EURURO Vol. 71 No. 5

Letter to the Editor

Re: Zhihua Lu, Guiting Lin, Amanda Reed-Maldonado,

Chunxi Wang, Yung-Chin Lee, Tom F. Lue. Low-intensity

Extracorporeal Shock Wave Treatment Improves

Erectile Function: A Systematic Review and

Meta-analysis. Eur Urol 2017;71:223–33

Low-intensity Extracorporeal Shock Wave Treatment of

Erectile Dysfunction: Does the Shadow Exceed the Light?

We read with great interest the article by Lu et al

[1] ,

as we

have previous experience and a long history with low-

intensity extracorporeal shock wave therapy (LI-ESWT) for

men with erectile dysfunction (ED). In contrast to the

findings reported by these authors, we have had little

success with LI-ESWT in our clinics and have mostly

discontinued its use. We were surprised by their findings

and question their conclusions and title, despite their sound

methodology and the numerous limitations carefully out-

lined in the discussion. While systematic reviews are the

cornerstone of evidence-based medicine, they only reflect

the data for a field and cannot overcome numerous limited-

quality studies. There are numerous examples of discre-

pancies between systematic reviews and the eventual large

randomized controlled (RCTs) trials

[2]

We are concerned that the authors present their findings

in a too positive light given the limitations of their data set.

For example, LI-ESWT for EDwas published for the first time

in 2010, but Lu et al include reports from 2005. These earlier

studies used the more classical high-intensity ESWL (as

used for the treatment of stones) for pelvic pain and

Peyronies disease with or without ED. Second, their

discussion details key weaknesses in the quality of the

data analyzed. Five of the seven studies included were of

nonrandomized cohort design. Furthermore, the RCTs

included had potential biases that could overcome the

benefits of their design (eg, they were not blinded). In total,

approximately 60% of the studies had a risk of bias in the

randomization. Only 17% of the studies analyzed had

adequate blinding for patients and doctors. Third, LI-ESWT

showed only some improvement in the group with mild ED

defined according to the International Index of Erectile

Function (IIEF), but not for moderate and severe ED. To our

eyes, this suggests a placebo response. Fourth, the longest

follow-up evaluated was 3 mo, so the reliability and

durability of this treatment were not demonstrated.

The main limiting factor of this work is the very

subjective IIEF questionnaire used to determine ESWL

outcomes. The IIEF questionnaire score changes dramati-

cally for modest responses. For example, using this

questionnaire, if responses change from ‘‘a few times’’ to

‘‘sometimes’’ then the total score can be improved by up to

5 points, which is approximately the difference found

within this review. How can this be clinically relevant? The

minimal clinically important difference domain of the IIEF

better assesses the true clinical efficacy of LI-ESWT according

to the model of Rosen et al

[3]

and is underlined by the

authors in their discussion as amore accurate andmeaningful

tool for evaluating the effect of LI-ESWT in patients with ED.

However this was not the case in the studies analyzed. In a

few studies, the erection hardness score did not show

significant improvement at 3 mo, only at 1 mo.

The only two relevant practical questions for considering

LI-ESWT in ED are:

(1) Did patients responding to a phosphodiesterase type

5 inhibitor (PDE5-I) need to continue its use after LI-

ESWT?

(2) If patients were not responding to a PDE5-I did they

respond after LI-ESWT?

These important practical aspects are not considered in

most studies analyzed in this review. It is our opinion that

[2_TD$DIFF]

[4_TD$DIFF]

is inappropriate to conclude that LI-ESWT should become

the first-line treatment for ED until the real clinical effects

of LI-ESWT have been carefully evaluated in high-quality

prospective studies.

Conflicts of interest:

The authors have nothing to disclose.

References

[1]

Lu Z, Lin G, Reed-Maldonado A, Wang C, Lee Y-C, Lue TF. Low- intensity extracorporeal shock wave treatment improves erectile function: a systematic review and meta-analysis. Eur Urol 2017;71:223–33

E U R O P E A N U R O L O G Y 7 1 ( 2 0 1 7 ) e 1 3 7 – e 1 3 8

ava ilable at

www.sciencedirect.com

journal homepage:

www.eu ropeanurology.com

DOI of original article:

http://dx.doi.org/10.1016/j.eururo.2016.05.050

http://dx.doi.org/10.1016/j.eururo.2016.09.018

0302-2838/