Acute urinary retention (AUR) is a significant urological emergency characterized by the sudden and often painful inability to achieve voluntary micturition despite a distended urinary bladder. It represents a major cause of emergency urological admissions, particularly among elderly men, and is associated with considerable morbidity if not promptly managed. Immediate bladder decompression through urethral catheterization remains the standard initial intervention to relieve discomfort, prevent progressive bladder damage, and reduce the risk of complications including urinary tract infection, excessive bladder distension, upper urinary tract deterioration, and renal impairment (1,2). The incidence of AUR increases considerably with advancing age, reflecting the increasing prevalence of underlying lower urinary tract disorders among older males (3).

Benign prostatic hyperplasia (BPH) is recognized as the most common underlying cause of AUR in aging men. Histological changes consistent with BPH begin to develop in middle age, with approximately half of men demonstrating evidence of prostatic enlargement by the sixth decade and prevalence increasing to nearly 80–90% among men over 80 years of age (4,5). Progressive enlargement of the prostate contributes to bladder outlet obstruction through increased urethral resistance, elevated intravesical pressure, and compensatory changes in bladder function. Over time, persistent obstruction may lead to detrusor muscle hypertrophy, impaired contractility, incomplete bladder emptying, and ultimately acute urinary retention (6). Epidemiological studies have demonstrated that men with untreated BPH carry a substantial lifetime risk of developing AUR, estimated at approximately 20–25%, highlighting retention as one of the most clinically important complications of progressive prostatic disease (7).

The conventional management of AUR involves immediate catheterization followed by assessment for definitive treatment of the underlying cause. Historically, many patients underwent early surgical intervention after an episode of retention; however, advances in pharmacological treatment, improved understanding of disease progression, and recognition of the potential for recovery of bladder function have shifted clinical practice toward initial conservative management using Trial Without Catheter (TWOC) before considering surgical options (8,9). TWOC provides an opportunity to assess whether bladder function can recover following decompression and whether spontaneous voiding can be achieved after temporary relief of obstruction. Successful TWOC may allow patients to avoid repeated catheterization, reduce hospital admissions, and delay or prevent surgical intervention in appropriately selected individuals (10).

Pharmacological optimization plays an important role in improving TWOC outcomes. Alpha-adrenergic receptor antagonists reduce smooth muscle tone within the prostate and bladder neck, thereby decreasing bladder outlet resistance and improving urinary flow. Several experimental and systematic reviews have demonstrated that initiation of alpha-blocker therapy before catheter removal significantly increases the probability of successful TWOC compared with no medical therapy (11–14). Consequently, current international guidelines recommend commencing alpha-blockers following catheterization in suitable patients presenting with AUR secondary to BPH to improve the likelihood of successful catheter removal (15).

Despite widespread acceptance of TWOC as a standard management strategy, the optimal duration of catheterization before attempting catheter removal remains uncertain. Early TWOC, commonly performed within 24 hours of catheter placement, offers several potential advantages, including improved patient comfort, reduced duration of hospital stay, decreased catheter-associated infection risk, and lower healthcare costs (16). However, premature catheter removal may occur before adequate recovery of detrusor function, resulting in persistent bladder outlet obstruction, incomplete bladder emptying, and increased likelihood of TWOC failure requiring re-catheterization (17).

Conversely, delayed TWOC, generally performed after 3–7 days of catheterization, may provide additional time for bladder decompression, restoration of detrusor contractility, and maximal therapeutic effect of alpha-blocker medication. Several studies have suggested that delayed catheter removal may improve spontaneous voiding rates and reduce treatment failure. However, prolonged catheterization is not without disadvantages and may increase the risk of catheter-associated urinary tract infection, urethral trauma, hematuria, discomfort, and reduced quality of life (18). Therefore, determining the appropriate balance between allowing sufficient bladder recovery and minimizing catheter-related complications remains a clinically important challenge.

Previous studies investigating the optimal timing of TWOC have reported inconsistent findings due to differences in study design, patient characteristics, duration of catheterization, use of concomitant medical therapy, and variations in definitions of successful catheter removal (19). Furthermore, evidence from South Asian populations remains limited, despite potential differences in patient demographics, healthcare facilities, disease presentation, and treatment practices compared with Western populations. The absence of strong regional evidence limits the ability to establish universally applicable recommendations for clinical practice (20).

Therefore, the present Quasi-experimental study  was conducted to compare the outcomes of TWOC performed after 24 hours versus after 5 days of catheterization in patients presenting with acute urinary retention secondary to benign prostatic hyperplasia. By evaluating successful catheter removal, re-catheterization rates, and catheter-related complications, this study aims to provide evidence regarding the optimal timing of TWOC and contribute to improved patient selection, better clinical decision-making, and reduction of unnecessary catheter-related morbidity.

