Non-invasive evaluation of bladder outlet obstruction in men suspected of benign prostatic hyperplasia: usefulness of the d index.

OBJECTIVE To compare a new index of voiding dysfunction (D) based purely on free uroflow vs. Abrams-Griffiths (A-G) number obtained from intubated flow, for classification of bladder outlet obstruction in men. PATIENTS AND METHODS Urodynamic tracings of 60 non-neurological patients (30 before transurethral resection of the prostate and of 30 men suspected of benign prostatic hyperplasia included in a medical therapy trial) were retrospectively analyzed. The Valentini-Besson-Nelson model was used to evaluate the value of the D index. A-G was obtained from intubated flows. Obstruction was defined as D > 32.5 cm H2O (translation of A-G criterion). RESULTS D showed 82.05% sensitivity with 66.66% specificity; the positive predictive value was 82.05% and the negative predictive value 66.66% for the whole population, 83.3 vs. 80.9% sensitivity with 58.3 vs. 77.7% specificity for pre- transurethral resection of the prostate vs. medical therapy group. CONCLUSION D index which can be obtained from a free uroflow appears as a valuable alternative to invasive urodynamic investigations when the diagnosis of bladder outlet obstruction needs to be more solidly established before a treatment decision or in men suspected of benign prostatic hyperplasia who elect for watchful waiting.