Numerous studies have demonstrated that the risk of thromboembolism, major bleeding, and death is lower when the proportion of TTR is higher, at least Indeed, random one off INR values give little insight into the degree of anticoagulation control, and many adverse outcomes (eg, bleeding) occur even within the therapeutic INR range of 2.0 to Thus, when VKAs are used, attention should be focused on the average individual TTR as a measure of the quality of anticoagulation control. Clinical guidelines on the management of AF advocate an individual TTR of at least $ 65%157,158 to maximize ef cacy and safety, and this should be the treatment target, although in clinical practice this may be more dif cult to achieve.153-156,159 An analysis of anticoagulation control in the Global Anticoagulation Registry in the Field [GARFIELD-AF] registry (n 9,934), a global observational study, revealed that only 1156 Evidence-Based Medicine [ 1 5 4 # 5 C H E S T N O V E M B E R 2 0 1 8 ] 41.1% had TTR $ 65% and of all the INR values, only 51.4% were in the therapeutic range (INR, 2.0 to 3.0), with one-third being subtherapeutic.155 After adjustment, the risk of stroke/systemic embolism (HR, 95% CI, 1.87-3.06), and major bleeding (HR, 1.54; 95% CI, 1.04-2.26) was greater with TTR < 65%, when compared with TTR $ 65%.155 TTR varies widely by geographical region (TTR $ 65%, An analysis of individual TTR from Swedish registries (n 40,449) revealed an overall mean individual TTR of 68.6% and signi cantly lower annual rates of thromboembolism (2.37% vs 4.41%), all-cause mortality when individual TTR was $ 70% compared with individual TTR < 70%, respectively.154 Recommendation 10. 