April 8, 2013

All clinical trial results should be published

If you’re one of the 40,000 or so people who has signed the Alltrials petition you will have received an email from Ben Goldacre asking for more help.

The  Declaration of Helsinki, the major document on research ethics in medicine, already states

30. Authors, editors and publishers all have ethical obligations with regard to the publication of the results of research. Authors have a duty to make publicly available the results of their research on human subjects and are accountable for the completeness and accuracy of their reports. They should adhere to accepted guidelines for ethical reporting. Negative and inconclusive as well as positive results should be published or otherwise made publicly available. Sources of funding, institutional affiliations and conflicts of interest should be declared in the publication. Reports of research not in accordance with the principles of this Declaration should not be accepted for publication.

The petition is trying to get these principles enforced. Publication bias isn’t just a waste of the voluntary participation of (mostly sick) people in research. Publication bias means we don’t know which treatments really work.

In my first job (as a lowly minion) in medical statistics, my boss was Dr John Simes, an oncologist. Back in the 1980s he had shown that publication bias in cancer trials gave the false impression that a more toxic chemotherapy regimen for ovarian cancer had substantial survival benefits to weigh against the side-effects.  Looking at all registered (published and unpublished) trials showed the survival benefit was small and quite possibly non-existent.  The specific treatment regimens he studied have long been outmoded, but his message is still vitally important.

These examples illustrate an approach to reviewing the clinical trial literature, which is free from publication bias, and demonstrate the value and importance of an international registry of all clinical trials.

Nearly thirty years later, we are still missing information about the benefits and risks of drugs.

For example, influenza researchers have used detailed simulation models to assess control strategies for pandemic flu. These simulation models need data about the effectiveness of drugs and vaccines.  When the next flu pandemic hits, we really need these models to be accurate, so it’s especially disturbing that Tamiflu is one of the drugs with substantial unpublished clinical trial data.

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »