Comparative effectiveness and safety of non-vitamin-K antagonist oral anticoagulants and warfarin in older adults with atrial fibrillation and diabetes

Abstract

Objective

To evaluate comparative effectiveness and safety of non-vitamin-K antagonist oral anticoagulants (NOACs) versus warfarin in Medicare beneficiaries with non-valvular atrial fibrillation (NVAF) and comorbid diabetes mellitus (DM).

Methods

A retrospective cohort study using 2014–2016 5% national Medicare data was undertaken. NVAF patients with DM aged ≥65 years having at least one prescription for NOACs or warfarin between July 2014 and December 2015 were included in the study. Propensity score matching was used to balance demographic and baseline clinical characteristics of patients in two treatment groups. Cardiovascular outcomes including stroke/systemic embolism (SE) and myocardial infarction (MI) were evaluated to measure effectiveness. Assessment of safety outcomes included intracranial hemorrhage (ICH), major gastrointestinal bleeding (MGB), bleeding from other sites (OB) and all-cause mortality. Stratified Cox proportional hazards models were used to estimate hazard ratios for the outcomes in the matched cohort.

Results

The matched sample consisted of 4582 patients (2291 pairs). Compared to warfarin, NOACs had a significantly lower risk of stroke/SE (hazard ratio (HR): 0.373, 95% confidence interval (CI): 0.247−0.564, p < .001) and all-cause mortality (HR: 0.783, CI: 0.656−0.873, p = .007). NOACs were found to significantly reduce the risk of ICH (HR: 0.500, CI: 0.300−0.834, p = .008) and OB (HR: 0.608, CI: 0.424−0.870, p = .007), but no difference was observed in the risk of MGB (HR: 0.862, CI: 0.640−1.160, p = .326) between NOACs and warfarin. The composite outcome demonstrated superior overall effectiveness and safety of NOAC therapy compared to warfarin therapy (HR: 0.685, CI: 0.587−0.801, p < .001).

Conclusion

Oral anticoagulation therapy with NOACs was found to be more effective than warfarin therapy among older adults with NVAF and comorbid DM.

Keywords:

• Warfarin
• novel oral anticoagulants
• atrial fibrillation
• diabetes
• Medicare

Transparency

Declaration of funding

No funding to be declared.

Declaration of financial/other relationships

No potential conflict of interest was reported by the authors.

Author contributions

S.K. and Y.Y. were involved in the study conception and design. Analysis and interpretation were conducted by S.K. under the guidance of Y.Y. and J.P.B. Primary draft of the manuscript was written by S.K., and reviewed critically for intellectual content by Y.Y., J.P.B. and B.B.

Acknowledgements

No assistance in the preparation of this article is to be declared.