International Journal of Cardiology 184 (2015) 306
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Obstructive sleep apnea and stroke risk in atrial fibrillation: Is there a correlation or not? Serdar Kalemci a, Ibrahim Altun b,⁎, Fatih Akin b, Murat Biteker b a b
Mugla Sitki Kocman University, Faculty of Medicine, Department of Chest Disease, Turkey Mugla Sitki Kocman University, Faculty of Medicine, Department of Cardiology, Turkey
a r t i c l e
i n f o
Article history: Received 10 January 2015 Accepted 21 February 2015 Available online 25 February 2015 Keywords: Atrial fibrillation Obstructive sleep apnea Stroke
We have read with great interest the article recently published by Chin Chang et al. entitled “Obstructive sleep apnea and the risk of ischemic stroke in patients with atrial fibrillation” [1]. However, we have some concerns about the article. Our first concern is about CHA2DS2VASc scores of the study groups. The CHA2DS2-VASc score evaluates factors such as vascular disease, hypertension, and diabetes as contributors to stroke risk. Although subjects with concomitant atrial fibrillation (AF) and obstructive sleep apnea (OSA) had a higher percentage of hypertension, diabetes, coronary artery disease, and peripheral arterial disease than those AF patients without OSA, the baseline CHA2DS2-VASc score is similar between both groups. How do the authors explain this discrepancy? Our second concern is about the different results of the previous studies. Whether AF plays an intermediary role in the relationship between OSA and stroke is unknown. Two recent studies suggest that OSA plays an additive causative role in the relationship between AF and stroke. Mansukhani et al. conducted a case–control study of patients who suffered stroke, nested in a population-based cohort of patients with OSA. In this population with OSA, those who suffered a first time
⁎ Corresponding author at: Muğla Sıtkı Koçman Üniversitesi Tıp Fakültesi, Orhaniye Mah., Haluk Özsoy Cad., 48000 Muğla, Turkey. E-mail address: [email protected] (I. Altun).
http://dx.doi.org/10.1016/j.ijcard.2015.02.065 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved.
ischemic stroke had much higher rates of AF than controls who did not have a stroke [2]. The 5.34-fold odds of having AF were significantly higher even after accounting for potential confounders. Yaranov and colleagues very recently evaluated the stroke risk attributed to OSA in patients with AF [3]. They showed that OSA is associated with an increased incidence of stroke, and this association remains significant after accounting for other cardiovascular risk factors. AF patients with OSA were 3.6 times more likely to have a first-time stroke than those without and this finding was independent of age, gender, body mass index, diabetes mellitus, hypertension, and coronary artery disease. In contrast to the above-mentioned studies, Chin Chang et al. found that ischemic stroke risk for AF patients with OSA concomitantly is similar as AF patients without OSA. We think that prospective studies are urgently needed to help answer important management questions, such as whether OSA should be considered in risk assessments for stroke or prophylactic anticoagulation. Conflict of interest The authors report no relationships that could be construed as a conflict of interest. References [1] C.C. Chang, C.C. Chiu, C.H. Chiang, C.C. Huang, W.L. Chan, P.H. Huang, et al., Obstructive sleep apnea and the risk of ischemic stroke in patients with atrial fibrillation, Int. J. Cardiol. 181C (Dec 3 2014) 144–146. http://dx.doi.org/10.1016/j.ijcard.2014. 12.019. [2] M.P. Mansukhani, A.D. Calvin, B.P. Kolla, R.D. Brown Jr., M.C. Lipford, V.K. Somers, et al., The association between atrial fibrillation and stroke in patients with obstructive sleep apnea: a population-based case–control study, Sleep Med. 14 (2013) 243e246. [3] D.M. Yaranov, A. Smyrlis, N. Usatii, A. Butler, J.R. Petrini, J. Mendez, et al., Effect of obstructive sleep apnea on frequency of stroke in patients with atrial fibrillation, Am. J. Cardiol. 115 (Feb 15 2015) 461–465.
