Original Contribution Sex Differences in Short-Term Outcomes After Acute Ischemic Stroke The Fukuoka Stroke Registry Fumi Irie, MD; Masahiro Kamouchi, MD, PhD; Jun Hata, MD, PhD; Ryu Matsuo, MD, PhD; Yoshinobu Wakisaka, MD, PhD; Junya Kuroda, MD, PhD; Tetsuro Ago, MD, PhD; Takanari Kitazono, MD, PhD; on behalf of the FSR Investigators* Background and Purpose—Variable sex differences in clinical outcomes after stroke have been reported worldwide. This study aimed to elucidate whether sex is an independent risk factor of poor functional outcome after acute ischemic stroke. Methods—Using the database of patients with acute stroke registered in the Fukuoka Stroke Registry in Japan from 1999 to 2013, 6236 previously independent patients with first-ever ischemic stroke who were admitted within 24 hours of onset were included in this study. Baseline characteristics were assessed on admission. Study outcomes included neurological improvement, neurological deterioration, and poor functional outcome (modified Rankin Scale score, 3–6 at discharge). Logistic regression analyses were performed to evaluate the association between sex and clinical outcomes. Results—Overall, 2398 patients (38.5%) were women. Severe stroke (National Institutes of Health Stroke Scale score, ≥8) on admission was more prevalent in women than in men. The frequency of neurological improvement or deterioration during hospitalization was not different between the sexes. After adjusting for possible confounders, including age, stroke subtype and severity, risk factors, and poststroke treatments, it was found that female sex was independently associated with poor functional outcome at discharge (odds ratio, 1.30; 95% confidence interval, 1.08–1.57). There was heterogeneity of the association between sex and poor outcome according to age: women had higher risk of poor outcome than men among patients aged ≥70 years, but no clear sex difference was found in patients aged 24 hours. Ischemic stroke was identified by computed tomography or MRI and was further classified into 4 subtypes: cardioembolic, lacunar, atherothrombotic, and unclassified infarction based on the Classification of Cerebrovascular Diseases III proposed by the National Institute of Neurological Disorders and Stroke.15 The classification was refined by taking into consideration the risk of underlying cardiac diseases and other causes proposed by the diagnosis criteria of the Trial of Org 10172 in Acute Stroke Treatment study (TOAST)16 and the Cerebral Embolism Task Force for ischemic stroke subtypes.17 Location of the culprit lesion was divided into 2 groups by neuroradiologists depending on the results of computed tomography or MRI: in the anterior circulation territory or in others. All patients in the FSR were treated in conformance with the Japanese Guidelines for the Management of Stroke.18,19 Of the 15 252 cases of stroke hospitalized within 7 days after onset that were registered between June 1999 and August 2013, 12 841 cases were classified as ischemic stroke. After excluding cases of arrival after 24 hours of onset (n=3072), those of prestroke disability (modified Rankin Scale [mRS] score, ≥2; n=2043) and those of recurrent stroke (n=1490), we included 6236 previously independent patients with first-ever ischemic stroke who were hospitalized within 24 hours of stroke onset in this study (Figure 1).

Clinical Assessments Risk factors and comorbidities were assessed: hypertension (systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg in the chronic stage [≈3 weeks after stroke onset], or history of antihypertensive medication), diabetes mellitus (according to the diagnostic criteria of the Japan Diabetes Society20 in the chronic stage or history of antidiabetic treatment), dyslipidemia (low-density lipoprotein

cholesterol ≥3.62 mmol/L, high-density lipoprotein cholesterol