ORIGINAL ARTICLE Safety and efficacy of oral anticoagulation therapy in Chinese patients with concomitant atrial fibrillation and hypertension LY Ho 1,4 , CW Siu 1,2,4 , WS Yue 1 , CP Lau 1 , GY Lip 3 and HF Tse 1,2 1 Division of Cardiology, Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; 2 Research Center of Heart, Brain, Hormone and Healthy Aging, LKS Faculty of Medicine, the University of Hong Kong, Hong Kong, China and 3 Haemostasis Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham, UK Limited evidence is available on the safety and efficacy of anticoagulants in non-valvular atrial fibrillation (AF) patients with concomitant hypertension. We investi- gated the safety and efficacy of 476 consecutive antic- oagulated Chinese outpatients with non-valvular AF and hypertension. Occurrence of ischaemic stroke and major bleeding, and international normalized ratio (INR) values during these events were recorded. There was no significant difference in anticoagulation control between patients with or without hypertension. INR- specific incidence rates of the events were calculated, which showed no excessive risk for ischaemic stroke (2.5 vs 1.6% per year, P ¼ 0.22) or major bleeding (3.9 vs 3.2% per year, P ¼ 0.29) in non-valvular AF patients with or without hypertension. In multivariate analysis, con- gestive heart failure, smoking and high CHADS2 score were independent predictors for ischaemic stroke, whereas use of antiplatelet agents was an independent predictor for bleeding. It can be noted that hypertension was not associated with ischaemic stroke or major bleeding. Hypertensive patients who achieved target blood pressure control (o130/80 mm Hg) had a lower ischaemic stroke (0.9 vs 3.1% per year, P ¼ 0.01), but similar bleeding risk compared with those not achieving target blood pressure. Our findings demonstrate the effects of hypertension on the outcomes of warfarin therapy; further investigation is needed to clarify whether more aggressive antihypertensive therapy could result in better outcomes in hypertensive patients with non-valvular AF. Journal of Human Hypertension (2011) 25, 304–310; doi:10.1038/jhh.2010.57; published online 1 July 2010 Keywords: AF; anticoagulation; anti-hypertensive therapy Introduction In population studies, hypertension is the most common aetiological factor associated with atrial fibrillation (AF), whereas in hospital series, coron- ary artery disease and congestive heart failure are the most common associated cardiovascular dis- eases. 1,2 In the general population, the risk of developing AF in patients with hypertension is 1.9 and 1.4 times higher than normotensive subjects in the Framingham 3 and Manitoba 4 studies, respec- tively. Although the absolute risk of developing AF among hypertensive patients is low, hypertension per se remains a major risk factor for AF because of its high prevalence in the general population. The concomitant presence of hypertension and AF poses a higher risk and poorer outcome after stroke than those with AF alone. 5 Furthermore, hypertension is associated with an increased risk of stroke severity, which was not shown to be statisti- cally significant. 6 As a result, hypertension is considered as one of the most common and important risk factors for the initiation of antic- oagulation therapy in non-valvular AF. 7 On the other hand, hypertension is associated with an increased risk of intracranial haemorrhage. 8 There is even greater concern about this bleeding risk with anticoagulation among the Chinese population given the higher prevalence of haemorrhagic stroke in such subjects. 9 Indeed, the recommended lowest effective intensity of anticoagulation for non-valvular AF in Caucasians may not be applicable to Far Eastern patients. For example, a study from Japan reported that the lowest effective international Received 1 November 2009; revised 5 March 2010; accepted 21 April 2010; published online 1 July 2010 Correspondence: Professor H-F Tse, Division of Cardiology, Department of Medicine, The University of Hong Kong, Room 1928, Block K, Queen Mary Hospital, Hong Kong, China. E-mail: hftse@hkucc.hku.hk 4 These authors contributed equally to this work. Journal of Human Hypertension (2011) 25, 304–310 & 2011 Macmillan Publishers Limited All rights reserved 0950-9240/11 www.nature.com/jhh