Retrospective Cohort Study Open Access
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Nephrol. May 25, 2023; 12(3): 40-55
Published online May 25, 2023. doi: 10.5527/wjn.v12.i3.40
Preemptive living donor kidney transplantation: Access, fate, and review of the status in Egypt
Rabea Ahmed Gadelkareem, Amr Mostafa Abdelgawad, Ahmed Reda, Mohammed Ali Zarzour, Nasreldin Mohammed, Hisham Mokhtar Hammouda, Mahmoud Khalil, Department of Urology, Assiut Urology and Nephrology Hospital, Faculty of Medicine, Assiut University, Assiut 71515, Egypt
Nashwa Mostafa Azoz, Department of Internal Medicine, Assiut University Hospital, Faculty of Medicine, Assiut University, Assiut 71515, Egypt
ORCID number: Rabea Ahmed Gadelkareem (0000-0003-4403-2859); Amr Mostafa Abdelgawad (0000-0002-4336-1573); Ahmed Reda (0000-0003-3699-5735); Nashwa Mostafa Azoz (0000-0002-8455-1920); Mohammed Ali Zarzour (0000-0003-1449-6118); Nasreldin Mohammed (0000-0002-0232-9497); Hisham Mokhtar Hammouda (0000-0003-2682-3876); Mahmoud Khalil (0000-0002-2564-5476).
Author contributions: Gadelkareem RA, Abdelgawad AM, and Zarzour MA designed the research, collected the data, and wrote the paper; Reda A, Azoz NM, and Mohammed N contributed to the statistical analysis, literature review, writing and revision; Hammouda HM and Khalil M contributed to the literature review, writing, revision and supervision of the work; All authors approved the paper.
Institutional review board statement: This study has been approved in 2017 by the Medical Ethics Committee of the Faculty of Medicine, Assiut University, Egypt as a topic in a research project titled "Outcome of living donor kidney transplantation in Assiut Urology and Nephrology Hospital". The institutional review board number is 17200148.
Informed consent statement: This article is a retrospective study. Patients were not required to give informed consent to the study because the manipulated data were anonymous and were obtained after each patient agreed to treatment by consent.
Conflict-of-interest statement: The authors have no financial relationships to disclose.
Data sharing statement: The data supporting this study are available from the corresponding author on reasonable request.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Rabea Ahmed Gadelkareem, MD, Assistant Professor, Department of Urology, Assiut Urology and Nephrology Hospital, Faculty of Medicine, Assiut University, Elgamaa Street, Assiut 71515, Egypt. rabeagad@aun.edu.eg
Received: January 11, 2023
Peer-review started: January 11, 2023
First decision: February 2, 2023
Revised: February 22, 2023
Accepted: March 14, 2023
Article in press: March 14, 2023
Published online: May 25, 2023

Abstract
BACKGROUND

Preemptive living donor kidney transplantation (PLDKT) is recommended as the optimal treatment for end-stage renal disease.

AIM

To assess the rate of PLDKT among patients who accessed KT in our center and review the status of PLDKT in Egypt.

METHODS

We performed a retrospective review of the patients who accessed KT in our center from November 2015 to November 2022. In addition, the PLDKT status in Egypt was reviewed relative to the literature.

RESULTS

Of the 304 patients who accessed KT, 32 patients (10.5%) had preemptive access to KT (PAKT). The means of age and estimated glomerular filtration rate were 31.7 ± 13 years and 12.8 ± 3.5 mL/min/1.73 m2, respectively. Fifty-nine patients had KT, including 3 PLDKTs only (5.1% of total KTs and 9.4% of PAKT). Twenty-nine patients (90.6%) failed to receive PLDKT due to donor unavailability (25%), exclusion (28.6%), regression from donation (3.6%), and patient regression on starting dialysis (39.3%). In multivariate analysis, known primary kidney disease (P = 0.002), patient age (P = 0.031) and sex (P = 0.001) were independent predictors of achievement of KT in our center. However, PAKT was not significantly (P = 0.065) associated with the achievement of KT. Review of the literature revealed lower rates of PLDKT in Egypt than those in the literature.

CONCLUSION

Patient age, sex, and primary kidney disease are independent predictors of achieving living donor KT. Despite its non-significant effect, PAKT may enhance the low rates of PLDKT. The main causes of non-achievement of PLDKT were patient regression on starting regular dialysis and donor unavailability or exclusion.

Key Words: Access to kidney transplantation, Donor regression, Kidney transplantation, Living donors, Preemptive kidney transplantation, Transplantation

Core Tip: Patients with preemptive access to kidney transplantation (PAKT) may have significant differences from those with conventional access to KT, warranting more evaluation. In this study, known primary kidney disease was an independent factor of achievement of living donor KT (LDKT). In addition, the older age and female sex were independent predictors of non-achievement of LDKT. However, unavailability, regression, and exclusion of LDs and patient regression on starting dialysis may prevent achievement of preemptive LDKT (PLDKT) in patients with PAKT. Despite its non-significant effect, PAKT may improve the low rates of PLDKT. The current literature review may refer to that PLDKT has comparable or variably better outcomes than the conventional LDKT. Hence, PLDKT is recommended as the first choice for each candidate patient. In Egypt, the rate of PLDKT is still lower than that of other countries, warranting implementation of effective strategies to promote PLDKT.



