Change in bladder capacity and prognostic predictors of post-transplant vesicoureteral reflux in pediatric kidney transplant recipients: a single-center retrospective cohort study

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However, vesicoureteral reflux (VUR) is a common occurrence post-KT. This single-center retrospective cohort study investigated bladder capacity changes, and identified post-transplant VUR predictors, in pediatric KT recipients. Methods Pediatric patients with or without pre-transplant anuria (< 0.5 mL/kg/h) who underwent KT, from January 2009 to December 2023, were analyzed. Expected bladder capacity (EBC) was calculated based on age. Maximum bladder capacity (MBC) and post-transplant VUR presence were evaluated using voiding cystourethrography. Logistic regression was used to identify independent risk factors for post-transplant VUR. Receiver operating characteristic curve analysis was used to determine the predicted probability of post-transplant VUR. Results Among 93 patients (males: 60%; median age: 6.1 [2.3–17.7] years), 25 (26.9%) had pre-transplant anuria. Bladder capacity (from 37.5 to 120 mL; p < 0.001) and MBC/EBC ratio (from 19.7 to 62.3%; p < 0.001) increased post-KT in only patients with anuria. Multivariate analyses revealed that pre-transplant MBC/EBC ratio predicted post-transplant VUR (odds ratio: 0.980, 95% confidence interval: 0.965–0.996; p = 0.006; sensitivity: 76.5%, specificity: 72.4%, area under the curve: 0.745 [cut-off: 57.8%]). Conclusions Pre-transplant MBC/EBC ratio is a useful bladder capacity indicator and predicts post-transplant VUR in pediatric KT recipients. Kidney transplantation vesicourethral reflux bladder capacity anuria expected bladder capacity maximum bladder capacity Figures Figure 1 Figure 2 Figure 3 Figure 4 INTRODUCTION Kidney transplantation (KT) is the gold-standard treatment for children with end-stage kidney disease (ESKD), and it significantly improves both quality of life and long-term survival [ 1 , 2 ]. Approximately 800 pediatric KTs are performed annually in the United States alone [ 3 ]. Nevertheless, post-KT urological complications, particularly vesicoureteral reflux (VUR), remain major clinical challenges [ 4 – 6 ]. Post-transplant VUR, a well-known risk factor for urinary tract infection (UTI) [ 7 , 8 ], can compromise graft function. Although the incidence of post-transplant VUR has previously been evaluated, ureteroneocystostomy techniques adopted during KT differ among studies [ 9 – 11 ]. Moreover, these studies included patients with lower urinary tract dysfunction [ 9 – 11 ], and this population may have differing development patterns of post-transplant VUR, confounding the risk and outcome of post-transplant VUR. Therefore, the specific risk factors for VUR development needs further clarification in a more homogeneous pediatric KT recipient population. Although the impact of post-transplant VUR on allograft graft survival and function has previously been explored [ 12 ], it remains moot. Post-transplant VUR does not affect kidney function; however, a pre-transplant atrophic bladder has been identified as a risk factor for post-transplant VUR [ 12 , 13 ]. Adults with a pre-transplant atrophic bladder are less likely to be affected because bladder capacity increases post-KT [ 14 , 15 ]. However, data regarding pediatric patients are limited [ 16 ]. Furthermore, a standardized definition of atrophic bladder in children is currently lacking, and the bladder capacity threshold that predisposes patients to post-transplant VUR remains undetermined. A healthy bladder expands with urine inflow; however, in prolonged ESKD, bladder dysfunction and decreased urine output result in decreased bladder capacity and anuria. Consequently, technical difficulties may arise when performing an anti-reflux re-implantation of an adult-sized ureter into a small bladder during KT. Despite these anatomical and functional challenges, evidence on the influence of bladder dynamics on post-operative vesicoureteral anastomosis outcomes in pediatric KT recipients remains limited. Therefore, this study aimed to investigate the relationship between pre- and post-KT bladder capacity changes and post-transplant VUR development in pediatric KT recipients, including those with pre-transplant anuria. Additionally, the specific risk factors associated with post-transplant VUR were identified to inform better management and surgical strategies. PATIENTS AND METHODS Study design and setting This retrospective cohort study included consecutive pediatric patients who underwent primary KT from January 2009 to December 2023 at the Toho University Omori Medical Center. Study criteria Patients who underwent pre- and post-KT voiding cystourethrography (VCUG) and extravesical ureteral re-implantation, using the Lich-Gregoir technique, during KT were included. Although pediatric KT recipients routinely undergo VCUG at our institution, patients who did not undergo post-KT VCUG owing to non-consent were excluded. Patients with bladder or lower urinary tract dysfunction, such as posterior urethral valve, neurogenic bladder, or cloacal malformation, and those who underwent augmentation cystoplasty or urinary diversion were excluded from the analysis. The included patients were divided into two groups based on the presence of pre-KT anuria (anuric and non-anuric groups). Anuria was defined as a daily urine output of < 0.5 mL/kg/h. None of the included patients had received anticholinergics pre- or post-KT. Data collection and participant follow up The patients’ pre- and post-transplant clinical data, including patient and donor characteristics, medical history, physical examination results, pre-transplant dialysis modalities, maximum bladder capacity (MBC), presence of VUR, cadaver or living donor, method of ureteral reimplantation, immunosuppressive drug use, graft function, patient and graft survival, cause of death, and graft loss, were manually extracted from their medical records. Data were collected until death, graft loss, or December 2023. The VUR grade was assessed according to a previous report [ 17 ]. The estimated glomerular filtration rate (eGFR) was calculated using a creatinine-based equation for Japanese children and adults [ 18 , 19 ]. Expected bladder capacity (EBC) was determined as follows: ([age (years) + 2] × 25; mL) [ 20 ]. The presence of VUR and MBC was evaluated using VCUG. Study procedure- surgery The extravesical Lich-Gregoir technique was used for anti-reflux ureteral re-implantation during KT. A 2 cm long submucosal tunnel was formed, and a temporary 5-Fr ureteral stent was used. The ureteral stent was removed on postoperative day 5, and the transurethral catheter, on postoperative day 6–7. At our institution, continuous antibiotic prophylaxis is typically not administered post-KT to prevent UTI. Study procedure- post-transplant immunosuppressive regimen Basiliximab was administered for induction, followed by triple immunosuppressive therapy with calcineurin inhibitors, mycophenolate mofetil or everolimus, and methylprednisolone. ABO-incompatible KT recipients underwent early treatment with mycophenolate mofetil, rituximab, and plasma exchange. The immunosuppressive regimen used in this study has previously been reported [ 21 , 22 ]. Ethical Considerations This study was approved by the Ethics Committee of Toho University Omori Medical Center (Approval numbers: M24014 and M23233) and conformed to the Declaration of Helsinki guidelines. The details of the study were disclosed on the institution’s website before study commencement, and the patients’ parents/guardians were provided the opportunity to withdraw their child/ward’s inclusion in the study using the opt-out method. The requirement for written informed consent was waived owing to the retrospective study design. Statistical Analysis Categorical data were expressed as number (percentage), and continuous data, as mean ± standard deviation or median with range or interquartile range (IQR), depending on the distribution normality, using the Shapiro–Wilk test. The Wilcoxon rank-sum and Fisher’s exact tests were used to compare continuous and categorical variables, respectively. The paired t-test was used to compare pre- and post-transplant data. Variables with missing values were excluded from the analysis to avoid information bias. Logistic regression models were used to identify the independent risk factors for post-transplant VUR. Multivariate logistic regression was used to assess the relationship between post-transplant VUR and sex, age, post-transplant VUR in the native kidney, and pre-transplant MBC/EBC ratio. The logistic regression results were expressed as odds ratios (OR) and 95% confidence intervals (CI). Multicollinearity between variables was considered if the variance inflation factor was > 10. Variables that were significant in the multivariable logistic regression analysis in predicting post-transplant VUR were assessed for validity (sensitivity, sensitivity, positive predictive value, negative predictive value, and accuracy). The Youden index (sensitivity + specificity − 1) was used to establish the optimal cut-off values from the receiver operating characteristic (ROC) curve. Spearman’s rank correlation coefficient ( r s ) was used to identify the association between post-transplant bladder capacity and anuria duration. All tests were two-sided, and p < 0.05 was considered statistically significant. Statistical analyses were performed using the JMP Pro 17 software (SAS Institute Inc., Cary, NC, US). RESULTS Participant selection Figure 1 illustrates the patient selection process. Overall, 183 patients aged < 18 years who underwent KT during the study period were screened. Among these, 53 patients without post-transplant data, 23 with urinary tract dysfunction, and 14 who underwent re-transplant were excluded. The remaining 93 were included in the final analysis and divided into the anuric and non-anuric groups with 25 (26.9%) and 68 (73.1%) patients, respectively. In this study, 14 patients who had undergone primary kidney transplantation are included. A total of 53 patients with missing post-transplant VCUG data and 23 patients with lower urinary tract dysfunction, including posterior urethral valve (n = 8), neurogenic bladder (n = 13), or cloacal malformation (n = 2), were excluded. VCUG, voiding cystourethrography Participant characteristics Table 1 lists the patient and transplantation characteristics. The median age at transplantation was 6.1 (2.3–17.7) years, and 56 patients (60.0%) were male. The median anuria duration was 12.5 months. In the non-anuric group, 32 patients (47.1%) underwent preemptive KT. All patients with anuria underwent pre-transplant dialysis (100% vs. 53%, p < 0.001), either peritoneal dialysis (84% vs. 50%, p = 0.004) or hemodialysis (16% vs. 3%, p = 0.0043), compared with those who were non-anuric. Among the 93 included patients, 11 (11.8%) weighed < 10 kg at the time of KT. Three of these patients had pre-transplant anuria. The extraperitoneal and intraperitoneal approaches were used for KT in 73 (78.5%) and 20 (21.5%) patients, respectively. Pre-transplant VUR in the native kidney was observed in 32 patients (34.4%). High-grade VUR (grade III–IV) was present in six patients (6.5%). Overall, 47 patients (50.5%) underwent unilateral or bilateral native nephrectomy before or during KT for the following reasons: 23 patients (48.9%) for securing a transplant bed, 15 (31.9%) for medical renal disease, and 9 patients (19.2%) for VUR or hydronephrosis. In the anuric group, 16 patients (64.0%) underwent pre-KT native nephrectomy, and 10 (40.0%) underwent bilateral nephrectomy. Three of these ten patients underwent bilateral nephrectomy for bilateral Wilms tumor and another three, for Denys–Drash syndrome. Table 1 Patient demographics and anthropometrics Variables All patients (n = 93) Anuric group (n = 25) Non-anuric