Drug testing funded by the pharmaceutical industry is four times more likely to show results favouring the sponsor's product than publicly funded research, a new report has found.
The study, to be published in the latest issue of the British Medical Journal, reinforces previous findings on some concerns with industry-sponsored research and the need for balance between publicly and privately funded testing.
Joel Lexchin, a professor at York University in Toronto and lead author of the study, and a team of researchers analyzed 30 research articles published over a period of two decades. The articles examined the outcome of drug research based on who had funded the work.
"These findings indicate a systematic bias in drug testing and this is a serious problem as an increasing number of clinical trials . . . are funded by the pharmaceutical industry," Professor Lexchin said.
He said he was surprised by the widespread bias. The team looked at a number of drugs, including those used for cancer treatments and for psychiatric problems.
"This is something that seems to indicate that, 'Yeah, there really is something out there.' It's not just one or two cases [where there is a bias] There's a real phenomenon out there," he said.
The study offers a number of possible explanations for these favourable results. Professor Lexchin said the drugs funded by pharmaceutical companies may be compared to inferior drugs because of the financial risk to companies from unfavourable test results.
There could also be a publication bias, he said, noting that industry-funded trials are less likely to be published than those with other sources of sponsorship.
"In the past few years, there have been a number of high-profile cases where manufacturers have attempted to suppress publication unfavourable to their products," he said.
A number of major medical journals have started establishing more rigorous criteria for accepting industry-sponsored research. But Professor Lexchin recommended that all clinical trials be registered in advance so researchers can access results, whether or not they are published.
He also noted that people who read these studies should examine the sources of funding.
Tim Caulfield, research director of the Health Law Institute at the University of Alberta, said this study backs what is emerging as a consensus about industry-sponsored research. Researchers need to act independently, even if they are being funded by a drug company, and the government must be aware that all research can't be privately funded, he said.
There needs to be a balance between public and private money in research, Mr. Caulfield said.
Caroline Alphonso