Background There have been few prospective controlled studies of kidney donors. Understanding the pathophysiologic effects of kidney donation is important for judging donor safety and improving our understanding of the consequences of reduced kidney function in chronic kidney disease. Study Design Prospective, controlled, observational cohort study. Setting & Participants 3-year follow-up of kidney donors and paired controls suitable for donation at their donor's center. Predictor Kidney donation. Outcomes Medical history, vital signs, glomerular filtration rate, and other measurements at 6, 12, 24, and 36 months after donation. Results At 36 months, 182 of 203 (89.7%) original donors and 173 of 201 (86.1%) original controls continue to participate in follow-up visits. The linear slope of the glomerular filtration rate measured by plasma iohexol clearance declined 0.36 ± 7.55 mL/min per year in 194 controls, but increased 1.47 ± 5.02 mL/min per year in 198 donors (P = 0.005) between 6 and 36 months. Blood pressure was not different between donors and controls at any visit, and at 36 months, all 24-hour ambulatory blood pressure parameters were similar in 126 controls and 135 donors (mean systolic blood pressure, 120.0 ± 11.2 [SD] vs 120.7 ± 9.7 mm Hg [P = 0.6]; mean diastolic blood pressure, 73.4 ± 7.0 vs 74.5 ± 6.5 mm Hg [P = 0.2]). Mean arterial pressure nocturnal dipping was manifest in 11.2% ± 6.6% of controls and 11.3% ± 6.1% of donors (P = 0.9). Urinary protein-creatinine and albumin-creatinine ratios were not increased in donors compared with controls. From 6 to 36 months postdonation, serum parathyroid hormone, uric acid, homocysteine, and potassium levels were higher, whereas hemoglobin levels were lower, in donors compared with controls. Limitations Possible bias resulting from an inability to select controls screened to be as healthy as donors, short follow-up duration, and dropouts. Conclusions Kidney donors manifest several of the findings of mild chronic kidney disease. However, at 36 months after donation, kidney function continues to improve in donors, whereas controls have expected age-related declines in function.
Bibliographical noteFunding Information:
Support: This study was funded by the National Institutes of Health (NIH) under the cooperative agreement U01 DK066013. The NIH participated in the interpretation of data, writing the report, and the decision to submit the report for publication. This study was also supported by the Minneapolis Medical Research Foundation, Minneapolis, MN, which did not participate in any aspect of the study. Financial Disclosure: The authors declare that they have no other relevant financial interests. Contributions: Research idea and study design: BLK, TA-H, RSK, ESK, AAP, TEP, HR, MWS, JJS, MRW; data acquisition: TA-H, RSK, ESK, AAP, HR, MRW; data analysis/interpretation: BLK, TA-H, AKI, RSK, PLK, ESK, RK, AAP, TEP, HR, MWS, JJS, MRW; statistical analysis: BLK, JJS. Each author contributed important intellectual content during manuscript drafting or revision and accepts accountability for the overall work by ensuring that questions pertaining to the accuracy or integrity of any portion of the work are appropriately investigated and resolved. BLK takes responsibility that this study has been reported honestly, accurately, and transparently; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.
- Assessing Long Term Outcomes in Living Kidney Donors (ALTOLD)
- Chronic kidney disease (CKD)
- glomerular filtration rate (GFR)
- kidney function
- kidney transplantation
- living kidney donation
- mineral and bone disorders
- parathyroid hormone (PTH)
- patient safety
- renal insufficiency
- unilateral nephrectomy
- uric acid