INTRODUCTION

Preemptive kidney transplantation (PKT) is defined as receiving kidney transplantation (KT) before initiation of maintenance dialysis in patients with end-stage renal disease (ESRD)[1,2]. This definition may vary from one KT program to another, where patients who receive dialysis sessions sporadically or as conditioning pre-transplantation sessions for no more than 1 wk may be included in this definition[2-6]. The evolution of PKT was more than 30 years ago[7], when it passed through an insidious course and gained variably insufficient interests among the physicians and surgeons in the KT community[1,5]. Many initiatives and programs have been triggered to promote PKT, especially in the sector of living donor kidney transplantation (LDKT). These initiatives promote living kidney donation (LKD) programs as the most effective contributor to PKT[4-7]. PKT is a time-based KT strategy controlled by setting the timing of KT surgery at a point just before the start of regular dialysis as much as possible. This philosophy represents the natural course of management of most diseases. However, it has generated debate along the different axes of KT, such as the proposed lead-time bias effect on the outcomes of PKT[8]. The incidence of PKT has improved gradually from 2% in its early years to 6%-7% in the last years. Most cases come from LDKT programs, where it may reach up to 34% in some countries that adopt LDKT programs[6,9]. The latter percentage refers to the fundamental role of LD in the promotion of PKT strategy[10]. Preemptive access to KT (PAKT) and waitlisting are other effective contributors to PKT. Hence, they are fundamental issues in PKT literature[1,11]. However, they have mostly been ignored in research from Egypt, where only LDKT is performed in adults[9,12-14] and pediatrics[15-17].

We assessed the percentage of patients with PAKT and their fate regarding the receipt of preemptive LDKT (PLDKT).

MATERIALS AND METHODS
Study design

A retrospective review was performed for the electronic and manual records of patients with ESRD who sought LDKT in our center from November 2015 to November 2022. The study included both patients with PAKT, which was defined as the presentation of a patient with chronic kidney disease (CKD) stage 4 or 5 for KT prior to the start of regular dialysis and those with conventional access to KT (CAKT). The exclusion criterion was patients who refused KT before starting the preparation for LDKT (Figure 1). The relevant demographic characteristics of the patients and potential donors including age, sex, and relatedness to the potential donors were reviewed. Also, the clinical data including the primary kidney disease, estimated glomerular filtration rate (eGFR) at presentation, outcomes of preparation to KT, causes of deferring LDKT, and fate of the patients and donors were studied. We used the CKD-Epidemiology Collaboration creatinine equation to estimate eGFR for patients with PAKT[18].

Figure 1
Figure 1 Flowchart of patients who accessed our center seeking living donor kidney transplantation. Relative to the status of dialysis at access, this chart shows the steps through which the patients and their potential donors were evaluated to achieve kidney transplantation. CLDKT: Conventional living donor kidney transplantation; PLDKT: Preemptive living donor kidney transplantation.

Also, a review of the literature was performed to assess PLDKT in KT studies from Egypt. The KT center volume, pre-KT characteristics, and percentages and outcomes of PLDKT were reviewed. Furthermore, the literature was reviewed for the incidence of PLDKT in studies from other countries and large-volume KT registries.

This study was conducted as a topic in a KT research project regarding the outcomes of LDKT at our center. The institutional review board number is 17200148/2017.

Statistical analysis

Statistical analyses were performed with EasyMedStat (version 3.21.4; www.easymedstat.com). Continuous variables are presented as the mean ± standard deviation and range. However, categorical variables are presented as the number and percentage of each category. We created two groups (PAKT and CAKT) according to the status of dialysis at the time of access to transplantation. Normality and hetereoskedasticity of continuous data were assessed with the White test (or with Shapiro-Wilk in multivariate analysis) and Levene’s test, respectively. Continuous outcomes were compared with the unpaired Student t-test, Welch t-test, or Mann-Whitney U test according to the data distribution. Categorical outcomes were compared with the chi-squared or Fisher’s exact test accordingly. Multivariate logistic regression was performed to assess the factors contributing to achievement of KT in our center. Data were checked for multicollinearity with the Belsley-Kuh-Welsch technique. P < 0.05 was considered statistically significant.

RESULTS

Between November 2015 and November 2022, 325 patients attended our center for KT. Twenty-one (6.5%) patients changed their mind or were not serious in accessing KT. The remaining 304 patients were differentiated into PAKT and CAKT groups (Figure 1). The former group included 32 patients (10.5%) who were not on dialysis at the time of access to KT and the latter group included 272 (89.5%) patients with a mean (range) duration of hemodialysis of 6.3 ± 10.5 (0.5–108) mo. Both groups were compared for their demographic and clinical characteristics (Table 1). Follow-up after regression or exclusion decision varied from 3 mo to 6 years.

