Safety of Switching From a Vitamin K Antagonist to a Non-Vitamin K Antagonist Oral Anticoagulant in Frail Older Patients With Atrial Fibrillation: Results of the FRAIL-AF Randomized Controlled Trial.

BACKGROUND: There is ambiguity whether frail patients with atrial fibrillation managed with vitamin K antagonists (VKAs) should be switched to a non-vitamin K oral anticoagulant (NOAC). METHODS: We conducted a pragmatic, multicenter, open-label, randomized controlled superiority trial. Older patients with atrial fibrillation living with frailty (≥75 years of age plus a Groningen Frailty Indicator score ≥3) were randomly assigned to switch from international normalized ratio-guided VKA treatment to an NOAC or to continued VKA treatment. Patients with a glomerular filtration rate <30 mL·min-1·1.73 m-2 or with valvular atrial fibrillation were excluded. Follow-up was 12 months. The cause-specific hazard ratio was calculated for occurrence of the primary outcome that was a major or clinically relevant nonmajor bleeding complication, whichever came first, accounting for death as a competing risk. Analyses followed the intention-to-treat principle. Secondary outcomes included thromboembolic events. RESULTS: Between January 2018 and June 2022, a total of 2621 patients were screened for eligibility and 1330 patients were randomly assigned (mean age 83 years, median Groningen Frailty Indicator score 4). After randomization, 6 patients in the switch-to-NOAC arm and 1 patient in the continue-with-VKA arm were excluded due to the presence of exclusion criteria, leaving 662 patients switched from a VKA to an NOAC and 661 patients continued VKAs in the intention-to-treat population. After 163 primary outcome events (101 in the switch arm, 62 in the continue arm), the trial was stopped for futility according to a prespecified futility analysis. The hazard ratio for our primary outcome was 1.69 (95% CI, 1.23-2.32). The hazard ratio for thromboembolic events was 1.26 (95% CI, 0.60-2.61). CONCLUSIONS: Switching international normalized ratio-guided VKA treatment to an NOAC in frail older patients with atrial fibrillation was associated with more bleeding complications compared with continuing VKA treatment, without an associated reduction in thromboembolic complications. REGISTRATION: URL: https://eudract.ema.europa.eu; Unique identifier: 2017-000393-11. URL: https://eudract.ema.europa.eu; Unique identifier: 6721 (FRAIL-AF study).

Interference in point-of-care international normalized ratio monitoring in patients with lupus anticoagulant is correlated with anti-ß2-glycoprotein I antibody titers.

Background: Patients with antiphospholipid syndrome (APS) receive anticoagulant therapy with vitamin K antagonists (VKAs) to prevent recurrent thrombosis. VKA treatment requires strict monitoring with an international normalized ratio (INR). It is known that lupus anticoagulants (LAs) can lead to elevated INR results with point-of-care-testing (POCT) devices, which could result in inadequate adaptation of anticoagulant therapy. Objective: To determine discrepancies between POCT-INR and laboratory-INR in patients who are LA-positive on VKA therapy. Methods: Paired INR testing was performed with 1 POCT device (CoaguChek XS) and 2 laboratory assays (Owren and Quick method) in 33 patients with LA-positive APS on VKA in a single-center cross-sectional study. Patients were tested for anti-ß2-glycoprotein I, anticardiolipin, and antiphosphatidylserine/prothrombin immunoglobulin (Ig) G and IgM antibodies. Agreement between assays was evaluated with Spearman's correlation, Lin's correlation coefficient, and Bland-Altman plots. Agreement limits were considered satisfactory if differences were ≤20% as determined by the Clinical and Laboratory Standards Institute. Results: We found poor agreement between POCT-INR and laboratory-INR based on Lin's concordance correlation coefficient (ρc) of 0.42 (95% CI, 0.26-0.55) between POCT-INR and Owren-INR, a ρc of 0.64 (95% CI, 0.47-0.76) between POCT-INR and Quick-INR, and a ρc of 0.77 (95% CI, 0.64-0.85) between Quick-INR and Owren-INR. High anti-ß2-glycoprotein I IgG antibody titers correlated with INR disagreement between POCT-INR and laboratory-INR. Conclusion: There is a disagreement between INR values measured with the CoaguChek XS and laboratory-INR in a proportion of patients with LA. Consequently, laboratory-INR monitoring should be preferred over POCT-INR monitoring in patients with LA-positive APS, especially in patients with high anti-ß2-glycoprotein IgG antibody titers.

Safety of switching from vitamin K antagonist to non-vitamin K antagonist oral anticoagulant in frail elderly with atrial fibrillation: rationale and design of the FRAIL-AF randomised controlled trial.

INTRODUCTION: Clinical guidelines recommend non-vitamin K antagonist oral anticoagulants (NOACs) over vitamin K antagonists (VKAs) for stroke prevention in most patients with atrial fibrillation (AF). Frail elderly were under-represented in the landmark NOAC-trials, leaving a knowledge gap on the optimal anticoagulant management (VKA or NOAC) in this increasing population. The aim of the Frail-AF (FRAIL-AF) study is to assess whether switching from international normalised ratio (INR)-guided VKA-management to a NOAC-based treatment strategy compared with continuing VKA-management is safe in frail elderly patients with AF. METHODS AND ANALYSIS: The FRAIL-AF study is a pragmatic, multicentre, open-label, randomised controlled clinical trial. Frail elderly (age ≥75 years plus a Groningen Frailty Indicator score ≥3) who receive VKA-treatment for AF in the absence of a mechanical heart valve or severe mitral valve stenosis will be randomised to switch to a NOAC-based treatment strategy or to continue INR-guided VKA-management. Patients with severe renal impairment (estimated glomerular filtration rate <30 mL/min/1.73 m2) will be excluded from randomisation. Based on existing trial evidence in non-frail patients, we will aim to explore whether NOAC-treatment is superior to VKA-therapy in reducing major or clinically relevant non-major bleeding events. Secondary outcomes include minor bleeding, the composite of ischaemic and haemorrhagic stroke, health-related quality of life and cost-effectiveness. The follow-up period for all subjects is 12 months. ETHICS AND DISSEMINATION: The protocol was approved by the Medical Research Ethics Committee of the University Medical Center Utrecht, the Netherlands and by the Central Committee on Research Involving Human Subjects, the Netherlands. All patients are asked written informed consent. Results are expected in 2022 and will be disseminated through peer-reviewed journals as well as presentations at national and international conferences. TRIAL REGISTRATION NUMBER: EudraCT: 2017-000393-11; The Netherlands Trial Registry: 6721 (FRAIL-AF study).