The diagnosis of benign prostatic obstruction: Development of a clinical nomogram

Building Dual AI Models and Nomograms Using Noninvasive Parameters for Aiding Male Bladder Outlet Obstruction Diagnosis and Minimizing the Need for Invasive Video-Urodynamic Studies: Development and Validation Study

BACKGROUND

Diagnosing underlying causes of nonneurogenic male lower urinary tract symptoms associated with bladder outlet obstruction (BOO) is challenging. Video-urodynamic studies (VUDS) and pressure-flow studies (PFS) are both invasive diagnostic methods for BOO. VUDS can more precisely differentiate etiologies of male BOO, such as benign prostatic obstruction, primary bladder neck obstruction, and dysfunctional voiding, potentially outperforming PFS.

OBJECTIVE

These examinations' invasive nature highlights the need for developing noninvasive predictive models to facilitate BOO diagnosis and reduce the necessity for invasive procedures.

METHODS

We conducted a retrospective study with a cohort of men with medication-refractory, nonneurogenic lower urinary tract symptoms suspected of BOO who underwent VUDS from 2001 to 2022. In total, 2 BOO predictive models were developed-1 based on the International Continence Society's definition (International Continence Society-defined bladder outlet obstruction; ICS-BOO) and the other on video-urodynamic studies-diagnosed bladder outlet obstruction (VBOO). The patient cohort was randomly split into training and test sets for analysis. A total of 6 machine learning algorithms, including logistic regression, were used for model development. During model development, we first performed development validation using repeated 5-fold cross-validation on the training set and then test validation to assess the model's performance on an independent test set. Both models were implemented as paper-based nomograms and integrated into a web-based artificial intelligence prediction tool to aid clinical decision-making.

RESULTS

Among 307 patients, 26.7% (n=82) met the ICS-BOO criteria, while 82.1% (n=252) were diagnosed with VBOO. The ICS-BOO prediction model had a mean area under the receiver operating characteristic curve (AUC) of 0.74 (SD 0.09) and mean accuracy of 0.76 (SD 0.04) in development validation and AUC and accuracy of 0.86 and 0.77, respectively, in test validation. The VBOO prediction model yielded a mean AUC of 0.71 (SD 0.06) and mean accuracy of 0.77 (SD 0.06) internally, with AUC and accuracy of 0.72 and 0.76, respectively, externally. When both models' predictions are applied to the same patient, their combined insights can significantly enhance clinical decision-making and simplify the diagnostic pathway. By the dual-model prediction approach, if both models positively predict BOO, suggesting all cases actually resulted from medication-refractory primary bladder neck obstruction or benign prostatic obstruction, surgical intervention may be considered. Thus, VUDS might be unnecessary for 100 (32.6%) patients. Conversely, when ICS-BOO predictions are negative but VBOO predictions are positive, indicating varied etiology, VUDS rather than PFS is advised for precise diagnosis and guiding subsequent therapy, accurately identifying 51.1% (47/92) of patients for VUDS.

CONCLUSIONS

The 2 machine learning models predicting ICS-BOO and VBOO, based on 6 noninvasive clinical parameters, demonstrate commendable discrimination performance. Using the dual-model prediction approach, when both models predict positively, VUDS may be avoided, assisting in male BOO diagnosis and reducing the need for such invasive procedures.

Is there a best timing for benign prostatic hyperplasia surgery?

INTRODUCTION

Treatment of lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH) has shifted over the last decades, with medical therapy becoming the primary treatment modality while surgery is being reserved mostly to patients who are not responding to medical treatment or presenting with complications from BPH. Here, we aim to to discuss the optimal timing of surgical management of LUTS/BPH.

MATERIALS AND METHODS

A literature search was conducted on Pub-Med/MEDLINE database to identify reports published from January 1990 until January 2022 by combining the following MeSH terms: "Lower Urinary Tract Symptoms"; "Prostatic Hyperplasia"; "Prostatic Hyperplasia/therapy"; "Prostatic Hyperplasia/complications"; "Treatment Outcome"; "Time-to-Treatment". Evidence supporting or not early surgical treatment of BPH was examined and reported in a pros and cons form.

RESULTS

The "pro early surgery" highlighted the superior efficacy and cost-effectiveness of surgery over medical treatment for BPH, as well as the possibility of worse postoperative outcomes for delayed surgical treatment. The "con early surgery" considered that medical therapy is efficient in well-selected patients and can avoid the serious risks inherent to surgical treatment of BPH including important sexual side effects.

