Abstract 15256: Predicting Out-of-office Blood Pressure in United States Adults

Abstract

Introduction: The Predicting Out-of-Office Blood Pressure in the Clinic (PROOF-BP) algorithm accurately estimates out-of-office BP to guide ambulatory BP monitoring (ABPM) among adults in the UK and Canada with suspected high BP. We tested the validity of PROOF-BP in a diverse US population and developed a US-specific algorithm. Methods: We pooled data from four US studies (CARDIA, JHS, Masked Hypertension Study, and Improving Detection of Hypertension Study) that assessed both office BP and 24-hour ABPM. We included participants with >=2 office and >=10 daytime ambulatory BP readings. PROOF-BP estimates the difference between office systolic BP (SBP) and diastolic BP (DBP) and daytime ambulatory SBP and DBP using clinic BP measurements and patient characteristics. We examined the performance of PROOF-BP in US data and then used multivariable linear regression to develop a new algorithm optimized for the US population. We tested the ability of PROOF-BP to discriminate high awake ambulatory SBP and DBP (SBP/DBP >=130/80 mm Hg) using the area under the receiver-operator curve (AUROC). Models were developed in a 70% randomly selected derivation set and tested in a 30% validation set. The optimal predicted ambulatory BP thresholds were defined as those that resulted in the smallest proportion of individuals recommended for ABPM with an overall classification error <20% among those not screened. Results: We analyzed 3,080 individuals with a mean (SD) age of 52.0 (11.9) years, 38% were male, and 54% were black. Mean (SD) office SBP/DBP was 121.8 (16.6)/75.3 (9.8) mm Hg, mean (SD) awake ambulatory SBP/DBP was 127.3 (13.5)/78.6 (8.8) mm Hg, and 51% had awake ABPM >=130/80 mm Hg. The discrimination for high awake ABPM was similar between the existing (AUROC SBP = 0.77, DBP = 0.73) and US-specific models (AUROC SBP = 0.77, DBP = 0.72). Optimal predicted ambulatory BP thresholds with the US-specific algorithm were 125-134/75-84 mm Hg, resulting in 55% of the pooled cohort recommended for ABPM; compared to 66% recommended by the 2017 ACC/AHA guidelines. Conclusions: Both the original and US-specific PROOF-BP algorithms predicted high out-of-office BP among US adults. PROOF-BP may be used to guide clinical decisions and resource allocation among individuals considered for ABPM.