Cutoffs for white-coat and masked blood pressure effects: an ambulatory blood pressure monitoring study

Abstract

The values used to define white-coat and masked blood pressure (BP) effects are usually arbitrary. This study aimed at investigating the accuracy of various cutoffs based on the differences (ΔBP) between office BP (OBP) and 24h-ambulatory BP monitoring (ABPM) to identify white-coat (WCH) and masked (MH) hypertension, which are phenotypes coupled with adverse prognosis. This cross-sectional study included 11,350 [Derivation cohort; 45% men, mean age = 55.1 ± 14.1 years, OBP = 132.1 ± 17.6/83.9 ± 12.5 mmHg, 24 h-ABPM = 121.6 ± 11.4/76.1 ± 9.6 mmHg, 25% using antihypertensive medications (AH)] and 7220 (Validation cohort; 46% men, mean age = 58.6 ± 15.1 years, OBP = 136.8 ± 18.7/87.6 ± 13.0 mmHg, 24 h-ABPM = 125.5 ± 12.6/77.7 ± 10.3 mmHg; 32% using AH) unique individuals who underwent 24 h-ABPM. We compared the sensitivity, specificity, positive and negative predictive values and area under the curve (AUC) of diverse ΔBP cutoffs to detect WCH (ΔsystolicBP/ΔdiastolicBP = 28/17, 20/15, 20/10, 16/11, 15/9, 14/9 mmHg and ΔsystolicBP = 13 and 10 mmHg) and MH (ΔsystolicBP/ΔdiastolicBP = -14/-9, -5/-2, -3/-1, -1/-1, 0/0, 2/2 mmHg and ΔsystolicBP = -5 and -3mmHg). The 20/15 mmHg cutoff showed the best AUC (0.804, 95%CI = 0.794-0.814) to detect WCH, while the 2/2 mmHg cutoff showed the highest AUC (0.741, 95%CI = 0.728-0.754) to detect MH in the Derivation cohort. Both cutoffs also had the best accuracy to detect WCH (0.767, 95%CI = 0.754-0.780) and MH (0.767, 95%CI = 0.750-0.784) in the Validation cohort. In secondary analyses, these cutoffs had the best accuracy to detect individuals with higher and lower office-than-ABPM grades in both cohorts. In conclusion, the 20/15 and 2/2 mmHg ΔBP cutoffs had the best accuracy to detect hypertensive patients with WCH and MH, respectively, and can serve as indicators of marked white-coat and masked BP effects derived from 24 h-ABPM.