Direct Oral Anticoagulant (DOAC) Dosing in Patients with Non-valvular Atrial Fibrillation (NVAF) in the United Kingdom: A Retrospective Cohort Study Using CPRD Gold Database.

INTRODUCTION: Per-label dosing of direct oral anticoagulants (DOACs) is important for the prevention of stroke and systemic embolism among patients with non-valvular atrial fibrillation (NVAF), especially those with poor renal function, advanced age, low body weight or concomitant P-glycoprotein inhibitors. The study described DOAC use and dosing patterns in patients with NVAF in the UK. METHODS: Using Clinical Practice Research Datalink (CPRD Gold), patients' profiles were described at DOAC initiation (1 January 2016-31 March 2021) and followed for a mean [standard deviation (SD)] 2 (1) years. Patients were categorised as under-dosing: received a lower dose with no indication for a reduced dose; over-dosing: received a standard dose with an indication for a reduced dose; per-label dosing, according to Summary Product Characteristics (SmPC). RESULTS: Forty thousand seven hundred forty-four adult patients with NVAF were identified (mean age: 75.3 (11.2) years; males: 55.4%); 22,827 (56.0%) initiated treatment with apixaban, 930 (2.3%) dabigatran, 5633 (13.8%) edoxaban and 11,354 (27.9%) rivaroxaban. Baseline Charlson comorbidity index ≥ 4 was 65.1%; CHA2DS2-VASc score ≥ 4 was 22.5%; HAS-BLED score ≥ 3 was 18.3%; ~ 2% had prior major bleed and 4.4% a stroke ≤ 2 years before DOAC initiation. Overall, 18.0% of patients received incorrect dosing (~ one in five). Under-dosing was highest for dabigatran (156, 16.8%) and over-dosing was highest for rivaroxaban (1084, 9.6%). Per-label dosing was highest for edoxaban (4773, 84.7%), followed by apixaban (18,756, 82.2%), rivaroxaban (9161, 80.7%) and dabigatran (732, 78.7%). Treatment persistence (no switching or discontinuation) was 79% among edoxaban users, followed by 75% for apixaban, 69% for rivaroxaban and 62% for dabigatran. About 15% of dabigatran users, 10% of rivaroxaban users, 5% of apixaban users and 4% of edoxaban users switched treatment to another DOAC during follow-up. CONCLUSION: Although most patients received per-label dosing, ~ one in five patients was incorrectly dosed with DOAC, which may lead to serious clinical consequences and increased healthcare burden.

Increased Risk of Stroke Due to Non-adherence and Non-persistence with Direct Oral Anticoagulants (DOACs): Real-World Analyses Using a Nested Case-Control Study from The Netherlands, Italy and Germany.

BACKGROUND: A high degree of adherence to direct oral anticoagulants is essential for reducing the risk of ischaemic stroke and systemic embolism in patients with atrial fibrillation, owing to the rapid decline in anticoagulation activity when doses are omitted (i.e. rebound effect). OBJECTIVE: We aimed to assess the relationship between non-adherence and non-persistence with direct oral anticoagulants and the incidence of ischaemic stroke in patients with atrial fibrillation. METHODS: A nested case-control study was conducted in the Netherlands, Italy and Germany among patients with atrial fibrillation starting direct oral anticoagulants between the drug approval date and the end of database availability. Patients with an ischaemic stroke during the follow-up were selected as cases and compared with matched controls (matched on age ± 5 years, sex, year of cohort entry date and CHA2DS2-VASc-score at cohort entry date). The cohort entry date was the first dispensing date. Study patients were those aged ≥ 45 years, with ≥ 1 year database history, ≥ 1 year follow-up and at least two direct oral anticoagulant dispensings after the cohort entry date. Adherence and persistence to direct oral anticoagulant treatment were defined as the proportion of days covered ≥ 80% or direct oral anticoagulant continuous use between the cohort entry date and the index date (i.e. date of ischaemic stroke), respectively. RESULTS: In The Netherlands, Italy and Germany, 105 cases and 395 controls, 1580 cases and 6248 controls, and 900 cases and 3570 controls were included, respectively. Odds ratios (ORs) for stroke among current users who were non-adherent compared to adherent users were 0.43 (95% confidence interval [CI] 0.09-1.96) in The Netherlands, 1.11 (95% CI 0.98-1.26) in Italy and 1.21 (95% CI 1.01-1.45) in Germany. The risk of stroke was significantly higher among non-persistent users compared with persistent users in all three databases [OR 1.56 (95% CI 1.00-2.44), OR 1.48 (1.32-1.65) and OR 1.91 (95% CI 1.64-2.22), respectively]. In The Netherlands and Germany, the risk of stroke was higher the longer a patient had stopped using direct oral anticoagulants. CONCLUSIONS: Both non-adherence (in Germany) and non-persistence increased the risk of stroke, either using a once-daily or twice-daily regime.

Adherence and Persistence with Once-Daily vs Twice-Daily Direct Oral Anticoagulants Among Patients with Atrial Fibrillation: Real-World Analyses from the Netherlands, Italy and Germany.

BACKGROUND: Direct oral anticoagulants are available for patients with atrial fibrillation. OBJECTIVE: This study compared adherence and persistence of once-daily (QD) vs twice-daily (BID) direct oral anticoagulants in patients with atrial fibrillation. METHODS: A cohort study was conducted in three databases in the Netherlands, Italy and Germany. Patients with AF starting direct oral anticoagulants after drug approval date were included. The index date was the date of first dispensing. Study patients were restricted to those aged ≥ 18 years, ≥ 1 year database history and ≥ 1 year follow-up. Adherence to treatment was defined as the proportion of days covered ≥ 80% between the index date and the date of last dispensing of the index regimen (i.e. exposure period). The proportion of days covered was also determined during the 12-month follow-up. Persistence was defined as continuous use from index to treatment discontinuation. RESULTS: In the Netherlands, Italy and Germany, respectively, 6068, 32,260 and 167,445 patients were included. The mean age of the patients was 70, 77 and 74 years, and 31%, 40% and 61% were QD users, all respectively. Among QD/BID users, 93/90%, 88/86% and 77/58%, respectively were adherent during the exposure period. Persistence rates at 1 year in QD/BID users were 60/59%, 13/14% and 46/31%, respectively. CONCLUSIONS: Adherence to treatment was high. In Germany, adherence was markedly higher in QD users compared with BID users. In Italy and the Netherlands, these differences were marginal. Persistence was low in all countries, but discontinuation was temporary. Only in Germany, persistence was markedly lower in BID users vs QD users.