Subtherapeutic Anticoagulation Control under Treatment with Vitamin K-Antagonists—Data from a Specialized Coagulation Service

Abstract

In contrast to overanticoagulation, evidence on risk factors and outcome of subtherapeutic oral anticoagulation (OAC) with vitamin K-antagonists (VKAs) under optimum care is limited. We investigated the clinical phenotype, anticoagulation control, and clinical outcome of 760 VKA patients who received OAC therapy by a specialized coagulation service in the thrombEVAL study (NCT01809015). During 281,934 treatment days, 278 patients experience ≥ 1 episode of subtherapeutic anticoagulation control and had lower quality of OAC therapy compared to 482 patients without subtherapeutic international normalized ratio: 67.6%, interquartile range (IQR) 54.9%/76.8% versus 81.0%, IQR 68.5%/90.4%; p < 0.001. In Cox regression analysis with adjustment for age, sex, cardiovascular risk factors, comorbidities, and treatment characteristics, female sex (hazard ratio [HR], 1.4, 95% confidence interval [CI], 1.0/1.9; p = 0.03), diabetes (HR, 1.4, 95% CI, 1.0/2.0; p = 0.03), and living alone (HR, 1.5, 95% CI, 1.1/2.1; p = 0.009) were independent risk factors of subtherapeutic anticoagulation control, whereas atrial fibrillation (HR, 0.6, 95% CI, 0.4/0.9; p = 0.02) and self-management of OAC therapy (HR, 0.2, 95% CI, 0.1/0.6; p = 0.001) were protective. In addition, active smoking (HR, 1.7, 95% CI, 0.9/3.0; p = 0.086) and living in a nursing home (HR, 1.6, 95% CI, 0.8/3.2; p = 0.15) indicated an elevated risk at the borderline of statistical significance. For the prediction of recurrent subtherapeutic anticoagulation, living alone was the only independent risk factor (HR, 1.7, 95% CI, 1.1/2.5; p = 0.013). The present study suggests that women, diabetics, and patients living alone experience an increased risk of low-quality VKA therapy and might potentially benefit from treatment with direct-acting anticoagulants.

Efficacy and safety of direct-acting oral anticoagulants compared to vitamin K antagonists in COVID-19 outpatients with cardiometabolic diseases

“…These include the identification and modification of causes of poor anticoagulation control with VKAs (eg. potential pharmacologic interactions), routine assessment of adherence to treatment, patient-centred education/counselling and educational programs for healthcare professionals, the use of multidose drug dispensing systems, self-management of VKA therapy, specialized anticoagulation clinics to improve adherence and a more careful follow-up [ 57 , 58 ]. Due to the COVID-19 pandemic, telemedicine visits and telehealth programs may help to achieve these objectives while minimize exposure risks for both patients and healthcare professionals [ 59 ].…”

A nurse‐led atrial fibrillation clinic: Impact on anticoagulation therapy and clinical outcomes

“…[28][29][30] It could be hypothesised that the careful and more frequent follow-up provided in the nurse-led clinic may identify potential users of DOACs more easily, eg because of poor anticoagulation control with VKAs. Given that labile INR or poor anticoagulation quality is associated with a raised risk of adverse events, 31,32 such patients would benefit from switching to DOACs. When DOACs are not an available option, the nurse-led clinic could be helpful in reminding patients of the importance of good adherence to VKAs, as well as review of interacting drugs/foods, and those factors affecting the quality of VKA therapy.…”

Relation of the ‘Atrial Fibrillation Better Care (ABC) Pathway’ to the Quality of Anticoagulation in Atrial Fibrillation Patients Taking Vitamin K Antagonists

“…However, the efficacy and tolerability of VKAs depends on the quality of anticoagulant control, as reflected by the mean time in therapeutic range (TTR) of international normalized ratio (INR) 2.0 to 3.0 [ 11 ]. Indeed, a high TTR translates into a lower risk of adverse events [ 12 , 13 , 14 ]. However, there is no evidence to date whether a more holistic approach to management of AF as reflected by the ABC pathway is associated with better quality of anticoagulation control in VKA users.…”