Objectives

• Assess the quality of INR control in a population-based cohort of new users of vitamin K antagonist with a diagnosis of atrial fibrillation.
• To describe the factors associated with suboptimal control of anticoagulation levels with VKA in the 12 months after starting VKA (patient characteristics, risk, use of healthcare resources).
• Assess the quality of INR control in atrial fibrillation patients treated with VKA in the region of Valencia, Spain.
• Quantified switching to Non-VKA oral anticoagulants (NOAC).

Quality of INR control and switching to non-Vitamin K oral anticoagulants between women and men with atrial fibrillation treated with Vitamin K Antagonists in Spain. A population-based, real-world study.

• Worldwide, there is growing evidence that quality of international normalized ratio (INR) control in atrial fibrillation patients treated with Vitamin K Antagonists (VKA) is suboptimal. However, sex disparities in population-based real-world settings have been scarcely studied, as well as patterns of switching to second-line Non-VKA oral anticoagulants (NOAC). We aimed to assess the quality of INR control in atrial fibrillation patients treated with VKA in the region of Valencia, Spain, for the whole population and differencing by sex, and to identify factors associated with poor control. We also quantified switching to Non-VKA oral anticoagulants (NOAC) and we identified factors associated to switching.
   
• Results: We included 22,629 patients, 50.4% were women. Mean TTR was 62.3% for women and 63.7% for men, and PINNR was 58.3% for women and 60.1% for men (p<0.001). Considering the TTR<65% threshold, 53% of women and 49.3% of men had poor anticoagulation control (p<0.001). Women, long-term users antiplatelet users, and patients with comorbidities, visits to Emergency Department and use of alcohol were more likely to present poor INR control. 5.4% of poorly controlled patients during 2015 switched to a NOAC throughout 2016, with no sex differences.
   
• Conclusion: The quality of INR control of all AF patients treated with VKA in 2015 in our Southern European region was suboptimal, and women were at a higher risk of poor INR control. This reflects sex disparities in care, and programs for improving the quality of oral anticoagulation should incorporate the gender perspective. Clinical inertia may be lying behind the observed low rates of switching in patient with poor INR control.

Group-based Trajectory Models to Assess Quality of INR Control and Its Association With Clinical Outcomes.

• The Time in Therapeutic Range (TTR) is the gold-standard measure used to assess the quality of oral anticoagulation with vitamin K antagonists. However, TTR is a static measure, and International Normalized Ratio (INR) control is a dynamic process. Group-based Trajectory Models (GBTM) can address this dynamic nature by classifying patients into different trajectories of INR control over time.
   
• Results: We included 8024 patients in the cohort who fulfilled the inclusion criteria; the mean number of INR determinations over the first year of treatment was 13.9. We identified 4 differential trajectories of INR control: Optimal (9.7% of patients, TTR: 83.8%), Improving (27.4% of patients, TTR: 61.2%), Worsening (28%; TTR: 69.1%), and Poor control (34.9%; TTR: 41.5%). In adjusted analysis, Poor and Worsening control patients had a higher risk of death than Optimal control patients (hazard ratio: 1.79; IC 95%, 1.36–2.36 and hazard ratio: 1.36; IC 95%, 1.02–1.81, respectively). Differences in other outcomes did not achieve statistical significance, except for a reduced risk of transient ischemic attack in the Improving Control group.
   
• Conclusions: GBTM may contribute to a better understanding and assessment of the quality of oral anticoagulation and may be used in addition to traditional, well-established measures such as TTR.

Funding