To externally validate the Young Academic Urologist (YAU) nomogram for the prediction of benign prostatic obstruction (BPO) in patients with lower urinary tract symptoms and benign prostatic enlargement.

Between January 2013 and September 2014, a consecutive series of patients with lower urinary tract symptoms and benign prostatic enlargement underwent standardized pressure flow studies (PFSs) in 2 tertiary Italian centers. Variables assessed were International Prostatic Symptom Score, Prostate Specific Antigen (PSA), prostate size, transitional zone volume, maximal urinary flow rate (Qmax), postvoid residual urine. BPO was defined as a Schäfer grade ≥3 at PFSs. Qmax and transitional zone volume were plotted on the YAU nomogram to predict the presence of BPO. Receiver operating characteristic curve analysis was used to evaluate predictive properties of the nomogram for the final diagnosis of BPO.

A total of 449 patients were consecutively enrolled. In those, 310 patients (69%) presented a BPO (Schäfer ≥3) at PFSs. The novel YAU nomogram presented an area under the curve of 0.76; 95% confidence interval: 0.72-0.82 for the diagnosis of BPO. At the best cutoff value of 80% (nomogram probability), the sensitivity was 74% and specificity was 79%, the positive predictive value was 89%, and the negative predictive value was 56%.

Although further studies are needed to confirm our results, the YAU nomogram was, in our experience, an excellent tool to predict the presence of BPO.