Researchers from the University of East Anglia are calling for medical trial data to be kept in national repositories.
A BMJ study published today reveals how a series of barriers stopped researchers from reviewing the effects of heart failure drugs such as beta blockers on patients.
Now they are calling for greater transparency in research and recommend that access to data should be a mandatory requirement of funding.
They warn that the risks of not doing so, could lead to "erroneous clinical decisions".