Mol Neurobiol DOI 10.1007/s12035-016-9799-0
Plasma Homocysteine and Prognosis of Acute Ischemic Stroke: a Gender-Specific Analysis From CATIS Randomized Clinical Trial Chongke Zhong 1 & Tan Xu 1,2 & Tian Xu 1,3 & Yanbo Peng 4 & Aili Wang 1 & Jinchao Wang 5 & Hao Peng 1 & Qunwei Li 6 & Deqin Geng 7 & Dongsheng Zhang 8 & Yuming Zhang 9 & Yonghong Zhang 1,2 & Xiang Gao 10 & Jiang He 1,2 & CATIS Investigation Groups
Received: 28 November 2015 / Accepted: 16 February 2016 # Springer Science+Business Media New York 2016
Abstract Elevated total homocysteine level (tHcy) has been hypothesized to be associated with morbidity and mortality of stroke; however, results regarding the association between plasma tHcy status and prognosis of acute ischemic stroke are inconsistent. Moreover, the gender effect on this association has yet to be explored. We thus prospectively investigated whether higher tHcy concentrations predicted poor stroke prognosis in Chinese adults. A total of 3309 acute ischemic stroke patients were included in this prospective multicenter study from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS). Baseline tHcy concentrations were quantitatively determined via enzymatic cycling assay. The primary outcome was a combination of death and major
disability at 3 months (modified Rankin scale scores 3–6) after hospitalization. Multivariate logistic regression models with restricted cubic splines were used to determine the association between baseline plasma tHcy and the subsequent outcome. Higher plasma tHcy concentrations were associated with increased risks of the primary outcome in women but not in men (Pinteraction = 0.016). Adjusted odds ratios comparing two extreme tHcy quartiles were 1.83 (95 % confidence interval 1.12–2.98; Ptrend = 0.02) in women and 0.87 (95 % confidence interval 0.61–1.25; Ptrend = 0.37) in men. The significant association between baseline tHcy status and stroke prognosis in women, but not in men, persisted in further subgroup analyses, stratified by age, baseline systolic blood pressure, and
Chongke Zhong, Tan Xu and Tian Xu contributed equally to this work. Electronic supplementary material The online version of this article (doi:10.1007/s12035-016-9799-0) contains supplementary material, which is available to authorized users. * Yonghong Zhang [email protected]
3
Department of Neurology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
* Xiang Gao [email protected]
4
Department of Neurology, Affiliated Hospital of North China University of Science and Technology, Hebei, China
* Jiang He [email protected]
5
Department of Neurology, Yutian County Hospital, Hebei, China
6
Department of Epidemiology, School of Public Health, Taishan Medical College, Shandong, China
7
Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Jiangsu, China
8
Department of Neurology and Cardiology, Dongping County People’s Hospital, Dongping, Shandong, China
9
Department of Neurology, Wenshang County Hospital of Traditional Chinese Medicine, Shandong, China
10
Department of Nutritional Science, The Pennsylvania State University, University Park, PA, USA
CATIS Investigation Groups 1
2
Department of Epidemiology, School of Public Health and Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Medical College of Soochow University, 199 Renai Road, Industrial Park District, Suzhou, Jiangsu Province 215123, China Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
Mol Neurobiol
other pre-specified factors. Elevated tHcy is positively associated with poor prognosis of acute ischemic stroke in women, but not in men. Further studies are needed to replicate our findings and to clarify the potential sex-specific mechanisms. Keywords Homocysteine . Acute ischemic stroke . Prognosis . Gender
Introduction Total homocysteine (tHcy) is a sulfur-containing amino acid and could cause atherogenesis and thrombogenesis via direct neurotoxicity, endothelial damage, vascular smooth muscle proliferation, and coagulation abnormalities [1, 2]. It is reported that approximately 75 % hypertensives have hyperhomocysteinemia in China. Elevated tHcy has thus been hypothesized to be associated with risk of developing stroke, especially in patients with hypertension [3, 4]. Some studies suggested that a 3-μmol/L reduction of tHcy was associated with 19– 24 % lower stroke risk [5, 6]. However, epidemiologic studies investigating the association between tHcy levels and the prognosis of ischemic stroke patients have yielded inconsistent results [7–13]; several studies have demonstrated a significant correlation [7–9], while others failed [10–13]. Interestingly, sex has been shown to affect tHcy concentration [14, 15], and some previous studies reported a sex difference in the relationship between homocysteine and risk of cardiovascular disease (CVD) [16–18]. Thus, there may be sex-specific associations between tHcy and functional disability or vascular events among ischemic stroke patients. To test this hypothesis, we conducted a prospective study to investigate the possible relationship between tHcy levels and 3-month prognosis of acute ischemic stroke, including deaths, major disability, and vascular events in both men and women in a large prospective multicenter study of the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS).
