Long-term impact of newly diagnosed atrial fibrillation during critical care: A 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.