New-onset atrial fibrillation is associated with increased mortality in critically ill patients: a systematic review and meta-analysis

Introduction: Atrial fibrillation (AF) is one of the most comorbid conditions in critically ill patients requiring intensive care unit (ICU). Multiple studies have suggested that there may be an association between new-onset AF and adverse outcome in critically ill patients. However, there are no meta-analyses to assess this association. Methods: Studies were systematically searched from electronic databases. Studies that examined the relationship between new-onset AF and adverse outcomes including mortality and length of stay in ICU patients were included. Studies that included patients with prior AF were excluded. The pooled effect size was calculated with a random-effect model, weighted for the inverse of variance, to determine an association between new-onset AF and in-hospital mortality. Heterogeneity was assessed with I-2. Results: Twelve studies were included. Pooled analysis showed statistically significant difference rate of the hospital mortality between patients with and without new-onset AF (OR 2.70; 95% CI 2.43-3.00). Subgroup analysis of only patients with sepsis or septic shock showed a significant association between new-onset AF and in-hospital mortality (OR 2.32; 95% CI 1.88-2.87). No significant heterogeneity was observed (I-2 = 0%) in both analyses. Pooled analysis of four studies also showed a significant association between new-onset AF and short-term mortality (OR 2.22; 95% CI 1.28-3.83) with moderate heterogeneity (I-2 = 67%). Conclusions: New-onset AF is associated with worse outcome in critically ill patients. Further studies should be done to evaluate for causality and adjust for confounders.