Patients with end-stage renal disease (ESRD) who are on dialysis for a long time may experience bladder problems as their urine output decreases and normal bladder filling is lacking. As a result, bladder capacity may be reduced and compliance may deteriorate, which can impact the success of kidney transplantation.

Our prospective observational study is designed to investigate how dialysis duration and residual urine output (diuresis) influence bladder capacity and compliance in ESRD patients who are waiting for kidney transplantation. The adult patients undergoing regular dialysis will be assessed clinically, and they will also be subjected to laboratory tests, imaging, and urodynamic studies.

Through this study, we aim to determine the frequency of bladder malfunction and its correlation with the length of dialysis and the amount of urine excretion. The results might enhance the pre-transplant workup and offer a basis for urological post-transplantation management that could minimize complications.

End-stage renal disease (ESRD) is related to major changes in lower urinary tract functions, mainly due to decreased urine production and prolonged bladder inactivity during dialysis. Therefore, the bladder might shrink and get stiff, the muscle of the bladder can contract involuntarily, and other abnormalities of urine storage and voiding can be detected.

Such urodynamic changes have fairly good clinical relevance since impaired bladder function not only increases the susceptibility to urinary tract infections, but also to vesicoureteral reflux, and it can have negative effects on renal transplant outcomes.

Dialysis duration and loss of residual urine production capacity are recognized as the main factors affecting bladder function. Dialysis patients who have been on the treatment for a long time and are anuric will develop more bladder dysfunction and damage than those with preserved urine output.

This prospective observational study is planned to take place at Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan. Adult patients aged 18-65 years with end-stage renal disease on maintenance dialysis for 6 to 24 months and awaiting renal transplantation will be enrolled through consecutive sampling.

After getting the informed consents, demographic and clinical data will be recorded, such as age, gender, body mass index, cause of ESRD, duration of dialysis, and urine output, which will be measured by a frequency-volume chart. The initial work-up will include examination of the urine, urine culture, and ultrasound examination of the kidneys, ureters, and bladder with measurement of post-void residual volume.

All eligible patients will be further evaluated with cystoscopy, uroflowmetry, and video-urodynamic studies to assess bladder morphology and function. The main outcome variables are bladder capacity and bladder compliance, whereas secondary variables include maximum urinary flow rate (Qmax), post-void residual volume, and the presence of lower urinary tract symptoms.

The acquired data will be statistically analyzed using appropriate methods to identify possible relationships between dialysis duration, diuresis status, and bladder function parameters. This study is conducted with the aim to estimate the prevalence of clinically significant bladder dysfunction and to identify high-risk patients who may benefit from early urological intervention prior to renal transplantation.

Inclusion Criteria:

• Patients aged 18-65 years diagnosed with end-stage renal disease (ESRD)
• Patients on maintenance dialysis for a duration of 6 to 24 months
• ESRD secondary to non-urological causes
• Patients awaiting renal transplantation

Exclusion Criteria:

• Patients with diabetes mellitus
• Patients with neurogenic bladder
• Patients with prior urological surgeries
• Patients with active urinary tract infection
• Patients with pre-existing lower urinary tract symptoms before dialysis
• Patients on medications affecting lower urinary tract function
• Patients with neurological or systemic diseases affecting bladder function

Adult patients with end-stage renal disease (ESRD) on maintenance dialysis and awaiting renal transplantation at Sindh Institute of Urology and Transplantation (SIUT), Karachi.

Individual participant data (IPD) will not be shared due to patient confidentiality, institutional policies, and the absence of a formal data-sharing framework. All collected data will be securely stored and used only for the purposes of this study in accordance with ethical approval.