Clinical trials and research - Why all research should be registered

Some studies are never published because they have disappointing or negative results.

The researchers might find, for example, that a potential new treatment or intervention appears to be no better than a placebo dummy pill.

Other reasons why research may not be published include:

  • The researchers may not finish writing a report because they move on to something new.
  • The researchers may not ask a journal to publish their findings.
  • The researchers may find what they've written is turned down by the editors of a journal.

Not being published is more than a matter of disappointment for researchers. If trials aren't published, there's a risk of other researchers attempting something similar again, with similar results, wasting time and resources.

There's also a danger that while one or more disappointing studies may remain unpublished and invisible, a single positive study will be published that may attract widespread attention.

The publication of the single study may result in the wrong belief that a treatment or intervention is more effective than it really is. The treatment may even be useless or harmful.

Well-designed studies should be published whatever the results because, disappointing or not, they add to the overall understanding of health and disease.

To reduce the risk of the results of studies never being published and remaining hidden, most clinical trials now have to be registered when they begin.

Trial registers, which contain a small amount of information about a trial, reduce the likelihood that trials will be forgotten about, and that unexpected or unwanted results will be overlooked.

On the register

More and more trials are now formally registered. This means some details are recorded, usually on a publicly accessible website, before they're started. The World Health Organization (WHO) has established what details should be recorded when a trial is registered.

Most clinical trials publicly funded in the UK – for example, by the National Institute for Health Research (NIHR) and the Medical Research Council (MRC) – have to be registered before they start to recruit people to take part in them. Since 2013, the registration of a clinical trial is a precondition for a favourable ethics opinion.

Many of the most important medical research journals, such as the British Medical Journal (BMJ) and The Lancet, won't publish reports of clinical trials that haven't first been registered. This means that research, whether formally published or not, can be identified by those collecting evidence or planning similar research.

What's on the register?

According to WHO, you should be able to find out the following information about any trial:

  • the title of the trial
  • the condition being studied
  • which treatment is being compared with which
  • who can and can't take part in the trial
  • whether people are currently being asked to join the trial
  • what the researchers are measuring to compare the effects of the treatments
  • the type of study
  • contact details for enquiries
  • who manages or funds the study
  • the number of people joining the trial
  • the date the trial was registered
  • the identifying number for the trial
  • where the trial is happening
  • when the first person joins the trial

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