Comparison of Two Numerical Parameters to Assess Detrusor Contractility in Prognosing Short-Term Outcome after Transurethral Resection of the Prostate.

Objective: To investigate and compare the influence of two numerical detrusor contractility parameters, the bladder contractility index (BCI) and the maximum Watts factor (WFmax), on transurethral resection of the prostate (TURP) outcome.

Methods: A retrospective study was conducted on 236 patients who had undergone urodynamic assessment preoperatively and TURP for benign prostatic obstruction. They were evaluated by International Prostate Symptom Score (IPSS) and uroflowmetry preoperatively and 3 months postoperatively. Related criteria were established to determine the overall efficacy of TURP. Logistic regression analysis and receiver operating characteristic curves were made to investigate the influence of the BCI and WFmax on TURP efficacy.

Results: Among the 236 patients, 195 treatments were effective and 41 ineffective. Multivariate analysis showed that both the BCI (OR 1.038) and the WFmax (OR 1.291) could influence TURP efficacy. For predicting TURP efficacy, the optimal cut-off values of the BCI and WFmax were 98.7 and 10.27 W/m2, respectively. The AUC, sensitivity and specificity of the BCI were 0.722, 78.5% and 61.0%; those of the WFmax were 0.761, 73.9% and 73.2%, with no significant difference (p > 0.05).

Conclusions: To some extent, the BCI and the WFmax can predict TURP efficacy equally well. A discrimination level of 10.27 W/m2 may be a threshold value for detrusor underactivity (DU); as regards the BCI, the current threshold value is appropriate to diagnose DU.