Table 1 A comparison of the demographic and clinical characteristics of the patients with preemptive access to kidney transplantation and those with conventional access to kidney transplantation, n (%).
Variables
PAKT, n = 32
CAKT, n = 272
P value
Age in yr, mean ± SD (range)31.7 ± 13 (13-60)32.1 ± 11.5 (12-66)0.677
Sex
Men22 (68.8)213 (78.3)0.263
Women10 (31.2)59 (21.7)
Primary kidney disease
Glomerulonephritis3 (9.4)8 (2.9)< 0.001
Hereditary disease3 (9.4)6 (2.2)
Obstructive uropathy4 (12.5)8 (2.9)
Systemic disease4 (12.5)14 (5.2)
Urolithiasis3 (9.4)7 (2.6)
Unknown15 (46.9)229 (84.2)
Number of potential donors1
Patients presented without donors8 (25)36 (13.2)0.088
With one donor17 (53.1)187 (68.8)
With two donors4 (12.5)40 (14.7)
With three donors3 (9.4)9 (3.3)
Donor evaluation24236
Patients with evaluated donors20194
With accepted donor(s)10 (50)89 (45.9)0.232
With one donor excluded7 (35)75 (38.7)
With two donors excluded0 (0)15 (7.7)
With three donors excluded1 (5)2 (1)
With excluded and accepted donors2 (10)13 (6.7)
Number of not evaluated donors per patient656
One donor3 (50)51 (91.1)0.024
Two donors3 (50)4 (7.1)
Three donors0 (0)1 (1.8)
Order of the accepted donor12102
First10 (83.3)87 (85.3)0.634
Second1 (8.3)11 (10.8)
Third1 (8.3)4 (3.9)
Accepted donor age (yr), mean ± SD (range)38.1 ± 9 (25-53)40.6 ± 10.4 (21-60)0.39
Patient-donor relatedness degree
First5 (41.7)55 (53.9)0.234
Second5 (41.7)40 (39.2)
Third1 (8.3)6 (5.9)
Unrelated1 (8.3)1 (1)
Sex of accepted donors
Women7 (58.3)66 (64.7)0.754
Men5 (41.7)36 (35.3)
Accepted donor commitment
Donated4 (33.3)55 (53.9)0.171
Regressed1 (8.3)16 (15.7)
Released7 (58.3)31 (30.4)
Number of excluded donors per patient
One donor7 (77.8)84 (80)0.262
Two donors1 (11.1)19 (18.1)
Three donors1 (11.1)2 (1.9)
Main causes of donor exclusion
Medical causes1 (10)51 (51.5)0.027
Immunologic mismatch7 (70)34 (34.3)
Combined medical and immunologic2 (20)14 (14.1)
Main causes of donor release528
Financial causes0 (0)3 (10.7)0.235
Patient death0 (0)3 (10.7)
Patient non-candidacy0 (0)10 (35.7)
Patient regression5 (100)12 (42.9)
Achievement of kidney transplantation
Failed25 (78.1)191 (70.2)0.568
Transplanted in our center4 (12.5)55 (20.2)
Transplanted in another center3 (9.4)26 (9.6)
Cause of non-achievement of transplantation in our center28191
Donor exclusion8 (28.6)88 (40.6)0.035
Donor regression1 (3.6)16 (7.4)
Donor unavailability7 (25)37 (17.1)
Financial causes1 (3.6)13 (5.6)
Patient non-candidacy0 (0)25 (11.5)
Patient death0 (0)5 (2.6)
Patient regression11 (39.3)33 (15.2)
Fate of recipients who failed to have transplantation in our center
Death0 (0)13 (6)0.213
On hemodialysis24 (85.7)147 (67.7)
Transplantation in another center3 (10.7)26 (12)
Unknown1 (3.6)31 (14.3)

In the PAKT group, 29 patients (90.6%) failed to receive PLDKT due to original donor unavailability (25%), exclusion (28.6%), regression (3.6%), financial causes (3.6%), and patients’ regression from KT when starting regular dialysis (39.3%) (Table 1). Hence, PLDKT was carried out in 3 patients only, representing 5.1% of the total KTs and 9.4% of patients with PAKT. One of these three patients died from complications of the coronavirus disease 2019, 6 mo after KT. The other 2 patients were still living with a functioning graft for 68 and 12 mo at the time of writing of this article. The detailed characteristics of patients with PAKT are presented as individual patients (Table 2). The mean (range) age was 31.7 ± 13 (13-60) years. Most of the patients presented with stage 5 CKD. The mean (range) for serum creatinine level and eGFR was 6 ± 1.6 (3.2–9.8) mg/dL and 12.8 ± 4.8 (7–28) mL/min/1.73 m2, respectively.