This prospective, parallel-group, Quasi-experimental study was conducted in the Department of Urology, Institute of kidney diseases, Hayatabad Medical Complex, Peshawar, Pakistan, over a six-month period following approval (Ref no: 701/chairman/R&E/Committee/IKD) from the Institutional Ethical Review Committee and the College of Physicians and Surgeons Pakistan (CPSP). The study was designed to compare the outcomes of Trial Without Catheter (TWOC) performed after 24 hours versus after 5 days of urethral catheterization in patients presenting with acute urinary retention (AUR) secondary to benign prostatic hyperplasia (BPH). The sample size was calculated using the WHO Sample Size Calculator for comparing two independent proportions. Based on previously reported TWOC success rates of 45% for early catheter removal and 62% for delayed catheter removal, with a confidence level of 95%, study power of 80%, and an equal allocation ratio (1:1), the minimum required sample size was calculated as 76 participants, with 38 patients allocated to each study group. Male patients aged 50–80 years presenting with the first episode of acute urinary retention secondary to ultrasound-confirmed benign prostatic hyperplasia were eligible for inclusion. Patients with previous prostatic surgery, recurrent urinary retention, urethral stricture or trauma, urinary tract infection, neurogenic bladder dysfunction, or known bladder or prostate malignancy were excluded from the study. Consecutive eligible patients who provided written informed consent were enrolled until the required sample size was achieved. Following admission, all patients underwent immediate bladder decompression with a Foley urethral catheter. Participants were assigned to one of two intervention groups based on the predefined TWOC timing protocol. Group A underwent trial without catheter (TWOC) after 24 hours, whereas Group B underwent TWOC after 5 days. Since this was a quasi-experimental design, allocation was based on the study protocol rather than randomization. Baseline demographic and clinical characteristics were recorded to assess comparability between the groups. Outcome assessment was performed using standardized criteria, including successful spontaneous voiding without the need for re-catheterization, post-void residual urine volume, and catheter-related complications. To minimize assessment bias, outcome measurements were conducted using consistent evaluation procedures throughout the study period. All clinically relevant events were documented, and patient safety was ensured through appropriate monitoring and management during follow-up. Baseline demographic and clinical information including age, body weight, height, body mass index (BMI), educational status, occupation, marital status, prostate size measured by ultrasonography, first episode of AUR, alpha-blocker use, and post-void residual urine volume were recorded using a standardized proforma. Patients assigned to Group A underwent catheter removal after 24 hours, whereas those allocated to Group B underwent catheter removal after five days. Alpha-blocker therapy was administered according to the institutional management protocol during the catheterization period. Following catheter removal, all patients were observed for six hours to assess spontaneous voiding. Successful TWOC was defined as spontaneous voiding of at least 150 mL without requiring re-catheterization, whereas failure was defined as inability to void or a post-void residual urine volume of ≥150 mL requiring repeat catheterization. Secondary outcomes included residual urine volume, re-catheterization, and catheter-related complications, including hematuria and urinary tract infection. Data were collected prospectively by the principal investigator under the supervision of a consultant urologist with more than five years of post-fellowship experience using a standardized data collection form. Data analysis was performed using IBM SPSS Statistics version 26. The distribution of continuous variables was assessed using the Shapiro–Wilk test. Normally distributed variables were summarized as mean ± standard deviation (SD) and compared using the independent-samples t-test, whereas non-normally distributed variables were expressed as median (interquartile range) and compared using the Mann–Whitney U test. Categorical variables were presented as frequencies and percentages and compared using the Chi-square test or Fisher's exact test, as appropriate. Variables demonstrating clinical relevance or a univariate p-value <0.20 were entered into a multivariable logistic regression model to identify independent predictors of successful TWOC. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were reported. Model calibration was assessed using the Hosmer–Lemeshow goodness-of-fit test, while predictive performance was evaluated using Nagelkerke's R² and overall classification accuracy. A two-sided p-value of <0.05 was considered statistically significant. All participants provided written informed consent prior to enrollment. The study was conducted in accordance with the ethical principles of the Declaration of Helsinki, and patient confidentiality was maintained by anonymizing all collected data before statistical analysis.

A total of 76 male patients with first-episode acute urinary retention secondary to benign prostatic hyperplasia were enrolled and randomized equally into two study groups. Group A (n = 38) underwent Trial Without Catheter (TWOC) after 24 hours of catheterization, whereas Group B (n = 38) underwent TWOC after 5 days. All participants completed the study, and no missing data or loss to follow-up was observed.

