Research Viewpoints CKD in Living Donors: Long-Term Follow-Up

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Haberal Guldehan; Yildirim Tolga; Yilmaz Seref Rahmi; Altun Bulent; Aki Fazil Tuncay; Erdem Yunus; Arici Mustafa: Chronic Kidney Disease Risk in Living Kidney Transplant Donors: A Long-Term Follow-Up Study. Nephron DOI 10.1159/000534397

Chronic kidney disease (as defined by KDIGO-CKD criteria) is fairly common among living kidney donors subjected to uni-nephrectomy, especially in older donors with age-associated decline in pre-transplant GFR. This was originally pointed out by Barri et al. in 2009 [1]. This might contribute to a slight excess of dialysis-requiring ESKD in such donors.

Haberal and co-workers from Hacettepe University in Ankara, Turkey, have re-examined this issue examining longer-term follow-up of about 71 months in 338 living donors (related and unrelated). The average age at donation was 47 years and all were Caucasian. A few subjects had hypertension pre-donation and the related–unrelated donor frequency is not specified. The eGFR (2009 CKD-EPI eGFR – creatinine) was 102 ± 15 mL/min/1.73 m2 prior to uni-nephrectomy. Thus, the immediate post-uni-nephrectomy eGFR was estimated to be 51 mL/min/1.73 m2. At last follow-up, the eGFR was 77 ± 17 mL/min/1.73 m2, indicating that the usual compensatory increase of eGFR (about 30–35%) following uni-nephrectomy had occurred. Using the KDIGO-CKD definition, only 6 donors developed an eGFR <45 mL/min/1.73 m2, while 41 had an eGFR of 45–59 mL/min/1.73 m2. A total of 12 donors had an eGFR >60 mL/min/1.73 m2 with some mild increase in urinary albumin to creatinine ratio values. No information is given on birth weight of any of the donors, and the original kidney diseases of intra-familial recipients is unknown. Post-donation hypertension was common in the donors, especially if eGFR was 60 mL/min/1.73 m2. Unfortunately, no control group of non-donors was included to evaluate the significance of this finding.

The results of this study confirm and extend those of Barri et al. [1]. They illustrate that applying the absolute thresholds of an eGFR of <60 mL/min/1.73 m2 to a cohort of living donors of varying age will inevitably lead to an increased “diagnosis” of CKD following uni-nephrectomy, especially in older donors. Whether this “CKD” will progress is highly uncertain, but new onset of hypertension and albuminuria in some living donors is of concern. Evaluation of nephron endowment (birth weight) will be crucial in future studies of “CKD” in living donors.

References

1. Barri Y, Parker III T, Kaplan B, Glassock R. Primum non nocere: is chronic kidney disease staging appropriate in living kidney transplant donors? Am J Transplant. 2009;9:657–660.