PS-BPC04-5: DIFFERENCE BETWEEN MORNING AND EVENING BLOOD PRESSURE AT HOME AND NOCTURNAL HYPOXIA IN THE GENERAL PRACTITIONER-BASED J-HOP STUDY

Abstract

Objective: The increase of morning home blood pressure (BP) compared to evening home BP defined as morning minus evening home BP (MEdif) was also associated with target organ damage and cardiovascular prognosis. A majority of previous studies have shown the determinant of MEdif from the point of demographic characteristics, but not from pathophysiological feature. Methods: The analysis of this study included participants from the baseline who performed home BP measurements and a portable pulse oximeter during nighttime in the Japan Morning-Home Blood Pressure (J-HOP) study, which is a practitioner-based, prospective, observational cohort study of a large Japanese outpatient population who had home BP measurement with the same validated device. Results: In the study of 1053 participants with at least cardiovascular risk, the prevalence of the individuals with 20 mmHg in MEdif was 14.0%. In univariate linear regression analysis, minimum SpO2 (beta = -0.19, P < 0.001) and oxygen desaturation index (beta = 0.06, P = 0.049) was associated with MEdif, but not in mean SpO2 (beta = -0.10, P = 0.496). After adjustment for covariates, only the association between minimum SpO2 and MEave was remained (beta = -0.15, P = 0.002). Dividing the participants into quartiles according to the minimum SpO2, the lowest (Odds ratio [OR], 1.98; 95% confidence interval [CI], 1.13–3.49) and third quartile (OR, 1.76; 95%CI, 1.02–3.04) were significantly determinant of those with ≧ 20 mmHg in MEdif than the top quartile. Conclusion: Increased MEdif in the Japanese population with at least one cardiovascular risk. When physicians find increased MEdif, especially greater than or equal to 20 mmHg, the possible impact of nocturnal hypoxia could be accounted.