Ambulatory Hypertension Subtypes and 24-Hour Systolic and Diastolic Blood Pressure as Distinct Outcome Predictors in 8341 Untreated People Recruited From 12 Populations

Abstract

Background— Data on risk associated with 24-hour ambulatory diastolic (DBP 24 ) versus systolic (SBP 24 ) blood pressure are scarce. Methods and Results— We recorded 24-hour blood pressure and health outcomes in 8341 untreated people (mean age, 50.8 years; 46.6% women) randomly recruited from 12 populations. We computed hazard ratios (HRs) using multivariable-adjusted Cox regression. Over 11.2 years (median), 927 (11.1%) participants died, 356 (4.3%) from cardiovascular causes, and 744 (8.9%) experienced a fatal or nonfatal cardiovascular event. Isolated diastolic hypertension (DBP 24 ≥80 mm Hg) did not increase the risk of total mortality, cardiovascular mortality, or stroke (HRs≤1.54; P ≥0.18), but was associated with a higher risk of fatal combined with nonfatal cardiovascular, cardiac, or coronary events (HRs≥1.75; P ≤0.0054). Isolated systolic hypertension (SBP 24 ≥130 mm Hg) and mixed diastolic plus systolic hypertension were associated with increased risks of all aforementioned end points ( P ≤0.0012). Below age 50, DBP 24 was the main driver of risk, reaching significance for total (HR for 1-SD increase, 2.05; P =0.0039) and cardiovascular mortality (HR, 4.07; P =0.0032) and for all cardiovascular end points combined (HR, 1.74; P =0.039) with a nonsignificant contribution of SBP 24 (HR≤0.92; P ≥0.068); above age 50, SBP 24 predicted all end points (HR≥1.19; P ≤0.0002) with a nonsignificant contribution of DBP 24 (0.96≤HR≤1.14; P ≥0.10). The interactions of age with SBP 24 and DBP 24 were significant for all cardiovascular and coronary events ( P ≤0.043). Conclusions— The risks conferred by DBP 24 and SBP 24 are age dependent. DBP 24 and isolated diastolic hypertension drive coronary complications below age 50, whereas above age 50 SBP 24 and isolated systolic and mixed hypertension are the predominant risk factors.