Non-publication of large randomized clinical trials: cross sectional analysis

BMJ: 10/29/13

Objective To estimate the frequency with which results of large randomized clinical trials registered with are not available to the public.

Design Cross sectional analysis

Setting Trials with at least 500 participants that were prospectively registered with and completed prior to January 2009.

Data sources PubMed, Google Scholar, and Embase were searched to identify published manuscripts containing trial results. The final literature search occurred in November 2012. Registry entries for unpublished trials were reviewed to determine whether results for these studies were available in the results database. Read more