Analysis The Related Risk Factors For Low Level Of High Density Lipoprotein Cholesterol In Patients With Ischemic Stroke

Objective: The low level of high density lipoprotein cholesterol as the most common form of dyslipidemia in Chinese and it is closely associated with the occurrence and recurrence of stroke, Besides it can predict the severity of the stroke in acute phase. It play a reverse cholesterol transport, anti-inflammatory, antioxidant, etc. in the normal state. However, it becomes pro-inflammatory and promote oxidation in the state of inflammation and metabolic abnormalities, because its structure and composition is modified by oxidation and glycosylation in the pathological state and it turns a risk factor for atherosclerosis development. So it is necessary to analysis the relationship between low HDL-C and the traditional vascular risk factors, such as age, sex, smoking, drinking, hypertension, diabetes and so on.Therefore, patients with ischemic stroke as the research object were enrolled in the study to analysis of the prevalence of low HDL-C, and analysis the correlation with vascular risk factors.Methods:1 objects of study: We collected data from patients with acute ischemic stroke that were admitted to our hospital from December 2006 and December 2012. Based on the modified TOAST(Trial of Org 10172 in Acute Stroke Treatment) classification, the diagnosis of large artery atherosclerosis(LAA) and small artery disease(SAD) were enrolled in the study, and all patients with standard population composition and vascular risk factors of registration. And we excluded patients who were diagnosed of cardiac strokes, strokes caused by other reasons or unknown reasons. The patents with Severe liver and kidney disease or whose clinical data was not complete were also excluded.2 Diagnostic criteria of the Low levels of high-density lipoprotein: ATP III guidelines were used to define low HDL-C level as(HDL-C≤1.03mmol/L), and/or a history of taking a lipid-lowering drug after diagnosis of hypercholesterolemia. Isolated low HDL-C was defined as(HDL-C≤1.03mmol/L in men and HDL-C≤1.29mmol/L in women and LDL<2.59mmol/L and triglyceride<1.7mmol/L).3 Diagnostic criteria of the other lipid metabolism disorders were determined according to ATP III guidelines: high total cholesterol level(TC≥5.18mmol/L), high triglycerides level(TG≥1.7mmol/L), high low- density lipoprotein cholesterol level(LDL-C≥2.59mmol/L).4 Statistical methods: Analyses were performed by SPSS 13.0 for Win- dows. With demographic situation, the TOAST classification, hypertension, diabetes, coronary heart disease, family history of cardiovascular disease, Smoking and drinking of all the patients as independent variables, and multivariate Logistic regression models were respectively performed with the univariate analysis which were statistically significant indicators, to determine the independent risk factors of low HDL-C level. Logistic regression analysis was used in multivariate analysis. P<0.05 was considered as statistically significant judgment.Results:1 1358 patients with ischemic stroke were included in this study, including 461 women and 897 men, the prevalence of low HDL-C level was 64.2% and it in isolated low HDL-C disease was 31.8%. The prevalence of low HDL- C level was 64.2% in women and 39.2% in men. the difference is statistically significant(χ2=29.074, P<0.01). LAA patients 795, and SAD 563.Among them, the LAA group of patients with low HDL-C prevalence was 61.0%, the SAD group was 39.0%(χ2=5.674, P<0.01).2 Analysis relationship between low HDL-C level and vascular risk factors: multiple logistic regression analysis showed strong associations with low HDL-C level and male, high TG, diabetes, and statins.(OR: 3.318, 2.529, 1.652, 1.457, P < 0.05). However, age(P=1.131), smoking(P=0.471), drinking(P=0.101), history of stroke(P=0.552), hypertension(P=0.657), coronary heart disease(P=0.937) and high LDL-C level(P=0.075)were not independently associated with low HDL-C. TC is positively correlated with HDL-C(OR=0.400, 95%CI0.301-0.530, P=0.000). A high level of TC is often associated with high HDL-C, which shows mutual conversion relation between them.Analysis Risk factors for different sex of ischemic stroke patients with low HDL-C level, the results showed: the independent risk factors of low HDL-C level of ischemic stroke in male patients was high TG, statin drugs, diabetes, smoking, drinking(OR:2.384, 1.715, 1.535, 1.475, 1.455; P<0.05). only high TG and diabetes were independent risk in female group(OR: 2.780, 1.910; P<0.05). Female is the protective factor of low HDL-C, Because estrogen may have increased content of mature HDL2. Smoking, drinking as independent risk of low HDL-C levels of ischemic stroke in male patients, that can induce HDL-C, which promote atherosclerosis and stroke.Analysis Risk factors for low HDL-C in different subtypes of ischemic stroke patients, the results showed: Male, high TG and diabetes as independent risk factors for different subtypes of ischemic stroke in patients with low HDL-C level; and the history of statin use only is closely related to low HDL-C level in patients with SAD(OR=2.0202,P=0.002). So high TG as one common type of abnormal metabolism of lipid in Asian, and high TG can decrease HDL-C through a variety of mechanisms: high TG can make the lecithin cholesterol acyltransferase(LCAT), lipoprotein lipase(LPL) activity decreased, so that the mature HDL-C metabolic disruption. And cholesterol ester transfer protein(CETP) activity increased, remove the cholesterol of HDL-C, resulting in HDL-C reconstruction, then reduce the content of HDL-C in blood. Diabetes is an independent risk factor for low HDL-C level, not only with high glucose can make HDL-C protein directly glycosylation, reduce the level of HDL-C. And diabetes often accompanied by insulin resistance and glucose utilization obstacle, one hand it can promote the decomposition of fat and inflammatory reaction to reduce HDL-C directly; on the other hand, promote secretion of TG rising, and high TG further reduce the HDL-C level.As a retrospective study, the type and period of statins in each enrolled patients are not identical, and different statins have different effects, so we are not sure statin use history as a risk factor of low HDL-C.3 Multiple logistic regression analysis relationship between isolated low HDL-C and vascular risk factors: male, diabetes, and statins drugs application as independent risk factors of isolated low HDL-C(OR: 2.557, 1.754, 2.152, P<0.01). The results suggest that isolated low HDL-C level as ischemic stroke risk factors should be paid attention to, because its clinical significance is equivalent to the low HDL-C level.Conclusions: The incidence of low HDL-C level is 64.2% in enrolled patients with ischemic stroke in the study, especially in the patients with LAA. Low HDL-C level is more likely to occur in male patients with high TG and diabetes. History of smoking, drinking are respectively independent risk factor of low HDL-C level in male patients.