Urinary tract infection is one of the most common complications after kidney transplantation and is associated with increased morbidity, prolonged hospitalization, and impaired graft outcomes. The duration of urethral catheterization is a modifiable risk factor for catheter-associated urinary tract infection. This randomized controlled trial compares early catheter removal on postoperative day 3 with standard catheter removal on postoperative day 6 in living donor kidney transplant recipients. The primary objective is to determine whether early catheter removal reduces 30-day urinary tract infections without increasing urinary complications requiring intervention.

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# Detailed Description

Urinary tract infection (UTI) is among the most frequent complications following kidney transplantation and remains a major source of postoperative morbidity. Catheter-associated urinary tract infections (CAUTIs) account for a substantial proportion of these infections because urethral catheterization is routinely performed after transplantation to protect the ureterovesical anastomosis, ensure continuous bladder drainage, and facilitate monitoring of urine output during the early postoperative period. However, prolonged catheterization increases the risk of bacterial colonization and infection, which may result in symptomatic UTI, pyelonephritis, bacteremia, prolonged hospitalization, increased healthcare costs, and potentially adverse graft outcomes.

The optimal duration of urethral catheterization after kidney transplantation remains uncertain. Current practice varies considerably among transplant centers, with catheter removal occurring anywhere from postoperative day (POD) 1 to POD 7 or later. This variation reflects the lack of high-quality randomized evidence balancing the potential benefits of earlier catheter removal against concerns regarding urinary retention, urinary leak, ureteral complications, and the need for catheter reinsertion.

Several observational studies and small randomized trials have suggested that early catheter removal may substantially reduce the incidence of postoperative urinary tract infections without increasing clinically significant urological complications. Nevertheless, differences in patient populations, surgical techniques, catheter removal protocols, and outcome definitions have limited the generalizability of previous findings. Consequently, no international consensus exists regarding the optimal timing of catheter removal after kidney transplantation.

The EARLY-KTx trial is a prospective, single-center, randomized controlled trial designed to compare early urethral catheter removal with standard catheter removal following living donor kidney transplantation. Eligible participants will be randomly assigned in a 1:1 ratio to undergo catheter removal either on postoperative day 3 (experimental group) or postoperative day 6 (standard care group). The study uses an open-label design because catheter removal timing cannot be concealed from participants or treating clinicians; however, whenever feasible, outcome assessment and data analysis will be performed by investigators blinded to treatment allocation (Prospective Randomized Open-label Blinded Endpoint [PROBE] design).

All participants will undergo standardized kidney transplantation using the institutional surgical technique, including ureteroneocystostomy with routine double-J ureteral stent placement, standardized perioperative antimicrobial prophylaxis, and standardized postoperative care. Both study groups will receive identical perioperative management, differing only in the timing of urethral catheter removal.

The primary objective is to determine whether early catheter removal reduces the incidence of urinary tract infection within 30 days after transplantation without increasing clinically significant urinary complications. The primary efficacy outcome is the incidence of microbiologically confirmed urinary tract infection, including asymptomatic bacteriuria, symptomatic urinary tract infection, complicated urinary tract infection, or transplant pyelonephritis occurring within 30 days after transplantation. The primary safety outcome is the occurrence of urinary complications requiring intervention, including urinary leak, ureteral stenosis, or other complications requiring catheter reinsertion, ureteral stenting, nephrostomy, or surgical intervention.

Secondary outcomes include urinary retention requiring recatheterization, postoperative pain, voiding symptoms, patient satisfaction, length of hospital stay, graft function assessed by serum creatinine, postoperative complications, reoperation, healthcare utilization, and cost-effectiveness. Participants will be followed for 12 months after transplantation to evaluate both early postoperative outcomes and medium-term graft and urological outcomes.

The findings of this trial are expected to provide high-quality evidence regarding the optimal timing of urethral catheter removal after kidney transplantation. If early catheter removal is shown to reduce infectious complications without compromising patient safety, the results may contribute to standardization of postoperative management protocols and improve outcomes for kidney transplant recipients.

Inclusion

Age ≥18 years Living donor kidney transplantation Pre-emptive kidney transplantation Preserved urine output Ability to provide written informed consent

Exclusion

Previous bladder or urethral surgery Complex urinary tract reconstruction Neurogenic bladder Active urinary tract infection at transplantation Pregnancy BMI <18 or >40 kg/m² Intraoperative blood loss >1000 mL

De-identified individual participant data (IPD) underlying the results reported in the primary publication, including demographic characteristics, baseline clinical variables, intervention assignment, primary and secondary outcome measures, and the study data dictionary, will be made available to qualified researchers upon reasonable request. Data will be shared only after publication of the primary study results, following approval by the study investigators and Rabin Medical Center, execution of an appropriate data use agreement, and confirmation that the proposed use is scientifically and ethically appropriate. All shared data will be fully de-identified in accordance with applicable privacy regulations and institutional policies.

Beginning 6 months after publication of the primary manuscript.

Access to de-identified individual participant data (IPD) and supporting study documents will be available to qualified researchers who submit a scientifically sound research proposal. Requests must be submitted to the Principal Investigator and approved by the study investigators and Rabin Medical Center in accordance with institutional policies. Approved investigators will receive access to the de-identified dataset, study protocol, statistical analysis plan, and data dictionary after execution of a Data Use Agreement (DUA) and any required ethics approvals. Data will be provided through a secure electronic transfer or institutional data-sharing platform and may be used only for the purposes described in the approved proposal.

The intervention cannot be blinded because catheter removal timing is apparent to participants and treating clinicians. Outcome assessment will be performed by investigators blinded to treatment allocation whenever feasible.