Hidden data, missing data, withholding data- whatever you call it, not all clinical trial data is publicly available, and we think that’s an issue. Regardless of the description, incomplete data is an impediment to ensuring that patients get the best care possible.

At its heart, evidence-based medicine aims to answer one important question: do treatments or tests do more harm than good? When we talk about appraising studies, we are trying to figure out if doing a diagnostic test, or performing an intervention, is going to help a patient more than it will harm them. Medicine is filled with uncertainty; the tools of EBM enable us as researchers, clinicians, policy makers and teachers to get it right, and we hope that as time goes on, we are able to get it right more and more often.

Making a clinical decision when we do not have all the information at hand is risky. Like driving too fast in foggy weather, practicing medicine on the basis of the results of incomplete clinical trial data sets us up for failure. The example of rosiglitazone (Avandia), in which some of the relevant data was withheld at the time of publication and drug approval, is one such example.

Rofecoxib (Vioxx), the ‘blockbuster’ arthritis pain tablet that was supposed to reduce GI bleeding associated with long-term NSAID use, did just that, in Merck’s ”on-treatment analysis”, which hid those who dropped out of the trial. When all the data was analyzed properly, including the dropouts in an “intention-to-treat” analysis, more people died in the rofecoxib group than in the control group, and the reduced GI events were for naught, made up for in spades by the increase in deaths secondary to cardiovascular events.

These are two of many examples of situations in which hidden data has caused harm, and cost lives. This is why the EBM world has been surprised by GSK’s recent announcement pledging to make all clinical trial data fully accessible to the public. The idea is that by allowing people to access all the data, made entirely anonymous, anyone will be able to analyze and investigate the results of clinical trials.

Several of our Evidence Live 2013 speakers are world leaders in this field- Ben Goldacre’s new book Bad Pharma is fast becoming a best-seller and deals with this topic directly- and the discussion should be lively and controversial when we come together in Oxford at the end of March 2013 for the conference.

For what it’s worth, we applaud the promise; it’s the sort of thing Archie Cochrane was talking about 40 years ago when he set out the challenge to set up a comprehensive repository of clinical trial evidence. But if history tells us anything, we’ll believe it when we see it.