991 When to perform pressure flow study in patients with lower urinary tract symptoms and benignprostatic enlargement: External validation of a novel clinical nomogram

Eur Urol Suppl 2014;13;e991 Print!

De Nunzio C.1, Trucchi A.1, Lombardo R.1, Gacci M.2, Carini M.2, Bonetto Gambrosier M.1, Tubaro A.1, YAU-BPH group

1Sant' Andrea Hospital, "La Sapienza" University of Rome, Dept. of Urology, Rome, Italy, 2Careggi Hospital, University of Florence, Dept. of

Urology, Florence, Italy

INTRODUCTION & OBJECTIVES:

Recently the Young Academic Urologist-BPH group developed a clinical nomogram for the prediction of benign prostatic obstruction (BPO)

in patients with lower urinary tract symptoms (LUTS) and benign prostatic enlargement (BPE) (Figure 1). Aim of our study was to externally

validate the YAU-BPH nomogram for the prediction of BPO in patients with LUTS/BPE.

Figure 1

MATERIAL & METHODS: Between January -September 2013, a consecutive series of patients with LUTS and BPE underwent

standardized pressure flow studies (PFS) before considering transurethral surgery. Variables assessed were IPSS, PSA, prostate size,

transitional zone volume (TZV), maximal urinary flow rate (Qmax), post void residual urine (PVR). Benign prostatic obstruction was defined

as a Schaefer grade ≥3 at PFS. Qmx, TZV were plotted on the YAU-BPH nomogram to predict the presence of BPO. Receiver-operator

characteristics (ROC) curve analysis was used to evaluate predictive properties of the nomogram for the final diagnosis of BPO.

RESULTS: A total of 342 patients were consecutively enrolled. Median age was 66 (IQR: 60/71) years, median IPSS was 15 (IQR: 10/19),

median BMI was 26 (IQR: 24/29) kg/m2. Median prostate volume and TZV were respectively: 50 cc (IQR: 36/70) and 24 cc (IQR: 15-35);

median Qmax was: 9.4 ml/sec (IQR: 7/12.6). 262 patients (76.6%)presented a BPO (Schaefer >3 ) at PFS. The novel YAU-BPH nomogram

presented an AUC of 0.65; 95%CI: 0.58- 0.71 for the diagnosis of BPO. At the best cut-off value of 80% (nomogram probability) the

sensitivity was 0.65 and specificity was 0.77, the positive predictive value was 88% and the negative predictive value was 32%.

CONCLUSIONS: In our experience the YAU-BPH nomogram performance accuracy is good (AUC: 0.65) with an excellent PPV (88%).

Although further multicenter studies are needed to confirm our results, the implementation of the YAU-BPH nomogram, in our experience

could reduce the number of unnecessary PFSs.