The mean age of the study population was comparable between the two groups (65.4 ± 7.4 years vs. 66.1 ± 7.3 years, p=0.685). Similarly, no statistically significant differences were observed in body mass index or prostate volume, indicating adequate baseline comparability. However, alpha-blocker therapy was more frequently administered in the delayed TWOC group (100.0%) than in the early TWOC group (57.9%, p<0.001) (Table 1).

Table 1. Baseline demographic and clinical characteristics

Independent-samples t-test for continuous variables and Chi-square test for categorical variables.

The primary outcome analysis demonstrated that delayed catheter removal significantly improved the success of TWOC. Successful spontaneous voiding was achieved in 30 patients (78.9%) in the 5-day group compared with 20 patients (52.6%) in the 24-hour group (p=0.015). Likewise, the need for re-catheterization was significantly lower among patients undergoing delayed TWOC (21.1% vs. 47.4%, p=0.015). Although catheter-related complications occurred less frequently following delayed catheter removal (21.1% vs. 31.6%), the difference was not statistically significant (p=0.306) (Table 2).

Table 2. Comparison of primary and secondary outcomes

Chi-square test.

In univariate analysis, prostate size, alpha-blocker therapy, and delayed catheter removal were significantly associated with successful TWOC. After multivariable adjustment, smaller prostate size (aOR 0.94, 95% CI 0.90–0.98; p=0.006) and alpha-blocker therapy (aOR 3.12, 95% CI 1.05–9.28; p=0.041) remained independent predictors of successful TWOC, whereas the association with delayed catheter removal narrowly missed statistical significance (aOR 2.85, 95% CI 0.98–8.30; p=0.055). Age and BMI were not significantly associated with TWOC success (Table 3).

Table 3. Logistic regression analysis for predictors of successful TWOC

Model performance: Hosmer– Lemeshow χ²=6.32 (p=0.612); Nagelkerke R²=0.342; overall classification accuracy=73.7%.

Subgroup analysis demonstrated that delayed TWOC was particularly beneficial among older patients (≥65 years) and those with larger prostate volumes (≥50 cc). Among patients aged ≥65 years, successful TWOC increased from 42.1% in the 24-hour group to 75.0% in the 5-day group (p=0.042). Similarly, in patients with prostate volumes ≥50 cc, delayed catheter removal significantly improved successful voiding (66.7% vs. 35.0%, p=0.043). No statistically significant interaction was observed among younger patients or those with smaller prostate volumes (Table 4).

Table 4. Stratified subgroup analysis of TWOC success

A total of 76 male patients with first-episode acute urinary retention secondary to benign prostatic hyperplasia were enrolled and randomized equally into two study groups. Group A (n = 38) underwent Trial Without Catheter (TWOC) after 24 hours of catheterization, whereas Group B (n = 38) underwent TWOC after 5 days. All participants completed the study, and no missing data or loss to follow-up was observed.

The mean age of the study population was comparable between the two groups (65.4 ± 7.4 years vs. 66.1 ± 7.3 years, p=0.685). Similarly, no statistically significant differences were observed in body mass index or prostate volume, indicating adequate baseline comparability. However, alpha-blocker therapy was more frequently administered in the delayed TWOC group (100.0%) than in the early TWOC group (57.9%, p<0.001) (Table 1).

Table 1. Baseline demographic and clinical characteristics

Independent-samples t-test for continuous variables and Chi-square test for categorical variables.

The primary outcome analysis demonstrated that delayed catheter removal significantly improved the success of TWOC. Successful spontaneous voiding was achieved in 30 patients (78.9%) in the 5-day group compared with 20 patients (52.6%) in the 24-hour group (p=0.015). Likewise, the need for re-catheterization was significantly lower among patients undergoing delayed TWOC (21.1% vs. 47.4%, p=0.015). Although catheter-related complications occurred less frequently following delayed catheter removal (21.1% vs. 31.6%), the difference was not statistically significant (p=0.306) (Table 2).

Table 2. Comparison of primary and secondary outcomes

Chi-square test.

In univariate analysis, prostate size, alpha-blocker therapy, and delayed catheter removal were significantly associated with successful TWOC. After multivariable adjustment, smaller prostate size (aOR 0.94, 95% CI 0.90–0.98; p=0.006) and alpha-blocker therapy (aOR 3.12, 95% CI 1.05–9.28; p=0.041) remained independent predictors of successful TWOC, whereas the association with delayed catheter removal narrowly missed statistical significance (aOR 2.85, 95% CI 0.98–8.30; p=0.055). Age and BMI were not significantly associated with TWOC success (Table 3).

