In reviewing 29 meta-analyses, which included 509 randomized controlled trials (RCTs), researchers from Canada and the United States discovered that only two reported the trial’s funding sources and none of them listed author-industry ties or employment by the pharmaceutical industry. The report is published in the March 9 issue of JAMA.

Among the trials that did report funding sources, 69% were industry funded; another 69% had at least one author with pharmaceutical industry financial ties. In seven of the 29 meta-analyses reviewed, 100% of included RCTs cited at least one form of disclosed conflict of interest (COI), yet reported only RCT funding sources; none reported RCT author-industry ties or employment.

"There is general agreement on the need for complete and transparent disclosure of COI in biomedical research. The results of the present study highlight a major gap in the reporting of COIs and suggest that, without a formal reporting policy, COIs from RCTs are unlikely to be reported when results are synthesized in meta-analyses," the authors wrote. "In addition to information on study funding, consumers of research, including patients and physicians, want researcher financial ties to industry to be disclosed and consider author-industry financial ties in assessing the quality of research evidence."

While guidelines recommend disclosure by authors of study funding sources and also of author-industry financial ties, there are no guidelines for the reporting in meta-analyses of COIs disclosed in included RCTs, according to the authors.