Early postoperative atrial fibrillation is associated with late mortality after cardiac surgery: a systematic review and reconstructed individual patient data meta-analysis

Background Early postoperative atrial fibrillation (early-POAF) is the most common complication after cardiac surgery. Although prior studies have demonstrated an association between early-POAF and late outcomes, it is questionable whether these long-term adverse events result from early-POAF or from comorbidities that underlie the development of early-POAF. Therefore, the aim of this study was to investigate the association of early-POAF with late mortality and stroke after adjustment for age and cardiovascular comorbidities. Methods A systematic search was conducted to identify studies reporting on late mortality after cardiac surgery in patients with and without early-POAF. Articles presenting Kaplan-Meier were included for a pooled analysis of late mortality (primary outcome) and stroke (secondary outcome). Individual time-to-event data were reconstructed from the Kaplan-Meier curves and incorporated into a multivariable mixed-effects Cox model. Results In total, 33 studies were included in the analysis for late mortality (131 031 patients) and 10 studies in the analysis for late stroke (42 042 patients). Overall, 36 991 patients had early-POAF with a pooled incidence of 31.5% (95% CI: 27.7 to 35.6%). Unadjusted analysis showed that early-POAF was significantly associated with late mortality (Hazard Ratio [HR] = 1.62, 95%CI: 1.58-1.67, P < 0.001) and late stroke (HR = 1.72, 95%CI: 1.61-1.85, P < 0.001). Early-POAF was significantly associated with late mortality (adjusted HR = 1.19, 95% CI: 1.07-1.33, P = 0.002), but not with late stroke (adjusted HR = 1.14, 95% CI: 0.96-1.35, P = 0.122) after adjustment for age, comorbidities, surgery type, and the random effects term. Conclusion Early-POAF after cardiac surgery is significantly associated with late mortality, but not with late stroke, after adjustments for age, sex, cardiovascular comorbidities, and type of surgery.