CONCLUSIONS

Clinical trials comparing the outcomes for prolonged medical therapy versus early surgical treatment could determine which approach is more beneficial in the long-term in context of the aging population. Until then, both approaches have their advantages and patients should be involved in the treatment decision.

Post-voided residual urine ratio as a predictor of bladder outlet obstruction in men with lower urinary tract symptoms: development of a clinical nomogram

PURPOSE

To confirm the correlation between post-void residual urine ratio (PVR-R) and BOO diagnosed by pressure-flow studies (PFS) in males with lower urinary tract symptoms (LUTS) and to develop a clinical nomogram.

METHODS

A consecutive series of patients aged 45 years or older with non-neurogenic LUTS were prospectively enrolled. Patients underwent standard diagnostic assessment for BOO including International Prostatic Symptoms Score, uroflowmetry, urodynamic studies, suprapubic ultrasound of the prostate, and ultrasound measurements of the bladder wall thickness (BTW). PVR-R was defined as follows: PVR-R = (PVR/total Bladder Volume [BV]) × 100). Logistic regression analysis was used to investigate predictors of pathological bladder emptying (BOO) defined as Schafer > II. A nomogram to predict BOO based on the multivariable logistic regression model was then developed.

RESULTS

Overall 335 patients were enrolled. Overall, 131/335 (40%) presented BOO on PFS. In a multivariable logistic age-adjusted regression model BWT (odds ratio [OR]: 2.21 per mm; 95% confidence interval [CI], 1.57-3.09; p = 0.001), PVR-R (OR: 1.02 per %; 95% CI, 1.01-1.03; p = 0.034) and prostate volume (OR: 0.97 per mL; 95% CI, 0.95-0.98; p = 0.001) were significant predictors for BOO. The model presented an accuracy of 0.82 and a clinical net benefit in the range of 10-90%.

CONCLUSIONS

The present study confirms the important role of PVR-ratio in the prediction of BOO. For the first time, we present a clinical nomogram including PVR-ratio for the prediction of BOO.

A Novel Nomogram Based on Initial Features to Predict BPH Progression

Objectives: The aim of this study was to establish a tool to identify patients at risk for pharmaceutical and surgical interventions for benign prostatic hyperplasia (BPH)-related lower urinary tract symptoms (LUTS) over a 10 year follow-up. Methods: The data of patients with mild to moderate male LUTS undergoing phytotherapy from January to December 2010 were reviewed. Patients were followed for 10 years through medical visits and telephone consultations. The outcomes were (1) treatment switch from phytotherapy or no therapy to alpha-blockers or 5α-reductase inhibitors (5-ARI), and (2) clinical progression (acute urinary retention or need for surgery). Two calibrated nomograms (one for each outcome) were constructed on significant predictors at multivariate analysis. Results: A total of 107 patients with a median age of 55 years at presentation were included; 47% stopped or continued phytotherapy, while 53% switched to alpha-blockers and/or 5-ARI after a median time of 24 months. One-third in the second group experienced clinical progression after a median time of 54 months. Age, symptom score, peak flow rate (Qmax), prostate-specific antigen (PSA), and post-void residual volume were significantly associated with the outcomes. According to our nomograms, patients switching therapy or progressing clinically had average scores of 75% and 40% in the dedicated nomograms, respectively, as compared to 25% and <5% in patients who did not reach any outcome. Conclusions: We developed a nomogram to predict the risk of pharmaceutical or surgical interventions for BPH-related LUTS at 10 years from presentation. On the basis of our models, thresholds of >75% and >40% for high risk and <25% and <5% for low risk of pharmaceutical or surgical interventions, respectively, can be proposed.

Presurgical bladder wall thickness is a useful marker to predict the postsurgical improvement of symptoms in patients with pelvic organ prolapse-related overactive bladder

Objectives

Pelvic organ prolapse (POP) is a cause of overactive bladder (OAB), and transvaginal mesh (TVM) surgery can improve the symptoms. Bladder wall thickness (BWT) is a useful and safe marker to evaluate bladder function in urinary disorders. The main purpose of this study is to clarify the relationship between BWT and changes in the OAB symptom score (OABSS) after TVM operation in patients with POP.

