Sex inventories: can questionnaires replace erectile dysfunction testing?

OBJECTIVES: "Paper and pencil" sexual inventories are widely used by the pharmaceutical industry for categorizing the severity of erectile dysfunction (ED) and for efficacy end points of drug therapy. The International Index of Erectile Function (IIEF) evaluates several domains of male sexual behavior: erection, orgasm, desire, and satisfaction. We compared the subjective IIEF score for erectile function with the severity and etiology of ED as determined by pharmacologic testing with prostaglandin E1 (PGE1) and color duplex Doppler ultrasound testing (penile blood flow study [PBFS]).
METHODS: Five questions from the IIEF that require the patient to quantify his erectile performance were compared with PBFS data. Examiners were unaware of IIEF scores during testing. PBFSs were performed after PGE1 injection, privacy, and self-stimulation; dosing was 6 microg (50 to 59 years) or 10 microg (60 years or older). PBFS diagnoses were arterial insufficiency (AI) for peak systolic velocity (PSV) less than 25 cm/s; cavernous venous occlusive disease (CVOD) for PSV greater than 35 cm/s and resistive index (RI) less than 0.9; and mixed vascular erectile dysfunction for a PSV from 25 to 35 cm/s and RI less than 0.9. A normal vascular diagnosis required a PSV greater than 35 cm/s and an RI of 0.9 or greater. Visual ratings of the erectile responses without Doppler assessment (inadequate, adequate, or excellent) were also compared with the IIEF and Viagra Study Group criteria (Q3+4).
RESULTS: Eighty-nine patients underwent the complete evaluation. Eight patients (9%) were found to be normal vascularly (mean PSV 40.9 cm/s, mean RI 0.99). Thirty-four patients (38%) had AI (mean PSV 17.5, mean RI 0.74), 33 patients (37%) had mixed vascular ED (mean PSV 29.1, mean RI 0.80), and 14 patients (16%) had CVOD (mean PSV 45.9, mean RI 0.73). The mean IIEF score for the normal responders was 13.3; patients with AI, mixed vascular ED, and CVOD had mean IIEF scores of 6.9, 8.5, and 8.1, respectively. IIEF and Q3+4 values differed significantly between the normal and abnormal groups (P<0.05 and P<0.025, respectively), but no statistically significant differences in IIEF or Q3+4 scores were noted among the subgroups of abnormal responders. Analysis of the visual ratings of erections demonstrated that IIEF scores were significantly different between inadequate and excellent responders (P<0.05).
CONCLUSIONS: IIEF scores did not statistically differentiate among the specific etiologies of ED as determined by evidence-based testing with PBFS. Furthermore, patients with normal results after testing with PGE1 (10 microg or less) had surprisingly low self-ratings of erectile performance (13 of 25 points). For the primary caregiver, the IIEF may help in the taking of the male sexual history, but for the specialist, sexual inventory scores will not distinguish among the various etiologies of vascular ED and do not predict the results of pharmacologic testing.