1. In this analysis of data from a prospective cohort of young adults, increased mean systolic blood pressure (SBP) and variability in SBP measurements were both linked to increased risk of cardiovascular disease (CVD) in later life.
2. Variability in SBP measurement was also associated with an increased risk of all-cause mortality.
Evidence Rating Level: 2 (Good)
Study Rundown: Hypertension remains one of the most common risk factors for the development of CVD. It has long been observed that blood pressure measurements can vary significantly between office assessments and that this variability is independently associated with CVD risk in older adults. The importance of blood pressure variability in young adults with or without hypertension is not known. This prospective cohort study, which used data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, sought to evaluate the risk of CVD and all-cause mortality in later life associated with variability of SBP measurements independent of mean SBP values. The study found that mean SBP was linked with increased risk of CVD, and SBP variability was associated with increased risk of CVD and all-cause mortality.
The current study demonstrates the potential importance of blood pressure variability independent of mean SBP values in predicting those at risk for CVD. Recognizing young patients earlier in life may help identify those that may benefit from lifestyle and pharmacotherapy interventions to reduce CVD risk later in life. The strengths of the study included the large population with long follow-up and balanced demographics for sex and ethnic background. The limitations of the study included the observational design as a potential source of bias, and the lack of data to delineate the optimal time interval with which to assess SBP variability.
In-Depth [prospective cohort]: This study used data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a prospective cohort study that enrolled adults aged 18 to 30 years from 4 centers in the United States from 1985-1986. The CARDIA cohort has been followed through 2015 with assessments at 2, 5, 7, 10, 15, 20, 25, and 30 years after baseline (year 0). Blood pressure was measured in a standardized method across all visits. Visit-to-visit variability in SBP was measured as a variability independent of the mean (VIM). The primary outcome was composite CVD events (fatal and nonfatal coronary heart disease, hospitalization for heart failure, stroke, transient ischemic attack, or intervention for peripheral artery disease). The secondary outcome was all-cause mortality. Participants were excluded if they withdrew consent, had a CVD event prior to their 10-year follow-up examination, were lost to follow-up, or had visits without baseline blood pressure measurement. The 3394 patients included in the study had a median follow-up of 20.0 years during which 162 CVD events and 181 deaths occurred. The risk for CVD was linked to mean SBP (hazard ratio [HR] 1.25 [95%CI, 0.90-1.74] for every 1 standard deviation increase in SBP), and VIM SBP (HR 1.23 [95%CI, 1.07-1.43]). The VIM SBP was also associated with an increased risk of all-cause mortality (HR 1.24 [95%CI, 1.09-1.41]).
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