Remark: When possible, experienced specialized anticoagulation clinics should be utilized for VKA and INR management. Factors Affecting INR Control: Many factors affect TTR, including patient-related aspects (eg, age, sex, socioeconomic status, diet, ethnicity, hospitalization, length of time on VKA, medical and psychiatric comorbidities, nonadherence, polypharmacy, genetic and health-care system-related factors, particularly how VKA is managed (by country, setting of OAC management [eg, anticoagulation clinic vs physician/community-based practices]),90,161,162 distance to OAC clinic,161,162 self-monitoring/self- frequency of INR monitoring, etc.156 It is also important to note that site-level variation in VKA management has also been demonstrated in RCTs163-167 and for NOACs.168 The value of dietary measures to improve anticoagulation control is debatable, and it is perhaps more relevant to maintain a stable dietary habit, avoiding wide changes in the intake of vitamin K.169 Among patients initiating VKA, the time to achieve therapeutic range has also been related to the likelihood of achieving a subsequently good TTR.170,171 The more common clinical factors in uencing TTR have been used to formulate the SAMe-TT2R2 (awarding 1 point for each of the following: sex [female]; age <60 years; medical history [$3 comorbidities: hypertension, diabetes, coronary heart disease/myocardial infarction, peripheral artery disease, heart failure, prior stroke, lung disease, liver disease or renal failure]; treatments [such as amiodarone]; smoking status [double]; and race [non- Caucasian, double]) score172,173 (Table 5). This clinical score is based on routine clinical parameters, which can be used to identify patients who may be able to attain good anticoagulation control (eg, TTR $ 65%) with a VKA and those who probably will not, where an NOAC may be preferred or where other interventions (eg, more frequent INR monitoring, patient education/counseling, etc) may need to be implemented to ensure good INR control. 