Changes in glomerular filtration rate after donation in living kidney donors: A single-center cohort study

Chronic Kidney Disease Risk in Living Kidney Transplant Donors: A Long-Term Follow-Up Study

BACKGROUND

Living kidney donors (LKD) may experience some untoward consequences following donation such as development of chronic kidney disease (CKD). In this study, we aimed to investigate the rate of development of CKD and factors affecting the development of CKD in LKDs during long-term follow-up from a center in Turkey.

METHODS

This study was a retrospective analysis of LKDs followed between January 2000 and December 2017. Pre-transplant and post-transplant clinical data of the 338 LKDs were recorded and compared. Factors affecting the development of stage 3 and later stages of CKD were analyzed.

RESULTS

Majority of the donors were females (64.2%), and the median age of all donors was 47 (39-54) years. Stage 3 CKD developed in 50 donors during the median follow-up of 71 months. Older age at the time of transplantation and a low pre-transplant estimated glomerular filtration rate (eGFR) were determined as the factors affecting the development of stage 3 CKD (p < 0.001, p < 0.001). The receiver operating characteristic analysis showed that the cut-off age for the development of stage 3 CKD was 50.5 years. Newly diagnosed hypertension was detected in 57 patients (16.8%) after the transplantation. While hypertension was seen at a rate of 42% in those with an eGFR <60 mL/min/1.73 m2, it was detected at 19.4% in the group with an eGFR >60 mL/min/1.73 m2 (p < 0.001).

CONCLUSION

These results reveal that being a LKD is associated with the development of CKD and hypertension. Age and eGFR values at the time of transplantation were the determinants for the development of CKD.

Acute kidney injury and the compensation of kidney function after nephrectomy in living donation

Acute kidney injury (AKI) incidence is growing rapidly, and AKI is one of the predictors of inpatient mortality. After nephrectomy, all the patients have decreased kidney function with AKI and recover from AKI. However, the characteristic and behavior of AKI is different from usual AKI and compensatory kidney function has been well known in the postoperative setting, especially in living donors. In this review, we have focused on the compensation of kidney function after nephrectomy in living donors. We discuss factors that have been identified as being associated with kidney recovery in donors including age, sex, body mass index, remnant kidney volume, estimated glomerular filtration rate, and various comorbidities.

Is Compensation Prediction Score Valid for Contralateral Kidney After Living-Donor Nephrectomy in the United States?

BACKGROUND

Compensation after living donor nephrectomy is well known, and a compensation prediction score (CPS) was made in Japan previously. The aim of this study was to perform external validation of CPS in the United States.

METHODS

We studied retrospectively 78 living donor nephrectomies in our institution. We defined a favorable compensation as a postdonation estimated glomerular filtration rate (eGFR) at 1 year of >60% of the predonation eGFR. We analyzed the living donors' clinical characteristics and outcomes and validated CPS score.

RESULTS

The median (range) donor age was 43 (21-63) years, and median body mass index was 26.9 (18.3-35.9) kg/m². Forty-four percent of donors were White. The donor predonation eGFR was 105 (61-134) mL/min/1.73 m², and the postdonation eGFR at 1 year was 73.2 (0-115) mL/min/1.73 m². Eighty-three percent of donors had a favorable compensation. The CPS was 9.6 (1.6-15.6) and showed strong diagnostic accuracy for predicting favorable compensation (area under the curve, 0.788; 95% confidence interval, 0.652-0.924; P = .001). The CPS showed a significant positive correlation with the postdonation eGFR at 1 year (R = 0.54; P < .001).

CONCLUSIONS

In the United States, the CPS would be a valid tool with which to predict a favorable compensation of remnant kidney function.

External Validation of a Predictive Model to Estimate Renal Function After Living Donor Nephrectomy

BACKGROUND

Transplantation from living donor nephrectomy (LDN) is the best treatment for end-stage renal disease but observed decrease in donor renal function is a major concern. The aim of this study was to externally validate a predictive model to estimate 1-y postdonation estimated glomerular filtration rate (eGFR) and risk of chronic kidney disease (CKD) in living donors.

METHODS

All LDN performed at Necker Hospital from January 2006 to May 2018 were retrospectively included. Observed eGFR (using CKD-EPI formula) at 1-y post LDN was compared with the predicted eGFR calculated with a formula developed at Toulouse-Rangueil and based on predonation eGFR and age. Pearson correlation, receiver operating characteristics curve (ROC curve), and calibration curve were used to assess external validity of the proposed prognostic model to predict postoperative eGFR and occurrence of CKD in donors.