group (n = 68) p - value Patients Sex, male, n (%) 56 (60) 12 (48) 44 (65) 0.159 Age at KT (years) 6.1 [4.0–11.9] 4.9 [3.9–12.9] 7.1 [4.1–11.7] 0.358 Height (cm) 105 [89.9–132.8] 98.1 [88.2–134.3] 106.0 [90.4–131.7] 0.527 Weight (kg) 15.1 [11.9–27.2] 14.5 [11.7–26.7] 16.4 [11.9–27.5] 0.564 Anuria duration (months) 12.5 [5.1–33.4] 12.5 [5.1–33.4] N/A Follow-up duration (years) 7.1 [3.9–10.1] 5.0 [3.0–9.9] 7.9 [4.9–10.4] 0.056 Dialysis characteristics Pre-transplant dialysis, n (%) 61 (66) 25 (100) 36 (53) < 0.001 Peritoneal dialysis, n (%) 55 (59) 21 (84) 34 (50) 0.004 Hemodialysis, n (%) 6 (6) 4 (16) 2 (3) 0.043 Dialysis duration (years) 1.4 [0.0–3.3] 3.2 [1.5–3.7] 0.2 [0.0–2.7] < 0.001 Primary disease CAKUT, n (%) 43 (46) 3 (12) 40 (58) < 0.001 Glomerular disease, n (%) 27 (29) 13 (54) 14 (20) 0.005 Cystic kidney disease, n (%) 12 (13) 4 (17) 8 (12) 0.728 Ischemic renal failure, n (%) 4 (5) (0) 4 (6) 0.571 Others, n (%) 7 (7) 4 (17) 3 (4) 0.081 VUR in native kidney and UTI VUR in native kidney, n (%) 32 (34) 11 (44) 21 (31) 0.325 Unilateral/Bilateral VUR, n (%) 15 (47) / 17 (53) 2 (18) / 9 (82) 13 (62) / 8 (38) 0.028 History of pre-KT UTI, n (%) 10 (11) 2 (8) 8 (12) 0.274 Transplantation Donor sex, male, n (%) 48 (52) 18 (72) 30 (44) 0.02 Donor age (years) 40.5 [34.9–45.9] 40.1 [33.6–44.2] 40.9 [35.6–47.9] 0.175 Living related donor, n (%) 88 (95) 22 (88) 66 (97) 0.118 Donor eGFR pre-nephrectomy (mL/min/1.73 m 2 ) 77.0 [70.1–89.8] 84.2 [70.9–92.7] 75.4 [69.9–86.1] 0.139 Number of HLA A/B/DR mismatches 2.4 ± 1.1 2.5 ± 1.1 2.3 ± 1.0 0.393 ABO-incompatible KT, n (%) 16 (17) 8 (32) 8 (12) 0.031 Cold ischemia time (min) 72.0 [56.5–92.0] 82.0 [58.0–115.5] 69.5 [56.0–87.5] 0.139 CAKUT, congenital anomalies of the kidney and urinary tract; eGFR, estimated glomerular filtration rate; HLA, human leukocyte antigen; KT, kidney transplantation; UTI, urinary tract infection; VUR, vesicoureteral reflux Values are presented as number (%), mean ± standard deviation, or median [interquartile range] Bladder Capacity Changes After Kidney Transplantation VCUG was performed at a median of 4.0 (IQR 3.0–6.0) months pre-operatively and 4.2 (IQR 3.5–5.1) months post-operatively, and the period from VCUG to KT was not significantly different in both groups. Pre- and post-KT bladder capacity values are presented in Table 2 . In the anuric group, 11 patients (44%) had a pre-transplant MBC of < 20 mL. Twenty patients (80.0%) in the anuric group and seven (10.3%) in the non-anuric group had a pre-transplant MBC/EBC ratio < 50%. The pre-transplant bladder capacity was significantly lower in the anuric group than in the non-anuric group (37.5 mL [10.0–104] and 170 mL [120–275], respectively; p < 0.001). Although bladder capacity increased in both groups post-KT, it remained significantly decreased in the anuric group (120 mL [80.0–200] and 200 mL [150–300], respectively; p = 0.002). Table 2 Bladder capacity before and after kidney transplantation Variables All patients (n = 93) Anuric group (n = 25) Non-anuric group (n = 68) p - value Pre-transplantation MBC (mL) 140 [75.0–265] 37.5 [10.0–104] 170 [120–275] <0.001 MBC/EBC ratio (%) 75.6 [35.5–103.3] 19.7 [6.7–34.5] 89.8 [66.3–113.7] <0.001 Period from VCUG to KT (months) 4.0 [3.0–6.0] 4.0 [3.5–8.0] 4.0 [3.0–5.8] 0.183 Post-transplantation MBC (mL) 180 [120–300] 120 [80.0–200] 200 [150–300] 0.002 MBC/EBC ratio (%) 82.6 [55.8–102.8] 62.3 [40.4–80.9] 90.3 [68.0–113.5] <0.001 Period from KT to VCUG (months) 4.2 [3.5–5.1] 3.8 [3.5–5.2] 4.2 [3.6–5.1] 0.404 EBC, expected bladder capacity; KT, kidney transplantation; MBC, maximum bladder capacity; VCUG, voiding cystourethrography. Values are presented as the median [interquartile range]. Correlation Between Anuria Duration and Pre-transplant Bladder Capacity In the anuric group, anuria duration and pre-transplant bladder capacity were correlated (MBC/EBC ratio) ( r s = -0.675, p < 0.001) (Fig. 2 ). Correlation Between Pre- and Post-transplant MBC/EBC Ratios The pre- and post-transplant MBC/EBC ratios were correlated ( r s = 0.557, p < 0.001) (data not presented). The relationship between the post- and pre-transplant MBC/EBC ratios is illustrated in Fig. 3 . In the anuric group, the pre- and post-transplant MBC/EBC ratios had a weak positive correlation ( r s = 0.371, p = 0.068), although not strictly statistically significant owing to the small number of patients with anuria (Fig. 3 (A) ). In the non-anuric group, the pre- and post-transplant MBC/EBC ratios were correlated ( r s = 0.493, p < 0.001) (Fig. 3 (B) ). Prevalence of Post-transplant VUR Table 3 presents the prevalence of post-transplant VUR. The overall prevalence of post-transplant VUR was 18.3% (n = 17). Post-transplant VUR occurred in ten patients (40.0%) (grade I: n = 5; grade III: n = 3; and grade IV: n = 2) in the anuric group and in seven patients (10.3%) (grade I: n = 3; grade II: n = 2; grade III: n = 1; and grade IV: n = 1) in the non-anuric group. A significant between-group difference was observed in the occurrence of post-transplant VUR (p = 0.002). In patients with a pre-transplant MBC/EBC ratio < 50%, the prevalence of post-transplant VUR was 36.0% (n = 9) and 1.4% (n = 1) in the anuric and non-anuric groups, respectively (p < 0.001). Table 3 Regression analysis results for the identification of risk factors for post-transplant vesicoureteral reflux Predictors Univariate analysis Multivariate analysis OR 95% CI p-value OR 95% CI p-value Male sex 0.284 0.094 0.854 0.021 Age (years) 0.903 0.784 1.041 0.139 VUR in the native kidney 3.507 0.184 10.38 0.022 MBC/EBC ratio (%) pre-KT 0.975 0.959 0.99 <0.001 0.98 0.965 0.996 0.006 CI, confidence interval; EBC, expected bladder capacity; KT, kidney transplantation; MBC, maximum bladder capacity; OR, odds ratio; VUR, vesicoureteral reflux Post-transplant VUR was observed in sixteen ureters (two bilateral and twelve unilateral) in the native kidney from fourteen patients (15.1%). In the anuric group, five ureters in four patients (16.0%) developed VUR (all grade I) (one bilateral and three unilateral), while two patients had new-onset VUR in the native kidney, observed on VCUG post-KT. In the non-anuric group, 11 ureters in 10 patients (14.7%) developed VUR (one bilateral and nine unilateral); VUR in the native kidney was grade I in seven ureters, grade II in three, and grade IV in one. No cases of worsening VUR grade were observed post-KT. Identification of the Risk Factors for Post-transplant VUR The risk of post-transplant VUR was calculated based on sex, age, VUR in the native kidney, and pre-transplant MBC/EBC ratio. Multivariate analysis revealed that post-transplant VUR was independently associated with pre-transplant MBC/EBC ratio (OR: 0.980, 95% CI: 0.965–0.996, p = 0.006) (Table 3 ). ROC Curve Analysis for Predicting Post-transplant VUR The results of the ROC curve analysis revealed that post-transplant VUR could be predicted by the pre-transplant MBC/EBC ratio (cut-off, 57.8%) with 76.5% sensitivity and 72.4% specificity (Fig. 4 ). The AUC was 0.757 (95% CI: 0.670–0.844, p < 0.001), and the positive predictive value, negative predictive value, and Youden’s index were 0.382, 0.932, and 0.488, respectively. Clinical Outcomes of Kidney Transplantation The clinical outcomes of kidney transplantation are presented in Table 4 . During the follow-up period, none of the 93 pediatric KT recipients had urinary complications such as postoperative urine leakage, transplant ureteral stenosis, or obstruction. Regarding post-transplant graft function, the eGFR at 5 years post-transplantation was comparable between the anuric and non-anuric groups, with no delay in graft function in either group. No differences in eGFR were observed between the anuric and non-anuric groups Table 4 Prevalence of post-transplant vesicoureteral reflux and clinical outcomes of kidney transplantation Variables All patients (n = 93) Anuric group (n = 25) Non-anuric group (n = 68) p - value Post-transplant VUR, n (%) 17 (18) 10 (40) 7 (10) 0.002 Grade Ⅰ 8 (47) 5 (50) 3 (43) 0.03 Grade Ⅱ 2 (12) 0 (0) 2 (29) 1.000 Grade Ⅲ 4 (23) 3 (30) 1 (14) 0.058 Grade Ⅳ 3 (18) 2 (20) 1 (14) 0.175 Post-transplant VUR in patients with pre-transplant MBC/EBC ratio < 50%, n (%) 10 (11) 9 (36) 1 (1) < 0.001 Post-transplant VUR in the native kidney, n (%) 14* (15) 4** (16) 10*** (15) 1.000 Unilateral VUR 12 (86) 3 (75) 9 (90) 1.000 Bilateral VUR 2 (14) 1 (25) 1 (10) 0.468 Post-transplant eGFR (mL/min/1.73 m 2 ) 1 year 74.9 ± 21.6 78.3 ± 23.1 73.8 ± 21.2 0.431 3 years 70.4 ± 18.9 75.9 ± 16.7 69.0 ± 19.4 0.259 5 years 64.8 ± 17.4 70.2 ± 18.6 63.5 ± 17.0 0.202 Prevalence of post-transplant UTI 4 (4) 1 (4) 3 (4) 1.000 *16 ureters from 14 patients, ** 5 ureters, all grade I; *** 11 ureters − 7 grade I, 3 grade II, and 1 grade IV EBC, expected bladder capacity; eGFR, estimated glomerular filtration rate; MBC, maximum bladder capacity; UTI, urinary tract infection; VCUG, voiding cystourethrography; VUR, vesicoureteral reflux Three patients (two in the anuric group and one in the non-anuric group) received sulfamethoxazole-trimethoprim prophylaxis to prevent UTI post-KT. Four of the ninety-three patients (4.3%) developed UTI during the follow-up period, including one patient (4.0%) in the anuric group and three patients (4.4%) in the non-anuric group, none of whom received sulfamethoxazole-trimethoprim prophylaxis. Among these four patients, post-transplant VUR (grade IV) was present in two patients, one of whom had pre-transplant anuria. Both patients were initiated on sulfamethoxazole-trimethoprim prophylaxis; however, UTI recurred. Therefore, a dextranomer/hyaluronic acid (Deflux®) injection was administered into the transplanted ureter via a pediatric cystoscope. One patient received a second Deflux® injection following UTI recurrence. However, this patient had residual post-transplant VUR and underwent ureteroureterostomy with the native ureter. DISCUSSION This retrospective cohort study investigated bladder capacity changes and post-transplant VUR in pediatric patients with ESKD who underwent KT. Pre-transplant MBC/EBC ratio was an independent predictor of post-transplant VUR development when using age-predicted bladder capacity as a specific indicator owing to the varying ages of the pediatric patients cohort in this study. In addition, patients with pre-transplant anuria exhibited an increase in bladder capacity early post-KT. Moreover, these patients had a higher incidence of post-transplant VUR than patients without pre-transplant anuria, although they did not have a higher incidence of UTI. In our study, we used the MBC/EBC ratio to evaluate bladder capacity changes. Pre- and post-KT bladder capacity changes have been reported in a cohort of Japanese patients aged < 18 years; this previous study, in which bladder capacity was evaluated according to an MBC/EBC ratio < 50%, revealed that bladder capacity increased 4 months post-KT, with an increase in the MBC/EBC ratio from 63.7–98.2% [ 13 ]. In our cohort, a significant correlation was observed between anuria duration and pre-transplant MBC/EBC ratio. Although an overall increase in bladder capacity was observed post-KT, the MBC/EBC ratio increased significantly from 19.7–62.3%, especially in the patients with pre-transplant anuria. Owing to the limited reports on bladder capacity in pediatric patients with ESKD and atrophic bladders, and because post-transplant VCUG is not routinely performed [ 23 ], data on bladder capacity in pediatric KT recipients are lacking. Therefore, the findings of the present study may provide valuable insights into bladder capacity in a cohort of pediatric patients with ESKD, including those with anuria, and may contribute to improved urological management and prognostic assessment pre- and post-KT. Children with a small bladder capacity and bladder dysfunction present operative challenges [ 14 , 24 ], and pre-transplant bladder augmentation has been recommended [ 25 ]. However, proceeding with KT without pre-transplant bladder augmentation has been suggested for pediatric patients with ESKD with a small bladder capacity and bladder dysfunction to avoid unnecessary surgery [ 16 ]. At our institution, bladder augmentation and/or urinary diversion is a pre-transplant option for patients with neurogenic bladder and bladder dysfunction. Therefore, ureteroneocystostomy was performed using the Lich-Gregoir technique, a common procedure for ureteral reimplantation during pediatric KT [ 26 ], without modification according to bladder capacity, and no postoperative leakage or obstruction and no technical problems with the procedure were observed. In a previous study, 12 pediatric patients with ESKD with atrophic bladder who did not undergo pre-transplant bladder augmentation underwent KT with an average intraoperative bladder capacity of 25 mL and no postoperative ureteral obstruction, similar to that reported in our study [ 16 ]. In our study, the MBC/EBC ratio of patients with pre-transplant anuria had a median value of 19.7%, and 44% had an MBC < 20 mL. These findings suggest that even in pediatric patients with severely reduced bladder capacity and pre-transplant anuria, Lich-Gregoir ureteroneocystostomy is safe, effective, and feasible without pre-transplant bladder augmentation. Our study results further support the notion that routine pre-transplant bladder augmentation may not be necessary in all cases, thus avoiding additional surgical burden. In our cohort, all patients underwent Lich-Gregoir ureteroneocystostomy, and post-transplant VUR occurred in 18.3% of them. In a previous study including 73 pediatric patients who underwent routine VCUG 6 months post-KT [ 12 ], all underwent the Lich-Gregoir procedure, and post-transplant VUR occurred in 34% of them (grade I: n = 4; grade II: n = 7; grade III: n = 7; and grade IV: n = 7). Although patient backgrounds did not include any mention of pre-transplant bladder capacity, the incidence of post-transplant VUR was higher than that in our study, and the frequency of high-grade post-transplant VUR (grade III–V) was high (41%) as well. Moreover, 40% of patients with pre-transplant anuria developed post-transplant VUR, which was significantly higher than the proportion of patients who were non-anuric. Another study including patients with atrophic bladder reported a post-transplant VUR rate of 41.6% [ 16 ], comparable with that in our study. In the previous study, patients with a small-capacity bladder (< 50 ml) and those who underwent bilateral surgical nephrectomy or medical nephrectomy were defined to have anuria, similar to those in our study. In another study, nine of seventy-one patients (12.7%) with atrophic bladder had post-transplant VUR [ 11 ]; however, either the Lich-Gregoir or the intravesical Politano-Leadbetter ureteroneocystostomies were performed during KT. Since the exact technique was not mentioned, a comparison could not be made with our study. In our cohort, the incidence of post-transplant VUR among patients with pre-transplant anuria was 10.3%, markedly lower than that previously reported in comparable populations [ 9 ]. This suggests that the consistent use of Lich-Gregoir ureteroneocystostomy may contribute to a reduced incidence of post-transplant VUR, even in patients at a higher risk due to anuria or suspected bladder dysfunction. The ROC curve analysis revealed that the pre-transplant MBC/EBC ratio cut-off value for predicting post-transplant VUR occurrence was 57.8%. Notably, although patients with pre-transplant anuria had a higher frequency of post-transplant VUR than those without pre-transplant anuria, the frequency of post-transplant UTI between both groups was not significantly different. Our study results can serve as an indicator for urinary tract screening before pediatric KT, and post-transplant VUR can be predicted from the pre-transplant MBC/EBC ratio. VCUG is a burdensome test for pediatric patients, and post-KT VCUG can be avoided in many cases (except for patients with neurogenic bladders); however, the cut-off values may be a useful indicator for clinicians. This study has some limitations. First, this was a single-center retrospective study, which may have resulted in patient selection bias. Second, the procedural policy is to ensure a submucosal tunnel length of at least 2 cm for ureteroneocystostomy during KT. However, the submucosal tunnel length was not measured peri-operatively. Therefore, the effect of submucosal tunnel length on allograft VUR could not be investigated. Third, the patients were operated on by different surgeons, which may have resulted in variations in the level of surgical skill and judgment. Nevertheless, all surgeries were performed under the same supervising surgeon, and homogeneity of the surgical technique was considered to have been maintained. Fourth, maximum bladder capacity measurements using VCUG may not accurately reflect the true functional capacity of the bladder [ 27 ]. Urodynamic studies could provide more comprehensive and reliable data on bladder capacity and function. Therefore, future prospective studies, including urodynamic studies, should evaluate the pathogenesis and treatment strategies for post-transplant VUR in pediatric patients with ESKD. In conclusion, our study found that the pre-transplant MBC/EBC ratio is a useful predictor of post-transplant VUR in pediatric KT recipients. A cut-off MBC/EBC ratio of 57.8% may help identify patients at a high risk of VUR, reducing the need for routine post-transplant VCUG. Bladder capacity improved significantly post-transplantation, even in patients with pre-transplant anuria, and Lich-Gregoir ureteroneocystostomy was safely performed without bladder augmentation. These results may provide valuable insight into the urological management of pediatric KT recipients, particularly those with severely reduced bladder capacity, and help formulate individualized screening and surgical planning strategies. Future prospective multicenter studies incorporating urodynamic evaluations should validate these findings and further refine strategies for optimizing bladder management and graft outcomes in pediatric KT recipients. Declarations Competing interests: The authors have no relevant financial or non-financial interests to disclose. Ethics approval: This study was approved by the Ethics Committee of Toho University Omori Medical Center (Approval numbers: M24014 and M23233) and was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Consent to participate : The requirement for informed consent was waived by the ethics committee owing to the retrospective study design. Consent for publication : Not applicable. Funding: Not applicable. Authors' contributions: YA designed the study. JH, M Maeda, and YH contributed to the data acquisition and analysis. YH, K Sakurabayashi, TY, YI, M Muramatsu, TK, SS, and K Saka contributed to data interpretation and critically revised the manuscript. YA wrote the first draft of the manuscript. All authors contributed to manuscript revision, read, and approved the final manuscript. Acknowledgments We would like to thank Editage for English language editing. Availability of data and material: The datasets generated during and/or analysed during the current study are not publicly available due to ethical and privacy restrictions but are available from the corresponding author on reasonable request. References McDonald SP, Craig JC, Australian and New Zealand Paediatric Nephrology Association (2004) Long-term survival of children with end-stage renal disease. N Engl J Med 350:2654–2662. https://doi.org/10.1056/nejmoa031643 Arze Aimaretti L, Arze S (2016) Preemptive renal transplantation–The best treatment option for terminal chronic renal failure. Transpl Proc 48:609–611. https://doi.org/10.1016/j.transproceed.2016.02.047 Lentine KL, Smith JM, Lyden GR et al (2025) OPTN/SRTR 2023 Annual Data Report: Kidney. Am J Transpl 25:S22–137. https://doi.org/10.1016/j.ajt.2025.01.020 Hewitt IK, Montini G, Marks SD (2023) Vesico-ureteric reflux in children and young people undergoing kidney transplantation. Pediatr Nephrol 38:2987–2993. https://doi.org/10.1007/s00467-022-05761-5 Routh JC, Yu RN, Kozinn SI, Nguyen HT, Borer JG (2013) Urological complications and vesicoureteral reflux following pediatric kidney transplantation. J Urol 189:1071–1076. https://doi.org/10.1016/j.juro.2012.09.091 Rossi V, Torino G, Gerocarni Nappo S et al (2016) Urological complications following kidney transplantation in pediatric age: A single-center experience. Pediatr Transpl 20:485–491. https://doi.org/10.1111/petr.12691 Tekgül S, Riedmiller H, Hoebeke P et al (2012) EAU guidelines on vesicoureteral reflux in children. Eur Urol 62:534–542. https://doi.org/10.1016/j.eururo.2012.05.059 Mattoo TK, Chesney RW, Greenfield SP et al (2016) Renal scarring in the randomized intervention for children with vesicoureteral reflux (RIVUR) trial. Clin J Am Soc Nephrol 11:54–61. https://doi.org/10.2215/CJN.05210515 Ranchin B, Chapuis F, Dawhara M et al (2000) Vesicoureteral reflux after kidney transplantation in children. Nephrol Dial Transpl 15:1852–1858. https://doi.org/10.1093/ndt/15.11.1852 Barrero R, Fijo J, Fernandez-Hurtado M, García-Merino F, León E, Torrubia F (2007) Vesicoureteral reflux after kidney transplantation in children. Pediatr Transpl 11:498–503. https://doi.org/10.1111/j.1399-3046.2006.00668.x Morrison CD, Shannon R, Rosoklija I et al (2019) Ureteral complications of pediatric renal transplantation. J Urol 201:810–814. https://doi.org/10.1016/j.juro.2018.08.082 Fontana I, Ginevri F, Arcuri V et al (1999) Vesico-ureteral reflux in pediatric kidney transplants: clinical relevance to graft and patient outcome. Pediatr Transpl 3:206–209. https://doi.org/10.1034/j.1399-3046.1999.00017.x Morizawa Y, Satoh H, Iwasa S et al (2020) Increasing bladder capacity and vesicoureteral reflux in pediatric kidney transplant patients. Int J Urol 27:1008–1012. https://doi.org/10.1111/iju.14348 Martin X, Aboutaieb R, Soliman S, el Essawy A, Dawahra M, Lefrancois N (1999) The use of long-term defunctionalized bladder in renal transplantation: Is it safe? Eur Urol 36:450–453. https://doi.org/10.1159/000020029 Inoue T, Satoh S, Saito M et al (2011) Correlations between pretransplant dialysis duration, bladder capacity, and prevalence of vesicoureteral reflux to the graft. Transplantation 92:311–315. https://doi.org/10.1097/TP.0b013e318223d7d6 Alexopoulos S, Lightner A, Concepcion W, Rose M, Salcedo-Concepcion K, Salvatierra O (2011) Pediatric kidney recipients with small capacity, defunctionalized urinary bladders receiving adult-sized kidney without prior bladder augmentation. Transplantation 91:452–456. https://doi.org/10.1097/TP.0b013e318204381a Lebowitz RL, Olbing H, Parkkulainen KV, Smellie JM, Tamminen-Möbius TE (1985) International system of radiographic grading of vesicoureteric reflux. International Reflux Study in Children. Pediatr Radiol 15:105–109. https://doi.org/10.1007/BF02388714 Uemura O, Ishikura K, Gotoh Y, Honda M (2018) Creatinine-based estimated glomerular filtration rate for children younger than 2 years. Clin Exp Nephrol 22:483–484. https://doi.org/10.1007/s10157-017-1460-3 Matsuo S, Imai E, Horio M et al (2009) Revised equations for estimated GFR from serum creatinine in Japan. Am J Kidney Dis 53:982–992. https://doi.org/10.1053/j.ajkd.2008.12.034 Hamano S, Yamanishi T, Igarashi T, Murakami S, Ito H (1999) Evaluation of functional bladder capacity in Japanese children. Int J Urol 6:226–228. https://doi.org/10.1046/j.1442-2042.1999.00049.x Hashimoto J, Hamasaki Y, Aoki Y et al (2023) Changes in graft function after living donor kidney transplantation in children. Pediatr Nephrol 38:291–297. https://doi.org/10.1007/s00467-022-05540-2 Kawamura T, Hamasaki Y, Takahashi Y et al (2020) ABO-incompatible pediatric kidney transplantation without antibody removal. Pediatr Nephrol 