Methods

BWT was measured by ultrasonography before and 6 months after surgery at three sites in the bladder: the anterior wall, trigone, and dome. Similarly, the OABSS was evaluated at the time of BWT measurement. Changes induced in BWT at each site and the mean BWT at all sites after TVM surgery were analyzed. Similarly, the relationship between presurgical BWT and the decrease in OABSS was investigated.

Results

TVM surgery improved OABSS in 30 patients (responders; 73.2%), while 11 patients were judged as nonresponders (26.8%). BWT at the anterior bladder wall and dome as well as the mean BWT at all three sites were significantly decreased by TVM surgery (P < .001). Similar trends were identified in OABSS responders; however, all markers showed no significant changes in OABSS nonresponders. All the BWT‐related markers before surgery were significantly lower in OABSS responders than in OABSS nonresponders.

Conclusions

BWT at the bladder anterior wall and dome, but not the trigone, were decreased by TVM surgery. We conclude that presurgical BWT may be a useful marker to predict the improvement in OAB symptoms by TVM surgery in patients with POP‐related OAB.

Phamacological treatment of persistant lower urinary tract symptoms after a transurethral resection of the prostate is predictive of a new surgical treatment: 10 years follow-up study

AIM

To evaluate possible risk factors of re intervention in patients with benign prostatic enlargement (BPE) undergoing transurethral resection of the prostate (TURP).

MATERIALS AND METHODS

A consecutive series of patients with LUTS and BPE underwent TURP in our center in 2004 and 2005 and they were then followed up to September 2016. Patients were assessed at baseline, 3-, 6-month postoperatively and yearly thereafter with medical history, international prostate symptom score, prostate specific antigen, maximal urinary flow rate, post void residual urine. Reoperation was defined as the requirement of a new TURP to relieve bothersome LUTS. Cox regression was used to determine covariates associated with reoperation rate and the Kaplan-Meier curve assessed the time to reoperation.

RESULTS

Overall, 92 patients were enrolled. Median follow up was 142 months. 13 patients underwent a second TURP during the follow-up period (reoperation rate was 14%); out of them 9/13 (69%) received medical treatment for persistent LUTS (p = .001). The need of LUTS/BPE pharmacological treatment after TURP is an independent risk factor for a second surgical procedure (odds ratio 9,3; p = .001). Out of the 13 patients treated with a re-TURP, 12 (92%) underwent surgery within 5 years of follow-up.

CONCLUSION

In our single center study, the need of LUTS/BPE pharmacological treatment was a predictive factor of a re-TURP. Considering that more than 90% of re-TURP were performed during the first 5 years of follow-up, it is assumable that a follow-up longer than 5 years is not needed in these patients.

Ultrasound prostate parameters as predictors of successful trial without catheter after acute urinary retention in patients ongoing medical treatment for benign prostatic hyperplasia: a prospective multicenter study

BACKGROUND

Alpha-blockers (ABs) are considered the standard treatment after initial management of acute urinary retention (AUR). However, no data are available on the predictors of a successful trial without catheter (TWOC) in patients previously on treatment with ABs and 5alpha reductase inhibitors (5ARI). The aim of our study was to investigate prostate ultrasound parameters as predictors of TWOC outcome.

METHODS

A consecutive series of patients, on treatment with ABs alone or in combination with 5ARI, experiencing AUR were prospectively enrolled. Clinical data (i.e., age, body mass index (BMI) and IPSS), urinary ultrasound features including hydronephrosis, prostate volume-TRUS, bladder wall thickness (BWT), intravesical prostatic protrusion more than 10mm (IPP≥10) were related to TWOC outcome performed seven days after AUR. A binary logistic regression analysis was computed to detect predictors of successful TWOC.

RESULTS

Overall,143 patients with a median age of 72 years (IQR 64-77) were enrolled. Seventy-mine patients (54%) with smaller prostate volume (59 [IQR 52-74] vs. 99 [IQR 74-125] mL, P=0.008) and a thinner BWT (5[IQR 4.8-5.2] vs. 5.2 [4.7-5.5] mm P=0.001) recovered voiding at TWOC. IPP≥10 was less common in patients with successful TWOC 11 (14%) vs. 33 (52%), P=0.001. On multivariate analysis, IPP<10mm (OR 6.10 [95%CI 2.61-14.20], P=0.001), lower IPSS (OR 0.95 [95% CI 0.89-0.99], P=0.045), smaller TRUS (OR 0.96 [95% CI 0.95-0.97], P=0.001), thinner BWT OR 1.23 (95%CI 0.73-0,92) P=0.001were the independent predictors of voiding recovery.

