Faculty Bibliography

Background -Data from before the 2000s indicate the majority of incident cardiovascular disease (CVD) events occur among US adults with systolic and diastolic blood pressure (SBP/DBP)>/=140/90 mmHg. Over the past several decades, BP declined and hypertension control has improved. Methods -We estimated the percentage of incident CVD events that occur at SBP/DBP<140/90 mmHg in a pooled analysis of three contemporary US cohorts: the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, the Multi-Ethnic Study of Atherosclerosis (MESA), and the Jackson Heart Study (JHS) (n=31,856; REGARDS=21,208; MESA=6,779; JHS=3,869). Baseline study visits were conducted in 2003-2007 for REGARDS, 2000-2002 for MESA, and 2000-2004 for JHS. BP was measured by trained staff using standardized methods. Antihypertensive medication use was self-reported. The primary outcome was incident CVD, defined by the first occurrence of fatal or non-fatal stroke, non-fatal myocardial infarction, fatal coronary heart disease, or heart failure. Events were adjudicated in each study. Results -Over a mean follow-up of 7.7 years, 2,584 participants had incident CVD events. Overall, 63.0% (95%CI: 54.9%-71.1%) of events occurred in participants with SBP/DBP<140/90 mmHg; 58.4% (95%CI: 47.7%-69.2%) and 68.1% (95%CI: 60.1%-76.0%) among those taking and not taking antihypertensive medication, respectively. The majority of events occurred in participants with SBP/DBP<140/90 mmHg among those <65 years (66.7%; 95%CI: 60.5%-73.0%) and >/=65 years (60.3%; 95%CI: 51.0%-69.5%), women (61.4%; 95%CI: 49.9%-72.9%) and men (63.8%; 95%CI: 58.4%-69.1%), and for whites (68.7%; 95%CI: 66.1%-71.3%), blacks (59.0%; 95%CI: 49.5%-68.6%), Hispanics (52.7% 95%CI: 45.1%-60.4%) and Chinese-Americans (58.5%; 95%CI: 45.2%-71.8%). Among participants taking antihypertensive medication with SBP/DBP<140/90 mmHg, 76.6% (95% CI: 75.8%-77.5%) were eligible for statin treatment but only 33.2% (95%CI: 32.1%-34.3%) were taking one and 19.5% (95%CI: 18.5%-20.5%) met the Systolic Blood Pressure Intervention Trial eligibility criteria and may benefit from a SBP target goal of 120 mmHg. Conclusions -While higher BP levels are associated with increased CVD risk, in the modern era, the majority of incident CVD events occur in US adults with SBP/DBP<140/90 mmHg. Although absolute risk and cost-effectiveness should be considered, additional CVD risk reduction measures for adults with SBP/DBP<140/90 mmHg at high risk for CVD may be warranted.

Background -Ambulatory blood pressure (BP) monitoring (ABPM) is the reference standard for out-of-clinic BP measurement. Thresholds for identifying ambulatory hypertension (daytime systolic BP [SBP]/diastolic BP [DBP] >/= 135/85 mmHg, 24-hour SBP/DBP >/= 130/80 mmHg, and nighttime SBP/DBP >/= 120/70 mmHg) have been derived from European, Asian and South American populations. We determined BP thresholds for ambulatory hypertension in a US population-based sample of African Americans. Methods -We analyzed data from the Jackson Heart Study (JHS), a population-based cohort study comprised exclusively of African-American adults (n=5,306). Analyses were restricted to 1,016 participants who completed ABPM at baseline in 2000-2004. Mean systolic BP (SBP) and diastolic BP (DBP) levels were calculated for daytime (10:00am-8:00pm), 24-hour (all available readings) and nighttime (midnight-6:00am) periods, separately. Daytime, 24-hour, and nighttime BP thresholds for ambulatory hypertension were identified using regression- and outcome-derived approaches. The composite of a cardiovascular disease (CVD) or all-cause mortality event was used in the outcome-derived approach. For this latter approach, BP thresholds were identified only for SBP as clinic DBP was not associated with the outcome. Analyses were stratified by antihypertensive medication use. Results -Among participants not taking antihypertensive medication, the regression-derived thresholds for daytime, 24-hour, and nighttime SBP/DBP corresponding to clinic SBP/DBP of 140/90 mmHg were 134/85 mmHg, 130/81 mmHg, and 123/73 mmHg, respectively. The outcome-derived thresholds for daytime, 24-hour, and nighttime SBP corresponding to a clinic SBP >/= 140 mmHg were 138 mmHg, 134 mmHg, and 129 mmHg, respectively. Among participants taking antihypertensive medication, the regression-derived thresholds for daytime, 24-hour, and nighttime SBP/DBP corresponding to clinic SBP/DBP of 140/90 mmHg were 135/85 mmHg, 133/82 mmHg, and 128/76 mmHg, respectively. The corresponding outcome-derived thresholds for daytime, 24-hour, and nighttime SBP were 140 mmHg, 137 mmHg, and 133 mmHg, respectively, among those taking antihypertensive medication. Conclusions -Based on the outcome-derived approach for SBP and regression-derived approach for DBP, the following definitions for daytime hypertension, 24-hour hypertension, and nighttime hypertension corresponding to clinic SBP/DBP >/= 140/90 mmHg are proposed for African Americans: daytime SBP/DBP >/= 140/85 mmHg, 24-hour SBP/DBP >/= 135/80 mmHg, and nighttime SBP/DBP >/= 130/75 mmHg, respectively.