Association between cancer, CHA₂DS₂VASc risk, and in-hospital ischaemic stroke in patients hospitalized for atrial fibrillation

Background Atrial fibrillation (AF) is commonly encountered in cancer patients. We investigated the CHA₂DS₂VASc score, and its association with in-hospital ischaemic stroke in patients with cancer who were hospitalized for AF. Methods and results Using the United States National Inpatient Sample, all hospitalizations with principal diagnosis of AF between October 2015 and December 2018 were stratified by cancer diagnosis, type, and CHA₂DS₂VASc risk categories (low risk, low-moderate risk, moderate-high risk). In-hospital ischaemic stroke and its association with the CHA₂DS₂VASc risk score was assessed across the groups using hierarchical multivariable logistic regression with adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). Discrimination of CHA₂DS₂VASc score for in-hospital ischaemic stroke was evaluated with Receiver Operating Characteristic and Area Under the Curve (AUC). Among 1 341 870 included hospitalizations, 71 965 (5.4%) had comorbid cancer. Cancer patients had a higher proportion of moderate-high CHA₂DS₂VASc risk compared with their non-cancer counterparts (86.5% vs. 82.3%, P < 0.001). Compared with their low CHA₂DS₂VASc risk counterparts, cancer patients in low-moderate and moderate-high risk scores had similar odds of developing stroke (aOR 1.28 95% CI 0.22–7.63 and aOR 1.78 95% CI 0.41–7.66, respectively). The CHA₂DS₂VASc risk score had poor discrimination for ischaemic stroke in the cancer group (AUC 0.538 95% CI 0.477–0.598). Conclusion Cancer patients with AF have high CHA₂DS₂VASc risk. Discrimination of CHA₂DS₂VASc for ischaemic stroke is lower in cancer than non-cancer patients, and CHA₂DS₂VASc may not be adequate in determining ischaemic risk in cancer population.