Erection hardness score or penile Doppler ultrasound: which is a better predictor of failure of nonsurgical treatment of erectile dysfunction?

Background: In the evaluation of men presenting for erectile dysfunction (ED), specific diagnostic tests, such as an intracavernous injection test (IIT) with Erection Hardness Score (EHS) assessment or penile Doppler ultrasound (PDU), may be necessary. Aim: The study sought to compare the prognostic value of PDU parameters with erection rigidity with EHS during IIT in predicting refractory ED after 5 years. Methods: Patients referred for ED were evaluated and had a PDU with at least 15 µg of intracavernous alprostadil and without any sexual stimulation. At 5 years of follow-up, current and past ED treatments were noted. Refractory ED was defined as having a penile prosthesis (PP) implanted, having failed nonsurgical treatments but having refused PP implantation, or having discontinuation of nonsurgical treatments due to loss of efficacy. Patients with hypogonadism and pelvic surgery were excluded. Receiver-operating characteristic curves were drawn and the area under the curve (AUC) was calculated. Outcomes: The outcome was the AUC for predicting refractory ED. Results: At 5 years, 69 men were still in follow-up with a mean age of 58.47 ± 10.39 years, and 13 (18.8%) were classified as having refractory ED. The AUC for the EHS, peak systolic velocity, end-diastolic flow, and resistive index to discriminate refractory ED were 0.820, 0.613, 0.730, and 0.714, respectively. Clinical Implications: EHS can be a good predictor of response to nonsurgical treatments in ED. Strengths and Limitations: This was a prospective study to compare IIT with PDU, and validated disease-specific questionnaires were used to assess both clinical efficacy and satisfaction. PDU was performed by a blinded third party. However, resulting from a single-center study, our sample size can be considered small, and the number of events observed was also low. Conclusion: Our data suggest that an abnormal EHS during an IIT is, at least, noninferior than an abnormal PDU in predicting those patients that will not respond to nonsurgical treatments and that will need a PP in long-term.