Table 3. Logistic regression analysis for predictors of successful TWOC

Model performance: Hosmer– Lemeshow χ²=6.32 (p=0.612); Nagelkerke R²=0.342; overall classification accuracy=73.7%.

Subgroup analysis demonstrated that delayed TWOC was particularly beneficial among older patients (≥65 years) and those with larger prostate volumes (≥50 cc). Among patients aged ≥65 years, successful TWOC increased from 42.1% in the 24-hour group to 75.0% in the 5-day group (p=0.042). Similarly, in patients with prostate volumes ≥50 cc, delayed catheter removal significantly improved successful voiding (66.7% vs. 35.0%, p=0.043). No statistically significant interaction was observed among younger patients or those with smaller prostate volumes (Table 4).

Table 4. Stratified subgroup analysis of TWOC success

The present Quasi-experimental study compared the outcomes of Trial Without Catheter (TWOC) performed after 24 hours and after 5 days of urethral catheterization in patients presenting with acute urinary retention (AUR) secondary to benign prostatic hyperplasia (BPH). The principal finding of this study was that delaying TWOC for five days significantly improved the likelihood of successful spontaneous voiding while reducing the requirement for re-catheterization compared with catheter removal after 24 hours. These findings suggest that a longer period of catheterization allows better recovery of bladder function and enhances the therapeutic effect of medical management before catheter removal. The overall success rate of TWOC was significantly greater in the delayed catheterization group (78.9%) than in the early catheterization group (52.6%). This observation is consistent with previous studies demonstrating that delayed catheter removal improves the probability of successful voiding by allowing temporary recovery of detrusor contractility following acute bladder overdistension (21,22). Christensen et al. reported that delaying TWOC was associated with higher spontaneous voiding rates than immediate catheter removal, although the optimal duration of catheterization varied across studies (23). Likewise, the systematic review by Yoon et al. concluded that prolonged catheterization combined with medical therapy improves TWOC success while decreasing early treatment failure (24). Our findings support these observations and provide additional evidence from a randomized controlled design conducted in a South Asian population. The higher success observed after delayed catheter removal is biologically plausible because temporary bladder decompression facilitates recovery of detrusor contractility while allowing adequate time for alpha-blockers to reduce bladder outlet resistance. A possible explanation for the higher success rate observed after five days is the physiological recovery of bladder function following acute urinary retention. Bladder overdistension during AUR may transiently impair detrusor muscle contractility because of ischemia, edema, and alterations in neuromuscular transmission. Maintaining bladder drainage for several days reduces intravesical pressure, promotes recovery of detrusor function, and improves subsequent voiding efficiency (25). Furthermore, prolonged catheterization provides sufficient time for alpha-adrenergic antagonists to relax smooth muscle within the prostate and bladder neck, thereby decreasing bladder outlet resistance before catheter removal (26). An important finding of the present study was the significantly lower rate of re-catheterization in the delayed TWOC group. Nearly half of the patients undergoing catheter removal after 24 hours required repeat catheterization, whereas only one-fifth of patients in the delayed group experienced TWOC failure (27). Re-catheterization is associated with increased patient discomfort, greater healthcare utilization, repeated emergency visits, and a higher likelihood of subsequent surgical intervention (28). Therefore, improving the initial success of TWOC may provide meaningful clinical and economic benefits for both patients and healthcare systems. Although catheter-related complications occurred less frequently in the delayed TWOC group, the difference did not reach statistical significance (29). Catheter-associated urinary tract infection and hematuria remain recognized complications of prolonged urethral catheterization (28). However, careful catheter care, adherence to aseptic techniques, and minimizing unnecessary catheter manipulation may substantially reduce these risks (30). Our findings indicate that the modest increase in catheterization duration did not result in a clinically important increase in complications, suggesting that the improved TWOC success outweighs the potential disadvantages of delayed catheter removal. Multivariable logistic regression identified prostate size as an independent predictor of successful TWOC. Increasing prostate volume was associated with progressively lower odds of spontaneous voiding after catheter removal. This finding is biologically plausible because larger prostates produce greater bladder outlet obstruction and higher urethral resistance, thereby reducing urinary flow even after temporary decompression (31). Similar associations have been reported in previous observational studies and systematic reviews, where prostate volume consistently predicted failure of conservative management following AUR (32,31). Alpha-blocker therapy also independently predicted successful TWOC in the present study. Patients receiving alpha-blockers were more likely to void successfully than those who did not receive medical therapy. These findings are consistent with several Quasi-experimental study s demonstrating that alpha-adrenergic antagonists significantly improve TWOC success by reducing smooth muscle tone within the prostate and bladder neck (34,35). Current European Association of Urology and American Urological Association guidelines recommend initiating alpha-blocker therapy immediately after catheterization in patients with AUR secondary to BPH because of its established clinical benefit (36). Subgroup analysis demonstrated that delayed TWOC was particularly advantageous among patients aged 65 years or older and those with prostate volumes of at least 50 cc (37). Elderly patients frequently exhibit impaired detrusor contractility, reduced bladder compliance, and more advanced bladder outlet obstruction, making additional recovery time before catheter removal especially beneficial (38). Likewise, patients with larger prostates generally experience greater obstruction and therefore derive greater benefit from prolonged decompression and pharmacological therapy. Although subgroup analyses should be interpreted cautiously because of limited statistical power, these observations may assist clinicians in selecting patients who are most likely to benefit from delayed TWOC (39). The findings of the present study have several important clinical implications. In many institutions, TWOC is attempted within 24 hours to reduce hospital stay and improve patient convenience. However, our results suggest that delaying catheter removal to five days significantly improves treatment success without substantially increasing catheter-related complications. Adoption of this strategy may reduce repeated catheterization, avoid unnecessary emergency visits, postpone or prevent surgery in selected patients, and improve overall patient satisfaction. These findings may therefore contribute to optimization of local clinical protocols for the management of AUR secondary to BPH. The strengths of this study include its study design, equal allocation of participants between study groups, standardized outcome assessment, and application of multivariable logistic regression to identify independent predictors of successful TWOC. The absence of missing data and complete follow-up further strengthened the internal validity of the study. Nevertheless, several limitations should be acknowledged. The study was conducted at a single tertiary care center with a relatively modest sample size, which may limit the generalizability of the findings. In addition, alpha-blocker therapy was more frequently administered in the delayed TWOC group. Although multivariable logistic regression was performed to adjust for this difference, residual confounding cannot be completely excluded. Long-term outcomes, including recurrence of urinary retention, progression to surgical intervention, and quality-of-life measures, were not evaluated. Furthermore, although assessor blinding was maintained, participant blinding was not feasible because of the nature of the intervention. Future multicenter randomized trials with larger populations and longer follow-up are warranted. In conclusion, the findings of this Quasi-experimental study indicate that delaying Trial Without Catheter to five days significantly improves spontaneous voiding success and reduces the need for re-catheterization compared with TWOC performed after 24 hours. Smaller prostate volume and alpha-blocker therapy were identified as independent predictors of successful catheter removal. These results support delayed TWOC as an effective conservative management strategy for patients presenting with acute urinary retention secondary to benign prostatic hyperplasia and may help guide future evidence-based clinical practice.