RESULTS

Four hundred donors were evaluated with a mean postoperative eGFR of 62.1 ± 14 mL/min/1.73m2. Significant correlation (Pearson r = 0.66; P < 0.001) and concordance (Bradley-Blackwood F = 49.189; P < 0.001) were observed between predicted and observed 1-y eGFR. Area under the receiver operating characteristic curve of the model relevant accuracy was 0.86 (95% CI, 0.82-0.89).

CONCLUSIONS

This study externally validated the formula to predict 1-y postdonation eGFR. The calculator could be an accurate tool to improve the selection of living kidney donor candidate.

Evaluation of postoperative kidney function after administration of 6% hydroxyethyl starch during living-donor nephrectomy for transplantation

PURPOSE

We aimed to investigate whether 6% HES 130/0.4 was associated with postoperative reduction of estimated glomerular filtration rate (eGFR) in donor patients who underwent nephrectomy for living kidney transplantation.

METHODS

This retrospective study included 213 living kidney transplant donors treated at Kyushu University Hospital in Japan from April 2014 to March 2018. Patients who were administered 6% HES 130/0.4 were allocated in the HES group (n = 108), and those who were not were allocated in the control group (n = 105). The postoperative decrements in estimated glomerular filtration rates (eGFRs) from preoperative values were calculated on postoperative days (PODs) 1, 3, and 14. Decline in kidney function (DKF) according to the Kidney Disease: Improving Global Outcomes (KDIGO) classification were analyzed by multivariable-adjusted ordinal logistic regression to estimate odds ratios (ORs) for postoperative DKF.

RESULTS

In HES group, administration amount of HES was median 9.4 [interquartile range: 8.2-14.3] ml/kg. Postoperative decrements in eGFR were similar in the control and HES groups on POD 1 (control group: mean 32.0 vs. HES group: 33.0 mL/min/1.73 m²), same as POD 3 (21.1 vs. 22.4 mL/min/1.73 m²) and POD 14 (26.0 vs. 25.9 mL/min/1.73 m²), even after adjusting for confounding factors. The multivariable-adjusted ORs for postoperative DKF did not significantly increase in the HES group on POD 1 (OR: 0.88), POD 3 (OR: 0.96), and POD 14 (OR: 0.52) compared with the control group.

CONCLUSION

Six percent HES 130/0.4 is not associated with postoperative renal dysfunction in donor patients undergoing nephrectomy for kidney transplantation.

Prediction model of compensation for contralateral kidney after living-donor donation

Background

Compensation of contralateral kidney function after living-donor kidney donation is well known, and many predictive factors have been proposed. However, no prediction model has been proposed. This study was performed to establish a tool with which to estimate the degree of compensation of the contralateral kidney after living-donor kidney donation.

Methods

We retrospectively analyzed 133 living donors for renal transplantation in our institution. We defined a favorable compensation as a post-donation estimated glomerular filtration rate (eGFR) at 1 year (calculated by the Chronic Kidney Disease Epidemiology Collaboration equation) of > 60% of the pre-donation eGFR. We analyzed the living donors’ clinical characteristics and outcomes.

Results

The median (range) donor age was 59 (24–79) years, median (range) body mass index was 22.9 (16.8–32.7) kg/m², and median (range) body surface area was 1.6 (1.3–2.0) m². All donors were Japanese, and 73% of the donors were biologically related. The median (range) donor pre-donation eGFR was 108.7 (82–144) ml/min/1.73 m², and the median (range) post-donation eGFR at 1 year was 86.9 (43–143) ml/min/1.73 m². Eighty-six percent of donors had compensatory hypertrophy. In the univariate analysis, age, female sex, history of hypertension, body surface area, and pre-donation eGFR were significantly associated with hypertrophy (p < 0.05). In the multivariate analysis, age, female sex, history of hypertension, and ratio of the remnant kidney volume to body weight were significantly associated with hypertrophy (p < 0.05). Based on these results, we created a compensation prediction score (CPS). The median (range) CPS was 8.7 (1.1–17.4). Receiver operating characteristic analysis showed strong diagnostic accuracy for predicting favorable compensation (area under the curve, 0.958; 95% confidence interval, 0.925–0.991, p < 0.001). The optimal cut-off value of the CPS was 5.0 (sensitivity, 92.0%; specificity, 89.5%). The CPS had a strong positive correlation with the post-donation eGFR (R = 0.797, p < 0.001).

Conclusion

The CPS might be useful tool with which to predict a favorable compensation of the contralateral kidney and remnant kidney function. If the CPS is low, careful management and follow-up might be necessary. Further investigations are needed to validate these findings in larger populations.