CONCLUSIONS

Patients receiving medical treatment for BPH and experiencing AUR still present a 54% probability of a successful TWOC. Ultrasound may help to identify patients with successful TWOC.

The role of bladder wall thickness in the evaluation of detrusor underactivity: Development of a clinical nomogram

AIMS

The aim of our study was to investigate noninvasive predictors for detrusor underactivity (DUA) in male patients with lower urinary tract symptoms (LUTS) and benign prostatic enlargement (BPE).

METHODS

A consecutive series of patients aged 45 years or older with non-neurogenic LUTS were prospectively enrolled. Patients underwent standard diagnostic assessment including International Prostatic Symptoms Score, uroflowmetry, urodynamic studies (cystometry and pressure-flow studies), transrectal ultrasound of the prostate, and ultrasound measurements of the bladder wall thickness (BWT). Logistic regression analysis was used to investigate predictors of DUA, defined as a bladder contractility index < 100 mm H₂ O. A nomogram was developed based on the multivariable logistic regression model.

RESULTS

Overall 448 patients with a mean age of 66 ± 11 years were enrolled. In a multivariable logistic age-adjusted regression model BWT (odds ratio [OR]: 0.50 per mm; 95% confidence interval [CI], 0.30-0-66; P = .001) and Qmax (OR: 0.75 per mL/s; 95% CI, 0.70-0.81; P = .001) were significant predictors for DUA. The nomogram based on the model presented good discrimination (area under the curve [AUC]: 0.82), good calibration (Hosmer-Lemeshow test, P > .05) and a net benefit in the range of probabilities between 10% and 80%.

CONCLUSIONS

According to our results, BWT and Qmax can noninvasively predict the presence of DUA in patients with LUTS and BPE. Although our study should be confirmed in a larger prospective cohort, we present the first available nomogram for the prediction of DUA in patients with LUTS.

Correlation of tools for objective evaluation of infravesical obstruction of men with lower urinary tract symptoms

Purpose

To identify how the most frequently used parameters in daily clinical practice diagnosing bladder outlet obstruction (BOO) due to benign prostate hyperplasia (BPH) correlate to each other.

Materials and methods

The study included 452 patients with lower urinary tract symptoms (LUTS) of the UNICAMP urology outpatient clinic of LUTS. Inclusion criteria: patients with BOO due to BPH who agreed to participate in the study. Exclusion criteria: patients with urinary tract infection, neurological diseases that compromised the lower urinary tract, prior prostatic surgery, radiotherapy or urethral stenosis. Patient assessment: history, international prostate symptoms score (IPSS), nocturnal quality of life score (NQoL) questionnaires, physical and digital rectal examination (DRE), PSA, transabdominal ultrasound with intravesical prostate protrusion (IPP), post-mictional residue and free uroflowmetry.

Results

There was no strong Spearman correlation among the studied variables. The only moderate correlations occurred between IPSS and NQoL (p <0001; c=0.56) and between IPP and prostate volume (p <0001; c=0.57). Weak correlations between IPP and post-mictional residue (p <0001; c=0.31) and free uroflowmetry (p <0001; c=-0.26); and between IPSS and free uroflowmetry (p <0001, c=-0.21) were observed.

Conclusion

In this study, we found moderate, weak, very weak and absent correlation among the various parameters used in the diagnosis and management of BOO due to BPH. As the value of these tools is variable, the creation of a logical and objective algorithm was not possible and the treatment is based on the interpretation of clinical symptoms.