35:95–102. https://doi.org/10.1007/s00467-019-04376-7 Zirngibl M, Buder K, Luithle T, Tönshoff B, Weitz M, Members of the (2022) Diagnostic and therapeutic management of vesico-ureteral reflux in pediatric kidney transplantation-results of an online survey on behalf of the European Society for Paediatric Nephrology. Pediatr Transpl 27:e14449. https://doi.org/10.1111/petr.14449 Salvatierra O Jr, Sarwal M, Alexander S et al (1999) A new, unique and simple method for ureteral implantation in kidney recipients with small, defunctionalized bladders. Transplantation 68:731. https://doi.org/10.1097/00007890-199909270-00004 Burns MW, Watkins SL, Mitchell ME, Tapper D (1992) Treatment of bladder dysfunction in children with end-stage renal disease. J Pediatr Surg 27:170–174. https://doi.org/10.1016/0022-3468(92)90306-r Zirngibl M, Weitz M, Luithle T et al (2023) Current management of symptomatic vesicoureteral reflux in pediatric kidney transplantation—a European survey among surgical transplant professionals. Pediatr Transpl 28:e14621. https://doi.org/10.1111/petr.14621 Guerra LA, Keays MA, Purser MJ, Wang SY, Leonard MP (2018) Pediatric cystogram: are we considering age-adjusted bladder capacity? Can Urol Assoc J 12:378–381. https://doi.org/10.5489/cuaj.5263 Cite Share Download PDF Status: Published Journal Publication published 08 Dec, 2025 Read the published version in Pediatric Nephrology → Version 1 posted Reviewers agreed at journal 11 Jul, 2025 Reviewers invited by journal 10 Jul, 2025 Editor assigned by journal 09 Jul, 2025 First submitted to journal 08 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7076491","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":483675867,"identity":"930ae63b-609e-48e9-a47f-df2f217e293e","order_by":0,"name":"Yujiro Aoki","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4ElEQVRIiWNgGAWjYJACxgYDGyCVAGLBxHgIakkDaWFsIEELw2F0LXiAwQHmhw9nFJyP5mdPYH/wcYcNWOQDg8wdPFrYjA03GNzOndnzgLFx5pk0sIgEA88zPFoYzCQfALVsuJHA2Mzbdrh+A1AE6JfDeLSwfwNqOZe7H6oFLEJAC4+Z5AaDA7kbJOBaePDbInmYp9hwhkFy7owzDxtnzmxLA4tIJODxC9/x9o0Pe/7Y5fa3Jx/48LHNBizy4WMP7hBTQDgAFinMQJzYcwCnFvkG7OI/cGsZBaNgFIyCEQcAHHRaAy4IOk8AAAAASUVORK5CYII=","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Yujiro","middleName":"","lastName":"Aoki","suffix":""},{"id":483675868,"identity":"04254484-05e2-41bd-9c47-6032c56abe38","order_by":1,"name":"Yuko Hamasaki","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yuko","middleName":"","lastName":"Hamasaki","suffix":""},{"id":483675869,"identity":"bdd51793-9242-4703-9a41-c26b89ec90c9","order_by":2,"name":"Junya Hashimoto","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Junya","middleName":"","lastName":"Hashimoto","suffix":""},{"id":483675870,"identity":"61abc6d2-3225-4910-b576-0791b1aa7757","order_by":3,"name":"Maho Maeda","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Maho","middleName":"","lastName":"Maeda","suffix":""},{"id":483675871,"identity":"daa5bada-e867-4751-bcab-ce95892d39fc","order_by":4,"name":"Kei Sakurabayashi","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Kei","middleName":"","lastName":"Sakurabayashi","suffix":""},{"id":483675872,"identity":"dd4bdd37-37fd-421a-8db0-84aa572d040b","order_by":5,"name":"Takashi Yonekura","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Takashi","middleName":"","lastName":"Yonekura","suffix":""},{"id":483675873,"identity":"8a39b608-77ae-4e69-a0e3-b11c0ea4cc65","order_by":6,"name":"Yoshihiro Itabashi","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yoshihiro","middleName":"","lastName":"Itabashi","suffix":""},{"id":483675874,"identity":"7f142552-b686-4e26-8425-d16d1ee6cf1a","order_by":7,"name":"Masaki Muramatsu","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Masaki","middleName":"","lastName":"Muramatsu","suffix":""},{"id":483675875,"identity":"f8d78bce-6ba0-4056-8976-415636d2a433","order_by":8,"name":"Takeshi Kawamura","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Takeshi","middleName":"","lastName":"Kawamura","suffix":""},{"id":483675876,"identity":"2efaf439-9fc7-4805-9da9-5d6e2de0e7f4","order_by":9,"name":"Seiichiro Shishido","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Seiichiro","middleName":"","lastName":"Shishido","suffix":""},{"id":483675877,"identity":"3cb01b15-fe81-4be4-8cf2-bd3cbe8e2b37","order_by":10,"name":"Ken Sakai","email":"","orcid":"","institution":"Toho University Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Ken","middleName":"","lastName":"Sakai","suffix":""}],"badges":[],"createdAt":"2025-07-08 15:45:58","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7076491/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7076491/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00467-025-07078-5","type":"published","date":"2025-12-08T15:56:54+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":86767730,"identity":"6f4c0853-9b59-4a2d-b2d6-c06697ce5505","added_by":"auto","created_at":"2025-07-15 11:18:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":24616,"visible":true,"origin":"","legend":"\u003cp\u003eFlow chart of the patient selection process\u003c/p\u003e","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7076491/v1/f14f1b9d43b238dfb8e187bd.png"},{"id":86767056,"identity":"06815f6d-b470-4d45-9ea2-5ff1de100202","added_by":"auto","created_at":"2025-07-15 11:10:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":10409,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation between pre-transplant MBC/EBC ratio and anuria duration\u003c/p\u003e\n\u003cp\u003ePre-transplant MBC/EBC ratio was negatively correlated with the duration of anuria (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e = −0.675, p \u0026lt; 0.001). EBC, expected bladder capacity; MBC, maximum bladder capacity\u003c/p\u003e","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7076491/v1/e0d61d9d8ed9c0c0c4394564.png"},{"id":86767049,"identity":"740f86e8-72bd-483e-9ded-02d2e3a36a43","added_by":"auto","created_at":"2025-07-15 11:10:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":18215,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation between post- and pre-transplant MBC/EBC ratios\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(A)\u003c/strong\u003e Pre- and post-transplant MBC/EBC ratios in patients with anuria has a weak positive correlation (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e = 0.371, p = 0.068). \u003cstrong\u003e(B)\u003c/strong\u003ePre- and post-transplant MBC/EBC ratios in patients with non-anuria are positively correlated\u0026nbsp; (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e = 0.493, p \u0026lt; 0.001). EBC, expected bladder capacity; MBC, maximum bladder capacity\u003c/p\u003e","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7076491/v1/67ddb46362913554da0d136b.png"},{"id":86767051,"identity":"c10459ad-d14d-42ec-9928-3584b313cc42","added_by":"auto","created_at":"2025-07-15 11:10:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":24193,"visible":true,"origin":"","legend":"\u003cp\u003eROC curve analysis for the ability of pre-transplant MBC/EBC ratio to predict post-transplant VUR\u003c/p\u003e\n\u003cp\u003eA pre-transplant MBC/EBC ratio cut-off value of 57.8%, resulting in an AUC of 0.757, predicts post-transplant VUR with 76.5% sensitivity and 72.4% specificity. AUC, area under the curve; EBC, expected bladder capacity; MBC, maximum bladder capacity; ROC, receiver operating characteristic; VUR, vesicoureteral reflux\u003c/p\u003e","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7076491/v1/9496256c2bb90205d08a6fbf.png"},{"id":98243487,"identity":"f3a4b108-7a0a-4b94-aa02-3b69b2f368ab","added_by":"auto","created_at":"2025-12-15 16:06:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1310554,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7076491/v1/eb793036-2101-4fb4-9474-4e7d6b327dd3.pdf"}],"financialInterests":"","formattedTitle":"Change in bladder capacity and prognostic predictors of post-transplant vesicoureteral reflux in pediatric kidney transplant recipients: a single-center retrospective cohort study","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eKidney transplantation (KT) is the gold-standard treatment for children with end-stage kidney disease (ESKD), and it significantly improves both quality of life and long-term survival [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Approximately 800 pediatric KTs are performed annually in the United States alone [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Nevertheless, post-KT urological complications, particularly vesicoureteral reflux (VUR), remain major clinical challenges [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e–\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e\u003cp\u003ePost-transplant VUR, a well-known risk factor for urinary tract infection (UTI) [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], can compromise graft function. Although the incidence of post-transplant VUR has previously been evaluated, ureteroneocystostomy techniques adopted during KT differ among studies [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e–\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Moreover, these studies included patients with lower urinary tract dysfunction [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e–\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], and this population may have differing development patterns of post-transplant VUR, confounding the risk and outcome of post-transplant VUR. Therefore, the specific risk factors for VUR development needs further clarification in a more homogeneous pediatric KT recipient population.\u003c/p\u003e\u003cp\u003eAlthough the impact of post-transplant VUR on allograft graft survival and function has previously been explored [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], it remains moot. Post-transplant VUR does not affect kidney function; however, a pre-transplant atrophic bladder has been identified as a risk factor for post-transplant VUR [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Adults with a pre-transplant atrophic bladder are less likely to be affected because bladder capacity increases post-KT [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. However, data regarding pediatric patients are limited [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Furthermore, a standardized definition of atrophic bladder in children is currently lacking, and the bladder capacity threshold that predisposes patients to post-transplant VUR remains undetermined.\u003c/p\u003e\u003cp\u003eA healthy bladder expands with urine inflow; however, in prolonged ESKD, bladder dysfunction and decreased urine output result in decreased bladder capacity and anuria. Consequently, technical difficulties may arise when performing an anti-reflux re-implantation of an adult-sized ureter into a small bladder during KT. Despite these anatomical and functional challenges, evidence on the influence of bladder dynamics on post-operative vesicoureteral anastomosis outcomes in pediatric KT recipients remains limited.\u003c/p\u003e\u003cp\u003eTherefore, this study aimed to investigate the relationship between pre- and post-KT bladder capacity changes and post-transplant VUR development in pediatric KT recipients, including those with pre-transplant anuria. Additionally, the specific risk factors associated with post-transplant VUR were identified to inform better management and surgical strategies.\u003c/p\u003e"},{"header":"PATIENTS AND METHODS","content":"\u003cp\u003e\u003cb\u003eStudy design and setting\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis retrospective cohort study included consecutive pediatric patients who underwent primary KT from January 2009 to December 2023 at the Toho University Omori Medical Center.