Sirisawat WanthongTomoyuki KabutoyaSatoshi HoshidePeera BuranakitjaroenKazuomi KarioJichi Medical UniversityFaculty of Medicine, Siriraj Hospital, Mahidol University2020-01-272020-01-272019-05-01Journal of Clinical Hypertension. Vol.21, No.5 (2019), 579-58617517176152461752-s2.0-85062995139https://repository.li.mahidol.ac.th/handle/20.500.14594/51685©2019 Wiley Periodicals, Inc. The correlations between organ damage and hourly ambulatory blood pressure (BP) have not been established. The patients were 1464 participants of the Japan Morning Surge-Home Blood Pressure (J-HOP) study participants who underwent ambulatory BP monitoring. The hourly systolic BP (SBP) at x o'clock was defined as the average of SBP values measured at times x − 30 minutes, x, and x + 30 minutes. The mean age was 64.8 ± 11.6 years. The percentage of male participants was 47.8%. The left ventricular mass index (LVMI) was significantly associated with SBP at 6 o'clock (r = 0.166, P < 0.001). The carotid intima-media thickness was significantly associated with SBP at 5 o'clock (r = 0.196, P < 0.001). After adjustment for age, sex, smoking, hyperlipidemia, diabetes mellitus, antihypertensive drug use, clinic SBP, and 24-hour ambulatory SBP, the correlations of the LVMI and hourly SBP at 6 o'clock remained significant (beta coefficient = 0.125, P < 0.01). In conclusion, morning ambulatory systolic BP especially at 5 and 6 o'clock was independently associated with organ damage.Mahidol UniversityMedicineArticleSCOPUS10.1111/jch.13498