EBM in action: Is laser treatment effective and safe for musculoskeletal pain?

To the Editor: The EBM in Action article on laser treatment by Del Mar et al1 raises my anxiety about the reliability of evidence-based medicine (EBM) in general and, at the very least, the authors' assessment of the question they set out to answer. One is seldom, if ever, in a position to understand the breadth and depth of an issue unless it is the subject of particular study. Most of us can not challenge statements made in such articles without an intimate knowledge of the literature. As laser therapy is the topic of my PhD thesis, I am in a unique position to have much of the literature on the subject at my fingertips.

The authors state in their conclusions that "low power laser therapy appears to be no more efficacious than placebo in relieving musculoskeletal pain". Several aspects of the analysis on which they base this conclusion cause me great concern. Firstly, they state that "The search report highlighted the high quality of evidence supporting the refined question". Quite the contrary. One of the two systematic reviews they cite2 has been criticised in the literature for its many inadequacies, not the least being that laser acupuncture and laser therapy are included in that review as if they were the same, which they are certainly not.3 In addition, the review by Beckerman et al concludes, with regard to musculoskeletal pain, that "the efficacy of laser therapy for musculoskeletal disorders seems, on average, to be larger than the efficacy of placebo treatment. More specifically, for rheumatoid arthritis, post-traumatic joint disorders and myofascial pain, laser therapy seems to have a substantial specific therapeutic effect".4 How can this fit with the conclusion of Del Mar et al? Furthermore, Gross et al state in their review, which consisted of three trials of laser therapy, that "In general, all therapies have not been studied in enough detail to adequately assess either efficacy or effectiveness".5 The choice of other articles by Del Mar et al is also somewhat mystifying in that, out of the nine references cited, one is in Russian and two in Danish. There are many other relevant articles in English that they have not cited.6,7

There is no doubt, as I myself have found, that it is difficult to search for this topic in the literature, as there are many terms used for laser therapy and the information comes from a broad range of sources. However, this is no excuse for a group that holds itself out to be "expert" in a field.

It is very disappointing to see such an incomplete review with such an inappropriate conclusion based on such a poor sample of the literature. If this is an example of EBM in action, then I think we should be very concerned.