The use of vitamin K antagonists (VKAs) by patients with COPD and atrial fibrillation is not associated with worse respiratory outcomes, according to findings of a national cohort study by Bård-Emil Vang Vang Gundersen, MD, and colleagues.
Although VKAs are an option for treatment of atrial fibrillation, direct oral anticoagulants (DOACs) are the recommended anticoagulant treatment for nonvalvular atrial fibrillation and atrial flutter. Because VKAs inhibit vitamin K recycling and may contribute to functional deficiency, the researchers hypothesized that patients treated with VKAs “might be at increased risk of disease progression, reflected by higher rates of AE-COPD [acute exacerbation of COPD] and all-cause mortality.”
They used Danish national health registers to identify 7,091 patients with moderate to severe COPD and atrial fibrillation or flutter who were receiving anticoagulation treatment. Of this group, 3,455 (48.7%) received VKAs, and the rest received DOACs.
The study’s primary end point was a composite of hospitalization due to AE-COPD and all-cause mortality within 365 days. Overall, 1,955 patients reached the end point within 365 days, 820 from the VKA group and 1,135 from the DOAC group.
In the adjusted analysis, treatment with VKA was associated with a slightly lower risk for hospitalization due to AE-COPD or death than treatment with a DOAC (adjusted hazard ratio [aHR], 0.87; 95% CI, 0.78-0.98; P=0.024). This relationship, however, was not statistically significant in sensitivity analyses that were restricted to complete cases (aHR, 0.88; 95% CI, 0.76-1.01; P=0.079) or inverse probability of treatment-weighted models (HR, 0.85; 95% CI, 0.72-1.01; P=0.070).
However, contrary to the initial hypothesis, the evidence did not show that there is any harm related to VKA therapy. “We did not observe an increased risk of experiencing an AE-COPD or death when being treated with VKAs. On the contrary, we observed a lower risk of AE-COPD or death among VKA users,” the authors wrote. They added, “This study has shown no negative impact of VKA treatment in patients with COPD.”
The researchers acknowledged that their observational study design limited their ability to draw causal conclusions and prevented them from examining pharmacologic mechanisms in detail. They recommended future randomized trials to gain a better understanding of long-term lung outcomes of anticoagulant treatment for patients with COPD and atrial fibrillation.
