Although the benefit of reducing blood pressure for primary and secondary prevention of stroke has been established, the effect of antihypertensive treatment in patients with acute ischemic stroke is uncertain.
To evaluate whether immediate blood pressure reduction in patients with acute ischemic stroke would reduce death and major disability at 14 days or hospital discharge.
Design, Setting, and Participants
The China Antihypertensive Trial in Acute Ischemic Stroke, a single-blind, blinded end-points randomized clinical trial, conducted among 4071 patients with nonthrombolysed ischemic stroke within 48 hours of onset and elevated systolic blood pressure. Patients were recruited from 26 hospitals across China between August 2009 and May 2013.
Patients (n = 2038) were randomly assigned to receive antihypertensive treatment (aimed at lowering systolic blood pressure by 10% to 25% within the first 24 hours after randomization, achieving blood pressure less than 140/90 mm Hg within 7 days, and maintaining this level during hospitalization) or to discontinue all antihypertensive medications (control) during hospitalization (n = 2033).
Main Outcomes and Measures
Primary outcome was a combination of death and major disability (modified Rankin Scale score ≥3) at 14 days or hospital discharge.
Mean systolic blood pressure was reduced from 166.7 mm Hg to 144.7 mm Hg (−12.7%) within 24 hours in the antihypertensive treatment group and from 165.6 mm Hg to 152.9 mm Hg (−7.2%) in the control group within 24 hours after randomization (difference, −5.5% [95% CI, −4.9 to −6.1%]; absolute difference, −9.1 mm Hg [95% CI, −10.2 to −8.1]; P < .001). Mean systolic blood pressure was 137.3 mm Hg in the antihypertensive treatment group and 146.5 mm Hg in the control group at day 7 after randomization (difference, −9.3 mm Hg [95% CI, −10.1 to −8.4]; P < .001). The primary outcome did not differ between treatment groups (683 events [antihypertensive treatment] vs 681 events [control]; odds ratio, 1.00 [95% CI, 0.88 to 1.14]; P = .98) at 14 days or hospital discharge. The secondary composite outcome of death and major disability at 3-month posttreatment follow-up did not differ between treatment groups (500 events [antihypertensive treatment] vs 502 events [control]; odds ratio, 0.99 [95% CI, 0.86 to 1.15]; P = .93).
Conclusion and Relevance
Among patients with acute ischemic stroke, blood pressure reduction with antihypertensive medications, compared with the absence of hypertensive medication, did not reduce the likelihood of death and major disability at 14 days or hospital discharge.
clinicaltrials.gov Identifier: NCT01840072
Stroke is the second leading cause of death and the leading cause of serious, long-term disability worldwide.1 Clinical trials have documented that lowering blood pressure reduces the risk of stroke in hypertensive2,3 and normotensive patients with a history of stroke or transient ischemic attack.4-6 Although the benefit of lowering blood pressure for primary and secondary prevention of stroke has been established, the effect of immediate antihypertensive treatment in patients with acute ischemic stroke and elevated blood pressure is uncertain.7,8 Elevated blood pressure is common during acute ischemic stroke. In the US National Hospital Ambulatory Medical Care Survey, 76.5% of patients with acute ischemic stroke had systolic blood pressures of 140 mm Hg or greater on arrival at the emergency department.9 Observational studies have reported that a decrease in blood pressure within the first 48 hours after symptom onset was associated with poorer, better, or no difference in adverse clinical outcomes among patients with acute ischemic stroke.10-12 There are no published clinical trials with sufficient statistical power to address the question of whether lowering blood pressure reduces adverse clinical outcomes among patients with acute ischemic stroke.
The China Antihypertensive Trial in Acute Ischemic Stroke (CATIS) was a multicenter randomized controlled trial designed to test whether moderate lowering of blood pressure within the first 48 hours after the onset of an acute ischemic stroke would reduce death and major disability at 14 days or hospital discharge. In addition, we also evaluated the effects of antihypertensive treatment during the acute phase of ischemic stroke on 3-month mortality, major disability, and vascular events, as assessed at a posttreatment follow-up visit.
