To elucidate the predictive factors regarding the treatment outcomes after transurethral resection of the prostate for symptomatic benign prostatic enlargement with detrusor underactivity.

A retrospective study was conducted in 190 patients with detrusor underactivity of 1397 men who had undergone transurethral resection of the prostate. All patients had completed the International Prostate Symptom Score and quality-of-life (QOL) questionnaires and had undergone a full urodynamic analysis before surgery. The outcomes were assessed at 3 and 12 months postoperatively using the International Prostate Symptom Score, QOL score, and peak urinary flow rate. The association between the baseline variables and improvement in the outcome variables was analyzed statistically.

Preoperative urodynamic abnormalities included bladder outlet obstruction in 58.9% and detrusor overactivity (DO) in 32.1%. Multivariate analysis suggested that the initial level of storage symptoms, as well as the QOL score, were predictive of an improvement in the QOL. Postoperative improvement in symptoms and QOL was consistently influenced by the presence of DO before surgery. The baseline degree of bladder outlet obstruction, as well as patient age, consistently influenced the improvement in the peak urinary flow rate.

In selected patients with benign prostatic enlargement associated with detrusor underactivity, greater baseline storage symptom scores and the presence of DO were negative predictive factors for QOL improvement. Baseline DO was also predictive of poorer improvement in the subjective symptoms after transurethral resection of the prostate. A greater degree of baseline bladder outlet obstruction positively predicted for postoperative peak urinary flow rate improvement, and patient age predicted negatively for it.