and Medical Subject Headings (MeSH) - nephrolithiasis, renal stones, renal transplantation and renal graft. Articles included conference proceedings and journal articles and were not excluded based on patient numbers. Primary outcome was donor stone-related event. Secondary outcomes were renal function upon follow-up or post-operative nephrectomy complications. In summary, 340 articles were identified through database search. We identified 14 studies (16 cohorts) comprising 432 live donors followed up for a median of 26 months post live kidney donation. Six donors donated the stone-free kidney whilst 23 live donors had bilateral stones. Mean stone size was 4.2 ± 1.4 mm (1-16) with average follow up duration of 21.1 months (1-149). Twelve studies provided primary outcome (n = 138 patients) and eight (n = 348) for secondary outcomes. One donor had a stone-related event upon follow up. A total of 195 patients had eGFR <60 upon follow up. However, they were not significantly different when compared to renal function of live donors that didn't have pre-donation nephrolithiasis. Many of the studies couldn't provide long term follow up, coupled with limited data regarding the nature of the pre-donation stone disease. In conclusion, this systematic review shows that we have very limited information upon which to base recommendation regarding pre-donation risk of post-donation complications. Longer term follow up is required and lifelong follow up with live donor registries will aid further understanding.

Long-term Medical Outcomes of Living Kidney Donors

Historically, to minimize risks, living kidney donors have been highly selected and healthy. Operative risks are well-defined, yet concern remains about long-term risks. In the general population, even a mild reduction in glomerular filtration rate (GFR) is associated with cardiovascular disease, chronic kidney disease, and end-stage kidney disease (ESKD). However, reduction in GFR in the general population is due to kidney or systemic disease. Retrospective studies comparing donors with matched general population controls have found no increased donor risk. Prospective studies comparing donors with controls (maximum follow-up, 9 years) have reported that donor GFR is stable or increases slightly, whereas GFR decreases in controls. However, these same studies identified metabolic and vascular donor abnormalities. There are a few retrospective studies comparing donors with controls. Each has limitations in selection of the control group, statistical analyses, and/or length of follow-up. One such study reported increased donor mortality; 2 reported a small increase in absolute risk of ESKD. Risk factors for donor ESKD are similar to those in the general population. Postdonation pregnancies are also associated with increased risk of hypertension and preeclampsia. There is a critical need for long-term follow-up studies comparing donors with controls from the same era, geographic area, and socioeconomic status who are healthy, with normal renal function on the date matching the date of donation, and are matched on demographic characteristics with the donors. These data are needed to optimize donor candidate counseling and informed consent.

Clinical and Kidney Structural Characteristics of Living Kidney Donors With Nephrolithiasis and Their Long-term Outcomes

Nephrolithiasis in living kidney donors is concerning due to the potential impact on long-term postdonation kidney function.