Trial Design and Participants
CATIS was a multicenter, single-blind, blinded end-points randomized clinical trial conducted in 26 hospitals across China. Details of the trial design and methods are summarized in the eMethods in Supplement. In brief, we recruited 4071 patients 22 years or older who had ischemic stroke, confirmed by computed tomography or magnetic resonance imaging of the brain within 48 hours of symptom onset and who had an elevated systolic blood pressure between 140 mm Hg and less than 220 mm Hg. Individuals with a systolic blood pressure of 220 mm Hg or greater or diastolic blood pressure of 120 mm Hg or greater were excluded because current clinical guidelines recommend antihypertensive treatment in such patients.7,13 In addition, patients with severe heart failure, acute myocardial infarction or unstable angina, atrial fibrillation, aortic dissection, cerebrovascular stenosis, or resistant hypertension, and those in a deep coma, were excluded. Patients treated with intravenous thrombolytic therapy (ie, intravenous recombinant tissue plasminogen activator [rtPA]) at baseline were excluded because of different requirements for blood pressure reduction.7
This study was approved by the institutional review boards at Tulane University in the United States and Soochow University in China, as well as ethical committees at the 26 participating hospitals. Written consent was obtained from all study participants or their immediate family members.
CATIS was designed to evaluate whether an antihypertensive treatment intervention aimed at lowering systolic blood pressure by 10% to 25% within the first 24 hours after randomization, achieving a systolic blood pressure less than 140 mm Hg and diastolic blood pressure less than 90 mm Hg within 7 days, and maintaining this level of blood pressure control during the remainder of a patient’s hospitalization would reduce adverse clinical outcomes compared with a control group not receiving antihypertensive treatment. Randomization was conducted centrally and was stratified by participating hospitals and use of antihypertensive medications. The randomization schedules were generated using SAS PROC PLAN in SAS and concealed until an eligible participant was ready for enrollment. After the study participants had been randomly assigned to the antihypertensive treatment or control group, all home antihypertensive medications were discontinued.
Our trial was designed to test a blood pressure reduction strategy rather than the efficacy of specific antihypertensive drugs. As such, several antihypertensive agents, including intravenous angiotensin-converting enzyme inhibitors (enalapril, first-line), calcium channel blockers (second-line), and diuretics (third-line), could be used individually or in combination in the intervention group to achieve the targeted blood pressure reduction according to a prespecified treatment algorithm (eFigure 1 in Supplement). Patients in the control group discontinued home antihypertensive medications. After their hospital discharge, patients in both groups were prescribed antihypertensive medications according to clinical guidelines.7,13 Although treating study physicians and nurses were not blinded to group assignment, trial participants as well as the investigators and research staff who collected study outcome data were masked to treatment allocation.
Demographic characteristics and medical history were collected at the time of enrollment. Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS; scores range from 0 to 42, with higher scores indicating a more severe neurologic deficit) by trained neurologists at baseline, 14 days or hospital discharge, and at a 3-month posttreatment follow-up visit.14 Computed tomography or magnetic resonance imaging of the brain was performed according to standard techniques to confirm the diagnosis of ischemic stroke in all trial participants. Three blood pressure measurements were obtained at baseline by trained nurses according to a common protocol adapted from procedures recommended by the American Heart Association.15 Blood pressure was measured with the participant in a supine position using a standard mercury sphygmomanometer and 1 of 4 cuff sizes (pediatric, regular adult, large adult, or thigh) based on participant arm circumference. After randomization, 3 blood pressure measurements were obtained every 2 hours for the first 24 hours, every 4 hours during the second and third days, and 3 times a day thereafter until hospital discharge or death.
The primary outcome was a combination of death within 14 days after randomization and major disability at 14 days or at hospital discharge if earlier than 14 days. The secondary outcome was a combination of all-cause mortality and major disability at the 3-month posttreatment follow-up. Major disability was defined as a score of 3 to 5 on the modified Rankin Scale at 14 days and 3 months after randomization. Scores on the modified Rankin Scale range from 0 to 6, with a score of 0 indicating no symptoms; a score of 5 indicating severe disability (ie, bedridden, incontinent, or requiring constant nursing care and attention); and a score of 6 indicating death.16 Since development of the initial CATIS protocol, ordinal analysis of the modified Rankin Scale scores is now recommended for acute stroke trials.17 Therefore, in the final statistical analysis plan, which was developed prior to initiation of data analysis, we included an ordered 7-level categorical score of the modified Rankin Scale as a secondary outcome for neurologic functional status. Other secondary outcomes included vascular disease events (eg, vascular deaths, nonfatal stroke, nonfatal myocardial infarction, hospitalized and treated angina, hospitalized and treated congestive heart failure, and hospitalized and treated peripheral arterial disease), recurrent fatal and nonfatal stroke, and all-cause mortality assessed at the 3-month posttreatment follow-up visit.
