December 11, 2014Open Access

Efficacy and Safety of Non-Vitamin K Antagonist Oral Anticoagulants vs. Warfarin in Japanese Patients With Atrial Fibrillation

Q: What is the clinical evidence from this study?

Study design: Meta-Analysis. Population: Non-valvular atrial fibrillation (n=1940). Intervention: Non-vitamin K antagonist oral anticoagulants (NOAC) vs. Warfarin. Primary outcome: Composite of stroke and systemic embolism (RR 0.45, 95% CI 0.24-0.85).

Key Result

Non-vitamin K antagonist oral anticoagulants reduced the risk of stroke and systemic embolism by 55% (RR 0.45) compared to warfarin in Japanese patients with non-valvular atrial fibrillation.

Study Design

Type

Meta-Analysis (n=1,940)

Structured PICO

Do NOACs reduce stroke and systemic thromboembolism compared to warfarin in Japanese patients with NVAF?

Population

1,940 Japanese patients with non-valvular atrial fibrillation (NVAF) pooled from 3 RCTs

Intervention

Non-vitamin K antagonist oral anticoagulants (NOAC)

Comparator

Warfarin

Outcome

Stroke and systemic thromboembolismhard clinical

NOACs are more efficacious than warfarin for preventing stroke and systemic embolism in Japanese patients with NVAF, with a trend toward lower bleeding risks.

Main Result

Effect estimate: RR 0.45 (95% CI 0.24-0.85)

Limitations

Heterogeneity between the 3 trials and residual confounding from differences in patient demography, comorbidities, and concomitant use of cardiovascular prevention strategies
The 3 trials investigated different oral anticoagulant drugs
Patients taking warfarin in the J-ROCKET AF trial had a target INR 1.6-2.6, while target INR was 2.0-3.0 in the other 2 trials
Half of the study patients were derived from the J-ROCKET AF trial, which was not powered to test for efficacy and evaluated efficacy in per-protocol groups

Abstract

BACKGROUND: Non-vitamin K antagonist oral anticoagulants (NOAC) have been developed as alternatives to warfarin. Until recently, the latter was the standard oral anticoagulant for patients with non-valvular atrial fibrillation (NVAF). The efficacy and safety of NOAC in Japanese patients with NVAF has been investigated in small trials or subgroups from global randomized control trials (RCT). METHODS AND RESULTS: We conducted a systematic review and meta-analysis of RCT, to compare the efficacy and safety of NOAC to those of warfarin in Japanese patients with NVAF. Published research was systematically searched for RCT that compared NOAC to warfarin in Japanese patients with NVAF. Random-effects models were used to pool efficacy and safety data across RCT. Three studies, involving 1,940 patients, were identified. Patients randomized to NOAC had a decreased risk for stroke and systemic thromboembolism (relative risk RR, 0.45; 95% CI: 0.24-0.85), with a non-significant trend for lower major bleeding (RR, 0.66; 95% CI: 0.29-1.47), intracranial bleeding (RR, 0.46; 95% CI: 0.18-1.16) and gastrointestinal bleeding (RR, 0.52; 95% CI: 0.25-1.08). CONCLUSIONS: NOAC are more efficacious than warfarin for the prevention of stroke and systemic embolism in Japanese patients with NVAF. The present findings offer clinicians a more comprehensive picture of NOAC as a therapeutic option to reduce the risk of stroke in Japanese NVAF patients.

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