Methods Study Subjects and Data Collection The CATIS was a multicenter, single-blind, blinded end-point randomized clinical trial conducted in 26 hospitals across China to test whether moderate lowering of blood pressure within the first 48 h after the onset of an acute ischemic stroke would reduce death and major disability at 14 days or hospital discharge. The design and main results of the CATIS have been reported previously [19]. Briefly, a total of 4071 patients, 22 years or older who had ischemic stroke, confirmed by computed tomography or magnetic resonance imaging of the
brain within 48 h of symptom onset and who had an elevated systolic blood pressure between 140 mmHg and less than 220 mmHg, were recruited in this trial. Considering some patients refused to offer blood samples and some collected samples were hemolyzed in storage or transport, a total of 3373 acute ischemic stroke patients were finally included in this analysis. There were no remarkable differences between enrolled and excluded patients of baseline characteristics (Supplemental Table I). This study was approved by the institutional review boards at Tulane University in the USA 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.
Assessment of Plasma Total Homocysteine Concentrations Blood samples were collected within 24 h of hospital admission after at last 8 h of fasting. All plasma and serum samples were frozen at −80 °C in the Central Laboratory of School of Public Health in Soochow University until laboratory testing. Plasma total homocysteine was determined by enzymatic cycling assay on the Cobas c 501 analyzer (Roche Diagnostics, Indianapolis, IN). Laboratory technicians who performed these measurements were blind to the clinical characteristics of the study participants.
Assessment of Potential Covariates Data on demographic characteristics, lifestyle risk factors, medical history, and time of stroke onset were collected at the time of enrollment. Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) by trained neurologists at baseline. 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 [20]. Blood pressure was measured with the participant in a supine position using a standard mercury sphygmomanometer and one of four cuff sizes (pediatric, regular adult, large adult, or thigh) based on participant arm circumference. The mean of three blood pressure measurements were used in analyses. Plasma glucose levels were measured by modified hexokinase enzymatic method. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were analyzed enzymatically using commercial reagents, and low-density lipoprotein cholesterol (LDL-C) levels were calculated using the Friedewald equation. Hyperglycemia was defined as fasting plasma glucose ≥6.1 mmol/l. The criterion of dyslipidemia was as follows: TC ≥6.22 mmol/l or TG ≥2.26 mmol/l or LDL-C ≥4.14 mmol/l or HDL-C
Plasma Homocysteine and Prognosis of Acute Ischemic Stroke: a Gender-Specific Analysis From CATIS Randomized Clinical Trial Chongke Zhong 1 & Tan Xu 1,2 & Tian Xu 1,3 & Yanbo Peng 4 & Aili Wang 1 & Jinchao Wang 5 & Hao Peng 1 & Qunwei Li 6 & Deqin Geng 7 & Dongsheng Zhang 8 & Yuming Zhang 9 & Yonghong Zhang 1,2 & Xiang Gao 10 & Jiang He 1,2 & CATIS Investigation Groups
Received: 28 November 2015 / Accepted: 16 February 2016 # Springer Science+Business Media New York 2016
Abstract Elevated total homocysteine level (tHcy) has been hypothesized to be associated with morbidity and mortality of stroke; however, results regarding the association between plasma tHcy status and prognosis of acute ischemic stroke are inconsistent. Moreover, the gender effect on this association has yet to be explored. We thus prospectively investigated whether higher tHcy concentrations predicted poor stroke prognosis in Chinese adults. A total of 3309 acute ischemic stroke patients were included in this prospective multicenter study from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS). Baseline tHcy concentrations were quantitatively determined via enzymatic cycling assay. The primary outcome was a combination of death and major
disability at 3 months (modified Rankin scale scores 3–6) after hospitalization. Multivariate logistic regression models with restricted cubic splines were used to determine the association between baseline plasma tHcy and the subsequent outcome. Higher plasma tHcy concentrations were associated with increased risks of the primary outcome in women but not in men (Pinteraction = 0.016). Adjusted odds ratios comparing two extreme tHcy quartiles were 1.83 (95 % confidence interval 1.12–2.98; Ptrend = 0.02) in women and 0.87 (95 % confidence interval 0.61–1.25; Ptrend = 0.37) in men. The significant association between baseline tHcy status and stroke prognosis in women, but not in men, persisted in further subgroup analyses, stratified by age, baseline systolic blood pressure, and
Chongke Zhong, Tan Xu and Tian Xu contributed equally to this work. Electronic supplementary material The online version of this article (doi:10.1007/s12035-016-9799-0) contains supplementary material, which is available to authorized users. * Yonghong Zhang [email protected]
3
Department of Neurology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
* Xiang Gao [email protected]
4
Department of Neurology, Affiliated Hospital of North China University of Science and Technology, Hebei, China
* Jiang He [email protected]
5
Department of Neurology, Yutian County Hospital, Hebei, China
6
