Prospective Cohort Study On Dynamic Changes In Blood Pressure And Risk Of Cardiovascular Disease

Objective: Cardiovascular Disease(CVD)is a multifactorial disease that seriously affects health,with high morbidity and mortality and heavy economic burden,especially in northeast China.Hypertension is a major risk factor for CVD,and lowering blood pressure(BP)in patients with hypertension can significantly reduce the incidence of CVD.However,the individual BP values fluctuate dynamically with time,and traditional studies that focus on the correlation between BP values at a single time point and CVD disease lose part of the disease information and fail to identify all patients at risk to achieve early intervention.Therefore,the current situation requires us to switch from the BP values at a single point of time to the study of dynamic changes in BP as soon as possible.However,such studies have not been found in rural areas of Northeast China,which are most affected by CVD.The purpose of this study was to analyze and compare the effects of the same level of BP changes on the risk of major adverse cardiovascular events(MACE)on over shortand long time intervals.Methods: This is a prospective cohort study.According to the purpose of the study,we defined BP changes during the period from 2004.1 to 2010.12 as long-term BP changes,and BP changes during the period from January 2008 to 2010.12 as short-term BP changes.We used the definition of short and long-term BP changes to identify two groups in the short-and long-term groups and collected new MACE(including stroke,myocardial infarction(MI),CVD death)during the period 2010.12-2017.12 as the study outcome.Subjects were divided into three categories,normal BP,prehypertension,and hypertension,based on the BP values measured at each survey and the information on antihypertensive treatment.BP may change from one level of BP to another or remain stable for each subject at different times of investigation.According to the grade change before and after the BP change,all subjects were divided into 9 categories based on the comprehensive cross combination principle.A multivariate Cox proportional hazard model was used to assess the hazard ratios(HRs)and 95% confidence intervals(CIs)of the risk of MACE in different BP categories.In the multivariate model,we adjusted the age and gender,ethnicity,systolic BP,diastolic BP,body mass index,current smoking,current drinking,physical activity,education level,taking antihypertensive medicine,family history of hypertension,the history of diabetes and hyperlipidemia.In addition,the Fisher r-to-Z correlation coefficient was used to evaluate the risk of MACE between the two groups by comparing the difference of the β coefficient between the short and long-term BP change groups.Results: This study included 22785 and 28366 study populations in the short-and long-term groups,respectively.During the median follow-up of 11.24 years in the short-and long-term groups,1331 MACE(968 strokes,307 MI,and 674 CVD deaths)and 1952 MACE(1433 strokes,440 MI,and 977 CVD deaths)were identified,respectively.The results of multivariate survival analysis showed that in the short-term group,going from prehypertension to hypertension,the risk of MACE(HR=1.37,95% CI: 1.14-1.64)and stroke(HR=1.54,95% CI: 1.25-1.91)increased,compared with maintaining the prehypertension;conversely,going from hypertension to prehypertension,participants had a decreased risk of MACE(HR=0.81,95% CI: 0.68-0.97)and stroke(HR=0.75,95% CI: 0.61-0.92),compared with maintaining the hypertension.Similarly,in the long-term group,subjects who changed from prehypertension to hypertension had an increased risk of MACE(HR=1.22,95% CI: 1.03-1.45)and stroke(HR=1.31,95% CI: 1.07-1.60),compared with maintaining the prehypertension;in contrast,subjects who changed from hypertension changed to prehypertension had a reduced risk of MACE(HR=0.85,95%CI: 0.74-0.97)and stroke(HR=0.79,95%CI: 0.68-0.93),compared with maintaining the hypertension.In addition,based on the comparison of Fisher r-to-Z β coefficients,except that long-term BP reduction from hypertension to prehypertension has no statistical significance for MACE risk,our results mainly show that short-term BP changes have a greater impact on MACE than long-term BP changes.Conclusion: Short-and long-terms BP changes were both associated with the risk of MACE.Increasing BP will increase the future risk of MACE while decreasing BP can reduce the risk of MACE.Furthermore,short-term BP changes had a stronger impact than did long-term changes on risk of MACE and stroke.Effectively reducing BP is an effective way to prevent CVD early.