Atrial fibrillation, venous thromboembolism, ischemic stroke, and all-cause mortality: The Tromso study

Background: Atrial fibrillation (AF) is associated with increased risk of ischemic stroke and all-cause mortality. Patients with AF are also at increased risk of venous thromboembolism (VTE), but information on how AF impacts VTE-related mortality is scarce. Objectives: To investigate the impact of AF on all-cause mortality in subjects with and without a thromboembolic event (VTE or ischemic stroke). Methods: We followed 29 833 participants from the Tromso study (1994-2008) through 2013 and recorded all deaths during follow-up. Incident AF, VTE, and ischemic stroke were registered as time-dependent exposures. We calculated mortality rates (MRs) by exposure during follow-up and obtained hazard ratios (HRs) for death with 95% confidence intervals (CIs). Results: A total of 2087 AF cases, 756 VTEs, and 1279 ischemic strokes were registered during a median follow-up of 18.7 years, and 4797 people (16.1%) died. The age-adjusted MR for participants without any event was 1.19 per 100 person-years (PY; 95% CI, 1.15-1.23). Compared to these participants, subjects with the joint AF + VTE exposure had a 3.7-fold increased risk of death (HR, 3.67; 95% CI, 2.77-4.66) in age- and sex-adjusted analyses, similar to the risk observed for VTE alone (HR, 3.76; 95% CI, 3.28-4.30). Participants with stroke had a 2.9-fold increased risk of death (HR, 2.85; 95% CI, 2.56-3.18), and the risk was further increased in participants with both AF and stroke (HR, 4.38; 95% CI, 3.85-4.98). Conclusions: AF was significantly associated with increased risk of death in participants with incident stroke. In contrast, concomitant AF was not associated with excess mortality risk in VTE patients.