## The parametric waiting time distribution model and its application in pharmacoepidemiologic studies

### Henrik Støvring, Section for Biostatistics, Aarhus University

Information on prescription redemptions are routinely registered in populationwide
electronic databases. In traditional pharmacoepidemiologic research the duration of
individual prescriptions is defined based on decision rules with clinical input.
We have recently proposed a parametric method to estimate prescription durations via
the waiting time distribution as an alternative. I will show how covariates can be
introduced in the model to improve precision. Finally, the model allows estimation
of the probability of a patient being treated on a given day and I will show how
this probability can be used as exposure measure to estimate the being treated.