The aim of our study was to investigate non-invasive predictors for Detrusor Underactivity (DU) in male patients with LUTS and benign prostatic enlargement (BPE).

Each new patient, aged 45 years or older with LUTS, due to benign prostatic enlargement, presenting at the Charing Cross Hospital, Dept. of Urology, London, United Kingdom and at the Department of Urology, Teramo Hospital, University of Aquila, Italy, was prospectively enrolled. Patients underwent standard diagnostic assessment including International Prostatic Symptoms Score (IPSS), uroflowmetry, urodynamic studies (cystometry and pressure flow studies), transrectal ultrasound and ultrasound measurements of the bladder wall thickness (BWT). A nomogram was generated based on the logistic regression model used to predict DU defined as a BCI<100 cmH2O. Accuracy of the nomogram was evaluated using the L-ROC

Overall 448 patients were enrolled. Mean age of the study cohort was 66± 11 years. DU was observed in 194/448 patients (43%). Patients with DU presented an lower Qmax (7.3 ± 3.1 ml/sec vs 12.5 ± 5.9 ml/sec; p= 0.01) and a lower BWT (3.4 ± 1.4 mm vs 4 ± 1.1; p= 0.001) when compared to patients without DU. IPSS, prostate volume and PVR demonstrated no statistically significant difference between patients with or without DU.

In a multivariable logistic, age-adjusted regression model BWT (OR: 0.51 per mm; CI: 0.40-0-66; p= 0.001) and Qmax (OR: 0.75 per ml/sec; CI: 0.70-0.81; p= 0.001) remained statistically significant predictors for DU. Calibration plot and decision curve analysis showed good calibration of the nomogram in the 10-85% probabilities. The nomogram predicting DU risk presented a predictive accuracy of 0.82 (Figure 1-2).

According to our results BWT and Qmax can non-invasively predict the presence of DU in patients with LUTS and BPE. Our study, although should be confirmed in a larger prospective cohort showed for the first time that BWT in male patients with LUTS and BPE could reflect the presence of DU.