Table 2 Detailed characteristics and fate of patients with preemptive access to kidney transplantation, n = 32.
Case Number
Age in yr
Sex
No. of Potential donors relatedness
Primary kidney disease
Serum creatinine in mg/dL
Stage of CKD, eGFR as mL/min/ 1.73 m2
PLDKT receipt
Cause of cancelled PLDKT
Fate of the patient
Case 148Male3 (Wife, Sister, daughter)Unknown8.55 (7)NoneDonor exclusionOn HD for 20 m then CLDKT in our center
Case 225Male1 (Mother)CMU5.55 (14)NoneDonor exclusionOn HD for 62 m
Case 328Male3 (Brothers)Unknown8.25 (8)NonePatient regressionOn HD for 74 m
Case 459Female2 (Sons)Diabetic nephropathy5.45 (11)NonePatient regressionOn HD 75 m
Case 547Male2 (Unrelated)ADPCKD4.85 (14)YesNALiving with a functioning graft for 68 m
Case 626Male1 (Brother)Urolithiasis7.85 (9)NonePatient regressionOn HD then lost to follow up
Case 727Male1 (Aunt)Unknown6.95 (10)NonePatient regressionOn HD then CLDKT in another center
Case 838Male1 (Unrelated)ADPCKD7.45 (9)NoneDonor exclusionOn HD for 34 m
Case 922FemaleNoneUnknown4.85 (12)None Donor unavailabilityOn HD for 33 m
Case 1019FemaleNoneUnknown3.54 (19)None Donor unavailabilityOn HD for 24 m
Case 1124MaleNoneGN4.44 (18)NoneDonor unavailabilityOn HD then lost to follow-up
Case 1213Male1 (Mother)Congenital VURD4.64 (18)YesNADied from COVID-19 complications
Case 1314Male1 (Mother)PUV5.34 (16)NoneDonor exclusionOn HD then CLDKT in another center
Case 1423Male1 (Mother)Urolithiasis5.15 (15)NonePatient regressionOn HD for 18 m
Case 1534Female1 (Sister)Unknown8.65 (8)NoneDonor regressionOn HD for 6 m before death
Case 1652Male1 (Brother)ADPCKD6.25 (10)NoneDonor exclusionOn HD for 28 m
Case 1719MaleNoneVURD3.24 (28)NoneDonor unavailabilityOn HD 24 m
Case 1836Male1 (Sister)Hypertensive nephropathy6.85 (10)NonePatient regressionOn HD for 26 m
Case 1934Male3 (Unrelated)ADPCKD7.55 (9)NoneDonor exclusionOn HD for 27 m
Case 2034Male 2 (Brother, Sister)Diabetic nephropathy8.45 (8)NonePatient regressionOn HD for 28 m
Case 2115Male1 (Mother)Unknown5.45 (15)NoneDonor exclusionOn HD for 6 m then lost to follow-up
Case 2244Male1 (Brother)Urolithiasis6.75 (10)NonePatient regressionOn HD for 8 m then lost to follow-up
Case 2340Female1 (Cousin)Unknown6.75 (7)NoneDonor regressionUnknown
Case 2444Male1 (Brother)Hyperuricemia5.65 (12)NoneDonor exclusionOn HD for 13 m
Case 2519Male1 (Mother)Congenital VURD4.74 (17)YesNALiving with a functioning graft for 12 m
Case 2623Female1 (Mother)Unknown6.35 (12)NonePatient regressionOn HD for 18 m
Case 2760MaleNoneUnknown5.65 (11)NoneDonor unavailabilityOn HD then CLDKT in another center
Case 2829Male1 (Sister)GN3.94 (19)NoneDonor exclusionOn HD 8 m
Case 2925Female1 (Brother)Unknown9.85 (7)None Patient regressionOn HD for 6 m
Case 3047FemaleNoneUnknown6.45 (12)NonePatient regressionOn HD for 16 m
Case 3125Male NoneFSGS4.54 (18)NoneDonor unavailabilityOn HD for 5 m
Case 3221FemaleNoneUnknown4.24 (18)NoneDonor unavailabilityOn HD for 3 m

In the current cohort of patients, the total number of patients who had been transplanted at our center (59 patients) or at other centers (29 patients) was 88 (28.9%) patients. In a comparison between the patients who achieved (59 patients) and those who failed to achieve (245 patients) LDKT in our center, there were significant differences in age (P = 0.034), sex (P < 0.001), primary kidney disease (P = 0.008), number of potential donors (P = 0.003), and acceptance/exclusion rate of evaluated donors (P < 0.001) per patient (Table 3).