Participants were followed up in person at month 3 by trained neurologists and research nurses unaware of treatment assignment. Data on medical history, deaths, vascular events, blood pressure, NIHSS score, and modified Rankin Scale score were obtained. Death certificates were obtained for deceased participants, and hospital data were abstracted for all vascular events. A trial-wide outcomes assessment committee, blinded to treatment assignment, reviewed and adjudicated vascular events based on criteria established in ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial).18
We estimated that with a sample of 4000 participants, the study would have 90% statistical power to detect an absolute risk reduction of 5% (or a relative risk reduction of 14%) in the primary outcome at a significance level of .05 for a 2-sided test.19 The expected event rate for the primary outcome in the control group was estimated to be 35% based on our pilot data, which are more conservative than those reported from previous studies.20 We further assumed that 8% of participants would be nonadherent or would be lost to follow-up.
Data were analyzed according to participants’ randomized treatment assignments, regardless of their subsequent medication status (intention-to-treat). The proportions of participants with the primary and secondary outcomes at 14 days or discharge and at 3-month posttreatment follow-up were compared between the antihypertensive treatment and control groups using a χ2 test at a 2-sided α level of 5%, without correction for multiple comparisons. Logistic regression analysis was used to estimate unadjusted odds ratios (ORs) and 95% CIs associated with antihypertensive treatment compared with no antihypertensive treatment. In a sensitivity analysis, ORs were adjusted for baseline age, sex, systolic blood pressure, NIHSS score, time from stroke onset to randomization, and history of antihypertensive medication use. Multiple imputation for missing data in the multivariable analyses was conducted using the Markov chain Monte Carlo method. In addition, the median and interquartile range of modified Rankin Scale scores were calculated, and the difference was compared using the Wilcoxon rank-sum test.21 Ordinal logistic regression was used to estimate the effect of blood pressure reduction on the full range of the modified Rankin scale.22
We assessed the heterogeneity of the treatment effect on the primary outcome in prespecified subgroups by age, sex, systolic blood pressure at baseline, NIHSS score at baseline, time from onset of stroke to randomization, history of hypertension, history of antihypertensive treatment, and subtypes of ischemic stroke by adding an interaction term in unadjusted logistic regression models. A data and safety monitoring board met at least annually to review the accumulating data for safety and to monitor the trial for either superiority or inferiority of blood pressure reduction on the clinical outcomes. Data analyses were performed using SAS version 9.4 (SAS Institute Inc) and Stata version 12 (StataCorp).
From August 2009 to May 2013, we screened 22 230 consecutive patients with acute ischemic stroke, and 4071 who were eligible and willing to participate were enrolled in CATIS (Figure 1).
Of the 4071 participants, 2038 were randomly assigned to receive antihypertensive treatment and 2033 were assigned to control. The mean age was 62.0 years; 64.0% of participants were men, 49.1% were taking antihypertensive medication at admission, and 77.9% had strokes of thrombotic subtype. Baseline characteristics were balanced between the 2 groups (Table 1).
The mean systolic and diastolic blood pressure levels differed significantly between the 2 comparison groups from 4 hours to 14 days after randomization (Figure 2, Table 2). Within 24 hours, the mean systolic blood pressure was reduced by 21.8 mm Hg (12.7%) in the treatment group and 12.7 mm Hg (7.2%) in the control group (difference, −9.1 mm Hg [95% CI, −10.2 to −8.1]; P < .001). At day 7, the mean systolic blood pressure was 137.3 mm Hg in the treatment group (with 65.7% achieving the target systolic blood pressure of <140 mm Hg) compared with 146.5 mm Hg in the control group (with 32.2% having a systolic blood pressure <140 mm Hg). At day 14, the mean systolic blood pressure was 135.2 mm Hg in the treatment group (with 72.0% achieving the target systolic blood pressure of <140 mm Hg) compared with 143.7 mm Hg in the control group (with 39.5% having a systolic blood pressure <140 mm Hg). The mean differences in systolic pressures between the 2 comparison groups were −9.3 mm Hg (95% CI, −10.1 to −8.4; P < .001) at day 7 after randomization and −8.6 mm Hg (95% CI, −9.7 to −7.4; P < .001) at day 14.
