WHEN patients are prescribed a drug, they might assume it had been subject to the closest scrutiny. They would be wrong. The results of about half of all clinical trials are never published. Companies are allowed to run many tests and publish only the ones with results they like. Unsurprisingly, negative results are far less likely to appear in public.
Regulators can see the results of every trial. But that provides only so much comfort. Officials may well be convinced that a particular drug has enough value for a few patients to pass the bar for approval, but that does not tell doctors whether the drug is better to prescribe than other treatments. And the regulators have limited resources. They cannot match the sort of scrutiny that comes from making all trial results public. Independent evaluations were important in raising concerns about the heart-attack risks associated with Vioxx, a painkiller that was recalled in 2004.
At best, this bias in published results has produced a polluted evidence base. Patients have been prescribed antidepressants that look much less effective when unpublished data are taken into account. The British...
from The Economist: Leaders http://ift.tt/1OzPqYz
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