From Dave McGlasson, George I just read an excellent article by Dr. Jeff Dlott of Quest Diagnostics, Dlott JS, George RA, Huang X, et al. National assessment of warfarin anticoagulation therapy for stroke prevention in atrial fibrillation. Circulation 2014;129: 1407–14 that discusses INR time in therapeutic range (TTR, 2–3) during the first 6 months of warfarin therapy. Dlott’s group assessed “real-world TTRs” based on 2.6 million INR values processed by Quest labs in the United States. These subjects had INR levels drawn because they were receiving warfarin for preventing ischemic stroke secondary to atrial fibrillation. The overall TTR was only 48%, which is abysmal. They also found that the fewer the subjects being monitored in a practice the smaller the TTR. Conversely, the more subjects managed in a practice the higher the TTR.
Using local records, I found the TTR in “real world subjects” was a lot lower than in the closely controlled clinical trials that compared warfarin to the target-specific oral anticoagulants (TSOACs, direct oral anticoagulants, DOACs). I wonder if you can put out the question of how well the TTR in your subscribers’ practices compares?