Using the C₂HEST score for predicting postoperative atrial fibrillation after cardiac surgery: A report from the Western Denmark Heart Registry, the Danish National Patient Registry, and the Danish National Prescription Registry

Objectives: New-onset postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery. A targeted approach is necessary for prophylactic handling of the complication. The authors tested the performance of the C₂HEST score to predict POAF in patients undergoing cardiac surgery. Design: Register-based cohort study. Setting: Three cardiothoracic centers. Participants: All adult patients undergoing cardiac surgery in Western Denmark between January 1, 2010, and December 31, 2018, were included. Data on patient comorbidities before surgery were obtained from the Western Denmark Heart Registry, the Danish National Patient Registry, and the Danish National Prescription Registry. Interventions: The C₂HEST score (C₂: Coronary Artery Disease/Chronic Obstructive Pulmonary Disease [1 point each]; H: Hypertension; E: Elderly [Age ≥75, 2 points]; S: Systolic Heart Failure [2 points]; T: Thyroid disease [hyperthyroidism]) was calculated for each patient. The primary outcome was POAF within the primary hospital stay. The C₂HEST score's discriminative ability was evaluated and compared with an age-stratified version (mC₂HEST) as well as 2 validated clinical risk models (CHADS₂ and CHA₂DS₂-VASc). Measurements and Main Results: Among the 14,279 patients included, 4,298 (30.1%) developed POAF. The C₂HEST score's performance was not significantly better than the CHADS₂ and CHA₂DS₂-VASc scores (area under the curve [AUC] 0.553 [95% confidence interval {CI} 0.543; 0.563] v 0.543 [95% CI 0.535; 0.552] and 0.565 [95% CI 0.555; 0.574], respectively). The age-modified (mC₂HEST) score showed only modest improvement in the risk model, with an AUC of 0.580 (95% CI 0.570; 0.590). Conclusion: The discriminative ability of the C₂HEST score, measured by the AUC, was limited in this population, and was not proven to be superior to the CHADS₂, CHA₂DS₂-VASc, and mC₂HEST scores in predicting POAF after cardiac surgery.