Risk factors in predicting a poor response to sildenafil citrate in elderly men with erectile dysfunction

To assess the clinical efficacy of sildenafil and the potential predictors of poor response to sildenafil in elderly patients with erectile dysfunction (ED).

The study included 162 patients (aged > or = 60 years) treated with sildenafil for at least 8 weeks; all patients were evaluated with a history, physical examination, measurement of total testosterone and a pharmacological erection test. Sexual function before and 8 weeks after treatment was assessed using the self-administered International Index of Erectile Function (IIEF). Treatment was considered successful when the patient attained a higher grade on the erectile function (EF) domain score, and an affirmative response to the overall assessment question. Factors influencing treatment outcome were evaluated by univariate and multivariate statistical analysis.

The overall efficacy with sildenafil was 47% (76/162). On univariate analysis, uncontrolled diabetes, current smoking, hypogonadism (<3 microg/L testosterone) and low pretreatment EF domain score (<17) were selected as predictors of a poor response. On multivariate logistic regression, a low pretreatment EF domain score was the strongest independent prognostic factor for a poor response (odds ratio 2.25, 95% confidence interval, 1.45-7.33), and this was followed by hypogonadism (1.89, 1.12-3.16) and current smoking (1.34, 1.04-3.52).

In a real clinical setting, sildenafil was effective for about half of the elderly men. The baseline EF domain score, hypogonadism and current smoking were significantly associated with failure of sildenafil. These results suggest that modifying reversible risk factors, e.g. stopping smoking and replacing testosterone, would be beneficial in augmenting the efficacy of sildenafil in elderly men.