Hypertension and obesity in living kidney donors

Living Donors' Age Modifies the Impact of Pre-Donation Estimated Glomerular Filtration Rate on Graft Survival

BACKGROUND

The global scarcity of organs for kidney transplants (KTs) has led to the increased acceptance of living donors (LDs) with minor abnormalities to increase the donor pool.. We sought to evaluate the effects of some of these LDs' clinical characteristics (older age, borderline renal function, hypertension, dyslipidemia, smoking, and obesity) on graft outcomes.

METHODS

We studied 352 recipients of LDKTs (1998-2020). Firstly, considering the recipients and KT variables, we identified relevant predictors of overall and censored graft failure (GF). Then, adjusting for these predictors, we explored LD variables as predictors of overall and censored GF in a multivariable Cox model.

RESULTS

The recipients from LD with higher eGFR (≥90 mL/min/1.73 m2) had significantly better overall and censored graft survival GS) at 15 y after KT (respectively, 67 and 75% vs. 46 and 46%, p < 0.001). Importantly, none of the remaining LD factors which were evaluated (hypertension, dyslipidemia, smoking, proteinuria, and obesity) were independent predictors of GF. In recipients from LDs < 50 y, having an eGFR < 90 was an independent predictor of overall GF [adjusted HR (95%CI) of 2.578 (1.120-5.795)] and censored GF [adjusted HR (95%CI) of 3.216 (1.300-7.959)], compared to recipients from LDs with eGFR ≥ 90. Contrarily, when donors were older, no difference in the risk of GF was observed between eGFR categories.

CONCLUSION

In our cohort, lower pre-donation eGFR had an impact on GS only in younger LDs. An age-adjusted eGFR cutoff may be pursued for improved donor admissibility.

Prediction of Renal Function in Living Kidney Donors and Recipients of Living Donor Kidneys Using Quantitative Histology

BACKGROUND

Living kidney donors (LKDs) are at increased risk of chronic kidney disease, whereas transplant recipients experience progressive reduction of graft function. We examined the predictive value of quantitative stereology on renal function in LKDs and recipients of living donor kidneys, based on perioperative biopsies from the donated kidney.

METHODS

Cortex volume of both donor kidneys was determined by contrast-enhanced computed tomography and single-kidney glomerular filtration rate (GFR) by 51 chrome-EDTA clearance together with renography. Glomerular density was used to estimate total glomeruli number in addition to glomerular volume, glomerular sclerosis, kidney fibrosis, and arteriole dimensions. GFR measurements were repeated 1 y after transplantation in both LKDs and recipients. Associations between GFR at follow-up and cortex volume and histomorphometric parameters after adjustment of age, gender, body mass index, smoking status, 24-h blood pressure, and single-kidney GFR were examined.

RESULTS

We included 49 LKDs (age, 51 ± 12 y) and 51 recipients (age, 44 ± 13 y). At follow-up, GFR was 71 ± 16 mL/min in LKDs and 61 ± 18 mL/min in recipients with hyperfiltration being more prominent in LKDs (30.4%) as compared to recipients (16.4%; P < 0.05). One-year GFR in donors correlated to cortex volume ( P < 0.001) but not to any histological parameters, whereas GFR in recipients correlated to the amount of interstitial fibrosis ( P < 0.01) but not to other histological parameters or cortex volume.

CONCLUSIONS

Kidney cortex volume, but not renal histology parameters, predicts 1-y renal outcome in LKDs. In contrast, the amount of interstitial fibrosis, but not cortex volume, predicts 1-y graft function in recipients.

Long-Term Follow-up of Over 600 Living Related Kidney Donors: Single-Center Experience

OBJECTIVES

Kidney transplant is the treatment of choice in patients with end-stage renal disease because it offers improved survival and better quality of life. Although most epidemiologic studies have suggested that living kidney donors have a minimal lifetime risk of developing end-stage renal disease, long-term complications and physiologic and psychologic sequelae resulting from donation remain unclear. Here, we examined the long-term results of living-related kidney donors who donated kidneys at the Başkent University Ankara Hospital over the past 25 years.

MATERIALS AND METHODS

We were able to examine 607 kidney transplant donors (mean age of 52.03 ± 11.54 years) who were seen at our center from 1986 to 2021 and who agreed to a general health evaluation. Collected data included donor age, sex, blood type, body mass index, duration after donation, blood pressure measurements, biochemical parameters, abdominal ultrasonograph for size, structure, and renal blood flow of the solitary kidney, comorbid conditions, chronic drug use, and surgical procedures after donation.

RESULTS

Mean time after donation was 10.4 ± 3.2 years. Twenty-four donors (3.9%) were diagnosed with diabetes and 21 (3.4%) with thyroid disease, 64 (10.5%) developed hypertension, and 48 (8.8%) developed atherosclerotic cardiovascular disease. Obesity was found to be an increasing problem in our donor population, with 174 (28.6%) developing mild to moderate obesity (body mass index >25 kg/m2). Older age, obesity, smoking, and hyperlipidemia were found to be the major and independent risk factors of both hypertension and atherosclerotic cardiovascular disease in donors. None of our donors developed endstage renal disease.

CONCLUSIONS

Obesity and hypertension were the most common comorbidities that developed in our kidney donor population. Our principle is to avoid unrelated and nondirected donors because of the possible long-term complications. Unrelated donors may be desperate if a family member needs donation in the future.