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStudy criteria\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePatients who underwent pre- and post-KT voiding cystourethrography (VCUG) and extravesical ureteral re-implantation, using the Lich-Gregoir technique, during KT were included. Although pediatric KT recipients routinely undergo VCUG at our institution, patients who did not undergo post-KT VCUG owing to non-consent were excluded. Patients with bladder or lower urinary tract dysfunction, such as posterior urethral valve, neurogenic bladder, or cloacal malformation, and those who underwent augmentation cystoplasty or urinary diversion were excluded from the analysis. The included patients were divided into two groups based on the presence of pre-KT anuria (anuric and non-anuric groups). Anuria was defined as a daily urine output of \u0026lt; 0.5 mL/kg/h. None of the included patients had received anticholinergics pre- or post-KT.\u003c/p\u003e\u003cp\u003e\u003cb\u003eData collection and participant follow up\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe patients’ pre- and post-transplant clinical data, including patient and donor characteristics, medical history, physical examination results, pre-transplant dialysis modalities, maximum bladder capacity (MBC), presence of VUR, cadaver or living donor, method of ureteral reimplantation, immunosuppressive drug use, graft function, patient and graft survival, cause of death, and graft loss, were manually extracted from their medical records. Data were collected until death, graft loss, or December 2023. The VUR grade was assessed according to a previous report [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The estimated glomerular filtration rate (eGFR) was calculated using a creatinine-based equation for Japanese children and adults [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Expected bladder capacity (EBC) was determined as follows: ([age (years) + 2] × 25; mL) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The presence of VUR and MBC was evaluated using VCUG.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStudy procedure- surgery\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe extravesical Lich-Gregoir technique was used for anti-reflux ureteral re-implantation during KT. A 2 cm long submucosal tunnel was formed, and a temporary 5-Fr ureteral stent was used. The ureteral stent was removed on postoperative day 5, and the transurethral catheter, on postoperative day 6–7. At our institution, continuous antibiotic prophylaxis is typically not administered post-KT to prevent UTI.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStudy procedure- post-transplant immunosuppressive regimen\u003c/b\u003e\u003c/p\u003e\u003cp\u003eBasiliximab was administered for induction, followed by triple immunosuppressive therapy with calcineurin inhibitors, mycophenolate mofetil or everolimus, and methylprednisolone. ABO-incompatible KT recipients underwent early treatment with mycophenolate mofetil, rituximab, and plasma exchange. The immunosuppressive regimen used in this study has previously been reported [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cb\u003eEthical Considerations\u003c/b\u003e\u003c/p\u003e\u003cp\u003e This study was approved by the Ethics Committee of Toho University Omori Medical Center (Approval numbers: M24014 and M23233) and conformed to the Declaration of Helsinki guidelines. The details of the study were disclosed on the institution’s website before study commencement, and the patients’ parents/guardians were provided the opportunity to withdraw their child/ward’s inclusion in the study using the opt-out method. The requirement for written informed consent was waived owing to the retrospective study design.\u003c/p\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eCategorical data were expressed as number (percentage), and continuous data, as mean ± standard deviation or median with range or interquartile range (IQR), depending on the distribution normality, using the Shapiro–Wilk test. The Wilcoxon rank-sum and Fisher’s exact tests were used to compare continuous and categorical variables, respectively. The paired t-test was used to compare pre- and post-transplant data. Variables with missing values were excluded from the analysis to avoid information bias. Logistic regression models were used to identify the independent risk factors for post-transplant VUR. Multivariate logistic regression was used to assess the relationship between post-transplant VUR and sex, age, post-transplant VUR in the native kidney, and pre-transplant MBC/EBC ratio. The logistic regression results were expressed as odds ratios (OR) and 95% confidence intervals (CI). Multicollinearity between variables was considered if the variance inflation factor was \u0026gt; 10. Variables that were significant in the multivariable logistic regression analysis in predicting post-transplant VUR were assessed for validity (sensitivity, sensitivity, positive predictive value, negative predictive value, and accuracy). The Youden index (sensitivity + specificity − 1) was used to establish the optimal cut-off values from the receiver operating characteristic (ROC) curve. Spearman’s rank correlation coefficient (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e) was used to identify the association between post-transplant bladder capacity and anuria duration. All tests were two-sided, and p \u0026lt; 0.05 was considered statistically significant. Statistical analyses were performed using the JMP Pro 17 software (SAS Institute Inc., Cary, NC, US).\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003e\u003cstrong\u003eParticipant selection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e illustrates the patient selection process. Overall, 183 patients aged\u0026thinsp;\u0026lt;\u0026thinsp;18 years who underwent KT during the study period were screened. Among these, 53 patients without post-transplant data, 23 with urinary tract dysfunction, and 14 who underwent re-transplant were excluded. The remaining 93 were included in the final analysis and divided into the anuric and non-anuric groups with 25 (26.9%) and 68 (73.1%) patients, respectively.\u003c/p\u003e\n\u003cp\u003eIn this study, 14 patients who had undergone primary kidney transplantation are included. A total of 53 patients with missing post-transplant VCUG data and 23 patients with lower urinary tract dysfunction, including posterior urethral valve (n\u0026thinsp;=\u0026thinsp;8), neurogenic bladder (n\u0026thinsp;=\u0026thinsp;13), or cloacal malformation (n\u0026thinsp;=\u0026thinsp;2), were excluded. VCUG, voiding cystourethrography\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eParticipant characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTable\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e lists the patient and transplantation characteristics. The median age at transplantation was 6.1 (2.3\u0026ndash;17.7) years, and 56 patients (60.0%) were male. The median anuria duration was 12.5 months. In the non-anuric group, 32 patients (47.1%) underwent preemptive KT. All patients with anuria underwent pre-transplant dialysis (100% vs. 53%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), either peritoneal dialysis (84% vs. 50%, p\u0026thinsp;=\u0026thinsp;0.004) or hemodialysis (16% vs. 3%, p\u0026thinsp;=\u0026thinsp;0.0043), compared with those who were non-anuric. Among the 93 included patients, 11 (11.8%) weighed\u0026thinsp;\u0026lt;\u0026thinsp;10 kg at the time of KT. Three of these patients had pre-transplant anuria. The extraperitoneal and intraperitoneal approaches were used for KT in 73 (78.5%) and 20 (21.5%) patients, respectively. Pre-transplant VUR in the native kidney was observed in 32 patients (34.4%). High-grade VUR (grade III\u0026ndash;IV) was present in six patients (6.5%). Overall, 47 patients (50.5%) underwent unilateral or bilateral native nephrectomy before or during KT for the following reasons: 23 patients (48.9%) for securing a transplant bed, 15 (31.9%) for medical renal disease, and 9 patients (19.2%) for VUR or hydronephrosis. In the anuric group, 16 patients (64.0%) underwent pre-KT native nephrectomy, and 10 (40.0%) underwent bilateral nephrectomy. Three of these ten patients underwent bilateral nephrectomy for bilateral Wilms tumor and another three, for Denys\u0026ndash;Drash syndrome.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePatient demographics and anthropometrics\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVariables\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAll patients (n\u0026thinsp;=\u0026thinsp;93)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAnuric group\u003c/p\u003e\n \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNon-anuric group (n\u0026thinsp;=\u0026thinsp;68)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep\u003cem\u003e-\u003c/em\u003evalue\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003ePatients\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSex, male, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e56 (60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 (48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e44 (65)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.159\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge at KT (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.1 [4.0\u0026ndash;11.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.9 [3.9\u0026ndash;12.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.1 [4.1\u0026ndash;11.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.358\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHeight (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e105 [89.9\u0026ndash;132.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e98.1 [88.2\u0026ndash;134.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e106.0 [90.4\u0026ndash;131.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.527\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWeight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.1 [11.9\u0026ndash;27.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14.5 [11.7\u0026ndash;26.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.4 [11.9\u0026ndash;27.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.564\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAnuria duration (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.5 [5.1\u0026ndash;33.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.5 [5.1\u0026ndash;33.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN/A\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFollow-up duration (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.1 [3.9\u0026ndash;10.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.0 [3.0\u0026ndash;9.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.9 [4.9\u0026ndash;10.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.056\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003eDialysis characteristics\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePre-transplant dialysis, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61 (66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36 (53)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePeritoneal dialysis, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55 (59)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21 (84)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34 (50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHemodialysis, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 (6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.043\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDialysis duration (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.4 [0.0\u0026ndash;3.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.2 [1.5\u0026ndash;3.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.2 [0.0\u0026ndash;2.