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What is the optimal blood pressure level for patients with atrial fibrillation treated with direct oral anticoagulants?
Objective: Limited data exist to inform blood pressure (BP) thresholds for patients with atrial fibrillation (AF) prescribed direct oral anticoagulants (DOAC) therapy in the real world setting.
Methods: Systolic blood pressure was measured in 9,051 primary care patients in England on DOACs for AF with post-initiation BP levels available within the Clinical Practice Research Datalink (CPRD). The incidence rate for the primary outcome of the first recorded event (defined as a diagnosis of first stroke, recurrent stroke, myocardial infarction, symptomatic intracranial bleed or significant gastrointestinal bleed) and of secondary outcomes all-cause mortality and cardiovascular mortality were calculated by post-initiation BP groups.
Results: The Cox proportional hazard ratio (HR) of an event (crude and adjusted HR 1.04 [95% CI 1.00-1.08], p=0.077 and 0.071, respectively) did not differ significantly with a 10mmHg increase in systolic BP. The hazard of all-cause mortality (crude HR 0.83 [95% CI 0.80-0.86], p=0.000; adjusted HR 0.84 [95% CI 0.81-0.87], p=0.000) and cardiovascular mortality (crude HR 0.92 [95% CI 0.85-0.99], p=0.021; adjusted HR 0.93 [95% CI 0.86-1.00], p=0.041) demonstrated a significant inverse relationship with a 10mmHg increase in systolic BP. Patients with a systolic BP within 161-210mmHg had the lowest all-cause death rate, while patients with systolic BP within 121-140mmHg had the lowest cardiovascular death rate.
Conclusion: Systolic BP values below 161mmHg are associated higher all-cause mortality, but lower event risk in patients with AF on DOAC therapy. The nadir systolic BP for lowest event rate was 120mmHg, for lowest cardiovascular mortality was 130mmHg and for lowest all-cause mortality was 160mmHg. This demonstrates a need for a prospective interventional study of BP control after initiation of anticoagulation.