english.prescrire.org > Spotlight > Archives : 2013 > Clinical research: access to raw data is essential

Spotlight: Archives

Every month, the subjects in Prescrire’s Spotlight.

2013 : 1 | 30 | 60

Clinical research: access to raw data is essential

Too frequently, the pharmaceutical companies alone hold the individual patient data from clinical trials, with the risk that further analyses of the results will be distorted.

Many clinical drugs trials are designed and financed by the companies commercialising them. They alone hold all the individual patient data gathered ("raw data"), which are subsequently coded, compiled and analysed. University hospital researchers publish reports on these trials in scientific journals; but have they had access to the raw data to carry out their analyses, or only to data already processed by the pharmaceutical companies?

According to one study, out of 69 clinical trials financed by pharmaceutical companies and published in The Lancet, 27 protocols stated that the data belonged to the firm, while 67 made no mention of the authors having access to the raw data.

When asked about this study, 39 authors responded to the question about their access to the data (57% of the articles). Only 26 stated they had had access to the raw data, while the others had access to data already processed (coded, compiled, analysed, etc.) by the firms. And only 13 authors checked the drug company's statistics using the raw data

The team behind this study considers that these results call for sweeping changes: journals should demand that authors have access to raw data for reports of clinical trials submitted for publication. More broadly, these data should be accessible to the public.

Access to raw data from clinical trials and pharmacovigilance is the only way of examining how the data have been coded, compiled and analysed. Making these data available allows fresh analyses to be carried out by teams who are independent of the firms.

It is in patients' best interests for their care to be based on all the available scientific evidence.

©Prescrire 1 January 2013

"Clinical research: access to raw data is necessary" Prescrire Int 2013; 21 (134): 4. (Pdf, free).
Download the full review.
Pdf, free