Risk Factors for Developing Low Estimated Glomerular Filtration Rate and Albuminuria in Living Kidney Donors

Anisha Dhalla; Pietro Ravani; Robert R Quinn; Amit X Garg; Alix Clarke; Huda Al-Wahsh; Krista L Lentine; Scott Klarenbach; Brenda R Hemmelgarn; Carol Wang; Ngan N Lam

doi:10.1016/j.xkme.2023.100767

Risk Factors for Developing Low Estimated Glomerular Filtration Rate and Albuminuria in Living Kidney Donors

Kidney Med. 2023 Dec 4;6(2):100767. doi: 10.1016/j.xkme.2023.100767. eCollection 2024 Feb.

Authors

Affiliations

¹ Cumming School of Medicine, Division of Nephrology, University of Calgary, Calgary, AB, Canada.
² Department of Medicine, Division of Nephrology, Western University, London, ON, Canada.
³ Center for Abdominal Transplantation, Saint Louis University Hospital, St. Louis, MO.
⁴ Department of Medicine, Division of Nephrology, University of Alberta, Edmonton, AB, Canada.

Abstract

Rationale & objective: Chronic kidney disease is associated with significant morbidity and mortality in the general population, but little is known about the incidence and risk factors associated with developing low estimated glomerular filtration rate (eGFR) and moderate-severe albuminuria in living kidney donors following nephrectomy.

Study design: Retrospective, population-based cohort study.

Setting & participants: Kidney donors in Alberta, Canada.

Exposure: Donor nephrectomy between May 2001 and December 2017.

Outcome: Two eGFR measurements <45 mL/min/1.73 m² or 2 measurements of moderate or severe albuminuria from 1-year postdonation onwards that were at least 90 days apart.

Analytical approach: Associations between potential risk factors and the primary outcome were assessed using Cox proportional hazard regression analyses.

Results: Over a median follow-up period of 8.6 years (IQR, 4.7-12.6 years), 47 of 590 donors (8.0%) developed sustained low eGFR or moderate-severe albuminuria with an incidence rate of 9.2 per 1,000 person-years (95% confidence interval, 6.6-11.8). The median time for development of this outcome beyond the first year after nephrectomy was 2.9 years (IQR, 1.4-8.0 years). Within the first 4 years of follow-up, a 5 mL/min/1.73 m² lower predonation eGFR increased the hazard of developing postdonation low eGFR or moderate-severe albuminuria by 26% (adjusted HR, 1.26; 95% CI, 1.10-1.44). Furthermore, donors were at higher risk of developing low eGFR or albuminuria if they had evidence of predonation hypertension (adjusted HR, 2.52; 95% CI, 1.28-4.96) or postdonation diabetes (adjusted HR, 4.72; 95% CI, 1.54-14.50).

Limitations: We lacked data on certain donor characteristics that may affect long-term kidney function, such as race, smoking history, and transplant-related characteristics.

Conclusions: A proportion of kidney donors at an incidence rate of 9.2 per 1,000 person-years will develop low eGFR or albuminuria after donation. Donors with lower predonation eGFR, predonation hypertension, and postdonation diabetes are at increased risk of developing this outcome.

Keywords: Albuminuria; chronic kidney disease; donor nephrectomy; kidney donation; living kidney donors; transplant.

Plain language summary

The purpose of this study was to understand the risk of developing kidney disease in living kidney donors after donation. We followed 590 donors in Alberta, Canada for almost 9 years. Approximately 8% of donors developed reduced kidney function (low estimated glomerular filtration rate) or increased protein in the urine (albuminuria). Donors with lower kidney function before donation, hypertension before donation, or diabetes after donation had a higher likelihood of experiencing these kidney outcomes. This research provides important insights to patients and health care providers to better support the long-term kidney health of living kidney donors.