In drug development, serious adverse event (SAE) is defined as any untoward medical occurrence during a human drug trial that at any dose The term "life-threatening" in the definition of "serious" refers to an event in which the patient was at risk of death at the time of the event; it does not refer to an event which hypothetically might have caused death if it were more severe.
[2] Adverse events are more broadly defined by international regulation as “Any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment.”[2] Investigators in human clinical trials are obligated to report these events in clinical study reports.
[4] Because of the lack of these data and uncertainty about methods for synthesising them, individuals conducting systematic reviews and meta-analyses of therapeutic interventions often unknowingly overemphasise health benefit.
[5] To balance the overemphasis on benefit, scholars have called for more complete reporting of harm from clinical trials.
A SUSAR (suspected unexpected serious adverse reaction) should be reported to a drug regulatory authority under an investigational license by using the CIOMS form (or in some countries an equivalent form).