Other Treatments for Ischemic Stroke
Other treatments for ischemic stroke were prescribed by the study participants’ physicians as part of their routine care according to Chinese stroke clinical guidelines and were balanced between the 2 groups (eTable 1 in Supplement). Patients in the control group discontinued home antihypertensive medications. For example, 33.4% of patients in the treatment group received heparin or low-molecular-weight heparin, compared with 34.1% in the control group (P = .63). In addition, 83.9% and 12.2% of patients in the treatment group received aspirin and clopidogrel, compared with 82.2% and 12.9% in the control group (P = .15 and .52). Furthermore, 2.6% of patients in the treatment group received intravenous fibrinolysis, compared with 2.3% in the control group (P = .55). Last, 2.3% of patients in the control group did not discontinue their home antihypertensive medications.
Clinical Outcomes at 14 Days or Hospital Discharge
At 14 days or hospital discharge, 683 of the trial participants (33.6%) in the antihypertensive treatment group, compared with 681 (33.6%) in the control group, had experienced death or a major disability (OR with antihypertensive treatment, 1.00 [ 95% CI, 0.88 to 1.14]; P = .98). The median score from the modified Rankin Scale was not significantly different between the 2 groups, and the odds of a higher modified Rankin Scale score were not associated with antihypertensive treatment (Table 2).
Clinical Outcomes at the 3-Month Posttreatment Follow-up Visit
At the 3-month visit, 84.5% of the participants in the antihypertensive treatment group and 75.4% in the control group reported the use of antihypertensive medications (P < .001) (Table 3). Blood pressure was significantly lower in the antihypertensive treatment group than in the control group (P < .001). Among participants in the antihypertensive treatment group, 500 (25.2%) died or had a major disability, compared with 502 (25.3%) in the control group (OR with antihypertensive treatment, 0.99 [95% CI, 0.86 to 1.15]; P = .93). The median modified Rankin Scale score, death rate, and vascular disease events were similar between the 2 comparison groups, whereas recurrent stroke was slightly and nonsignificantly reduced in the antihypertensive treatment group (OR, 0.65 [95% CI, 0.40 to 1.04]; P = .07).
At 14 days or hospital discharge, the effects of antihypertensive treatment on the primary outcome were consistent across all prespecified subgroups (Figure 3). At the 3-month posttreatment follow-up visit, ORs for the primary outcome were not significantly different across the prespecified subgroups, except for time from stroke onset to treatment (Figure 4). Among patients who received antihypertensive treatment 24 hours or more after stroke onset, blood pressure lowering was associated with a significant reduction in the primary outcome (OR, 0.73 [ 95% CI, 0.55 to 0.97]; P = .03).
After adjustment for baseline age, sex, systolic blood pressure, NIHSS score, time from stroke onset to randomization, and history of antihypertensive medication use, the OR with antihypertensive treatment was 1.09 (95% CI, 0.92 to 1.28; P = .33) for death or major disability at 14 days or hospital discharge and 1.05 (95% CI, 0.89 to 1.25; P = .55) for death or major disability at the 3-month posttreatment follow-up visit.
In this randomized clinical trial, mean systolic blood pressure was reduced by 12.7% within the first 24 hours after randomization and was less than 140 mm Hg by day 5 and afterward in patients with acute ischemic stroke who received antihypertensive treatment within 48 hours of symptom onset. In addition, blood pressure remained significantly lower at 3 months’ follow-up in the antihypertensive treatment group compared with the control group. However, the primary outcome of death or major disability was not different at 14 days or hospital discharge and at 3-month posttreatment follow-up after randomization between the antihypertensive treatment group and the control group, in whom antihypertensive medications had been discontinued during their hospitalization. Median modified Rankin Scale scores were not significantly different between the 2 comparison groups at 14 days or discharge and at 3-month posttreatment follow-up. Furthermore, rates of vascular events, recurrent stroke, and all-cause mortality were not significantly different between the 2 comparison groups at the 3-month posttreatment follow-up visit. These findings suggest that unless a patient’s systolic blood pressure is 220 mm Hg or more or diastolic pressure is 120 mm Hg or more, the decision to lower blood pressure with antihypertensive treatment in patients with acute ischemic stroke does not improve or worsen outcome and therefore should be based on individual clinical judgment.
