Factors predicting the success of a trial without catheter in acute urinary retention secondary to benign prostatic hyperplasia.

Trial without catheter (TWOC) is a common practice in acute urinary retention (AUR) secondary to benign prostatic hyperplasia (BPH) although it is not successful in all patients. We conducted this study to identify the factors predicting the success or failure of TWOC in this subset of patients. Sixty-four patients with first episode of AUR secondary to BPH were enrolled in this study. These patients were given tamsulosin 0.4 mg daily for 3 days and TWOC was performed. Baseline international prostate symptom score (IPSS), residual volume of urine drained after catheterization (RU), prostate size (PS) and intravesical prostatic protrusion (IPP) by transabdominal ultrasound were recorded. TWOC was successful in 28 (43.75%) and failed in 36 (56.25%) patients. Discriminant analysis was done to evaluate the predictive factors. IPP, IPSS, PS and RU were found to predict the outcome of TWOC. A prediction model, using cut off values, was derived using receiver operating characteristic curves (ROC). A cut-off value of 8 mm for IPP detected failures with specificity of 89% and success with a sensitivity of 92% with area under ROC (AUROC) of 0.98. Similarly cut-off values of 16 for IPSS (specificity 84%, sensitivity 81%, AUROC = 0.90), 40 gm for PS (specificity 73%, sensitivity 84%, AUROC = 0.89); and 800 ml for RU (specificity 82%, sensitivity 64%, AUROC = 0.81) were derived. IPP, baseline IPSS, PS and RU can predict the outcome of TWOC. Among these factors, IPP is the most accurate in predicting the success of TWOC.