Table 3 A comparison of the variables affecting the achievement (n = 59) and non-achievement (n = 245) of kidney transplantation in our center, n (%).
Variables
Achievement, n = 59
Non-achievement, n = 245
P value
Age in yr, mean ± SD (range)29 ± 9.9 (13-57)32.8 ± 11.9 (12-66)0.034
Sex
Male56 (94.9)179 (73.1)< 0.001
Female3 (5.1)66 (26.9)
Dialysis status
Preemptive access4 (6.8)28 (11.4)0.354
On regular dialysis55 (93.2217 (88.6)
Primary kidney disease
Unknown causes41 (69.5)202 (82.4)0.008
Systemic diseases3 (5.1)18 (7.4)
Renal diseases15 (25.4)25 (10.2)
Number of potential donors per patient1
Donor unavailability0 (0)44 (18)0.003
One donor43 (72.9)161 (65.7)
Two donors13 (22)31 (12.6)
Three donors3 (5.1)9 (3.7)
Outcome of donor evaluation1
Accepted48 (81.4)51 (32.9)< 0.001
Excluded0 (0)100 (64.5)
Excluded and accepted11 (18.6)4 (2.6)
Number of not-evaluated donors per patient1
One donor4 (100)51 (86.4)> 0.999
Two donors0 (0)7 (11.9)
Three donors0 (0)1 (1.7)
Chronological order of accepted donor1n = 59n = 55
First48 (81.4)49 (89.1)0.596
Second8 (13.6)4 (7.3)
Third3 (5.1)2 (3.6)
Age of accepted donors, mean ± SD (range)40.2 ± 10.9 (21-60)40.5 ± 9.5 (26-58)0.937
Degree of relatedness of accepted donors1
First34 (57.6)26 (47.3)0.339
Second20 (33.9)25 (45.4)
Third3 (5.1)4 (7.3)
Unrelated2 (3.4)0 (0)
Sex of accepted donor1
Male20 (33.9)21 (38.2)0.779
Female39 (66.1)34 (61.8)
Number of excluded donors per patient1n = 11n = 102
One donor8 (72.7)82 (80.4)0.572
Two donors3 (27.3)17 (16.7)
Three donors0 (0)3 (2.9)
Main causes of donor exclusion1n = 9n = 100
Medical causes5 (55.6)47 (47)0.462
Immunologic mismatches2 (22.2)39 (39)
Combined medical and immunologic causes2 (22.2)14 (14)

In multivariate analysis, known primary kidney disease (P = 0.002) was associated with higher rates of achievement of KT in our center. In addition, female sex (P = 0.001) and older patients (P = 0.031) were significantly associated with lower rates of achievement of KT in our center. However, PAKT (P = 0.065) and multiple potential donors (P = 0.529) were not significantly associated with the rate of achievement of KT in our center (Table 4).

Table 4 Multivariate logistic regression analysis of the variables influencing the achievement of kidney transplantation in our center.
Variables
Modality
Odds ratio
P value
AgeYounger vs older0.97 (0.94-0.997)0.031
SexMen vs women0.14 (0.04-0.46)0.001
Dialysis statusPreemptive vs on dialysis0.31 (0.09-1.1)0.065
Primary kidney diseaseKnown vs unknown3.24 (1.5-6.9)0.002
Number of potential donorsOne vs multiple0.81 (0.42–1.57)0.529

Review of the literature for PLDKT in studies from Egypt revealed that only eight articles addressed PLDKT (Table 5). These articles were from three academic centers only, including seven original research and one opinion article. The percentage of PLDKT varied between 6.4% in adults and 23% in pediatrics. No articles addressed the PAKT or waitlisting. The reported patient and graft survival rates were similar to those of conventional LDKT (CLDKT) in the literature.

Table 5 Preemptive living donor kidney transplantation in publications from Egypt.
Ref.
Publishing place
Settings
Type
Aim
Scope relative to PLDKT
Target age group
Outcomes relative to ELDKT/ CLDKT
Number of patients; PLDKT/Total (Percentage of PLDKT)
El-Agroudy et al[12]TransplantationMansoura UniversityRetrospective comparativeCompare outcomes of CLDKT & PLDKTSpecificMixedComparable, except in death with functioning graft was due to CVD in PLDKT vs respiratory infections in CLDKT82/1279 (6.4%)
Bakr and Ghoneim[14]Saudi J Kidney Dis TransplMansoura UniversityRetrospective seriesPresent experience in KTGeneralMixedOverall graft survival rates were 76% and 52% at five and 10-yr, respectively82/1690 (4.9%)
El-Husseini et al[15]Pediatr NephrolMansoura UniversityRetrospective seriesEvaluate outcomes of pediatric LDKTGeneralPediatrics5-yr graft survival was 73.6%51/216 (23%)
Mosaad et al[16]Dial TransplMansoura UniversityRetrospective seriesStudy LDKT survival in low-weight childrenGeneralPediatricsPLDKT might provide better graft survival9/63 (14.3%)
Saadi et al[13]Egyptian J Int MedCairo UniversityRetrospective seriesIdentify KT Epidemiology in Cairo University hospitalsGeneralMixedMost of patients and donors were males, mostly as LDKT14/282 (5%)
1Gadelkareem et al[9]Afr J UrolAssiut UniversityProspective comparative Compare short term outcomes of ELDKT & PLDKTSpecificAdultsComparable, except AR higher in ELDKT; Lymphocele incidence was higher in PLDKTPLDKT 30/45; ELDKT 15/45
Gadelkareem et al[8]Exp Tech Urol NephrolAssiut UniversityOpinionSuppose that lead time should not be a bias effect in PKTSpecificMixedLead time is a mere character of PKT rather than a biasNA
Fadel et al[17]Pediatr TransplCairo UniversityRetrospective seriesPresent experience in pediatric KTGeneralPediatricsTimely referral and parent education were recommendedPLDKT 11/148 (7%); ELDKT 59/148 (40%)
Index studyWorld J NephrolAssiut UniversityRetrospective seriesPresent experienceSpecificMixedUrological causes are main contributorPLDKT 3/59 (5.1%)