There are limited data from clinical trials on the effect of antihypertensive treatment in patients with acute ischemic stroke. A meta-analysis of clinical trials assessing the calcium channel blocker nimodipine showed no neuroprotective effect in patients with acute ischemic stroke.23 Two of these trials reported that nimodipine therapy within 48 hours of stroke onset was associated with worse clinical outcomes in patients with acute ischemic stroke.24,25 Recently, a few preliminary randomized trials of blood pressure reduction in acute ischemic stroke have been published.26-29 A phase 2 pilot trial of therapy with the angiotensin receptor blocker candesartan cilexetil was stopped early because of significantly lower mortality and fewer vascular events at 12 months in the treatment group, although blood pressure was similar between the 2 study groups.26 However, a larger phase 3 trial (SCAST [Scandinavian Candesartan Acute Stroke Trial]) of candesartan therapy enrolling 2029 patients with acute stroke (ischemic or hemorrhagic) showed that the composite vascular end point did not differ between the treatment groups at 6 months, despite a significant difference in blood pressure.29 Furthermore, poorer functional outcomes were reported in the candesartan group. Two other preliminary trials enrolling patients with acute ischemic or hemorrhagic stroke also indicated that antihypertensive treatment failed to reduce adverse clinical events.27,28
Several aspects of our study are novel. This is, to our knowledge, the first randomized trial with sufficient statistical power to test the effect of immediate blood pressure reduction on adverse clinical outcomes in patients with acute ischemic stroke. Previous large trials have been conducted in patients with acute intracerebral hemorrhage30 or in patients with either acute ischemic or hemorrhagic stroke.29 In addition, this trial compares active antihypertensive treatment with the temporary discontinuation of antihypertensive medications in control participants during hospitalization. Furthermore, this study tests an antihypertensive treatment strategy using a single drug or a combination of multiple drug classes to achieve target blood pressure levels during hospitalization. On the other hand, SCAST was designed to examine the effect of the angiotensin receptor blocker candesartan compared with placebo on clinical outcomes in patients with acute stroke.29 The difference in systolic blood pressure between candesartan and placebo was 0.4 mm Hg within 24 hours and 4.9 mm Hg by day 7.29 The current trial achieved significantly greater blood pressure reduction between the treatment and control groups. However, the findings from this trial indicate that antihypertensive treatment did not reduce or increase death or major disability in patients with acute ischemic stroke.
The effects of antihypertensive treatment on the composite outcome of death and major disability at 14 days or discharge and at 3-month posttreatment follow-up were consistent across subgroups defined by age, sex, systolic blood pressure at admission, NIHSS score, time from onset of stroke to randomization, history of hypertension, current use of antihypertensive medications, and subtypes of ischemic stroke. The time from stroke onset to antihypertensive treatment was 15 hours on average, with a wide range. The study findings should be applicable to various subgroups of patients with acute ischemic stroke.
Our study had more than 90% statistical power to detect a 5% absolute risk reduction (or 14% relative risk reduction) in the composite outcome of death and major disability, which was recommended as a clinically meaningful risk reduction in acute stroke trials.19 In addition, mean systolic blood pressure was reduced by 12.7% within the first 24 hours and systolic pressure less than 140 mm Hg was achieved by day 5 in the antihypertensive treatment group. Sufficient statistical power and well-separated blood pressure levels during the trial minimize the probability of false-negative findings in our study.
