Glucosamine

CRD COMMENTARY: The authors clearly stated the research question and the inclusion criteria for the review. They conducted a limited review of the literature, and although it is unlikely that additional studies have been missed, they did not address issues of bias by searching for unpublished or non-English studies. The primary trials were tabulated and the content of each of the individual trials was discussed in detail in the text of the review. The quality of the included trials was not assessed or scored, and it was not reported how judgements about the inclusion of studies were made. The criteria and methods used to extract the data were also not stated. Pending additional research, the results should be viewed with caution since the results of the trials could only be pooled in a narrative review, without statistical analysis or measurement of the heterogeneity between the studies. In addition, the authors agreed that there were flaws in the original study designs.