Guideline-adherent antithrombotic treatment improves outcomes in patients with atrial fibrillation: Insights from the community-based Darlington atrial fibrillation registry

Objective: To assess the influence of guideline-adherent versus non-adherent
antithrombotic treatment (ATT) on stroke and mortality rates in atrial fibrillation (AF) primary care population.

Patients and Methods: We used Darlington Registry cohort which included 105,000 patients from March 31, 2012, through March 31, 2013. Guideline-adherence in ATT was assessed against 2014 National Institute for Health and Care Excellence (NICE) guidelines, which recommend oral anticoagulation (OAC) for stroke prevention as a default management unless a truly “low-risk” of stroke (CHA2DS2-VASc=0 in men and 1 in women) is evident.

Results: Overall, 2259 (2.15%) AF patients were identified, of which 36.1% were undertreated, 50.8% guideline-adherent and 13.1% over-treated. OAC was declined by 5.0% and contraindicated at 8.3%. Overall, 67 (3.0%) incident strokes occurred, of which 66 (98.5%) in high-risk patients (CHA2DS2-VASc ≥2). For the high-risk cohort, one-year stroke rates were 4.5% (95% CI 3.2-6.3) for under-treatment, 1.9% (95% CI 1.2-2.9) for guideline-adherence, and 7.2% (95% CI 4.4-11.6) for over-treatment; corresponding mortality rates were 16.1%
(95% CI 13.6-19.0), 8.0% (95% CI 6.5-9.8), and 8.2% (95% CI 5.2-12.7), respectively. On multivariable analysis, both under- and over-treatment of high-risk patients were associated with significant increase in stroke rates (OR 2.32, 95% CI 1.30-3.14, P=.005 and OR 2.28, 95% CI 1.12-4.63, P=.02, respectively). Under-treatment was also associated with a significant increase in all-cause mortality (OR 1.59, 95% CI 1.14-2.21, P=.006).

Conclusion: Only half of eligible AF patients are prescribed OAC in accordance with guideline recommendations. Guideline-adherent ATT significantly reduces the risk of stroke and improves survival.