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Hyperbaric oxygen for MS


Bandolier's piece on interferons for MS ( Bandolier 58 ) drew requests for evidence on the effectiveness of hyperbaric oxygen. We thought this was known to be ineffective, but it appears still to be a topic of interest. We found a helpful systematic review [1] carried out a few years ago.

Review


The review used a comprehensive searching strategy to find controlled studies in which hyperbaric oxygen at about two atmospheres was compared with a control group (usually normal air or gas mixture without oxygen enrichment at lower pressures, usually at or just above one atmosphere) in patients with multiple sclerosis. The approach was to grade all the 14 trials found against 10 criteria for methodological assessment. These included items like randomisation and blinding, size, inclusion criteria etc.

Trials which scored 7 out of 10 or more on these criteria went on for further analysis. One of the eight trials included was not randomised, and four of the six excluded were randomised. All of the included studies were double blind.

Results


The reviewers used changes in EDSS ( Bandolier 58 ), a scale that sets out to measure functional ability in multiple sclerosis. The mean score at entry in most trials was 5 to 6.5, which indicates a moderate disability. The mean age of patients was early to mid 40s with an average duration of disease of 12-14 years. Apart from the original trial of hyperbaric oxygen in 1983, none of the others provided any evidence for a beneficial effect of hyperbaric oxygen. The reviewers also mentioned that there was no evidence for improvement in other areas like bladder function. Adverse effects were minor.

Comment


Profoundly negative, if somewhat unsatisfying. Actual data extracted from the individual trials are not presented, and while that may be understandable, it does mean one is totally dependent upon the judgement of the reviewers. A re-analysis might, for instance, concentrate on the randomised trials given the well understood bias found in non-randomised trials.

Purchasers who buy hyperbaric oxygen therapy for multiple sclerosis might need an updated review before changing practice because they will need to persuade patients and their carers that it does no good. It probably isn't cheap either, and with limited funds it would be appropriate to ask whether better value for money couldn't be obtained from interventions with known efficacy. Bandolier could find no new randomised trials published since the review was completed.

Reference

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  1. J Kleijnen, P Knipschild. Hyperbaric oxygen for multiple sclerosis: Review of controlled trials. Acta Neurologica Scandinavica 1995 91: 330-334.



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