The relationship among lower urinary tract symptoms, prostate specific antigen and erectile dysfunction in men with...

We evaluated the associations among lower urinary tract symptoms, prostate specific antigen (PSA) and erectile dysfunction (ED) in men with benign prostatic enlargement enrolled in the Proscar (Merck, Whitehouse Station, New Jersey) Long-Term Efficacy and Safety Study.

The Proscar Long-Term Efficacy and Safety Study was a 4-year, randomized, double-blind, placebo controlled study that enrolled 3,040 men with moderate to severe lower urinary tract symptoms and an enlarged prostate gland. Two questions assessed ED. A logistic regression model, including the effect of patient age, was used to examine the relationships among quasi-American Urological Association Symptom Score (AUASS), PSA, and ED at baseline. Changes in ED scores from baseline to study closeout were analyzed with ANOVA.

A total of 2,981 patients had baseline data available for analysis. Mean age was 64 years, mean quasi-AUASS was 15, mean PSA was 2.8 ng/ml and mean prostate volume was 55 cm. At baseline every 1 point increase in quasi-AUASS was associated with a 2% increased risk of ED even after controlling for age (p <0.001). At 48 months in placebo but not in finasteride treated men a 1-unit decrease in quasi-AUASS was associated with a slight but statistically significant decrease in ED. No association existed between increasing PSA and ED on baseline or longitudinal analysis.

We found a moderately strong association between baseline quasi-AUASS and the ED rate in men with an enlarged prostate, a finding that was supported by longitudinal data in the placebo arm. The absence of a relationship between PSA and ED highlights the need for further investigation into the mechanisms of benign prostatic hyperplasia related sexual dysfunction.