From Mexico to Mali: four years in the history of clinical trial registration.

In the 4 years between the Ministerial Forums on research and health held in Mexico in 2004 and Mali in 2008, the landscape of clinical trial registration changed significantly. When the ICMJE announced that they would no longer consider publishing the findings of clinical trials unless the research had been prospectively registered, they were key to shifting the way the clinical trials community thinks about research transparency. The argument in favour of greater transparency had been building for more than 20 years. By 2004 there was consistent and convincing evidence of the existence of publication bias and the damage this does to people's ability to make well informed decisions about health care. There is now increasing acceptance that the registration of clinical trials in a publicly accessible registry is a scientific, ethical and moral responsibility. In 2004, less than 3000 clinical trials were registered on databases meeting ICMJE criteria. There are now more than 19000 and, in some countries, prospective registration in a publicly accessible registry is now a legal requirement. Further, since October 2008, prospective registration is required if researchers wish to comply with the Declaration of Helsinki. However, despite these advances and incentives, trial registration in many countries remains far from comprehensive and stronger enforcement mechanisms may be needed in those countries.