COMPARISONS OF THE PREDICTIVE VALUE OF MORNING AND EVENING BLOOD PRESSURE FOR NOCTURNAL HYPERTENSION AND MORNING BLOOD PRESSURE SURGE

Abstract

Objective: Evidences showed that morning blood pressure (BP) surge (MS) and nocturnal hypertension (NH) may increase the risk of cardiovascular events. The purpose of this study is to determine whether morning and evening hypertension can be used to predict NH and MS in hypertensive patients. Design and method: Participants with BP over 140/90 mmHg from 11 medical centers in Taiwan were included in the cohort. Every participant had ambulatory BP monitoring (ABPM) and home blood pressure values that were taken twice daily (morning and evening). According to the ABPM data, MS and NH were characterized as overnight BP 120 and/or 70 mmHg and sleep-trough morning (6AM-8AM) BP rise larger than 43.67 mmHg, respectively. The cut point of both morning home BP hypertension (MHBP) and evening home BP hypertension (EHBP) were 135/85 mmHg. We used MHBP and EHBP separately and together in logistic regression models to analyze the predictive value for NH and MS, adjusting for potential confounders, such as age, sex, alcohol usage, and smoking. Results: A total of 1621 individuals were included, with a median age of 58.9 years. MHBP and EHBP were present in 17.93% and 15.8% respectively. NH was present in 76.25% (n = 1361) and MS was present in 9.69% (n = 173) of the cohort. The accuracy of MHBP to predict NH, MS and NH or MS were 0.843, 0.889 and 0.865 respectively. The accuracy of EHBP to predict NH, MS and NH or MS were 0.837, 0.887 and 0.862 respectively. After adjusting for potential confounders, both MHBP and EHBP can significantly predict NH, MS and the combination of both. EHBP outperformed MHBP of predicting NH (OR 5.57 vs 1.65). The relationship between EHBP and NH or MS was also stronger for EHBP than for MHBP (OR 10.44 vs 2.37). Nevertheless, MHBP had a marginally higher predictive value for MS than EHBP (OR 2.40 vs 1.88). Conclusions: EHBP showed more predictive of NH and MHBP has a better predictive value of MS in hypertensive subjects. Both MHBP and EHBP are useful for detecting NH or MS and should not be overlooked for overall BP control.