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrimary disease\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCAKUT, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43 (46)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40 (58)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGlomerular disease, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27 (29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13 (54)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14 (20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCystic kidney disease, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 (13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 (12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.728\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIschemic renal failure, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.571\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOthers, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7 (7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.081\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003eVUR in native kidney and UTI\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVUR in native kidney, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32 (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11 (44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21 (31)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.325\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUnilateral/Bilateral VUR, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15 (47) / 17 (53)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (18) / 9 (82)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13 (62) / 8 (38)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.028\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHistory of pre-KT UTI, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10 (11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 (12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.274\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003eTransplantation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDonor sex, male, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48 (52)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18 (72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 (44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDonor age (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.5 [34.9\u0026ndash;45.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.1 [33.6\u0026ndash;44.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.9 [35.6\u0026ndash;47.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.175\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLiving related donor, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e88 (95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22 (88)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66 (97)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.118\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDonor eGFR pre-nephrectomy (mL/min/1.73 m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e77.0 [70.1\u0026ndash;89.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e84.2 [70.9\u0026ndash;92.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e75.4 [69.9\u0026ndash;86.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.139\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNumber of HLA A/B/DR mismatches\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.393\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eABO-incompatible KT, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16 (17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 (32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 (12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.031\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCold ischemia time (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72.0 [56.5\u0026ndash;92.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e82.0 [58.0\u0026ndash;115.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e69.5 [56.0\u0026ndash;87.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.139\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eCAKUT, congenital anomalies of the kidney and urinary tract; eGFR, estimated glomerular filtration rate; HLA, human leukocyte antigen; KT, kidney transplantation; UTI, urinary tract infection; VUR, vesicoureteral reflux\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eValues are presented as number (%), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation, or median [interquartile range]\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cstrong\u003eBladder Capacity Changes After Kidney Transplantation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eVCUG was performed at a median of 4.0 (IQR 3.0\u0026ndash;6.0) months pre-operatively and 4.2 (IQR 3.5\u0026ndash;5.1) months post-operatively, and the period from VCUG to KT was not significantly different in both groups. Pre- and post-KT bladder capacity values are presented in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. In the anuric group, 11 patients (44%) had a pre-transplant MBC of \u0026lt;\u0026thinsp;20 mL. Twenty patients (80.0%) in the anuric group and seven (10.3%) in the non-anuric group had a pre-transplant MBC/EBC ratio\u0026thinsp;\u0026lt;\u0026thinsp;50%. The pre-transplant bladder capacity was significantly lower in the anuric group than in the non-anuric group (37.5 mL [10.0\u0026ndash;104] and 170 mL [120\u0026ndash;275], respectively; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Although bladder capacity increased in both groups post-KT, it remained significantly decreased in the anuric group (120 mL [80.0\u0026ndash;200] and 200 mL [150\u0026ndash;300], respectively; p\u0026thinsp;=\u0026thinsp;0.002).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv align=\"left\" class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eBladder capacity before and after kidney transplantation\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVariables\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAll patients (n\u0026thinsp;=\u0026thinsp;93)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAnuric group (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNon-anuric group (n\u0026thinsp;=\u0026thinsp;68)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep\u003cem\u003e-\u003c/em\u003evalue\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003ePre-transplantation\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMBC (mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e140 [75.0\u0026ndash;265]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37.5 [10.0\u0026ndash;104]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e170 [120\u0026ndash;275]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMBC/EBC ratio (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e75.6 [35.5\u0026ndash;103.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19.7 [6.7\u0026ndash;34.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e89.8 [66.3\u0026ndash;113.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePeriod from VCUG to KT (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.0 [3.0\u0026ndash;6.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.0 [3.5\u0026ndash;8.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.0 [3.0\u0026ndash;5.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.183\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003ePost-transplantation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMBC (mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e180 [120\u0026ndash;300]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e120 [80.0\u0026ndash;200]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e200 [150\u0026ndash;300]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMBC/EBC ratio (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e82.6 [55.8\u0026ndash;102.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62.3 [40.4\u0026ndash;80.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90.3 [68.0\u0026ndash;113.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePeriod from KT to VCUG (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.2 [3.5\u0026ndash;5.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.8 [3.5\u0026ndash;5.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.2 [3.6\u0026ndash;5.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.404\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eEBC, expected bladder capacity; KT, kidney transplantation; MBC, maximum bladder capacity; VCUG, voiding cystourethrography. Values are presented as the median [interquartile range].\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cstrong\u003eCorrelation Between Anuria Duration and Pre-transplant Bladder Capacity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the anuric group, anuria duration and pre-transplant bladder capacity were correlated (MBC/EBC ratio) (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e = -0.675, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrelation Between Pre- and Post-transplant MBC/EBC Ratios\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe pre- and post-transplant MBC/EBC ratios were correlated (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e = 0.557, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (data not presented). The relationship between the post- and pre-transplant MBC/EBC ratios is illustrated in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e. In the anuric group, the pre- and post-transplant MBC/EBC ratios had a weak positive correlation (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e = 0.371, p\u0026thinsp;=\u0026thinsp;0.068), although not strictly statistically significant owing to the small number of patients with anuria (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e \u003cstrong\u003e(A)\u003c/strong\u003e). In the non-anuric group, the pre- and post-transplant MBC/EBC ratios were correlated (\u003cem\u003er\u003c/em\u003e\u003csub\u003e\u003cem\u003es\u003c/em\u003e\u003c/sub\u003e = 0.493, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e \u003cstrong\u003e(B)\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrevalence of Post-transplant VUR\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTable\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e presents the prevalence of post-transplant VUR. The overall prevalence of post-transplant VUR was 18.3% (n\u0026thinsp;=\u0026thinsp;17). Post-transplant VUR occurred in ten patients (40.0%) (grade I: n\u0026thinsp;=\u0026thinsp;5; grade III: n\u0026thinsp;=\u0026thinsp;3; and grade IV: n\u0026thinsp;=\u0026thinsp;2) in the anuric group and in seven patients (10.3%) (grade I: n\u0026thinsp;=\u0026thinsp;3; grade II: n\u0026thinsp;=\u0026thinsp;2; grade III: n\u0026thinsp;=\u0026thinsp;1; and grade IV: n\u0026thinsp;=\u0026thinsp;1) in the non-anuric group. A significant between-group difference was observed in the occurrence of post-transplant VUR (p\u0026thinsp;=\u0026thinsp;0.002). In patients with a pre-transplant MBC/EBC ratio\u0026thinsp;\u0026lt;\u0026thinsp;50%, the prevalence of post-transplant VUR was 36.0% (n\u0026thinsp;=\u0026thinsp;9) and 1.4% (n\u0026thinsp;=\u0026thinsp;1) in the anuric and non-anuric groups, respectively (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRegression analysis results for the identification of risk factors for post-transplant vesicoureteral reflux\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003ePredictors\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eUnivariate analysis\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eMultivariate analysis\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOR\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOR\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMale