Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 2004; 9: 09
To systematically investigate the relationship between methodological quality, vested interest of authors and direction of conclusion in reviews of spinal manipulation (SM) for back pain.
Systematic review of reviews of SM for back pain (1993 to March 2004). Included reviews were PubMed listed in English with an abstract, categorised as a review or metanalysis, presented evidence from two or more referenced clinical trials and giving a conclusion about the effectiveness of SM for back pain. The methodological quality of reviews was assessed using a predefined 5-point scoring system: explicit and repeatable search strategy (+1), inclusion criteria (+1), emphasis given to RCTs (+1), explicit quality assessment of clinical trials (+1), and explicit method used to reach a conclusion (+1).
Of 29 reviews included, 16 reached an overall positive conclusion, seven a negative conclusion and six a neutral conclusion. There were statistically significant pairwise correlations between each of the three factors: direction of conclusion, methodological quality and authorship by at least one qualified osteopath or chiropracter (DC or DO). The data indicate that most reviews are of poor quality, poor-quality reviews tend to reach positive conclusions, high-quality reviews tend to reach negative conclusions and DC/DO qualified authors write reviews of poor methodological quality that reach positive conclusions.
The outcome of reviews of spinal manipulation for back pain are strongly influenced by methodological quality and by the profession of the authors. Most high-quality reviews reach negative conclusions and the effectiveness of spinal manipulation for back pain is less certain than many reviews suggest.
