Prostate volume and serum prostate-specific antigen as predictors of acute urinary retention. Combined experience from three large multinational placebo-controlled trials.

Objectives: We evaluated prostate volume and prostate-specific antigen (PSA) as predictors of acute urinary retention (AUR) in men with benign prostatic enlargement (BPE).

Methods: Data were pooled from 3 identical 2-year, multinational, multicenter, non-US, placebo-controlled finasteride trials in 4,222 men with BPE and no evidence of prostate cancer.

Results: The 2-year incidence of spontaneous AUR was higher in placebo patients with enlarged prostates (4.2% in men with prostate volume > or =40 ml vs. 1.6% in the <40 ml group) and higher PSA levels (3.9% in men with PSA > or =1.4 ng/ml vs. 0.5% in the <1.4 ng/ml group) at baseline. Finasteride reduced AUR incidence by 61% in men with larger prostates, by 63% in men with higher PSA levels, and by 47% in men with smaller prostates, compared with placebo.

Conclusions: BPE patients with larger prostate volumes, higher PSA levels and no evidence of prostate cancer have an increased risk of developing AUR and therefore derive the greatest benefit from the risk reduction seen with finasteride therapy.