A comparison of the International Index of Erectile Function and erectile dysfunction studies

OBJECTIVE: To evaluate the ability of the five-item version of the International Index of Erectile Function (IIEF-5) to diagnose the vascular aetiology and severity of erectile dysfunction (ED), and to compare it with pharmacological testing and duplex Doppler ultrasonography, as such questionnaires are widely used by the pharmaceutical industry to categorize the severity of ED and to assess the efficacy of drug therapy. PATIENTS AND METHODS: In all, 80 patients (mean age 45.2 years, sd 14.0; mean duration of ED 3.5 years) were reviewed by an examiner unaware of their IIEF scores during testing. Penile blood flow was assessed in each patient after an intracavernosal injection with prostaglandin-E1 (10 micro g), with self-stimulation in privacy. The peak systolic velocity, end diastolic velocity and resistive index were measured for the vascular diagnosis. Visual ratings of erectile responses were also used for analysis. RESULTS: Of the 80 patients, 30 had a normal vascular response, 38 arterial insufficiency and 12 were diagnosed with venous leakage. There was no significant difference in the IIEF scores among patients with a normal vascular response, arterial insufficiency or venous leakage. Analysis of visual ratings of erections showed no difference in IIEF scores among the different groups of patients. CONCLUSION: The IIEF was designed and developed specifically for assessing and evaluating sexual function in clinical trials. However, as shown here, the IIEF cannot and should not be used as a tool to diagnose or compare specific vascular causes of ED.