Is the Blue Cross Meta analysis reliable?

By Jan Tunér

As often pointed out, it takes a combined knowledge of medicine, scientific methods and physics to evaluate (or to perform) a study of the therapeutic laser modality. This combination is not always seen, and it can lead to incorrect conclusions. Such incorrect analyses are sometimes the basis for governmental authorities in charge of funding clinical studies and reimbursement.

The basic problem of several negative evaluations is a lack of understanding of laser parameters. For a correct outcome of a study, the researchers must have complete control (and understanding) of the dosage windows and the different properties of the wavelengths. Positive results from laser studies are found within “therapeutic windows” of dosage. If negative and positive studies are carefully scrutinised, it is obvious that the vast majority of negative results is due to low dosage or, rarely, over dosage. This window is fairly wide but most negative reports still do not fall within its frame. It is also very important to be able to make an independent analysis of the dosage claimed. Further to that, it is not uncommon that the dosage is miscalculated.

It has previously been found [1,2,3] that the first three Cochrane evaluation of the effect of laser therapy [4,5,6] are of little value. The critical comments on [4] are available on the Cochrane home page, but obviously not observed by the several authors, since they do make a reference to the wound healing analysis, but without any of the critical comments. Re-evaluations of negative Meta analyses of laser therapy for musculoskeletal conditions have turned out positive [7] if an analysis of the dosage has been included in the study.

As an example of the situation, we have here chosen a report named Wound-Healing Technologies: Low-Level Laser and Vacuum-Assisted Closure prepared for: Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services, and prepared by Blue Cross and Blue Shield Association Technology Evaluation Center Evidence-based Practice Center (EPC) Chicago, Illinois. Year of publication: 2004.

The authors have identified 11 studies said to be meeting the inclusion criteria. Reading the manuscript one can see that the authors are very qualified in the field of medicine and scientific methodology, but still lacking adequate knowledge about the field they are about to evaluate. Pressure ulcers and crural ulcers are “put in the same basket” but do not have same pathology and require different treatment parameters. The main problem with pressure ulcers is that the patient continuously is exposed to the pressure and the possibilities for healing are lower than for crural ulcers. If laser is used and the pressure is removed, healing is faster than for conventional therapy alone [8]. And further to that, all wavelengths in this analysis are put into the same basket. But each wavelength has a different therapeutic window.

The search for studies is not too impressing. A number of studies are listed as excluded from the study, and for very good reasons, since they are not at all related to the studied topic (tooth extraction, muscle injuries, etc). If high standard laser therapy studies in general were to be identified, the list would have looked quite different.

Papers using a proper dose analysis concept are e.g. [10, 11, 14].

Let us now look at the eleven studies:

Crural ulcers

Franek, Krol, and Kucharzewski, 2002. (810 nm), 4 J/cm^2
No serious objections.

Bihari and Mester, 1989. HeNe, HeNe/830, 4 J/cm^2
This early positive study does have shortcomings in design and reporting. It is interesting to note that it is the only study using HeNe, beside Santoianni, and HeNe is the best wavelength for wound healing [13] but not for pain relief.

Santoianni, Monfrecola, Martellotta, et al., 1984. HeNe
Appears to be a sound study but a confirmation on the used dosage cannot be extracted from the text.

Lundeberg and Malm, 1991. GaAs. Disqualified study
This study has previously been criticized for complete lack of dose control and other shortcomings. Lundeberg has been exposed as a scientific cheater. This study is not qualified for any evaluation.

Iusim, Kimchy, Pillar, et al., 1992: Not a laser study
The instrument used here is not a laser but an incoherent light source.

Lagan, McKenna, Witherow, et al., 2002. Not a  laser study
This is a combined laser/LED study ((660-950 nm) and should therefore be excluded.

Nussbaum, Biemann, and Mustard, 1994. Not a laser study
The authors used a combination of 820 nm laser and an array of 30 LED:s of three different wavelengths. Thus, again, this is not a laser study.

Crous and Malherbe, 1988 . Unknown parameters
The scarce reporting of parameters in this paper does not offer an opportunity for evaluation.

Pressure ulcers

Malm and Lundeberg, 1991 GaAs. Disqualified study
This study has previously been criticized for complete lack of dose control and other shortcomings. Lundeberg has been exposed as a scientific cheater. This study is not qualified for any evaluation

Lucas , van Gemert, and de Haan, 2003 , 904 nm. A good study, 1 J/cm^2. on stage III pressure ulcers. Possible negative feature: same irradiation over wound and skin.

Lucas, Coenen,and De Haan, 2000 (pressure)
904 nm, 1 J/cm^2 stated. 12 x 8 mW, 125 s (12 J) spread over a standard area of 30 cm^2 = 0.4 J/cm^2. Spread over 30 cm^2 irrespective of wound size. 0.4 J/cm^2, 904 nm for open wound is fair, over skin too low.

As can be seen from the above:

  1. 6 studies should not have been included because of unavailable information or because they were not laser studies.
  2. 3 acceptable studies for crural ulcers. 2 different wavelengths.
  3. 2 acceptable studies for pressure ulcer, one wavelength.
  4. No dosage analysis has been performed or discussed
  5. No treatment technique difference has been addressed


Two conclusions can be drawn from the above:

  1. Even with a better and more updated selection of studies and a proper evaluation of these, LPT for crural and pressure ulcers would still not lead to the conclusion that the documentation is at an acceptable level.
  2. The material of the study is not sufficient for a meta analysis
  3. From the Blue Cross study one would get the impression that the lack of effect of laser therapy for the conditions is confirmed by the chosen studies. Such a conclusion cannot be drawn. The present documentation does not confirm the effectiveness of laser therapy for these conditions, nor does it disprove it. It simply shows that there are not enough qualitative studies for the time being. Future and better designed studies are needed before any definite conclusions can be made, and it is not yet time to throw out the baby with the bathing water.

What can be done to improve future studies?
The World Association for Laser Therapy has published dosage recommendations for musculoskeletal conditions and is working on a similar document for wound healing. The association has also published Standard for conduct of randomized controlled trials and Standard for conduct of systematic reviews and meta-analyses [12] Although these concern musculoskeletal conditions, much can be applied to other conditions. The Scientific Secretary of WALT is also available for advice.


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2. Tunér J, Hode L. The Cochrane analyses – can they be improved?

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5. Brosseau L, Welch V, Wells G et al. Low level laser therapy (classes I, II and III) for treating rheumatoid arthritis. In: The Cochrane Library. Issue 4, 2000. Oxford: Update Soft­ware.

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13. al-Watban F, Zhang X Y. Comparison of the effects of laser therapy on wound healing using different laser wavelengths. Laser Therapy. 1996; 8 (2): 127-136.

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