OPTIMAL THRESHOLDS FOR AMBULATORY BLOOD PRESSURE IN PATIENTS WITH HIGH CARDIOVASCULAR RISK

Objective: Recent 2017 American College of Cardiology/American Heart Association hypertension guideline suggested new ambulatory blood pressure (ABP) thresholds, however there are arguments whether it is optimal for defining hypertension. The objective of this study was to find optimal ABP thresholds for outcomes especially in patients with high cardiovascular risk. Design and method: From the Cardiovascular and Metabolic Disease Etiology Research Center – High Risk Cohort (CMERC-HI), 2026 patients who had 24-hour ABP monitoring data were selected. Baseline 24-hour ABP, daytime ABP, nighttime ABP, morning ABP threshold were determined separately using Cox proportional hazard model with propensity scores adjustment. The composite of cardiovascular disease (CVD) outcomes (hospitalization with MI, stroke, or heart failure) and all-cause mortality were primary end-points of this study. Results: A total of 2026(median age, 60 years, 52.6% male) subjects were analyzed in this study. Median follow-up was 3.4 years. There were 54 CVD outcomes and all-cause mortality (8.1 per 1000 person-years). Compared to 24-hour ABP <135/85 mmHg, 24-hour ABP more than 135/85 mmHg was associated with significantly poor outcomes (HR 1.49, 95% CI, 1.02–2.17). However, 24-hour ABP more than 130/80 mmHg and 24-hour ABP more than 125/75 were not associated with significantly higher risk. For daytime ABP, the threshold of 140/90 mmHg was significantly related to higher risk of CVD outcomes or death, (HR 1.78, 95% CI, 1.04–3.05) rather than ABP 135/85 mmHg or 130/80 mmHg. For nighttime ABP, no cut-off level other than 125/75 mmHg (HR 1.58, 95% CI, 1.08–2.32) was statistically meaningful. There was no adequate threshold for morning ABP in this analysis. Conclusions: In patients with high risk for CVD, 135/85mmHg for 24hr-ABP, 140/90 mmHg for daytime ABP, 125/75 mmHg for nighttime ABP seemed to be the threshold associated with increased outcomes. The BP threshold suggested by the ACC/AHA guideline was not significantly associated with increased outcomes.