Long-term vitamin K antagonists treatment patterns of Non-Valvular Atrial Fibrillation (NVAF): a population-based cohort study

Risk of fracture in patients with non-valvular atrial fibrillation initiating direct oral anticoagulants vs. vitamin K antagonists

AIMS

To determine the risk of fracture associated with direct oral anticoagulants (DOACs) compared with vitamin K antagonists (VKAs) in patients with non-valvular atrial fibrillation (NVAF), accounting for cumulative duration of use.

METHODS AND RESULTS

Using Quebec administrative healthcare databases, we formed a cohort of all patients aged 40 years or older newly diagnosed with NVAF, who filled a first prescription for DOACs or VKAs between 2011 and 2014. Exposure was modelled as a time-varying variable whereby patients were considered unexposed up to 180 days of cumulative duration of use (to account for a biologically meaningful exposure) and exposed thereafter. The final cohort included 10 306 new users of DOACs and 15 357 new users of VKAs. After propensity score-based fine stratification and weighting, use of DOACs for 180 days or greater was associated with a 35% decreased risk of fracture [crude incidence rates 7.5 vs. 15.3 per 1000 person-years; adjusted hazard ratio (HR) 0.65, 95% confidence interval (CI) 0.46-0.91] compared to VKA duration ≥180 days. Direct oral anticoagulants use was also associated with a lower risk of hip fracture (HR 0.51, 95% CI 0.31-0.86) compared with VKAs. There was no difference in the rate of fracture for shorter duration of use (HR 1.10; 95% CI 0.79-1.53). The risk was not modified by age, sex, chronic kidney disease, osteoporosis, history of fracture or falls.

CONCLUSION

Prolonged use of DOACs is associated with a lower risk of fracture compared with VKAs. These findings support the first-line recommendation for DOACs in patients with NVAF.

Non-Vitamin K Antagonist Oral Anticoagulants and Risk of Serious Liver Injury

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) are relatively new drugs used for stroke prevention in nonvalvular atrial fibrillation (NVAF). However, there are concerns that their use may be associated with hepatotoxic effects.

OBJECTIVES

The purpose of this study was to determine whether the use of NOACs is associated with an increased risk of serious liver injury compared with the use of vitamin K antagonists (VKAs) in NVAF patients with and without prior liver disease.

METHODS

Using the administrative databases of the Canadian province of Quebec's health insurances, the authors conducted a cohort study among patients newly diagnosed with NVAF between January 2011 and December 2014. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of serious liver injury (defined as either a hospitalization or related death) were estimated using time-dependent Cox proportional hazards models, comparing current use of NOACs to current use of VKAs separately among patients with or without prior liver disease.

RESULTS

The cohort comprised 51,887 patients, including 3,778 with prior liver disease. During 68,739 person-years of follow-up, 585 patients experienced a serious liver injury. Compared with current use of VKAs, current use of NOACs was not associated with an increased risk of serious liver injury in patients without or with prior liver disease (adjusted HR: 0.99; 95% CI: 0.68 to 1.45; and adjusted HR: 0.68; 95% CI: 0.33 to 1.37, respectively).

CONCLUSIONS

Compared with VKAs, NOACs were not associated with an increased risk of serious liver injury irrespective of baseline liver status. Overall, these results provide reassurance regarding the hepatic safety of NOACs.

Profiling Clinical Characteristics and Treatment Patterns Among Non-Valvular Atrial Fibrillation Patients: A Real-World Analysis in Dubai, United Arab Emirates

Background:

There is a dearth of real-world evidence regarding patient characteristics, Oral Anti-Coagulant (OAC) treatment, and International Normalized Ratio (INR) patterns in Dubai, United Arab Emirates (UAE).

Methods:

This was a retrospective observational study among newly diagnosed adult Non-valvular Atrial Fibrillation (NVAF) patients in the Dubai Real World Claims Database. Selected patients had at least one activity claim during the 12 months pre-index date (baseline period), and a pharmacy claim for apixaban, dabigatran, rivaroxaban, or warfarin from 01 JAN 2015-31 JUL 2017. Patients with valvular heart disease, cardiac surgery, venous thromboembolism, transient atrial fibrillation, pregnancy, or OAC claims during baseline were excluded. Comorbidities and treatment patterns related to OAC use, index dosing, baseline medications, and INR patterns were described.

Results:

Among 5,072 NVAF patients, 468 met the study criteria. A minority of them (14.3%) were prescribed warfarin, and the most frequently prescribed non-vitamin K antagonist OACs (NOACs) were rivaroxaban (33.3%) and apixaban (31.4%), followed by dabigatran (20.9%). Patients’ mean age was 59 years and mean CHA2DS2-VASc score was 2.3, with most frequent comorbidities of diabetes mellitus, hypertension, coronary artery disease, and peripheral vascular disease. Additionally, 51% and 33% were on statins and aspirin, respectively, while 39% were on other anticoagulant agents. A large proportion of dabigatran patients were on a lower dose (57%). INR patterns revealed 13% of rivaroxaban, 12% of apixaban, and 7% of dabigatran patients had INR claims.

Conclusion:

This study provides relevant insights into the use of OACs in real-world clinical practice settings in Dubai, UAE.

The use of anticoagulants in patients with non-valvular atrial fibrillation between 2005 and 2014: A drug utilization study using claims data in Japan

Background

Anticoagulant therapy is recommended in patients with atrial fibrillation (AF) but remains underused. The proper use of anticoagulants has been encouraged in guidelines frequently published over the past two decades.

Materials and methods

In this study, we used insurance claims data collected from 2005 to 2014 to investigate the prevalence and incidence of non-valvular AF (NVAF) patients aged 20 to 74 years standardized to the Japanese population in 2012 and subdivided by stroke prevention drug type. We estimated the frequency of coagulation monitoring in patients with incident NVAF undergoing warfarin therapy in 2011 and later.

Results

From 2005 to 2014, the standardized prevalence of NVAF increased from 117/100,000 to 278/100,000 and the proportion of anticoagulant users increased from 38.4% to 58.0%, while that of antiplatelet monotherapy decreased from 32.3% to 12.0%. The standardized incidence of NVAF was stable at ~40/100,000 patient-years. The proportion of those patients who started anticoagulant soon after the initial diagnosis increased from 19.9% to 49.1% from 2006 to 2013. Among patients who started warfarin, switchers to DOAC had more frequent coagulation monitoring than non-switchers.

Conclusion

The use of anticoagulant therapy has gradually increased in patients with NVAF in Japan during the study period from 2005 to 2014.

Use of direct oral anticoagulants in patients with nonvalvular atrial fibrillation according to clinical profile

The majority of patients with atrial fibrillation should receive oral anticoagulation to reduce the risk of stroke. The limitations of vitamin K antagonists have led to an underuse of anticoagulants in clinical practice which has been associated with a higher risk of stroke, hospitalizations and healthcare costs. Direct oral anticoagulants (DOACs) overcome some of the limitations of vitamin K antagonists and may therefore increase the use of oral anticoagulants in clinical practice. Since no head-to-head trials have been performed, only indirect comparisons can be made among them. In this review, the results of the Phase III randomized controlled trials with DOACs were analyzed, trying to determine whether one or more DOACs could be especially recommended according to different clinical conditions.