Lars Andersen, Time-dependent propensity scores: an application

Dear BEMCers,

This month, we are sharing a summary prepared by a student earning credit for the BEMC together with a photo. Thanks to the student, who prefers to remain anonymous!

This past Wednesday, Lars Andersen from Aarhus, Denmark, lectured on the use of time-dependent propensity score matching to address changes of treatment and covariates over time at the BEMC. After giving a general outline, Andersen introduced the immortal time bias as well as the related concept of “resuscitation bias” and explained how the latter can be avoided using risk set matching. As time-variant confounding remains an issue in the analysis phase, Lars Andersen introduced time-dependent propensity score matching as a strategy to deal with such a challenge.

As a clinician, Andersen explained how the nature of his clinical field and research questions inform his methodological choices. To illustrate these methods, Andersen elaborated on one of his papers dealing with tracheal intubation during cardiac arrests. In the paper, the authors could demonstrate that intubation lowered the chance of survival in an analysis using time-dependent propensity score matching while the unadjusted analysis revealed the opposite.

lars_andersenbemc

See you in March!