In addition, a review of the English literature for the incidence of PLDKT in other countries revealed higher rates than those from Egypt. However, they reported on PKT from both LDs and deceased donors. There were higher rates of PKT in patients who received LDKT than in those who received deceased donor KT (Table 6). In 1987, Migliori et al[19] were the first to evaluate the effects and outcomes of PKT in a large study from the United States, reporting a PKT rate of 7.6%. They were followed by two European studies with variable rates[20,21]. Then, five studies presented data from registries from United States and Canada and reported higher PKT rates up to 21% of the total KTs and more than 29% of LDKTs[22-26]. In addition, three studies from Japan, Australia, and Korea presented PLDKT rates up to 22% in patients receiving LDKT[27-29]. In 2009, two studies of mixed LD and deceased donor KTs showed higher rates of PLDKT about 39%[30,31]. Between 2011 and 2016, five studies of pediatric and adult KT showed similar rates[2,32-35]. In the last 3 years, many studies have reported high PLDKT rates more than 34%of LDKTs[36-38].

Table 6 Frequency of preemptive living donor kidney transplantation in publications from other countries/registries, n (%).
Ref.Countryand/or RegistryTotal KT NumberPKTLDKT number (Percentage of PLDKT)PKT per donor type
LD
DD
Migliori et al[19]United States1742132 (7.6%)1056 (9.1)96 (73)36 (27)
Berthoux et al[20]ERA-EDTA353482545 (7.2)1097 (73.3)804 (31.6)1741 (68.4)
Asderakis et al[21] United Kingdom1463161 (11)118 (19.5)23 (14)138 (86)
Papalois et al[22] United States1849385 (20.8)1074 (29.1)313 (81.3)72 (18.7)
1Mange et al[23]United States; USRDS84891819 (21.4)1819 (21.4)1819 (100)NA
Kasiske et al[24]United States; UNOS388365126 (13.2)13078 (24)3145 (61.4)1981 (38.6)
Gill et al[25] Canada; CORR409635996 (14.6)11290 (26.6)2999 (50.5)2967 (49.5)
Ashby et al[26]United States; OPTN/SRTR10233117885 (17.5)44033 (26.3)11601 (65)6284 (35)
1Ishikawa et al[27]Japan; JRTR834112 (13.4)834 (13.4) 112 (100) NA
1Milton et al[28]ANZDATA2603578 (22)578 (22)578 (100)NA
1Yoo et al[29]Korea49981 (16.2)499 (16.2)81 (100)NA
Gore et al[30]United States; UNOS4109011026 (26.8)15940 (39.4)6282 (57)4744 (43)
Witczak et al[31]Norway3400809 (24)1415 (36.3)514 (64)295 (36)
2Kramer et al[32]ERA-EDTA1829444 (21.2)1073 (11.5)123 (72)321 (28)
Grams et al[33]United States; UNOS15273119471 (12.8)NA11554 (59)7917 (41)
1Grace et al[34]ANZDATA4105660 (16.1)2058 (16.1)660 (100)NA
2Patzer et al[35]United States; USRDS57741117 (19.3)2598 (28.8)747 (67)370 (33)
Jay et al[2]United States; UNOS14125424609 (17)46373 (31)14503 (59)10106 (41)
Prezelin-Reydit et al[36]France; REIN223453112 (14)2031 (34)690 (22.2)2422 (77.8)
1Kim et al[37]South Korea1984429 (21.6)1984 (21.6)429 (100)NA
2Prezelin-Reydit et al[38]France; REIN1911380 (19.8)240 (37.5)90 (23.7)290 (76.3)
DISCUSSION

We addressed the topic of PKT in Egypt, because there is a question that whether the reported incidence of PLDKT correlates with the international values. Because this question may entail addressing the barriers and the promoting strategies of PLDKT, we performed this retrospective study to assess the outcomes of patients accessed KT at our center. In addition, review of PLDKT publications coming from Egypt was carried out in the context of the international literature, either as specific studies for PLDKT within LDKT cohorts or as combined LDKT and deceased donor KT researches. There is significant variability in the rates of PKT all over the world. In most studies, the proportions of PLDKT are higher than those of PKT in deceased donor KT. Most of these studies showed significantly higher incidences in adults and pediatrics. However, because the total percentages of LDKT are lower than those of KT from deceased donors, the frequency of PKT from deceased donors represented the majority of cases of PKT in some studies. However, relative to the total numbers of donor source, the percentages of PLDKT of total LDKTs are steadily higher than those of PKT from the total deceased donor KTs (Table 6).

In Egypt, there is an obvious lack of research on PKT represented by the small number of studies that was found in this topic[12-16]. These studies were mostly retrospective and presented as few centers’ experiences or small cohorts of patients. Hence, the volume of research on PLDKT is relatively small, referring to that PKT does not seem to be in the focus of research. PLDKT has just been mentioned as a category within the total cohorts of KT from centers with well-established KT programs[13,17]. On the other hand, a few studies were specifically conducted to study PLDKT outcomes in comparison to CLDKT[9,12]. This may be a part of the lack in the international literature, which has a slowly propagating body of research on PKT[33,38]. Currently, the literature refers to some sort of practical negligence of PKT in many forms, including disparities in access to PKT among the waitlisted patients. In a study from the United States, relative to the rates of White (38%) and Black (31%) patients on the waiting list, there was a significant difference between the rates of White (65%) and Black (17%) patients who had PKT in 2019[1]. Also, there is a substantially lower rates of PAKT among certain demographic groups that may face challenges in engaging with complex health care systems. Patients with low levels of education and those with physician-dependent choice of KT are other groups with disparities in the access to PKT. Inequities in access to KT require substantial efforts and multiple remedies[1]. Unfortunately, there is no studies have been conducted in Egypt to measure the rates of access to PLDKT so far. The current study showed that PAKT represented only 10.5% of patients who were referred to KT in our center.

