Kalyvianakis D et al, 2018: Low-Intensity Shockwave Therapy for Erectile Dysfunction: A Randomized Clinical Trial Comparing 2 Treatment Protocols and the Impact of Repeating Treatment.
Kalyvianakis D, Memmos E, Mykoniatis I, Kapoteli P, Memmos D, Hatzichristou D.
Department of Urology, University of Crete, Heraklion, Greece; 1st Department of Urology and Center for Sexual and Reproductive Health, Aristotle University of Thessaloniki, Thessaloniki, Greece; Institute for the Study of Urological Diseases, Thessaloniki, Greece.
Abstract
BACKGROUND: There is lack of evidence-based optimization of the protocol for low-intensity shockwave therapy for erectile dysfunction. Furthermore, the safety and efficacy of repeating shockwave therapy have not been explored.
AIM: To compare the efficacy and safety of 6 and 12 treatment sessions within a 6-week treatment period and investigate the effect of repeat treatment after a 6-month period in a 2-phase study. METHODS: Patients with vasculogenic erectile dysfunction that responded to phosphodiesterase type 5 inhibitors were randomized into 2 groups: low-intensity shockwave therapy sessions once (group A, n = 21) or twice (group B, n = 21) per week for 6 consecutive weeks (phase 1). Patients who completed 6-month follow-up were offered 6 additional sessions (phase 2); group A received 2 sessions per week and group B received 1 session per week. Patients were followed for 6 months.
OUTCOMES: International Index for Erectile Function erectile function domain (IIEF-EF) score, minimally clinical important differences (MCIDs), Sexual Encounter Profile question 3 (SEP3) score, and triplex ultrasonographic parameters.
RESULTS: In phase 1, groups A and B showed improvement in IIEF-EF score, MCID, SEP3 score, and mean peak systolic velocity compared with baseline. MCIDs were achieved in 62% of group A and 71% of group B, and the percentage of yes responses to SEP3 was 47% in group A and 65% in group B (P = .02). Mean peak systolic velocity at baseline and at 3-month follow-up were 29.5 and 33.4 cm/s for group A and 29.6 and 35.4 cm/s for group B (P = .06). In phase 2, group A showed a greater increase in the percentage of yes responses to SEP3 (group A = +14.9; group B = +0.3). When the impact of the total number of sessions received was examined, MCIDs in IIEF-EF score from baseline were achieved in 62%, 74%, and 83% of patients after 6, 12, and 18 sessions, respectively. No treatment-related side effects were reported.
CLINICAL IMPLICATIONS: The total number of low-intensity shockwave therapy sessions affects the efficacy of erectile dysfunction treatment. Retreating patients after 6 months could further improve erectile function without side effects. 12 sessions can be delivered within 6 weeks without a 3-week break period.
STRENGTHS AND LIMITATIONS: This study lacked a sham-controlled arm. However, all patients were randomized to different groups, and baseline characteristics were similar between groups. Also, all patients were confirmed by triplex ultrasonography to have arterial insufficiency.
CONCLUSION: Patients can benefit more in sexual performance from 12 sessions twice per week compared with 6 sessions once a week. Shockwave therapy can be repeated up to a total of 18 sessions.
J Sex Med. 2018 Mar;15(3):334-345. doi: 10.1016/j.jsxm.2018.01.003. Epub 2018 Feb 1.
Comments 1
The unexperienced reader has to become familiar with the term minimally clinical important differences (MCID). He will find the first description in 1989 ( Jaeschke R, Singer J, Guyatt GH. Measurement of health status. Ascertaining the minimal clinically important difference. Control Clin Trials. 1989 Dec;10(4):407-15), where it was introduced to evaluate changes of dyspnea, fatigue, and emotional function in patients with chronic heart failure and chronic lung disease resp. “The minimal clinically important difference (MCID) can be defined as the smallest difference in score in the domain of interest which patients perceive as beneficial and which would mandate, in the absence of troublesome side effects and excessive cost, a change in the patient's management.” Put in simple words it means an improvement which a study patient regards as beneficial irrespective of the changes of classical study goals.
To better understand the present publication one also has to keep in mind that the primary goal of the 2-phase study was “... to examine, for the 1st time, (i) the safety and efficacy of 6 vs. 12 sessions of LiST and (ii) the safety and efficacy of a second round of shockwave therapy.”
Somehow this is a technique to circumvent the problem to have to document a positive effect on what is really interesting but may not be shown without jeopardizing the whole work to failure.
The study is well done and to use MCID may help to show changes which cannot be demonstrated with the classical study outcomes. I agree to a statement by the authors: “Our study offers several answers to questions raised in systemic reviews and meta-analysis regarding the appropriate use of this novel method: number of sessions, frequency of sessions per week, breaks between treatment sessions, and safety of multiple sessions.”
A contemporaneous classical study on the same subject showing no statistically significant changes is: Effect of Linear Low-Intensity Extracorporeal Shockwave Therapy for Erectile Dysfunction-12-Month Follow-Up of a Randomized, Double-Blinded, Sham-Controlled Study. Fojecki GL, Tiessen S, Osther PJS. Sex Med. 2018 Mar;6(1):1-7. The interested reader should compare these two studies.