Our study must be interpreted in light of several limitations. The trial excluded patients with acute ischemic stroke and blood pressure of 220/120 mm Hg or greater, so the study findings cannot be applied to such patients. However, less than 0.1% of patients with acute stroke in US emergency departments9 and less than 0.5% of the 22 230 patients assessed for eligibility in our study had an admission blood pressure of 220/120 mm Hg or greater. In addition, patients treated with intravenous thrombolytic therapy (ie, intravenous rtPA) at baseline were excluded from this trial. Although intravenous rtPA is the standard treatment for acute ischemic stroke, the proportion of patients who received the therapy is low.31-33 For example, of 1 154 247 patients with acute ischemic stroke in a US national registry, only 66 692 (5.8%) were treated with intravenous rtPA.33 Only 2.4% of patients with acute ischemic stroke were treated with intravenous thrombolytic therapy (1.6% with intravenous rtPA) in the China National Stroke Registry.34 Therefore, our findings most likely are applicable for the majority of patients, who currently do not receive intravenous thrombolytic therapy. Patients included in this trial had a lower median NIHSS score of 4 (interquartile range, 2-8), compared with 7 (interquartile range, 2-10) in Chinese national registry data.35 We did not detect a significant interaction between NIHSS score and blood pressure reduction in this trial. Another limitation of this trial is the lack of repeated neurologic function tests and brain imaging studies within the first 24 hours of blood pressure lowering. These measures might provide early indicators to identify patient subgroups that might be more benefited or harmed by blood pressure reduction.30 In addition, this trial was conducted exclusively in Chinese patients. The management of acute stroke may not be representative of Western populations; eg, there was a high use of heparin among the study patients. However, previous studies have demonstrated that the association between blood pressure and stroke is consistent between Chinese and Western populations.4,30
Among patients with acute ischemic stroke, blood pressure reduction with antihypertensive medications, compared with the absence of hypertensive medication, did not reduce the likelihood of death and major disability at 14 days or hospital discharge.
Corresponding Authors: Jiang He, MD, PhD, Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1440 Canal St, Ste 2000, New Orleans, LA 70112 (email@example.com). Yonghong Zhang, MD, PhD, Department of Epidemiology, School of Public Health, Medical College of Soochow University, 199 Renai Rd, Suzhou 215123, China (firstname.lastname@example.org).
Author Contributions: Drs He and Y. Zhang had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Drs He and Y. Zhang contributed equally to this work.
Published Online: November 17, 2013. doi:10.1001/jama.2013.282543.
Study concept and design: He, Y. Zhang, Bazzano, J. Chen.
Acquisition of data: He, Y. Zhang, Tan Xu, D. Wang, C.-S. Chen, Tong, Liu, Tian Xu, Ju, Y. Peng, H. Peng, Q. Li, Geng, J. Zhang, D. Li, F. Zhang, L. Guo, Sun, X. Wang, Cui, Y. Li, Ma, Yang, Y. Gao, X. Yuan, J. Chen.
Analysis and interpretation of data: He, Y. Zhang, Zhao, C.-S. Chen, J. Chen.
Drafting of the manuscript: He, Y. Zhang.
Critical revision of the manuscript for important intellectual content: He, Y. Zhang, Tan Xu, Zhao, D. Wang, C.-S. Chen, Tong, Liu, Tian Xu, Ju, Y. Peng, H. Peng, Q. Li, Geng, J. Zhang, D. Li, F. Zhang, L. Guo, Sun, X. Wang, Cui, Y. Li, Ma, Yang, Y. Gao, X. Yuan, Bazzano, J. Chen.
Statistical analysis: He, Zhao, C.-S. Chen.
Obtained funding: He, Y. Zhang.
Administrative, technical, or material support: He, Y. Zhang, Bazzano.
Study supervision: He, Y. Zhang, J. Chen.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: This study was supported by Tulane University and Collins C. Diboll Private Foundation, both in New Orleans, Louisiana; Soochow University, a Project of the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, and the National Natural Science Foundation of China (grant 81320108026). The Changzhou Pharmaceutical Factory provided the study drug (enalapril) for this trial.
Role of the Sponsor: The funding agencies had no role in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; the preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication.
