Randomised controlled trials (RCTs) that compared phosphodiesterase-5 inhibitors versus placebo in men with benign prostatic hyperplasia suffering from lower urinary tract symptoms were eligible for inclusion. Trials that compared phosphodiesterase-5 inhibitors versus alpha blockers or that used a combination of both were excluded.
The primary outcome was the change from baseline in the International Prostate Symptom Score (I-PSS). Secondary outcomes were quality of life, maximum urinary flow rate, and the International Index of Erectile Function Erectile Function domain.
The included trials studied the phosphodiesterase-5 inhibitors sildenafil (50 to 100mg), tadalafil (2.5 to 20mg) and vardenafil (10mg) versus placebo in patients aged 45 years and over. Most trials only included men who had benign prostatic hyperplasia lower urinary tract symptoms for at least six months. The I-PSS score was at least 12 (where reported).
Two reviewers performed study selection, and disagreements were resolved by consultation with a third reviewer.