sex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.284\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.094\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.854\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.021\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.903\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.784\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.041\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.139\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVUR in the native kidney\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.507\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.184\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMBC/EBC ratio (%) pre-KT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.975\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.959\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.965\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.996\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.006\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"11\"\u003eCI, confidence interval; EBC, expected bladder capacity; KT, kidney transplantation; MBC, maximum bladder capacity; OR, odds ratio; VUR, vesicoureteral reflux\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003ePost-transplant VUR was observed in sixteen ureters (two bilateral and twelve unilateral) in the native kidney from fourteen patients (15.1%). In the anuric group, five ureters in four patients (16.0%) developed VUR (all grade I) (one bilateral and three unilateral), while two patients had new-onset VUR in the native kidney, observed on VCUG post-KT. In the non-anuric group, 11 ureters in 10 patients (14.7%) developed VUR (one bilateral and nine unilateral); VUR in the native kidney was grade I in seven ureters, grade II in three, and grade IV in one. No cases of worsening VUR grade were observed post-KT.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIdentification of the Risk Factors for Post-transplant VUR\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe risk of post-transplant VUR was calculated based on sex, age, VUR in the native kidney, and pre-transplant MBC/EBC ratio. Multivariate analysis revealed that post-transplant VUR was independently associated with pre-transplant MBC/EBC ratio (OR: 0.980, 95% CI: 0.965\u0026ndash;0.996, p\u0026thinsp;=\u0026thinsp;0.006) (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eROC Curve Analysis for Predicting Post-transplant VUR\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe results of the ROC curve analysis revealed that post-transplant VUR could be predicted by the pre-transplant MBC/EBC ratio (cut-off, 57.8%) with 76.5% sensitivity and 72.4% specificity (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). The AUC was 0.757 (95% CI: 0.670\u0026ndash;0.844, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the positive predictive value, negative predictive value, and Youden\u0026rsquo;s index were 0.382, 0.932, and 0.488, respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Outcomes of Kidney Transplantation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe clinical outcomes of kidney transplantation are presented in Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e. During the follow-up period, none of the 93 pediatric KT recipients had urinary complications such as postoperative urine leakage, transplant ureteral stenosis, or obstruction. Regarding post-transplant graft function, the eGFR at 5 years post-transplantation was comparable between the anuric and non-anuric groups, with no delay in graft function in either group. No differences in eGFR were observed between the anuric and non-anuric groups\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePrevalence of post-transplant vesicoureteral reflux and clinical outcomes of kidney transplantation\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVariables\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAll patients (n\u0026thinsp;=\u0026thinsp;93)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAnuric group (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNon-anuric group (n\u0026thinsp;=\u0026thinsp;68)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep\u003cem\u003e-\u003c/em\u003evalue\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePost-transplant VUR, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17 (18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10 (40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7 (10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade Ⅰ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 (47)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5 (50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade Ⅱ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0 (0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade Ⅲ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (23)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.058\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade Ⅳ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.175\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePost-transplant VUR in patients with pre-transplant MBC/EBC ratio\u0026thinsp;\u0026lt;\u0026thinsp;50%, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10 (11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 (36)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePost-transplant VUR in the native kidney, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14* (15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4** (16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10*** (15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUnilateral VUR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 (86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 (90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBilateral VUR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.468\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePost-transplant eGFR (mL/min/1.73 m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e74.9\u0026thinsp;\u0026plusmn;\u0026thinsp;21.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78.3\u0026thinsp;\u0026plusmn;\u0026thinsp;23.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e73.8\u0026thinsp;\u0026plusmn;\u0026thinsp;21.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.431\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e70.4\u0026thinsp;\u0026plusmn;\u0026thinsp;18.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e75.9\u0026thinsp;\u0026plusmn;\u0026thinsp;16.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e69.0\u0026thinsp;\u0026plusmn;\u0026thinsp;19.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.259\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e64.8\u0026thinsp;\u0026plusmn;\u0026thinsp;17.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e70.2\u0026thinsp;\u0026plusmn;\u0026thinsp;18.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e63.5\u0026thinsp;\u0026plusmn;\u0026thinsp;17.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.202\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePrevalence of post-transplant UTI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003e*16 ureters from 14 patients, ** 5 ureters, all grade I; *** 11 ureters \u0026minus;\u0026thinsp;7 grade I, 3 grade II, and 1 grade IV\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eEBC, expected bladder capacity; eGFR, estimated glomerular filtration rate; MBC, maximum bladder capacity; UTI, urinary tract infection; VCUG, voiding cystourethrography; VUR, vesicoureteral reflux\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThree patients (two in the anuric group and one in the non-anuric group) received sulfamethoxazole-trimethoprim prophylaxis to prevent UTI post-KT. Four of the ninety-three patients (4.3%) developed UTI during the follow-up period, including one patient (4.0%) in the anuric group and three patients (4.4%) in the non-anuric group, none of whom received sulfamethoxazole-trimethoprim prophylaxis. Among these four patients, post-transplant VUR (grade IV) was present in two patients, one of whom had pre-transplant anuria. Both patients were initiated on sulfamethoxazole-trimethoprim prophylaxis; however, UTI recurred. Therefore, a dextranomer/hyaluronic acid (Deflux\u0026reg;) injection was administered into the transplanted ureter via a pediatric cystoscope. One patient received a second Deflux\u0026reg; injection following UTI recurrence. However, this patient had residual post-transplant VUR and underwent ureteroureterostomy with the native ureter.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis retrospective cohort study investigated bladder capacity changes and post-transplant VUR in pediatric patients with ESKD who underwent KT. Pre-transplant MBC/EBC ratio was an independent predictor of post-transplant VUR development when using age-predicted bladder capacity as a specific indicator owing to the varying ages of the pediatric patients cohort in this study. In addition, patients with pre-transplant anuria exhibited an increase in bladder capacity early post-KT. Moreover, these patients had a higher incidence of post-transplant VUR than patients without pre-transplant anuria, although they did not have a higher incidence of UTI.\u003c/p\u003e\u003cp\u003eIn our study, we used the MBC/EBC ratio to evaluate bladder capacity changes. Pre- and post-KT bladder capacity changes have been reported in a cohort of Japanese patients aged\u0026thinsp;\u0026lt;\u0026thinsp;18 years; this previous study, in which bladder capacity was evaluated according to an MBC/EBC ratio\u0026thinsp;\u0026lt;\u0026thinsp;50%, revealed that bladder capacity increased 4 months post-KT, with an increase in the MBC/EBC ratio from 63.7\u0026ndash;98.2% [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In our cohort, a significant correlation was observed between anuria duration and pre-transplant MBC/EBC ratio. Although an overall increase in bladder capacity was observed post-KT, the MBC/EBC ratio increased significantly from 19.7\u0026ndash;62.3%, especially in the patients with pre-transplant anuria. Owing to the limited reports on bladder capacity in pediatric patients with ESKD and atrophic bladders, and because post-transplant VCUG is not routinely performed [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], data on bladder capacity in pediatric KT recipients are lacking. Therefore, the findings of the present study may provide valuable insights into bladder capacity in a cohort of pediatric patients with ESKD, including those with anuria, and may contribute to improved urological management and prognostic assessment pre- and post-KT.\u003c/p\u003e\u003cp\u003eChildren with a small bladder capacity and bladder dysfunction present operative challenges [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], and pre-transplant bladder augmentation has been recommended [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. However, proceeding with KT without pre-transplant bladder augmentation has been suggested for pediatric patients with ESKD with a small bladder capacity and bladder dysfunction to avoid unnecessary surgery [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. At our institution, bladder augmentation and/or urinary diversion is a pre-transplant option for patients with neurogenic bladder and bladder dysfunction. Therefore, ureteroneocystostomy was performed using the Lich-Gregoir technique, a common procedure for ureteral reimplantation during pediatric KT [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e], without modification according to bladder capacity, and no postoperative leakage or obstruction and no technical problems with the procedure were observed. In a previous study, 12 pediatric patients with ESKD with atrophic bladder who did not undergo pre-transplant bladder augmentation underwent KT with an average intraoperative bladder capacity of 25 mL and no postoperative ureteral obstruction, similar to that reported in our study [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In our study, the MBC/EBC ratio of patients with pre-transplant anuria had a median value of 19.7%, and 44% had an MBC\u0026thinsp;\u0026lt;\u0026thinsp;20 mL. These findings suggest that even in pediatric patients with severely reduced bladder capacity and pre-transplant anuria, Lich-Gregoir ureteroneocystostomy is safe, effective, and feasible without pre-transplant bladder augmentation. Our study results further support the notion that routine pre-transplant bladder augmentation may not be necessary in all cases, thus avoiding additional surgical burden.