Thousands of patients who took place in clinical trials may never learn whether the drugs or devices were faulty, the New York Times says. Although the US Congress recently required manufacturers to disclose results of approved products, it did not require disclosure of non-approved products. Hence, people with implanted medical devices such as shunts or breast implants could be at risk.

For everyone involved in the research, “there is a tremendous incentive to go on, to forget about the old and move on to the new,” said Drummond Rennie, a deputy editor at the Journal of the American Medical Association.

Although researchers conducting clinical studies are not required to disclose test results to participants, they are supposed to alert them to emerging product dangers. They are also supposed to follow the health of participants. But this often is neglected.

Industry successfully lobbied Congress against disclosure of the results of trials which failed. The manufacturers argued that releasing data about them would confuse patients and would give away valuable information to competitors about devices under development that might succeed later on.