Objective: To compare the quality of natural product clinical trials published in alternative medicine journals versus those published in conventional medicine journals.
Design: Systematic search and review of the literature. Randomized controlled trials of natural products were included if they were published in English between 2003 and 2008. Articles were categorized by their journal of publication (alternative medicine versus conventional medicine). Two independent reviewers evaluated study quality using guidelines from the Cochrane Collaboration. The results with respect to the primary outcome (positive or negative) were also assessed.
Results: Thirty articles were evaluated, 15 published in alternative medicine journals and 15 in conventional medicine journals. Of articles published in alternative medicine journals, 33.33% (n = 5) were considered low quality, and none were considered high quality. Of articles published in conventional medicine journals, 26.67% (n = 4) were considered low quality and 6.67% (n = 1) were considered high quality. Two thirds of all trials reviewed were of unclear quality, due to inadequate reporting of information relating to the study's methodology. Similar proportions of positive and negative primary outcomes were found in alternative and conventional medicine journals, and low-quality articles were not more likely to report a positive primary outcome (Fisher's exact test, two-tailed p = .287).
Conclusion: The quality of natural product randomized controlled trials was similar among alternative and conventional medicine journals. Efforts should be made to improve the reporting of natural product clinical trials for accurate determinations of study quality to be possible.