An evaluation of epidemiological and reporting characteristics of complementary and alternative medicine (CAM) systematic reviews (SRs)

Abstract

Background: Systematic reviews (SRs) are abundant. The optimal reporting of SRs is critical to enable clinicians to use their findings to make informed treatment decisions. Complementary and alternative medicine (CAM) therapies are widely used therefore it is critical that conduct and reporting of systematic research in this field be of high quality. Here, methodological and reporting characteristics of a sample of CAM-related SRs and a sample of control SRs are evaluated and compared.

Methods: MEDLINE(®) was searched to identify non-Cochrane SRs indexed from January 2010 to May 2011. Control SRs were retrieved and a search filter was used to identify CAM SRs. Citations were screened and publications that met a pre-specified definition of a SR were included. Pre-designed, standardized data extraction forms were developed to capture reporting and methodological characteristics of the included reviews. Where appropriate, samples were compared descriptively.

Results: A total of 349 SRs were identified, of which 174 were CAM-related SRs and 175 were conventional SRs. We compared 131 CAM-related non-Cochrane SRs to the 175 conventional non-Cochrane reviews. Fifty-seven percent (75/131) of CAM SRs specified a primary outcome compared to 21% (37/175) of conventional sample reviews. Reporting of publication bias occurred in less than 5% (6/131) of the CAM sample versus 46% (80/175) of the conventional sample of SRs. Source of funding was frequently and consistently under-reported. Less than 5% (11/306) of all SRs reported public availability of a review protocol.

Conclusion: The two samples of reviews exhibited different strengths and weaknesses. In some cases there were consistencies across items which indicate the need for continued improvements in reporting for all SR reports. We advise authors to utilise the PRISMA Statement or other SR guidance when reporting SRs.

Figure 1. Defining a ‘systematic review’.

Figure 2. Flow diagram of included systematic reviews.