This Quasi-experimental study demonstrates that delayed Trial Without Catheter (TWOC) performed after five days of urethral catheterization provides superior outcomes compared with early TWOC after 24 hours in patients presenting with acute urinary retention secondary to benign prostatic hyperplasia. Patients undergoing delayed catheter removal achieved a significantly higher rate of successful spontaneous voiding and required fewer episodes of re-catheterization, suggesting improved recovery of bladder function and enhanced response to conservative management. Although prolonged catheterization carries potential risks, including catheter-associated urinary tract infection, hematuria, and patient discomfort, no significant increase in complications was observed in the five-day TWOC group. The findings indicate that extending catheterization for a short period may provide sufficient time for detrusor recovery and pharmacological optimization, particularly with alpha-blocker therapy. Multivariable analysis identified smaller prostate volume and alpha-blocker use as independent predictors of successful TWOC, emphasizing the importance of patient selection when planning catheter removal. Subgroup analysis further suggested that elderly patients and individuals with larger prostate volumes may particularly benefit from delayed TWOC. Therefore, delayed TWOC after five days may be considered an effective and safe conservative strategy for appropriately selected patients with AUR secondary to BPH. Larger multicenter studies with longer follow-up are recommended to validate these findings and assess long-term outcomes, including recurrence of urinary retention and the need for surgical intervention.

AUTHOR CONTRIBUTIONS

Concept and study design: Muhammad Ayaz Khan, Muhammad Kamran Khan

Data collection: Muhammad Ayaz Khan

Data analysis and interpretation: Muhammad Ayaz Khan

Manuscript drafting: Muhammad Ayaz Khan

Critical revision of the manuscript: Muhammad Kamran Khan

Final approval of the manuscript: All authors.

ACKNOWLEDGMENTS

The authors sincerely acknowledge the Department of Urology, Hayatabad Medical Complex, Peshawar, for providing the facilities required to conduct this study. We also thank all patients who voluntarily participated in this research.