Perspective:

The data published here differ from prior publications of clinical trials for NOACs versus warfarin in atrial fibrillation, in that data from small phase II studies are included, and the results are aggregated for all of the novel agents. For the clinician, this offers little insight, as the phase II studies are so small that they would not alter the results from the large phase III studies. Furthermore, for the practicing clinician, a better understanding of the risks versus benefits is needed for individual agents, and it is probably not valid to assess the NOACs as a group. Each of the NOACs had individually demonstrated a statistically significant reduction in the incidence of intracranial hemorrhage, so this finding can certainly be generalizable and is a major advantage of the NOACs over warfarin. As for proven mortality and stroke risk reduction versus warfarin, only high-dose dabigatran and apixaban can make that claim based on RCTs, with rivaroxaban falling just short of superiority in the intention-to-treat analysis. Such individual agent comparisons seem the only reasonable data to consider when making patient management decisions. Aggregating data for all NOACs does not make sense, and should not be used to make clinical decisions. Most importantly, as the authors emphasize, real-world data are clearly needed to corroborate that the results obtained in closely monitored clinical trials are reproducible.