Results from clinical studies on drugs and medical devices affect how doctors practice medicine and thereby the treatments offered to patients. However, clinical research is increasingly sponsored by companies that make these products, either because the companies directly perform the studies, or fully or partially fund them. Previous research has found that pharmaceutical industry sponsored studies tend to favor the sponsors’ drugs more than studies with any other sources of sponsorship. This suggests that industry sponsored studies are biased in favor of the sponsor’s products.

This review is an update of a previous review that looked at sponsorship of drug and device studies. The primary aim of the review was to find out whether the published results and overall conclusions of industry sponsored drug and device studies were more likely to favor the sponsors’ products, compared with studies with other sources of sponsorship. The secondary aim was to find out whether such industry sponsored studies used methods that increase the risk of bias , again compared with studies with other sources of sponsorship. In this update, we carried out a comprehensive search of all relevant papers of empirical studies published from 2010 to February 2015 and included 27 new papers, yielding a total of 75 papers included in our review .