Impact of atrial fibrillation on the development of ischemic stroke among cancer patients classified by CHA 2 DS 2 -VASc score-a nationwide cohort study

// Wei-Syun Hu 1, 2 and Cheng-Li Lin 3 1 School of Medicine, College of Medicine, China Medical University, Taichung 40402, Taiwan 2 Division of Cardiovascular Medicine, Department of Medicine, China Medical University Hospital, Taichung 40447, Taiwan 3 Management Office for Health Data, China Medical University Hospital, Taichung 40447, Taiwan Correspondence to: Wei-Syun Hu, email: weisyunhu@gmail.com Keywords: atrial fibrillation; cancer; CHA 2 DS 2 -VASc score; ischemic stroke Received: August 14, 2017      Accepted: January 01, 2018      Published: January 10, 2018 ABSTRACT Purpose: The current study aimed to explore the impact of atrial fibrillation (AF) on risk of ischemic stroke among cancer patients classified by CHA 2 DS 2 -VASc score. Methods: Study participants were identified from Registry for Catastrophic Illness Patient Database. All cancer patients whether they had comorbid AF or not were divided into 4 groups according to their CHA 2 DS 2 -VASc score-a score of 0–1, 2–3, 4–5 and >5. Competing risk analysis was used to evaluate the subhazard ratios (SHRs) and 95% confidence intervals (CIs) of incident ischemic stroke between cancer patients with and without AF according to their CHA 2 DS 2 -VASc score. Results: A total of 781473 patients with cancer were identified. Of them, 21134 had comorbid AF whereas the remaining 760339 patients did not. After controlling for the confounding factors and the competing risk of death, among cancer patients, those with AF were associated with the highest risk of ischemic stroke than those without AF while their CHA 2 DS 2 -VASc score was 0~1 (adjusted SHR [aSHR] = 4.15, 95% CI = 3.29–5.23). Among those with a CHA 2 DS 2 -VASc score of >5, the AF group exhibited a 1.82-fold higher risk of ischemic stroke than the non-AF group (95% CI = 1.34–2.47). Conclusions: The impact of AF on risk of ischemic stroke was attenuated with advancing CHA 2 DS 2 -VASc score in patients with cancer.