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

Abstract

Rationale & ObjectiveChronic 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 eGFR and moderate-severe albuminuria in living kidney donors following nephrectomy. Study DesignRetrospective, population-based cohort study. Setting& Participants: Kidney donors in Alberta, Canada. ExposureDonor nephrectomy between May 2001 and December 2017. Outcome2 estimated glomerular filtration rate (eGFR) measurements <45 mL/min/1.73 m2 or 2 measurements of moderate or severe albuminuria from one-year post-donation onwards that were at least 90 days apart. Analytical ApproachAssociations between potential risk factors and the primary outcome were assessed using Cox proportional hazard regression analyses. ResultsOver a median follow-up period of 8.6 years (interquartile range [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 1000 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 four years of follow-up, a 5 mL/min/1.73 m2 lower pre-donation eGFR increased the hazard of developing post-donation low eGFR or moderate-severe albuminuria by 26% (aHR, 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 pre-donation hypertension (aHR, 2.52; 95% CI, 1.28-4.96) or post-donation diabetes (aHR, 4.72; 95% CI, 1.54-14.50). LimitationsWe lacked data on certain donor characteristics that may impact long-term kidney function such as race, smoking history, and transplant-related characteristics. ConclusionsA 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 pre-donation eGFR, pre-donation hypertension, and post-donation diabetes are at increased risk of developing this outcome.