To the Editor Hernandez et al1 presented a study comparing the bleeding risk from a 5% random sample of Medicare patients treated with dabigatran etexilate or warfarin who were newly diagnosed as having atrial fibrillation. It is important to put their results into perspective with the very different results of the recently published study by Graham et al2 involving a 1-year–longer study period and a more than 50-fold–larger dabigatran population of Medicare patients compared with those in the study by Hernandez et al1 (67 207 vs 1302). Some of those data2 had been published in May 20143 but were not discussed by Hernandez et al.1 To better understand the discrepant results of the 2 studies, some open questions have to be considered.
Zint K, Kreuzer J. A Methodological Appraisal of Recent Real-World Data Publications on Dabigatran. JAMA Intern Med. 2015;175(7):1244. doi:10.1001/jamainternmed.2015.1280