Letters: The effect of conservative therapies on patients suffering from chronic low back pain

To the editor:

Over the last few years there have been an increased number of randomized controlled trials (RCT) examining the effect of conservative therapies on patients suffering from chronic low back pain. Good research requires that one follow the so-called golden standard of the RCT. This can be extremely problematic, and several review studies indicate that flawed research methodology often hampers the evaluation of the effectiveness of a treated method. We believe that this also applies to Indahl et al's study. However, they are to be commended for their major efforts investigating their approach to treating chronic low back pain as a benign, self-limiting condition by light normal activity. They draw firm conclusions from their investigation, based on what they call "highly valid results". We do, however, question some of them.

Return to work may be regarded the ultimate success of an intervention. However, the validity and sensitivity of return to work as an outcome measure remains questionable. 

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Indahl and colleagues showed promising results with their experiment. However, in the light of the potential confounders presented above, their conclusions need to be interpreted with caution.