The effect of combination treatment with low-intensity shockwave therapy and daily tadalafil on severe erectile dysfunction: a double-blind, randomized, sham-controlled clinical trial

Abstract

Background: Patients with severe erectile dysfunction (ED) remain the most challenging group in terms of available noninvasive treatment modalities.

Aim: The study sought to assess the role of combination therapy with low-intensity shockwave therapy (LiST) and daily tadalafil 5 mg in a highly select group of patients with severe vasculogenic ED through a double-blind, randomized trial.

Methods: Forty-eight sexually active men were randomly assigned to 12 sessions of LiST 3 times weekly and tadalafil 5 mg once daily (n = 34) or sham therapy and tadalafil (n = 17) for 4 weeks. Patients were assessed at 1 and 3 months after completion of treatment.

Outcomes: Improvement of erectile function was evaluated through the International Index of Erectile Function-Erectile Function domain (IIEF-EF) or 6-item IIEF and the Sexual Encounter Profile (SEP) diary. The primary outcome was the difference between the groups in the IIEF-EF at 3 months after completion of treatment. Secondary outcomes comprised (1) the difference between the groups in the IIEF-EF at 1 month after completion of treatment, (2) the difference between the groups in the "yes" responses to question 3 of the SEP diary at 1 and 3 months, and (3) the treatment-related adverse events. The number of patients attaining a minimal clinically important difference in the IIEF-EF (improvement of at least 7 points) was also assessed.

Results: After treatment, the absolute scores in the IIEF-EF were higher in patients receiving LiST and tadalafil vs sham therapy and tadalafil both at the 1-month (12.1 ± 2.4 vs 10.2 ± 1.7; P = .002) and at the 3-month (12.9 ± 2.1 vs 10.8 ± 1.8; P < .001) evaluation. Between the 2 groups, the proportion of "yes" responses to question 3 of the SEP diary was not statistically significant, whereas the number of patients attaining a minimal clinically important difference in the IIEF-EF was statistically significant only at the 3-month evaluation. No adverse events occurred.

Clinical implications: Application of LiST in patients with severe vasculogenic ED receiving daily dose tadalafil may further improve erectile function compared with tadalafil as a stand-alone treatment on the short term.

Strengths and limitations: Although we provided the first study in the field, severe vasculogenic ED was defined based on medical history and clinical examination and not based on penile ultrasound measures.

Conclusion: The combination of 12 sessions LiST 3 times weekly and daily tadalafil for 4 weeks led to a 2-point difference in the IIEF-EF compared with sham therapy and daily tadalafil among patients with severe vasculogenic ED after 1 and 3 months from completion of treatment.

Keywords: combination therapy; erectile dysfunction; erectile function; low-intensity shockwave therapy; sham-controlled trial; tadalafil.