From the reviewed literature, the reported incidence of PLDKT in the different Egyptian KT centers was relatively lower than the international values (Tables 5 and 6). The range was 5%-6% of the total KTs that were performed in these centers[12,13]. However, the incidence was higher, when PLDKT was studied in a certain category of population, such as pediatrics with low-body weight[16,17]. Similarly, the rate of PLDKT was 5.1% in the current study. However, these values are still significantly lower than the values reported in the international literature (Table 6).

Patients with PAKT may have high education levels, payment resources, married status, residence near to KT centers, and younger age than those with CAKT. Unknown primary diseases and glomerulonephritis seemed to be the most common categories of primary kidney disease in adults[9,12,21]. Among pediatrics, reflux nephropathies, nephrotic syndromes, and congenital anomalies are the commonest primary diseases[15,16]. In addition, PLDKT patients had a lower likelihood of testing positive for hepatic viruses and receiving a blood transfusion than the CLDKT patients[12]. Of the 304 patients who accessed LDKT in our center, only 32 patients had PAKT. In turn, only 3 patients succeeded in having PLDKT and they included 2 children and 1 adult patient. They had congenital or hereditary diseases as primary causes of ESRD and the donors were unrelated donor in one case and mothers in the other 2 cases.

A large retrospective study from Mansoura Urology and Nephrology Center studied the course and outcomes of PLDKT and reported an incidence of 6.4%. In addition, it showed that there was only a significant difference in the percentages of patients who died with functioning grafts due to cardiovascular disorders and respiratory infections. The former cause was higher in PLDKT, while the latter was higher in CLDKT[12]. In a smaller prospective comparative study, we found that the incidence of acute graft rejection was significantly higher among early LDKT (ELDKT) patients than in PLDKT patients. However, the incidence of lymphoceles was significantly higher in PLDKT patients than in patients receiving ELDKT[9]. In the current study, the rates of non-candidacy and death during preparation to KT were lower in patients with PAKT (0%) than in patients with CAKT (10.7% and 35.7%, respectively). These rates may be because patients in the former group were healthier than those in the latter group.

The previous characteristic may be a surrogate of the concerns raised about the proposed effect of the lead-time bias on the advantaged outcomes of PLDKT. However, there may be a different perspective, regarding this postulation. We hypothesized that the proposed effects are a mere component of the strategy of PKT. This could simply be explained by considering the PKT and non-PKT as consecutive rather than parallel processes along the course of ESRD. PKT is an early step in the management of ESRD. So, the time factor should be considered a promotor rather than a confounder to PKT process. On the other hand, the idea of removal of the lead-time bias means discarding the spirit of the entire process of PKT[8]. The best support of this perspective is studying the outcomes of KT relative to the time-point at which KT is performed. Goldfarb-Rumyantzev et al[39] designed a study based on this idea and it revealed significant survival advantages when KT was performed before 180 d of dialysis.

Internationally, many articles have addressed the barriers of PKT. The unavailability of a suitable, willing donor is a major confounder to PLDKT[40-42]. In accordance, the current results revealed that younger age, male sex, and known primary kidney disease of patients accessing KT in our center were independent predictors of achievement of KT after preparation. However, the dialysis status (PAKT vs CAKT), number of potential donors, and their acceptance/exclusion rates were not significantly associated with the achievement of KT. The non-significant effect of PAKT may be attributed to the delayed access of the patients with ESRD. Most of our patients with PAKT were in stage 5 CKD and a mean eGFR of 12.8 ± 4.8 mL/min/1.73 m2, when they first presented to our clinic. This value of eGFR is comparable to the reported values that allow successful PLDKT[33,43], but these patients were not prepared or waitlisted before presentation to the KT unit. Hence, they needed long duration for preparation, which might be, with donor exclusion, the causes of missing the chance of PLDKT. In addition, the delayed access might be attributed to absence of a well-configured waitlisting programs in our country to refer and prepare patients at the suitable stages of ESRD. On the other hand, there are many underlying primary renal diseases that may predispose to a very late presentation of a significant proportion of patients, such as the status of pending dialysis at first discovery of their ESRD[44].

Problems of unavailability of a well-integrated healthcare system that facilitates early detection of CKD patients and timely referral to KT centers should be practically considered. Paradoxically and despite the observable social fear of ESRD, which may progress up to a disease phobia in developing countries[45], there are many patient-related factors that influence early diagnosis and management of CKD patients such as the cultural and health illiteracies[44]. As a developing country, the healthcare authorities in Egypt have a large burden of challenges which seem hard to be overcome due to factors such as low per-capita income and slowly progressing corrections of the healthcare systems[15]. Also, the ethical problems that have been raised about KT practice in Egypt represent another major confounder to correction[46]. However, the recent policies in the Egyptian national healthcare system seem to be promising as a mass modification to overcome these problems, including the new national health insurance coverage and national KT programs.

