AbstractBackgroundObservational data can be used to complement inferences about treatment effects from randomized trials. To increase confidence in the use of observational data for this purpose, one can first benchmark, that is, demonstrate the observational analysis can replicate an index trial’s findings, before using the observational data to estimate what the index trial could not estimate.MethodsWe use observational Swedish registry data to emulate a target trial similar to the Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia (TASTE) randomized trial, which found no difference in the risk of death or myocardial infarction by 1 year when comparing percutaneous coronary intervention with and without thrombus aspiration among individuals with ST-elevation myocardial infarction. We benchmark the emulation estimates against the trial estimates at 1 year, then extend the emulation’s follow up to 3 years and estimate effects in subpopulations that were underrepresented in the trial.ResultsLike TASTE, the observational analysis found no difference in the risk of death or myocardial infarction by 1 year in the groups with or without thrombus aspiration (risk difference 0.7 (−0.7, 2.0) and -0.2 (−1.3, 1.0) for death and myocardial infarction respectively), so benchmarking was considered successful. We additionally show no difference in the risk of death or myocardial infarction by 3 years, or within subpopulations by 1 year.ConclusionsBenchmarking before using observational data to extend treatment effects from a randomized trial allows us to understand if the observational data, and assumptions made when analyzing these data, can be trusted to deliver valid estimates of treatment effects.
IgM antibodies against phosphorylcholine measured early after acute ST-elevation myocardial infarction in relation to atherosclerotic disease burden and long-term clinical outcome
