Choice of time period to identify confounders for propensity score matching affected the estimate: A retrospective cohort study of drug effectiveness in asthmatic children

To control for confounding by indication in comparative (drug) effectiveness studies, propensity scores (PS) methods may be utilized. Since childhood diseases or outcomes often present as acute events, we compared the effect of using different look back periods in electronic health care data, to construct PSs. This was applied in our research on the effect of a combination of inhaled corticosteroids/long-acting beta-2-agonists (ICS+LABA), either as fixed combination or used as loose combination (2 separate inhaler devices) in the prevention of severe asthma exacerbations.
Source: Journal of Clinical Epidemiology - Category: Epidemiology Authors: Source Type: research