Department of Epidemiology, School of Public Health, Taishan Medical College, Shandong, China
7
Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Jiangsu, China
8
Department of Neurology and Cardiology, Dongping County People’s Hospital, Dongping, Shandong, China
9
Department of Neurology, Wenshang County Hospital of Traditional Chinese Medicine, Shandong, China
10
Department of Nutritional Science, The Pennsylvania State University, University Park, PA, USA
CATIS Investigation Groups 1
2
Department of Epidemiology, School of Public Health and Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Medical College of Soochow University, 199 Renai Road, Industrial Park District, Suzhou, Jiangsu Province 215123, China Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
Mol Neurobiol
other pre-specified factors. Elevated tHcy is positively associated with poor prognosis of acute ischemic stroke in women, but not in men. Further studies are needed to replicate our findings and to clarify the potential sex-specific mechanisms. Keywords Homocysteine . Acute ischemic stroke . Prognosis . Gender
Introduction Total homocysteine (tHcy) is a sulfur-containing amino acid and could cause atherogenesis and thrombogenesis via direct neurotoxicity, endothelial damage, vascular smooth muscle proliferation, and coagulation abnormalities [1, 2]. It is reported that approximately 75 % hypertensives have hyperhomocysteinemia in China. Elevated tHcy has thus been hypothesized to be associated with risk of developing stroke, especially in patients with hypertension [3, 4]. Some studies suggested that a 3-μmol/L reduction of tHcy was associated with 19– 24 % lower stroke risk [5, 6]. However, epidemiologic studies investigating the association between tHcy levels and the prognosis of ischemic stroke patients have yielded inconsistent results [7–13]; several studies have demonstrated a significant correlation [7–9], while others failed [10–13]. Interestingly, sex has been shown to affect tHcy concentration [14, 15], and some previous studies reported a sex difference in the relationship between homocysteine and risk of cardiovascular disease (CVD) [16–18]. Thus, there may be sex-specific associations between tHcy and functional disability or vascular events among ischemic stroke patients. To test this hypothesis, we conducted a prospective study to investigate the possible relationship between tHcy levels and 3-month prognosis of acute ischemic stroke, including deaths, major disability, and vascular events in both men and women in a large prospective multicenter study of the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS).
Methods Study Subjects and Data Collection The CATIS was a multicenter, single-blind, blinded end-point randomized clinical trial conducted in 26 hospitals across China to test whether moderate lowering of blood pressure within the first 48 h after the onset of an acute ischemic stroke would reduce death and major disability at 14 days or hospital discharge. The design and main results of the CATIS have been reported previously [19]. Briefly, a total of 4071 patients, 22 years or older who had ischemic stroke, confirmed by computed tomography or magnetic resonance imaging of the
brain within 48 h of symptom onset and who had an elevated systolic blood pressure between 140 mmHg and less than 220 mmHg, were recruited in this trial. Considering some patients refused to offer blood samples and some collected samples were hemolyzed in storage or transport, a total of 3373 acute ischemic stroke patients were finally included in this analysis. There were no remarkable differences between enrolled and excluded patients of baseline characteristics (Supplemental Table I). This study was approved by the institutional review boards at Tulane University in the USA 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.
Assessment of Plasma Total Homocysteine Concentrations Blood samples were collected within 24 h of hospital admission after at last 8 h of fasting. All plasma and serum samples were frozen at −80 °C in the Central Laboratory of School of Public Health in Soochow University until laboratory testing. Plasma total homocysteine was determined by enzymatic cycling assay on the Cobas c 501 analyzer (Roche Diagnostics, Indianapolis, IN). Laboratory technicians who performed these measurements were blind to the clinical characteristics of the study participants.
Assessment of Potential Covariates Data on demographic characteristics, lifestyle risk factors, medical history, and time of stroke onset were collected at the time of enrollment. Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) by trained neurologists at baseline. 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 [20]. Blood pressure was measured with the participant in a supine position using a standard mercury sphygmomanometer and one of four cuff sizes (pediatric, regular adult, large adult, or thigh) based on participant arm circumference. The mean of three blood pressure measurements were used in analyses. Plasma glucose levels were measured by modified hexokinase enzymatic method. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were analyzed enzymatically using commercial reagents, and low-density lipoprotein cholesterol (LDL-C) levels were calculated using the Friedewald equation. Hyperglycemia was defined as fasting plasma glucose ≥6.1 mmol/l. The criterion of dyslipidemia was as follows: TC ≥6.22 mmol/l or TG ≥2.26 mmol/l or LDL-C ≥4.14 mmol/l or HDL-C
