PEAK NOCTURNAL HOME BLOOD PRESSURE AS AN EARLY AND STRONG NOVEL RISK FACTOR FOR STROKE: THE PRACTITIONER-BASED NATIONWIDE J-HOP NOCTURNAL BP STUDY

Abstract

Objective: Recent evidence suggests a correlation between nighttime blood pressure BP) measured through ambulatory BP monitoring (ABPM), the nocturnal BP dipping phenotype, and cardiovascular risk. However, the clinical implications of elevated peak nighttime home BP are currently unknown. This analysis investigated the association between peak nighttime home systolic BP (SBP) and cardiovascular events in outpatients with one or more cardiovascular risk factors. Design and method: In the Japan Morning Surge-Home Blood Pressure (J-HOP) study, nighttime home BP was automatically measured three times every night for 14 days using a nighttime home BP monitoring device (HEM-5001, Omron Healthcare) at baseline. Peak nighttime home SBP was defined as average of the highest three values recoded during the 14-night measurement period. Cardiovascular events (stroke, coronary artery disease, heart failure, aortic dissection) were tracked over a mean 7.1 years’ follow-up period. Results: This analysis included 2545 individuals (mean age 63.3±10.3 years, 49% male) with their nighttime home BPs. After adjustment for covariates (including age, sex, and average office, morning, evening, and nighttime home SBP), individuals with peak nighttime home systolic blood pressure (SBP) in the highest quintile (Q5, >=149.0 mmHg) demonstrated a significantly elevated risk of stroke compared to those in the lowest quintile (Q1, <119.3 mmHg) (hazard ratio [HR] 4.24, 95% confidence interval [CI] 1.07–16.77; p=0.039 overall and 8.92, 1.49–53.43; p=0.017 in the subgroup with >=6 nighttime home SBP measurements). Even when controlling for average real variability of nighttime BP, peak nighttime home SBP remained an independent predictor of stroke risk. On spline regression analysis, the average peak nighttime home SBP cut-off value for predicting an increased risk of incident stroke was 136 mmHg. Conclusions: We propose exaggerated peak nighttime home SBP determined from >=6 measurements as a novel risk factor for stroke, independent of conventional office and home BP values.