Bladder outlet obstruction in men with acute urinary retention: an urodynamic study

Abstract

To identify clinical predictors of bladder outlet obstruction (BOO) in men with the first episode of spontaneous acute urinary retention (AUR), in order to facilitate patient selection for early de-obstructive prostate surgery. A multichannel urodynamic investigation was performed in 156 consecutive men ≥ 50 years five days following AUR. Clinical routine parameters were evaluated for their ability to predict BOO, which was defined as a BOO-index (BOOI) >40. Univariable and multivariable logistic regression models were fitted. A nomogram was constructed from significant variables of a reduced multivariable model. Discrimination and calibration of the nomogram were assessed. The mean age of the 156 men was 71.6 years, and the mean drained volume was 953 mL. Seventy-two men (46.2 %) had severe AUR-associated pain. On urodynamic evaluation, 79 (50.6 %) were obstructed (BOOI > 40). In multivariable regression analysis, age (p = 0.014) drained volume (p = 0.044) and pain intensity (p < 0.001) were independently associated with BOO. These variables formed the basis of the nomogram, which predicted BOO with a bootstrap-corrected accuracy of 78.2 %. The positive predictive value, sensitivity, and specificity of a 70 % nomogram cutoff was 83, 51, and 90 %, respectively. Decision-curve analysis demonstrated a net benefit with use of the nomogram. The routine clinical parameters age, drained volume, and pain intensity are independent predictors of BOO in men with AUR. According to our model, patients with a nomogram predicted BOO probability of >70 % might be candidates for early surgery. External validation of the nomogram is advocated.