Anticoagulation in critically ill patients with new-onset atrial fibrillation: Insights from a retrospective cohort study

Abstract

Background: New-onset atrial fibrillation (NOAF) is associated with worse short-term prognosis among critically ill patients, and the benefit of anticoagulation is uncertain.

Objective: We aimed to evaluate whether anticoagulation at hospital discharge for critically ill patients presenting with NOAF is associated with improved survival.

Methods: Retrospective Cohort Study using the Medical Information Mart for Intensive Care (MIMIC)-IV database, which comprises data from patients admitted to the intensive care units (ICUs) at Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. We included patients diagnosed with NOAF during admission to ICUs between 2008 and 2019 and excluded patients with pre-existing atrial fibrillation (AF), admission related to cardiac surgery and previous anticoagulant use. We did a propensity-score matched (PSM) 1:1 to compare survival between patients discharged on anticoagulation (ACO) vs no anticoagulation and a Cox regression model to assess the primary outcome of long-term survival post-hospital discharge. We censored the patients at 3 different time points and performed another 3-sensitivity analysis to assess the robustness of the results.

Results: A total of 495 patients received ACO therapy, and 2021 patients did not. Matching demonstrated adequate covariate balance, with both groups comprising 495 patients postmatching. Out of hospital mortality rate after PSM was 30.9% vs 38.4% in the ACO and non-ACO groups, respectively. Patients in the ACO group exhibited greater long-term survival (hazard ratio [HR] 0.72, 95% CI 0.58-0.89, P = .003). The benefit was present in the PSM analysis censored at 90 days (HR 0.63, 95% CI 0.43-0.94, P = .02), 1 year (HR 0.55, 95% CI 0.41-0.793, P < .001), and 5 years (HR 0.7, 95% CI 0.56-0.88, P = .002).These findings also remained consistent across the 3 other sensitivity analyses performed.

Conclusion: Anticoagulant prescription at hospital discharge for patients with NOAF during ICU stay was associated with longer survival.

Keywords: Anticoagulation; Critically ill; Intensive care; New-onset atrial fibrillation; Warfarin.