Kidney Microstructural Features at the Time of Donation Predict Long-term Risk of Chronic Kidney Disease in Living Kidney Donors

Abstract

Objective: To determine whether microstructural features on a kidney biopsy specimen obtained during kidney transplant surgery predict long-term risk of chronic kidney disease in the donor. Patients and Methods: We studied kidney donors from May 1, 1999, through December 31, 2018, with a follow-up survey for the results of recent blood pressure and kidney function tests (estimated glomerular filtration rate [eGFR] and proteinuria). If not recently available, blood pressure and eGFRs were requested from a local clinic. Microstructural features on kidney biopsy at the time of donation were assessed as predictors of hypertension and kidney function after adjusting for years of follow-up, baseline age, sex, and clinical predictors. Results: There were 807 donors surveyed a mean 10.5 years after donation. An eGFR less than 45 mL/ min/1.73 m 2 in 6.4% (43/673) of donors was predicted by larger glomerular volume per standard deviation (odds ratio [OR], 1.48; 95% CI, 1.08 to 2.04) and nephron number below the age-specific 5th percentile (OR, 3.38; 95% CI, 1.31 to 8.72). An eGFR less than 60 mL/min/1.73 m 2 in 42.5% (286/ 673) of donors was not predicted by any microstructural feature. Residual eGFR (postdonation/predonation eGFR) was predicted by nephron number below the age-specific 5th percentile (difference, À6.07%; 95% CI, À10.24% to À1.89%). Self-reported proteinuria in 5.1% (40/786) of donors was predicted by larger glomerular volume (OR, 1.42; 95% CI, 1.08 to 1.86). Incident hypertension in 18.8% (119/633) of donors was not predicted by any microstructural features. Conclusion: Low nephron number for age and larger glomeruli are important microstructural predictors for long-term risk of chronic kidney disease after living kidney donation.

Renal function outcomes and kidney biopsy features of living kidney donors with hypertension

“…However, the goal was to determine whether any definition of hypertension at the time of donation predicts long‐term risk of kidney disease regardless of whether interim events after donation also contribute to kidney disease risk. Donors who participated in the survey may also have recall bias; however, in a prior study we showed that there was an excellent correlation comparing serum creatinine from medical chart and reported from the survey at follow‐up from the same patient 46 …”

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

“…As reported previously, self-reported data have been validated when compared to objective in available medical records. 17 , 23 The survey was not designed to assess for stone recurrence and not all SFs had medical records for review, thus stone recurrence during follow-up was not assessed.…”

“…The Aging Kidney Anatomy study cohort has detailed biopsy characteristics of kidneys in living donors and their long-term outcomes. 16 , 17 This cohort offers a unique opportunity to study the clinical and structural characteristics of donors with nephrolithiasis and their long-term outcomes.…”

Early increase in single-kidney glomerular filtration rate after living kidney donation predicts long-term kidney function

“…5 A recent study identified a low nephron number for age as predictor for long-term risk of chronic kidney disease after living kidney donation. 6 Whether reduced nephron number or cortical kidney volume, which has also been linked with post-donation kidney function 7,8 , are associated with a less pronounced post-donation increase in single-kidney GFR is unknown.…”