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Open Access Highly Accessed Research article

Paradoxical effect of obesity on hemorrhagic transformation after acute ischemic stroke

Chi Kyung Kim12, Wi-Sun Ryu3, Beom Joon Kim4 and Seung-Hoon Lee12*

Author Affiliations

1 Department of Neurology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Republic of Korea

2 Clinical Research Center for Stroke, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea

3 Department of Neurology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea

4 Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea

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BMC Neurology 2013, 13:123  doi:10.1186/1471-2377-13-123

Published: 23 September 2013



Among the patients with established coronary artery diseases, obese patients tend to have a more favorable prognosis, which is called as obesity paradox. Interestingly, mildly obese patients who underwent coronary revascularization had a lower risk of bleeding. In this context, we have investigated the association between obesity and hemorrhagic transformation (HTf) after acute ischemic stroke.


A total of 365 patients with first-ever acute ischemic stroke were included in this study. Demographic, clinical and radiological information was collected and HTf was evaluated through follow-up T2*-weighted gradient-recalled echo MRI performed usually within 1 week after occurrence of stroke. Body mass index was calculated, and obesity was defined using the World Health Organization Western Pacific Regional Office criteria.


The HTf was identified in 59 patients (16.2%). As the severity of obesity increased, the occurrence of HTf decreased. Compared with the normal weight group and after controlling possible confounders including acute and previous treatment, stroke severity and subtype, the risk of HTf decreased significantly in the obese group (odds ratio, 0.39; 95% confidence interval, 0.17-0.87).


The better outcome for HTf seen in obese patients suggests the existence of a “bleeding-obesity paradox” in acute ischemic stroke.

Obesity; Hemorrhagic transformation; Bleeding-obesity paradox; Ischemic stroke; Body mass index