Group Information: The China Antihypertensive Trial in Acute Ischemic Stroke (CATIS) Investigators:Study steering committee: Jiang He (chair), Jing Chen, Weijun Tong, Yonghong Zhang, Tan Xu; Data and safetymonitoring board: Paul K. Whelton (chair), Jose Biller, C. Lillian Yau, Zhenxin Zhang, Xingquan Zhao. Study and data coordinating center:Tulane University School of Public Health and Tropical Medicine and School of Medicine, New Orleans, Louisiana: Lydia A. Bazzano, Chung-Shiuan Chen, Jing Chen, L. Lee Hamm, Jiang He, Tanika N. Kelly, Shengxu Li, Sheryl Martin-Schild, Katherine T. Mills, Qi Zhao; School of Public Health, Medical College of Soochow University, Suzhou, China: Xiaoqing Bu, Fanlong Kong, Hongmei Li, Hao Peng, Lingyan Tang, Weijun Tong, Aili Wang, Ke Wang, Jiahui Wu, Juan Xu, Tan Xu, Tian Xu, Mingzhi Zhang, Shaoyan Zhang, Yonghong Zhang. Participating hospitals: Department of Neurology, Affiliated Hospital of Hebei United University, Hebei, China (Dali Wang, Yanbo Peng, Li Zhang, Xiaojing Zhao, Suling Gao, Jiang Zhang); Department of Neurology, Yutian County Hospital, Hebei, China (Changjie Liu, Jinchao Wang, Lingjun Kong, Yanhong Wu, Yanan Cao, Baoli Liu); Department of Neurology, Kerqin District First People’s Hospital of Tongliao City, Inner Mongolia, China (Zhong Ju, Bing Zhao, Haiying Liu, Maoli Bu, Yongjiang Li); School of Public Health, Taishan Medical College, Shandong, China (Qunwei Li); Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Jiangsu, China (Deqin Geng, Fangfang Zhu, Junjun Shan, Chao Ren, Yanbo Cheng); Department of Neurology, the 88th Hospital of PLA, Shandong, China (Jintao Zhang, Cuiling Zhou, Yulan Zhao, Yujie Bi, Na Zhong); Department of Internal Medicine, Feicheng City People’s Hospital, Shandong, China (Dong Li, Cuilan Liang, Shanliang Qiao, Guansheng Zhang, Wei Wang); Department of Neurology, Tongliao Municipal Hospital, Inner Mongolia, China (Fengshan Zhang, Yanqiu Du, Jianhui Zhang, Shuhua He); Department of Neurology, Siping Central Hospital, Jilin, China (Libing Guo, Qingjuan Du, Chunying Zhang, Wenhui Ma); Department of Cardiology, the First Affiliated Hospital of China Medical University, Liaoning, China (Yingxian Sun); Department of Neurology, Jilin Central Hospital, Jilin, China (Xuemei Wang, Jiale Liu, Yongshun Wang, Dawei Yin); Department of Neurology, General Hospital of First Automobile Works, Jilin, China (Yong Cui, Jing Tian, Hong Chang, Yonghong Gao); Department of Neurology, Tangshan Worker’s Hospital, Hebei, China (Yongqiu Li, Haifeng Gao, Dongsen Zhang); Department of Neurology, the First Affiliated Hospital of Jilin University, Jilin, China (Dihui Ma); Department of Neurology, Dongping County People’s Hospital, Shandong, China (Dongsheng Zhang, Jianjun Cui); Department of Neurology, the Second People’s Hospital of Huaian City, Jiangsu, China (Guang Yang, Liandong Zhao, Jinlong Zheng); Department of Neurology, Affiliated Hospital of Chengde Medical College, Hebei, China (Yanjun Gao, Liang Zhao); Department of Neurology, Kailuan General Hospital, Hebei, China (Xiaodong Yuan, Shujuan Wang); Department of Neurology, Anshan Changda Hospital, Liaoning, China (Xiujie Han, Dan Zhou, Yulin Song); Department of Neurology, Wenshang County Chinese Traditional Medicine Hospital, Shandong, China (Mingyu Zhang); Department of Neurology, the First Affiliated Hospital of Harbin Medical University, Heilongjiang, China (Shurong Duan); Department of Neurology, First People’s Hospital of Kezuohouqi, Inner Mongolia, China (Tao Feng); Department of Neurology, Suzhou Kowloon Hospital of Shanghai Jiaotong University School of Medicine, Jiangsu, China (Jizhen Li); Department of Neurology, Anshan Hospital of the First Affiliated Hospital, China Medical University, Liaoning, China (Suzhen Liu, Likui Hu); Department of Neurology, Anshan Central Hospital, Liaoning, China (Wei Hu); Department of Neurology, Anshan Shuangshan Hospital, Liaoning, China (Chun Nie); Department of Neurology, Affiliated Hospital of Inner Mongolia National University, Inner Mongolia, China (Nuenjiya Zhao).
Additional Contributions: We thank the study participants and their relatives and the clinical staff at all participating hospitals for their support and contribution to this project.
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