Multimorbidity in atrial fibrillation for clinical implications using the Charlson Comorbidity Index

Background: Predicting survival in atrial fibrillation (AF) patients with comorbidities is challenging. This study aimed to assess multimorbidity in AF patients using the Charlson Comorbidity Index (CCI) and its clinical implications. Methods: We analyzed 451,368 participants from the Korea National Health Insurance Service-Health Screening cohort (2002-2013) without prior AF diagnoses. Patients were categorized into new-onset AF and non-AF groups, with a high CCI defined as >= 4 points. Antithrombotic treatment and outcomes (all-cause death, stroke, major bleeding, and heart failure [HF] hospitalization) were evaluated over 9 years. Results: In total, 9.5% of the enrolled patients had high CCI. During follow-up, 12,241 patients developed new-onset AF. Among AF patients, antiplatelet drug use increased significantly in those with high CCI (adjusted odds ratio [OR] 1.05, 95%confidence interval [CI] 1.02-1.08, P < .001). However, anticoagulants were significantly less prescribed in patients with high CCI (OR 0.97, 95%CI 0.95-0.99, P = .012). Incidence of adverse events (all-cause death, stroke, major bleeding, HF hospitalization) progressively increased in this order: low CCI without AF, high CCI without AF, low CCI with AF, and high CCI with AF (all P < .001). Furthermore, high CCI with AF had a significantly higher risk compared to low CCI without AF (all-cause death, adjusted hazard ratio [aHR] 2.52, 95% CI 2.37-2.68, P < .001; stroke, aHR 1.43, 95% CI 1.29-1.58, P < .001; major bleeding, aHR 1.14, 95% CI 1.04-1.26, P = .007; HF hospitalization, aHR 4.75, 95% CI 4.03-5.59, P < .001). Conclusions: High CCI predicted increased antiplatelet use and reduced oral anticoagulant prescription. AF was associated with higher risks of all-cause death, stroke, major bleeding, and HF hospitalization compared to high CCI.