\u003c/p\u003e\u003cp\u003eIn our cohort, all patients underwent Lich-Gregoir ureteroneocystostomy, and post-transplant VUR occurred in 18.3% of them. In a previous study including 73 pediatric patients who underwent routine VCUG 6 months post-KT [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], all underwent the Lich-Gregoir procedure, and post-transplant VUR occurred in 34% of them (grade I: n\u0026thinsp;=\u0026thinsp;4; grade II: n\u0026thinsp;=\u0026thinsp;7; grade III: n\u0026thinsp;=\u0026thinsp;7; and grade IV: n\u0026thinsp;=\u0026thinsp;7). Although patient backgrounds did not include any mention of pre-transplant bladder capacity, the incidence of post-transplant VUR was higher than that in our study, and the frequency of high-grade post-transplant VUR (grade III\u0026ndash;V) was high (41%) as well. Moreover, 40% of patients with pre-transplant anuria developed post-transplant VUR, which was significantly higher than the proportion of patients who were non-anuric. Another study including patients with atrophic bladder reported a post-transplant VUR rate of 41.6% [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], comparable with that in our study. In the previous study, patients with a small-capacity bladder (\u0026lt;\u0026thinsp;50 ml) and those who underwent bilateral surgical nephrectomy or medical nephrectomy were defined to have anuria, similar to those in our study. In another study, nine of seventy-one patients (12.7%) with atrophic bladder had post-transplant VUR [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]; however, either the Lich-Gregoir or the intravesical Politano-Leadbetter ureteroneocystostomies were performed during KT. Since the exact technique was not mentioned, a comparison could not be made with our study. In our cohort, the incidence of post-transplant VUR among patients with pre-transplant anuria was 10.3%, markedly lower than that previously reported in comparable populations [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This suggests that the consistent use of Lich-Gregoir ureteroneocystostomy may contribute to a reduced incidence of post-transplant VUR, even in patients at a higher risk due to anuria or suspected bladder dysfunction.\u003c/p\u003e\u003cp\u003eThe ROC curve analysis revealed that the pre-transplant MBC/EBC ratio cut-off value for predicting post-transplant VUR occurrence was 57.8%. Notably, although patients with pre-transplant anuria had a higher frequency of post-transplant VUR than those without pre-transplant anuria, the frequency of post-transplant UTI between both groups was not significantly different. Our study results can serve as an indicator for urinary tract screening before pediatric KT, and post-transplant VUR can be predicted from the pre-transplant MBC/EBC ratio. VCUG is a burdensome test for pediatric patients, and post-KT VCUG can be avoided in many cases (except for patients with neurogenic bladders); however, the cut-off values may be a useful indicator for clinicians.\u003c/p\u003e\u003cp\u003eThis study has some limitations. First, this was a single-center retrospective study, which may have resulted in patient selection bias. Second, the procedural policy is to ensure a submucosal tunnel length of at least 2 cm for ureteroneocystostomy during KT. However, the submucosal tunnel length was not measured peri-operatively. Therefore, the effect of submucosal tunnel length on allograft VUR could not be investigated. Third, the patients were operated on by different surgeons, which may have resulted in variations in the level of surgical skill and judgment. Nevertheless, all surgeries were performed under the same supervising surgeon, and homogeneity of the surgical technique was considered to have been maintained. Fourth, maximum bladder capacity measurements using VCUG may not accurately reflect the true functional capacity of the bladder [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Urodynamic studies could provide more comprehensive and reliable data on bladder capacity and function. Therefore, future prospective studies, including urodynamic studies, should evaluate the pathogenesis and treatment strategies for post-transplant VUR in pediatric patients with ESKD.\u003c/p\u003e\u003cp\u003eIn conclusion, our study found that the pre-transplant MBC/EBC ratio is a useful predictor of post-transplant VUR in pediatric KT recipients. A cut-off MBC/EBC ratio of 57.8% may help identify patients at a high risk of VUR, reducing the need for routine post-transplant VCUG. Bladder capacity improved significantly post-transplantation, even in patients with pre-transplant anuria, and Lich-Gregoir ureteroneocystostomy was safely performed without bladder augmentation. These results may provide valuable insight into the urological management of pediatric KT recipients, particularly those with severely reduced bladder capacity, and help formulate individualized screening and surgical planning strategies. Future prospective multicenter studies incorporating urodynamic evaluations should validate these findings and further refine strategies for optimizing bladder management and graft outcomes in pediatric KT recipients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCompeting interests:\u003c/h2\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003ch2\u003eEthics approval:\u003c/h2\u003e\n\u003cp\u003eThis study was approved by the Ethics Committee of Toho University Omori Medical Center (Approval numbers: M24014 and M23233) and was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe requirement for informed consent was waived by the ethics committee owing to the retrospective study design.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003ch2\u003eFunding:\u003c/h2\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003ch2\u003eAuthors\u0026apos; contributions:\u003c/h2\u003e\n\u003cp\u003eYA designed the study. JH, M Maeda, and YH contributed to the data acquisition and analysis. YH, K Sakurabayashi, TY, YI, M Muramatsu, TK, SS, and K Saka contributed to data interpretation and critically revised the manuscript. YA wrote the first draft of the manuscript. All authors contributed to manuscript revision, read, and approved the final manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgments\u003c/h2\u003e\n\u003cp\u003eWe would like to thank Editage for English language editing.\u003c/p\u003e\n\u003ch2\u003eAvailability of data and material:\u003c/h2\u003e\n\u003cp\u003eThe datasets generated during and/or analysed during the current study are not publicly available due to ethical and privacy restrictions but are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMcDonald SP, Craig JC, Australian and New Zealand Paediatric Nephrology Association (2004) Long-term survival of children with end-stage renal disease. 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Can Urol Assoc J 12:378\u0026ndash;381. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5489/cuaj.5263\u003c/span\u003e\u003cspan address=\"10.5489/cuaj.5263\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pediatric-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pnep","sideBox":"Learn more about [Pediatric Nephrology](http://link.springer.com/journal/467)","snPcode":"467","submissionUrl":"https://www.editorialmanager.com/pnep/default2.aspx","title":"Pediatric Nephrology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Kidney transplantation, vesicourethral reflux, bladder capacity, anuria, expected bladder capacity, maximum bladder capacity","lastPublishedDoi":"10.21203/rs.3.rs-7076491/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7076491/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eKidney transplantation (KT) is the preferred treatment for pediatric end-stage kidney disease. However, vesicoureteral reflux (VUR) is a common occurrence post-KT. This single-center retrospective cohort study investigated bladder capacity changes, and identified post-transplant VUR predictors, in pediatric KT recipients.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003ePediatric patients with or without pre-transplant anuria (\u0026lt;\u0026thinsp;0.5 mL/kg/h) who underwent KT, from January 2009 to December 2023, were analyzed. Expected bladder capacity (EBC) was calculated based on age. Maximum bladder capacity (MBC) and post-transplant VUR presence were evaluated using voiding cystourethrography. Logistic regression was used to identify independent risk factors for post-transplant VUR. Receiver operating characteristic curve analysis was used to determine the predicted probability of post-transplant VUR.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eAmong 93 patients (males: 60%; median age: 6.1 [2.3\u0026ndash;17.7] years), 25 (26.9%) had pre-transplant anuria. Bladder capacity (from 37.5 to 120 mL; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and MBC/EBC ratio (from 19.7 to 62.3%; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) increased post-KT in only patients with anuria. Multivariate analyses revealed that pre-transplant MBC/EBC ratio predicted post-transplant VUR (odds ratio: 0.980, 95% confidence interval: 0.965\u0026ndash;0.996; p\u0026thinsp;=\u0026thinsp;0.006; sensitivity: 76.5%, specificity: 72.4%, area under the curve: 0.745 [cut-off: 57.8%]).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003ePre-transplant MBC/EBC ratio is a useful bladder capacity indicator and predicts post-transplant VUR in pediatric KT recipients.\u003c/p\u003e","manuscriptTitle":"Change in bladder capacity and prognostic predictors of post-transplant vesicoureteral reflux in pediatric kidney transplant recipients: a single-center retrospective cohort study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-15 11:10:34","doi":"10.21203/rs.3.rs-7076491/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-07-11T06:48:03+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-10T18:55:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-09T08:30:02+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pediatric Nephrology","date":"2025-07-08T11:45:13+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pediatric-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pnep","sideBox":"Learn more about [Pediatric Nephrology](http://link.springer.com/journal/467)","snPcode":"467","submissionUrl":"https://www.editorialmanager.com/pnep/default2.aspx","title":"Pediatric Nephrology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"32642694-13cd-49b8-8075-0eada3fff15f","owner":[],"postedDate":"July 15th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-15T16:00:27+00:00","versionOfRecord":{"articleIdentity":"rs-7076491","link":"https://doi.org/10.1007/s00467-025-07078-5","journal":{"identity":"pediatric-nephrology","isVorOnly":false,"title":"Pediatric Nephrology"},"publishedOn":"2025-12-08 15:56:54","publishedOnDateReadable":"December 8th, 2025"},"versionCreatedAt":"2025-07-15 11:10:34","video":"","vorDoi":"10.1007/s00467-025-07078-5","vorDoiUrl":"https://doi.org/10.1007/s00467-025-07078-5","workflowStages":[]},"version":"v1","identity":"rs-7076491","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7076491","identity":"rs-7076491","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}