Long-Term Impact of Newly Diagnosed Atrial Fibrillation During Critical Care: A South Korean Nationwide Cohort Study

Background: The long-term risks of thromboembolism and mortality are unknown in patients who survived following atrial fibrillation (AF) newly diagnosed during critical care. Methods: Using the Korean National Health Insurance Service database, we identified 30,869 adults who survived for > 6 months following AF newly diagnosed during critical care (ICU-AF), 269,751 control subjects with non-ICU AF (AF-control), and 439,868 control subjects without AF (No-AF) from 2005 to 2013. We performed propensity score matching and compared the risks of stroke/systemic embolism and all-cause mortality. Results: The adjusted hazard ratios (HRs) for long-term stroke/systemic embolism in the patients with ICU-AF were 0.93 (95% CI, 0.88-0.98) compared with the AF-control group and 1.50 (95% CI, 1.42-1.60) compared with the No-AF group. The adjusted HRs of the ICU-AF group for long-term mortality were 1.73 (95% CI, 1.70-1.83) and 3.20 (95% CI, 3.08-3.33) compared with the AF-control and No-AF groups, respectively. The risks of stroke/systemic embolism and mortality were significantly higher in the ICU-AF group than in the No-AF group after excluding patients with AF recurrence (adjusted HR, 1.08; 95% CI, 1.01-1.17), regardless of the causes of critical care and cardiovascular or noncardiovascular surgery. Conclusions: The patients who survived following AF newly diagnosed during critical care remained at a higher risk of long-term stroke/systemic embolism and mortality than the patients without AF regardless of AF recurrence and the causes of critical care. Close follow-up and continuous anticoagulation might be needed for these patients.