Use of odds ratio with event studies

Jenny Hope talks about the use and mis-use of odds-ratio in medical science.  How can 2% become 20%? | Understanding Uncertainty:

"An odds ratio is a standard measure that statisticians and epidemiologists (yes, them again) use to measure an association between an exposure (here statins) and an event (muscle problems). It is defined as the odds of the event given the exposure, divided by the odds without the exposure."

Why not use this quantitative measure of the effect of an event as an addition to an event study.  The Event Study provides the picture of the effect of the event but the odds ratio should compare aftermath with and without the event.