Epidemiology Of Dyslipidemia And Prevention Of Stroke Events With Lipid-lowering And Blood-pressure-lowering In Rural Hypertensive Patients Of Liaoning

IntroductionCardiovascular disease(CVD) is a major cause of mortality in most developed and developing countries.In China,CVD accounted for nearly 40%of all deaths. Hypertension and dyslipidemia play crucial rules in the development of CVD.The results of recently published ASCOT study(Anglo-Scandinavian Cardiac Outcomes Trial) showed that with lipid- lowering and blood-pressure-lowering treatment in high risk hypertensive patients could reduce 27%stroke events.However,we have few data about whether we can get benefits from lipid-lowering treatment in low risk or moderate risk hypertensive patients.Meanwhile,above-mentioned studies were conducted in cities;the data were extraordinarily scarce in China especially in countryside.In our conducted survey,37.8%of the rural population(aged≥35 years) in Liaoning province had hypertension.However,the figure for the whole country was only 26.1%(aged 35-74 years).Research has found that hypertension and dyslipidemia are often observed concomitantly,but the studies of dyslipidemia in Chinese hypertensive patients are few.The objectives of the current study were to estimate the prevalence of dyslipidemia and its associated factors among the rural population with hypertension in Liaoning.Based on the epidemiology study,we further assess benefits of lipid-lowering and blood pressure-lowering in the prevention of stroke among rural Chinese hypertensive patients.MethodsA cross-sectional survey of dyslipidemia was conducted from 2004 to 2006 in Liaoning province of China.The study used a cluster multistage sampling method, which included samples from rural hypertensives in the northern,southern,western, eastern,and the central regions of Fuxin County in Liaoning province.Only one small town was selected from each region.Finally,ten rural villages near each small town were randomly selected from different geographic areas.A total of 6,412 hypertensives aged≥35 years(2,805 men,3,607 women) completed the survey and had a serum cholesterol measurement.Criterion of dyslipidemia was classified on the basis of the Third Report of the Expert Panel on Detection,Evaluation,and Treatment of High Blood Cholesterol in Adults(ATPⅢ).2701 rural hypertensive patients(with or without other cardiovascular risk factors) who completed the cross-sectional survey were randomized to antihypertensive regimen or antihypertensive combined with lipid-lowering regimen from 2006.The levels of blood pressure,levels of lipids, adverse effects of medicine and stroke events were followed up.The procedures followed were in accordance with ethical standards of the responsible committee on human experimentation of China Medical University.The SPSS 11.5 statistical software was used for data analysis.The numeration data were expressed as rate or constituent ratio.The measurement data were expressed as mean±standard deviation.The rate comparison among groups used chi square test and a test for trend was used to analyze the significance of an increase or decrease in prevalence across age groups and classification of blood pressure.To evaluate the association between blood lipids and risk factors,we used multiple logistic regression analysis.Paired t-test was used to compare blood pressure before and after intervention.For the main analyses of stroke events we used the log-rank procedure and the Cox's proportional hazards model to calculate CI.Cumulative incidence curves were generated by the Kaplan-Meier method for all major endpoints.For all comparisons,p values＜0.05 were considered statistically significant.ResultsThe main founding was that 34.4%had borderline high total cholesterol(TC), 16.9%had high TC,respectively,and the prevalence.8.8%had low high-density lipoprotein cholesterol(HDL-C),and the prevalence was significantly higher in men than in women(10.4 vs.7.5%,p＜0.001).The population with borderline high,high, and very high low-density lipoprotein cholesterol(LDL-C) was 15.7,3.5,and 0.9%, respectively.In addition,15.9%had borderline high triglycerides(TG),17.8%had high TG and 2.0%had very high TG.For TC,LDL-C,and TG,the prevalence was significantly higher in women than in men(p＜0.001).In the borderline high group,the prevalence of dyslipidemia was decreased with the severity of co-morbidities;however, the prevalence was increased in the high and very high group.But it was significant in the high LDL-C,TG group and in the very high TG group.The prevalence of TC increased with the increased stage of blood pressure.In contrast,the prevalence of HDL-C decreased with the increased stage of blood pressure(p＜0.05).After adjusting for independent variables,TC and TG had the same risk with fasting plasma glucose (FPG) and body mass index.Risk factors of TC and LDL-C were women,age and FPG, Mongolia nationality as a protective factor positively correlated with TC,LDLC,and TG.Women,age,drinking,and classification of blood pressure were protective factors but Mongolia nationality was a risk factor for HDL-C.After a median follow-up of 1.67 years,258 patients were lost to follow up and the rate was 9.6%in the prospective study.For participants,about 44.4%of the subjects were men,and 55.6%were women.All subjects selected were between 35 and 88 years old and the average age was 57.72±10.84 years.Main baseline characteristics of participants such as age,sex,systolic blood pressure,diastolic blood pressure,TC,and LDL-C in these two groups were well matched(p＞0.05).By the end of follow up, compared with antihypertensive group,the levels of blood pressure were significantly decreased in the combination therapy group(-28.58mmHg vs -26.20mmHg,p＜0.05). The levels of TC,LDL-C and HDL-C decreased significantly in the combination therapy group,the rate was 11.33%,12.78%and 3.76%,respectively(p＜0.05).By the risk stratification of dyslipidemia,compared with antihypertensive group,moderate or higher levels risk patients had lower incidence of non-fatal ischemic stroke(HR:0.192, 95%CI:0.042-0.876),fatal and non-fatal stroke(HR:0.262,95%CI:0.075-0.916),total cardiovascular events(HR:0.324,95%:0.107-0.982) in the combination therapy group (p＜0.05).The analysis of adverse effects show that compared with antihypertensive group,the combination therapy group had slightly higher adverse effects of gastrointestinal tract(8.9%vs.2.7%) and exanthema(1.4%vs.0.4%).However,the serious adverse events,such as muscle soreness,liver enzyme greater than 3 times the upper limit of normal,creatine kinase greater than 5 times the upper limit of normal were not significant between the two groups(p＞0.05).The patients who withdrawal drugs because of adverse effects of medicine had no different in the two groups(5.1% vs.3.2%,p＞0.05).Conclusions1.The prevalence of dyslipidemia was relatively high among rural hypertensive patients and there were many modifiable risk factors for dyslipidemia such as hypertension,weight,and impaired glucose metabolism.To prevent dyslipidemia and to reduce the increasing burden of CVD in rural areas,the first aim is to reduce these risk factors.2.The antihypertensive combined with lipid-lowering treatment was valid and safe.Systolic blood pressure could be further decreased by combination therapy. Compared with antihypertensive group,the incidence of stroke of moderate or higher levels risk patients was also significantly decreased.