Erectile dysfunction and diabetes mellitus

Abstract

Background: Erectile dysfunction (ED) is highly prevalent, affecting ≥50% of men with diabetes mellitus (DM) worldwide. Objective: This article reviews current knowledge on the epidemiology and underlying pathophysiology of ED in men with DM, diagnostic modalities, and treatment options. Methods: A MEDLINE literature search was conducted for articles published in English from inception of the database through November 2008, using the terms erectile dysfunction, diabetes, epidemiology, pathophysiology, phosphodiesterase inhibitors, intracavernosal injection, and penile prosthesis. Data on the epidemiology, diagnosis, and treatment of ED were extracted from all relevant articles. Results: The literature search revealed 685 original articles and reviews, 67 of which were selected for inclusion in this review. DM may cause ED through a number of pathophysiologic changes, including neuropathy, endothe-lial dysfunction, cavernosal smooth muscle structural/functional changes, hormonal changes, and psychological effects. The diagnosis of ED in men with DM is based on their sexual and medical histories and results of validated questionnaires such as the International Index of Erectile Function. Laboratory examinations are usually limited to testosterone and prolactin levels that may independently contribute to ED because specialized examinations are not necessary in most diabetic men with ED. The first step in the treatment of ED in men with DM includes glycemic control and treatment of diabetic comorbidities. The associated hypogonadism must also be treated; otherwise, pharmacologic treatment may be less efficacious or not efficacious at all. Phosphodiesterase type-5 (PDE-5) inhibitors have revolutionized the treatment of ED, and they are considered first-line treatment, with a mean efficacy rate of 50% and a favorable safety profile. Intracavernous administration of vasoactive drugs is the second-line medical treatment when PDE-5 inhibitors have failed. Alprostadil is the most widely used drug for this condition, but the combination of papaverine, phentolamine, and alprostadil represents the most efficacious pharmacologic treatment option for patients whose ED does not respond to monotherapy. Excellent functional and safety results have been reported for penile prosthesis implantation, and this approach, along with proper counseling, can be considered for selected patients with treatment-refractory ED. Conclusions: ED is common in men with DM, who represent one of the most difficult-to-treat subgroups of ED patients. PDE-5 inhibitors are the first-line treatment option, followed by intracavernosal injections and implantation of a penile prosthesis.