Baseline living-donor kidney volume and function associate with 1-year post-nephrectomy kidney function

Living donors may develop kidney dysfunction more often than equally healthy populations. The purpose of this study was to determine whether computed tomography‐assessed remaining kidney volume indexed to body surface area (RKV/BSA) was associated with 1‐year post‐nephrectomy renal function independent of baseline renal function. Using multivariable regression, we modeled 1‐year estimated glomerular filtration rate (eGFR) and eGFR <60 mL /min/1.73 m² and considered pre‐determined baseline eGFR subgroups in 151 consecutive donors. Mean ± SD baseline age, eGFR, RKV, BSA, and RKV/BSA were 38 ± 11 years, 97 ± 16 mL/min/1.73 m², 153 ± 29 mL, 1.9 ± 0.2 m², and 80.0 ± 12.8 ml/m², respectively; 50% were female and 94% were white. Mean baseline eGFR was greater with increasing RKV/BSA tertiles (92 ± 14, 97 ± 16, 107 ± 16 mL/min/1.73 m²; P < 0.001). Post‐nephrectomy eGFR remained separated by RKV/BSA tertiles. At baseline, each SD greater RKV/BSA and eGFR was independently associated with higher adjusted 1‐year eGFR by 2.4 and 9.2 mL/min/1.73 m². Each SD greater age associated with 2.2 mL/min/1.73 m² lower adjusted 1‐year eGFR. Adjusted odds of 1‐year eGFR <60 increased significantly for donors with RKV/BSA <80 mL/m². With baseline eGFR <90, probability of 1‐year eGFR <60 increased to >80% with decreasing RKV/BSA values below 80 mL/m². Those with baseline eGFR >100 rarely developed 1‐year eGFR <60 if RKV/BSA remained >60 mL/m². RKV/BSA independently associated with 1‐year eGFR <60, especially with lower baseline eGFRs. Additional studies should evaluate the predictive utility of this measure and its potential role in donor evaluations and informed consent.

External validation of a proposed prognostic model for the prediction of 1-year postoperative eGFR after living donor nephrectomy

PURPOSE

The goal of this study was to externally validate the recently proposed prognostic model for the prediction of estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m² 1 year after living donor nephrectomy.

METHODS

130 living kidney donors (median age at donation 52.3 years, range 24.7-75.6 years) were investigated before and after donation between March 2000 and April 2016. Preoperative eGFR values varied between 61.7 and 148.4 ml/min (mean: 89, median: 88). Observed eGFR 1 year after transplantation (±45 days) ranged between 36.3 and 97.1 ml/min (mean: 55, median: 53). 70.8% of donors displayed eGFR values < 60 ml/min 1 year after donation. Predicted eGFR 1 year after donation was determined using the prognostic model proposed by Benoit et al. (Int Urol Nephrol 49(5):793-801. doi: 10.1007/s11255-017-1559-1 , 2017): postoperative eGFR ml/min/1.73 m² = 31.71 + (0.521 × eGFR in ml/min prior to donation -0.314 × Age in years at donation). Pearson correlation and receiver operating characteristics curve (ROC-curve) were used to assess external validity of the proposed prognostic model to predict postoperative eGFR in ml/min and eGFR < 60 ml/min.

RESULTS

The correlation between predicted and observed eGFR 1 year after donation was significant (p < 0.001; R ² = 0.594). The area under the ROC-curve (AUROC) demonstrated a high sensitivity and specificity for predicted eGFR values < 60 ml/min (AUROC = 0.866).

CONCLUSIONS

The proposed prognostic model for the prediction of postoperative eGFR was successfully validated in our cohort. We therefore consider the model as generally applicable.

Predictive model of 1-year postoperative renal function after living donor nephrectomy

OBJECTIVE

Kidney transplantation from a living donor nephrectomy (LDN) is the best treatment for end-stage renal disease, but decrease in donor renal function is often revealed. The aim of this study was to evaluate the association between preoperative factors and postoperative estimated glomerular filtration rate (eGFR) and test a predictive model to estimate postoperative eGFR, 1 year after LDN.

PATIENTS AND METHODS

We reviewed 226 records of consecutive patients who underwent laparoscopic live donor nephrectomy between 2006 and 2014 in a single tertiary center. Of these, complete data on 202 patients were analyzed. A training (2/3 of the whole population) and a validation set (1/3) were randomized. A multivariate regression model was used to identify predictors and a formula to estimate of 1-year postoperative eGFR in the training set, using the CKD-EPI formula. Then, the formula was subjected to internal validation using the validation set using receiver operating characteristic (ROC) curves.

