The Association Between Serum Uric Acid Levels And Ischemic Stroke In Essential Hypertension Patients

BackgroundStroke is a disease with high incidence rate,high disability rate,high mortality rate,high recurrence rate and many complications.It is the most important cause of death,chronic disability,epilepsy,dementia,depression and sleep disorders.Stroke is one of the leading causes of death in the United States,Canada,Europe,Japan and other high-income regions behind coronary heart disease and cancer.Now there are 795 thousand new strokes every year in the United States,resulting in 200 thousand deaths.The National Institutes of health estimates that the annual medical cost for stroke is more than 62 billion dollars.Besides,stroke has become the leading cause of death in China,with incidence rate and mortality rate of 246.8/10 million and 114.8/10 million,respectively,accounting for nearly 1/3 of the total number of deaths worldwide.The incidence of stroke is affected by many factors,such as the sharp rise of hypertension,diabetes,metabolic syndrome,smoking and overweight.It is generally believed that uric acid is closely related to hypertension,metabolic syndrome and diabetes.One previous study has shown that serum uric acid(SUA)levels are closely related to stroke.In addition,a study conducted in Japan showed that SUA was independently associated with non-fatal stroke.However,other studies have found that in women,SUA does not predict stroke risk alone,but it is related to the risk factors of stroke.It was also found that there was no association between SUA and stroke in Chinese hypertension population after adjusting the risk factors of cardiovascular and cerebrovascular diseases.Even some studies have found that compared with placebo group,in patients with acute ischemic stroke treated with ateplase,uric acid treatment can reduce the infarct expansion of patients and obtain a good prognosis.At present,the relationship between SUA and stroke is still controversial,especially in the specific population such as hypertension and obesity.The relationship is still not clear by finding the literature in recent years at home and abroad,especially the research on the relationship between SUA and ischemic stroke in hypertension patients is still limited in China.The purpose of this study is to explore the relationship between SUA and ischemic stroke in essential hypertension.The study is divided into three parts.The first part is the baseline characteristics of stroke and SUA.The second part is the relationship between SUA and ischemic stroke in essential hypertension.The third part is the predictive value of SUA for ischemic stroke in essential hypertension.Objectives1.To explore the relationship between SUA and ischemic stroke in patients with essential hypertension2.To explore the predictive value of SUA on ischemic stroke in patients with essential hypertensionMethodsThis retrospective study recruited the essential hypertension population who completed the annual physical examination from September 2011 to December 2012 in Liao-bu community health service center,Dongguan City,Guangdong Province.All the subjects signed the informed consent,were interviewed and completed a standardized questionnaire.Besides,All the subjects were measured the blood pressure,blood routine,blood biochemistry and blood lipid.All subjects were followed up to December 31,2016 with a mean follow-up of 4.5 years.The subjects were divided into four groups according to the concentration of uric acid.According to the diagnosis criteria of ischemic stroke,the new onset ischemic stroke population and the normal population were matched by 1:1 to determine whether there was any difference between the two groups.Considering the influence of gender on SUA,the relationship between SUA and ischemic stroke in different gender subgroups was analyzed.In this study,Cox proportional hazard model was used to estimate hazard ratio(HR)and confidence interval(CIS),and propensity score,Kaplan Meier survival curve and ROC curve were used to evaluate the relationship between SUA and risk of ischemic stroke.Results1.A total of 5473 eligible patients with essential hypertension were included in this study,with an average age of 62.02±13.76 years,including 2666 males(48.71%)and 2807 females(51.29%).During an average follow-up of 4.5 years,155 new ischemic stroke patients were found.2.According to the SUA quartile,we found that in different concentrations of uric acid groups,gender,body mass index(BMI),diastolic blood pressure(DBP),fasting blood glucose(FBG),total cholesterol(TC),triglyceride(TG),low-density lipoprotein(LDL-C),high-density lipoprotein(HDL-C),estimated glomerular filtration rate(eGFR),smoking,drinking,new onset stroke,coronary artery disease(CAD)history and medication history were statistically different(all P<0.05),while diabetes history and systolic blood pressure(SBP)was not found.Although age increased with the increase of SUA,no statistical significance was found in this trend.3.Compared with the normal group,there are statistical differences in TC,TG,SUA,smoking and antihypertensive drug treatment in the new onset stroke group,which is also consistent with the current consensus of stroke risk factors.4.In gender based subgroup analysis,after adjusting for age,gender,BMI,smoking,drinking,FBG,TG,TC,HDL-C,LDL-C,SBP,eGFR,antihypertensive drug treatment history,diabetes history and CAD history,the risk of ischemic stroke increased by 53%(95%CI:1.14,1.92,P<0.001)for each standard deviation(SD)of SUA increased in male population,35%in female group and 41%in the whole group.When uric acid was used as the grouping variable,the risk of ischemic stroke increased with the increase of uric acid concentration,and the risk of men was higher than that of women(Q4 HR 1.89,95%CI:1.21,2.18 p<0.001,male vs HR 1.58,95%CI:1.16,1.89 p<0.001,female).5.The incidence of ischemic stroke from the lowest to the highest quartiles were 7(0.51%),26(1.90%),53(3.87%)and 69(5.04%),respectively(P<0.001).The log rank test was performed to verify the association between SUA levels and ischemic stroke.6.The area under the ROC curve(AUC)of SUA was 0.7476(95%CI:0.7098,0.7855,P<0.001).The sensitivity and specificity were 0.7548 and 0.6076,respectively.It indicated that SUA has a better predictive value for ischemic stroke.ConclusionIn conclusion,this study showed that elevated SUA levels were associated with higher incidence of ischemic stroke in Chinese patients with essential hypertension.SUA was an independent risk factor for ischemic stroke.In patients with hypertension,SUA has a good predictive value for ischemic stroke and may be a good marker of ischemic stroke.