ABSTRACT
RCTs are a potentially important source of information on adverse events associated with medical interventions [1]. RCTs of medical interventions may address both ef cacy and safety issues, though traditionally RCTs focus mainly on the ef cacy of treatment. Moreover, harms data from randomized trials tend to be poorly collected, analyzed, and reported [2-5]. Recording and reporting of both ef cacy and safety issues in RCTs is of a great importance, directly affecting the quality of these clinical trials, and if this is done in an adequate way, then we may appraise the bene ts and harms of each intervention in such a way that may affect clinical practice. Evaluation of harms has traditionally relied on nonrandomized studies, in particular surveillance, but this leaves considerable room for missing important harms. On the other hand, RCTs may have better experimental control and protection against bias than observational studies have, and they may use more active surveillance for recording adverse events, thus recognizing important harms. If evidence on adverse events is available from large-scale randomized trials, then we may also address serious, yet uncommon harms.