Development and validation of a clinical nomogram predicting bladder outlet obstruction via routine clinical parameters in men with refractory nonneurogenic lower urinary tract symptoms

We aimed to develop and validate a clinical nomogram predicting bladder outlet obstruction (BOO) solely using routine clinical parameters in men with refractory nonneurogenic lower urinary tract symptoms (LUTS). A total of 750 eligible patients ≥50 years of age who had previously not responded (International Prostate Symptom Score [IPSS] improvement <4 points) to at least three different kinds of LUTS medications (including a-blocker) for the last 6 months were evaluated as subcohorts for nomogram development (n = 570) and for split-sample validation (n = 180). BOO was defined as Abrams–Griffiths number ≥40, or 20–39.9 with a slope of linear passive urethral resistance ratio >2 cmH₂O ml⁻¹ s⁻¹. A stepwise multivariable logistic regression analysis was conducted to determine the predictors of BOO, and b-coefficients of the final model were selected to create a clinical nomogram. The final multivariable logistic regression model showed that age, IPSS, maximum urinary flow rate, postvoid residual volume, total prostate volume, and transitional zone index were significant for predicting BOO; these candidates were used to develop the final nomogram. The discrimination performance of the nomogram was 88.3% (95% CI: 82.7%–93.0%, P < 0.001), and the nomogram was reasonably well-fitted to the ideal line of the calibration plot. Independent split-sample validation revealed 80.9% (95% CI: 75.5%–84.4%, P < 0.001) accuracy. The proposed BOO nomogram based solely on routine clinical parameters was accurate and validated properly. This nomogram may be useful in determining further treatment, primarily focused on prostatic surgery for BOO, without impeding the detection of possible BOO in men with LUTS that is refractory to empirical medications.

External validation of Imamura nomogram as a tool to predict preoperatively laser semi-rigid ureterolithotripsy outcomes

BACKGROUND

We aimed to validate Imamura nomogram for prediction of stone free rate in patients undergoing ureterolithotripsy (ULT).

METHODS

From January 2013 to June 2016, patients undergoing laser semi-rigid ULT were prospectively enrolled at our center. All patients were preoperatively assessed with clinical history, blood samples, uranalysis and non-contrast enhanced computed tomography (CT). Treatment efficacy was assessed 1 month later by non-contrast enhanced CT. ROC curve was used to evaluate the performance characteristics of Imamura nomogram.

RESULTS

Overall, we enrolled 275 patients. Median age was 55 years (IQR: 46/64), median length of stone was 9.8 mm (IQR: 7.5/12). Pyuria was detected in 6/275 (2.1%) patients. Stones were located at ureteropelvic junction in 55/275 (19%) patients, proximal ureter in 74/275 (26%) patients, middle and distal ureter in 66/275 (24%) patients and 82/275 (30%) patients, respectively. At 1-month follow-up, 209/275 (76%) patients were stone free. Imamura nomogram presented an AUC of 0.67 (95% CI: 0.580-0.761) for the prediction of stone free rate. At the best cut-off value of 75%, sensitivity was 76%, specificity was 55%, positive predictive value (PPV) was 83% and negative predictive value was 45%.

CONCLUSIONS

We firstly validated Imamura nomogram in a European cohort study. It proved a reasonable accuracy (area under curve: 0.67) and a good PPV (83%). Further studies should confirm our results to support the routine clinical use of Imamura nomogram as a tool to predict ULT outcomes.

Detrusor overactivity increases bladder wall thickness in male patients: A urodynamic multicenter cohort study

AIMS

To evaluate the role of Bladder wall thickness (BWT) as a predictor of Detrusor overactivity (DO) in patients with Lower urinary tract symptoms (LUTS)/Benign prostatic enlargement without Bladder Outlet Obstruction.

METHODS

From January 1996 to December 2000, each new patient, aged 45 years or older with LUTS, underwent standard diagnostic assessment, urodynamic studies (cystometry and pressure flow studies), and ultrasound measurements of the bladder wall thickness (BWT) in two centers. In order to exclude the possible effect of benign prostatic obstruction (BPO) on detrusor thickness, patients with a Schaefer class was ≥2 were excluded from the study. The area under the receiver operating characteristics curve (AUC) quantified the predictive accuracy (PA) of BWT for the diagnosis of DO.

RESULTS

Overall 195 patients were enrolled. DO was observed in 98/195 patients (50%). The BWT presented an AUC of 0.70; 95% CI: 0.62-0.77 for the diagnosis of DO. At the best cut-off value of 3.85 mm sensitivity was 73%; specificity was 59%; positive predictive value (64%, PPV). Negative predictive value (69%, NPV).

CONCLUSIONS

Our study firstly showed, how BWT in male patients may be a consequence of DO other than BPO. Our finding, if confirmed in further studies, could limit the accuracy of BWT in patients with DO and BPO.