Penile Compression Release Index Revisited: Evaluation and Comparison with Other Noninvasive Tools in the Prediction of Bladder Outlet Obstruction in Men with Benign Prostatic Enlargement

AIM: To determine the discriminatory power of penile urethral compression-release index (PCRI), clinical prostate score (CLIPS) and bladder outlet obstruction index 2 (BOON2) for the detection of bladder outlet obstruction (BOO), and the associated bladder abnormality in patients with benign prostatic enlargement (BPE). MATERIAL AND METHODS: In study was included of 135 patients with proven BPE underwent urodynamic measurement (UDM) and PCR maneuver. PCR Index was calculated following the formula: (Qs-Qss)/Qss x 100(%). CLIPS score was calculated based on non-invasive variables (prostate volume, maximal urinary flow, residual urine and voided volume), while BOON2 was calculated using the formula intravesical prostate protrusion (IPP)-3 x Qmax-0.2 x mean voided volume. UDM results were plotted on Schaefer and URA nomograms. RESULTS: A comparative analysis was made using ROC curves. The area under the curve (AUC) for PCRI is 0.85 (PTP 91.3%), while AUC for CLIPS and BOON2 is 0.8 (PTP 77.6%) and 0.82 (PTP 74.5%), respectively. PCRI with the cut-off point of 96% clearly distinguishes obstructed patients with normocontractile detrusor and the presence of detrusor overactivity (DO), versus those unobstructed. CLIPS (>10) shows good BOO prediction, but without the possibility of distinguishing between detrusor contractility grade and the occurrence of DO. BOON2 has shown that impaired contractility has influence on this number in obstructed patients. CONCLUSION: PCRI is a very good noninvasive urodynamic test for a group-wise detection of BOO in patients with BPE and associated bladder co-morbidities; it is therefore superior in comparison with to CLIPS or BOON2.