Outcomes of kidney‐transplanted patients with history of intestinal reconstruction of the urinary tract

Abstract Background Due to increased risk of pyelonephritis, patients with intestinal reconstruction of the lower urinary tract (IRLUT) have long been advised against kidney transplantation. The aim of this study was to compare the outcomes of transplantation between patients with IRLUT and patients with normal LUT (NLUT) using propensity score matching method. Methods The study included 23 kidney recipients with IRLUT matched to 46 kidney recipients with NLUT using known allograft survival and pyelonephritis risk factors as covariates. One‐, 5‐, and 10‐year graft survival, pyelonephritis, and surgical complications occurrence and graft function were compared. Results One‐, 5‐, and 10‐year graft survival were 96%, 91%, and 63% in the IRLUT group and 96%, 88%, and 70% in the NLUT group, respectively (p = 0.72). Patients with IRLUT had increased cumulative risk of pyelonephritis at 10 years (70% vs. 19%; log‐rank < 0.01) without impacting graft function or rejection occurrence. There was no difference in overall surgical complication, but patients with IRLUT had more urological complications than patients with NLUT (62% vs. 28%; p < 0.01). Conclusions Our case‐control study consolidates the results regarding the safety of transplantation in patients with IRLUT using a strong validated matching method and provides new insights regarding graft function, pyelonephritis, and surgical complications in this population.

and that of metabolic acidosis and an increased risk of lithiasis have been reported to be 70%. [7][8][9][10][11] These results have been reported in studies conducted in small cohorts or uncontrolled studies that did not adjust for potential risk factors known to impact allograft survival. [11][12][13][14] Our study aimed to report kidney allograft survival in patients who underwent LUT reconstruction for ESRD due to LUT abnormalities. Kidney transplant recipients who underwent intestinal reconstruction of the LUT (IRLUT) were matched to kidney transplant recipients without LUT abnormalities (NLUT) by the propensity score.
We compared patient and graft survival, surgical complications, the occurrence of pyelonephritis, and graft function between the two study groups.

| Study population
We included 26 consecutively treated patients who previously underwent IRLUT and underwent kidney transplantation between November 1, 2004 and September 1, 2016, at two French centers (Necker Hospital in Paris and Tours University Hospital). Reconstruction involved Bricker or Mitrofanoff deviation, with or without associated enterocystoplasty for malformations or urothelial cancer. We conducted a retrospective case-control study using propensity score matching. The controls were kidney transplanted patients with NLUTs selected from the Paris kidney transplant cohort.

| Clinical data
Data were retrieved from the Données Informatisées et VAlidées en Transplantation (DIVAT) (www.divat.fr) and ASTRE informatized databases. Missing data were individually collected from the patient files.
Patients provided written informed consent regarding data collection, data processing, and biopsy. Anonymous data exploitation was performed. Each patient from the present study provided written informed consent to be included in the DIVAT and ASTRE databases.

| Transplantation running
The transplantation allocation system was identical for both centers and followed the rules of the French national agency for organ procurement (Agence de la Biomédecine). All transplants were compatible based on the ABO blood group, and negative cytotoxicity cross matching for immunoglobulin G T cell and B cell complements was required for all recipients.

| Baseline characteristics of patients with a NLUT
Patients #16, #17, and #24 could not be matched according to the propensity score, so that we were able to match 23 IRLUT patients to 46 NLUT patients using the propensity scores and the criteria described in Section 2 (
T A B L E 2 Characteristics of the patients who underwent lower urinary tract (LUT) reconstruction (IRLUT) and patients with a normal LUT (NLUT) after matching

| Pyelonephritis episodes
More patients in the IRLUT group than in the NLUT group had at least one episode of pyelonephritis (65% vs. 17%, p < 0.01). The probability of having pyelonephritis at 10 years was 70% in the patients who underwent IRLUT and 19% in the patients with a NLUT (logrank < 0.01) (Figure 3). In the IRLUT group, 15 (Table 3B).

| Rejection
No significant difference between the two study groups was observed in the incidence of rejection episodes (p = 0.43). Seven Thus, pretransplant or peritransplant surgery to correct LUT remains the safest option for successful transplantation. 4,21,22 The optimal interval between reconstruction and transplantation has been debated, but most of the authors have recommended reconstruction before transplantation for improved patient education, bladder capacity with a saline physiologic solution and healing. 7,14,23,24 In our study, the median time between reconstruction and kidney transplantation was 31 months, which is longer than the interval described in previous studies, probably because the diagnosis and therapeutic strategies concerning LUT abnormalities have evolved over the past decades; moreover, the strategy probably should differ according to the time  Some other cofounding variables regarding allograft survival might thus be missing and induce interpretation bias. We tried to include in the score the most relevant ones so that our results remain interpretable.
To confirm our findings and expand our knowledge, our results should be confirmed by other studies, and studies should focus on identifying risk factors associated with poor outcomes using larger cohorts. Surgical techniques regarding the type of reconstruction, urological anastomosis and medical strategy regarding infection prophylaxis, and managing acidosis should be studied in detail.

| CONCLUSION
Our results confirm that renal transplantation is safe in patients who have undergone intestinal reconstruction of the low urinary tract in comparison to matched patients with a low urinary tract with normal function. However, this population has an increased risk of several complications warranting expert management and close follow-ups.