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Obstructive sleep apnea and stroke risk in atrial fibrillation: Is there a correlation or not? Serdar Kalemci a, Ibrahim Altun b,⁎, Fatih Akin b, Murat Biteker b a b
Mugla Sitki Kocman University, Faculty of Medicine, Department of Chest Disease, Turkey Mugla Sitki Kocman University, Faculty of Medicine, Department of Cardiology, Turkey
a r t i c l e
i n f o
Article history: Received 10 January 2015 Accepted 21 February 2015 Available online 25 February 2015 Keywords: Atrial fibrillation Obstructive sleep apnea Stroke
We have read with great interest the article recently published by Chin Chang et al. entitled “Obstructive sleep apnea and the risk of ischemic stroke in patients with atrial fibrillation” [1]. However, we have some concerns about the article. Our first concern is about CHA2DS2VASc scores of the study groups. The CHA2DS2-VASc score evaluates factors such as vascular disease, hypertension, and diabetes as contributors to stroke risk. Although subjects with concomitant atrial fibrillation (AF) and obstructive sleep apnea (OSA) had a higher percentage of hypertension, diabetes, coronary artery disease, and peripheral arterial disease than those AF patients without OSA, the baseline CHA2DS2-VASc score is similar between both groups. How do the authors explain this discrepancy? Our second concern is about the different results of the previous studies. Whether AF plays an intermediary role in the relationship between OSA and stroke is unknown. Two recent studies suggest that OSA plays an additive causative role in the relationship between AF and stroke. Mansukhani et al. conducted a case–control study of patients who suffered stroke, nested in a population-based cohort of patients with OSA. In this population with OSA, those who suffered a first time
⁎ Corresponding author at: Muğla Sıtkı Koçman Üniversitesi Tıp Fakültesi, Orhaniye Mah., Haluk Özsoy Cad., 48000 Muğla, Turkey. E-mail address: [email protected] (I. Altun).
http://dx.doi.org/10.1016/j.ijcard.2015.02.065 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved.
ischemic stroke had much higher rates of AF than controls who did not have a stroke [2]. The 5.34-fold odds of having AF were significantly higher even after accounting for potential confounders. Yaranov and colleagues very recently evaluated the stroke risk attributed to OSA in patients with AF [3]. They showed that OSA is associated with an increased incidence of stroke, and this association remains significant after accounting for other cardiovascular risk factors. AF patients with OSA were 3.6 times more likely to have a first-time stroke than those without and this finding was independent of age, gender, body mass index, diabetes mellitus, hypertension, and coronary artery disease. In contrast to the above-mentioned studies, Chin Chang et al. found that ischemic stroke risk for AF patients with OSA concomitantly is similar as AF patients without OSA. We think that prospective studies are urgently needed to help answer important management questions, such as whether OSA should be considered in risk assessments for stroke or prophylactic anticoagulation. Conflict of interest The authors report no relationships that could be construed as a conflict of interest. References [1] C.C. Chang, C.C. Chiu, C.H. Chiang, C.C. Huang, W.L. Chan, P.H. Huang, et al., Obstructive sleep apnea and the risk of ischemic stroke in patients with atrial fibrillation, Int. J. Cardiol. 181C (Dec 3 2014) 144–146. http://dx.doi.org/10.1016/j.ijcard.2014. 12.019. [2] M.P. Mansukhani, A.D. Calvin, B.P. Kolla, R.D. Brown Jr., M.C. Lipford, V.K. Somers, et al., The association between atrial fibrillation and stroke in patients with obstructive sleep apnea: a population-based case–control study, Sleep Med. 14 (2013) 243e246. [3] D.M. Yaranov, A. Smyrlis, N. Usatii, A. Butler, J.R. Petrini, J. Mendez, et al., Effect of obstructive sleep apnea on frequency of stroke in patients with atrial fibrillation, Am. J. Cardiol. 115 (Feb 15 2015) 461–465.