The limitations of the current study included the small number of patients who had PLDKT, which made us unable to perform statistical analyses for the independent factors of failure of most patients with PAKT to achieve PLDKT. However, this is the first study from Egypt to address this very viable topic at a national review basis. Hence, it may unmask the vague situation of PLDKT in Egypt by configuring a step forward in building more integrated KT systems.

Based on relevant literature review, we may recommend implementation of different strategies to promote PLDKT in Egypt. Encouragement of LKD is the main strategy that should be extensively studied, because our national KT program is currently devoted to LDKT only. Minimally-invasive approaches such as laparoscopic living donor nephrectomy should be introduced to all centers of KT. Also, the regulations of LKD should be organized under a well-configured national donation program, including donor exchange programs. Furthermore, promotion of healthcare facilities of early detection of CKD and education of the contributors of PLDKT process are crucial strategies for this topic. The latter includes the education of the physicians (representing the moderator of the process), ESRD patients (representing the key start of the process), and publics (representing the source of the potential donors) about the benefits of PKT.

CONCLUSION

Patients with PAKT may have significant differences from those with CAKT regarding age, sex, primary kidney disease, and number of potential donors at presentation to a KT center. A primary kidney disease diagnosis is an independent factor of achievement of LDKT. In addition, older age and female sex are independent predictors of non-achievement of LDKT. On the other hand, unavailability, regression, and exclusion of LDs and patient regression when reach dialysis may hinder the achievement of PLDKT in patients with PAKT. Despite its non-significant effect, PAKT may improve the low rates of PLDKT. The current literature review may refer to that PLDKT has comparable or slightly better outcomes than those of CLDKT. Hence, PLDKT is recommended as the first choice for each candidate patient. In Egypt, PLDKT may have similar barriers to those presented elsewhere in the literature, including the shortage of donors, delayed presentation of patients and socioeconomic factors. As a result, the rate of PLDKT is still low in Egypt, warranting implementation of many strategies to promote PLDKT. They include encouraging LKD, introduction of minimally-invasive living donor nephrectomy, configuring a specific program for LKD, and education of the physicians, patients and publics about the benefits of PKT.

ARTICLE HIGHLIGHTS
Research background

Despite its low rates, preemptive living donor kidney transplantation (PLDKT) is recommended as the optimal treatment for end-stage renal disease. However, its rate is still lower than the expected rates worldwide.

Research motivation

Promotion of the rate of PLDKT seems to be a modifiable variable for improvement of the total outcomes of KT.

Research objectives

To assess the rate of achievement of PLDKT among patients accessing KT in our center and to review the status of PLDKT in Egypt in the context of the international literature.

Research methods

We performed a retrospective review of the records of patients who accessed KT in our center from November 2015 to November 2022. The demographic and clinical characteristics of the patients and their potential donors were reviewed. Also, the literature was reviewed for PLDKT status in Egypt.

Research results

Of 304 patients accessed KT, 32 patients (10.5%) had preemptive access to KT (PAKT). The means of age and estimated glomerular filtration rate were 31.7 ± 13 years and 12.8 ± 3.5 mL/min/1.73 m2, respectively. Fifty-nine patients had KT, including three PLDKTs only (5.1% of the total KTs and 9.4% of PAKT). Twenty-nine patients (90.6%) failed to receive PLDKT due to donor unavailability (25%), exclusion (28.6%), regression from donation (3.6%), and patient regression on starting dialysis (39.3%). In multivariate analysis, known primary kidney disease (P = 0.002), patient age (P = 0.031) and sex (P = 0.001) were independent predictors of achievement of KT in our center. However, PAKT was not significantly (P = 0.065) associated with the achievement of KT. Review of the literature revealed lower rates of PLDKT in Egypt, including the current results, than the internationally reported rates.

Research conclusions

Patient age, sex, and primary kidney disease are independent predictors of achieving LDKT. Despite its non-significant effect, PAKT may improve the low rates of PLDKT. The main causes of non-achievement of PLDKT were patient regression on starting regular dialysis and donor unavailability or exclusion.

Research perspectives

Studying the factors that may promote the early access of ESRD patients to KT may improve the rates of PLDKT. This latter strategy may improve the whole outcomes of the process of KT, including avoidance of the inconveniences of dialysis and improvement of the graft and patient survival rates.

Footnotes

Provenance and peer review: Invited article; Externally peer reviewed.

Peer-review model: Single blind

Corresponding Author's Membership in Professional Societies: Egyptian Urological Association.

Specialty type: Transplantation

Country/Territory of origin: Egypt

Peer-review report’s scientific quality classification

Grade A (Excellent): 0

Grade B (Very good): B

Grade C (Good): 0

Grade D (Fair): D

Grade E (Poor): 0

P-Reviewer: Salvadori M, Italy; Sureshkumar KK, United States S-Editor: Ma YJ L-Editor: Filipodia P-Editor: Ma YJ

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