RESULTS

Two hundred and two LLDN were evaluated with a mean preoperative eGFR of 94.1 ± 15.5 ml/min/1.73 m² and postoperative eGFR of 64.6 ± 14.5 ml/min/1.73 m² (p < 0.0001). In multivariable analysis, age and preoperative eGFR were independent predictors of postoperative eGFR in the training set. A formula to estimate postoperative eGFR was generated with Pearson r = 0.70 in the training cohort and 0.65 in the validation cohort (both p < 0.0001). Area under the ROC curve of the formula was 0.89 in the training cohort and 0.83 in the validation cohort (both p < 0.0001).

CONCLUSIONS

Preoperative eGFR and age are predictors of postoperative eGFR after LDN. The internally validated predictive model of postoperative eGFR developed could be an accurate tool to improve the selection of LDN candidates.

Acceptability of older adults as living kidney donors

PURPOSE OF REVIEW

Kidney transplantation from a living kidney donor (LKD) is associated with better long-term survival and quality of life for a patient with end-stage renal disease (ESRD) than dialysis. We reviewed recent literature on the acceptability and outcomes of older adults as LKDs, which may be misunderstood in routine care.

RECENT FINDINGS

Studies report that receiving a kidney from an older LKD is associated with worse recipient and graft survival compared with receiving a kidney from a younger LKD, but similar recipient and graft survival to receiving a kidney from a standard criteria deceased donor. A kidney from a younger vs. older LKD results in better graft survival in younger recipients, whereas the graft survival is similar in older recipients. Compared with healthy matched nondonors, older LKDs have a similar risk of death and cardiovascular disease and the absolute risk of ESRD after 15 years remains less than 1%. The estimated predonation and postdonation lifetime risk of ESRD varies by age, sex and race with lower incidences in individuals who are older, female and white (vs. African-American).

SUMMARY

Donor and recipient outcomes from several studies support the acceptability of older adults as LKDs.

Follow-up rates of living kidney donor in Japan: A single center study

Long-term follow-up of kidney donors is needed not only for the individual donor's benefit but also to establish analyzable databases to improve the selection criteria for future donors. We collected data including the date of transplantation, the date of the last follow-up, donor's age, sex, their relationship to the recipient, renal function, proteinuria, and the prevalence of hypertension. Of 124 donors, 52 donors were not being followed up. The mean duration of follow-up was 4.3 ± 3.6 years. Follow-up rates were 83.9%, 74.6%, and 59.2% at 1 year, 2 years, and 5 years postdonation, respectively. Of those not being followed up, 75% dropped out. Follow-up rates did not differ between parent and spouse donors 5 years (57.1% vs. 71.4%; P = 0.4) postdonation. Similarly, follow-up rates at 5 years did not differ between donors aged 60 years or older and those younger than 60 (57.5% vs. 61.3%; P = 0.6). Of 72 donors being followed up, 75.0% had estimated glomerular filtration rate of <60 mL/min/1.73 m², 8.3% had proteinuria, and 41.7% had hypertension requiring medication. There is a limitation to the endeavor of each transplant center to follow-up all their donors. Long-term donor follow-up in Japan requires a national registration system and mandates transplant center participation.

Five-year follow-up after live donor nephrectomy - cross-sectional and longitudinal analysis of a prospective cohort within the era of extended donor eligibility criteria

To establish the outcome of live kidney donors 5 years after donation, we investigated the risk for progressive renal function decline and quality of life (QoL). Data on estimated glomerular filtration rate (eGFR), creatinine, hypertension, QoL and survival were assessed in a prospective cohort of 190 donors, who donated between 2008 and 2010. Data were available for >90%. The mean age predonation was 52.8 ± 11.5 years, 30 donors having pre-existent hypertension. The mean follow-up was 5.1 ± 0.9 years. Eight donors had died due to non-donation-related causes. After 5 years, the mean eGFR was 60.2 (95% CI 58.7-62.7) ml/min/1.73 m² , with a median serum creatinine of 105.1 (95% CI 102.5-107.8) μmol/l. eGFR decreased to 33.6% and was longitudinally lower among men than women and declining with age (P < 0.001), without any association on QoL. Donors with pre-existent and new-onset hypertension demonstrated no progressive decline of renal function overtime compared to nonhypertensives. No donors were found with proteinuria, microalbuminuria or at risk for end-stage renal disease. After an initial decline postdonation, renal function remained unchanged overtime. Men and ageing seem to affect renal function overtime, while decreased renal function did not affect QoL. These data support further stimulation of living kidney donation programmes as seen from the perspective of donor safety.