Objective

2

To explore the characteristics of circadian rhythm of blood pressure in patients with masked hypertension （MH） and its relationship with twelve two-hour peirods， providing a basis for early detection and intervention of MH.

Methods

2

Patients who underwent 24-hour ambulatory blood pressure examination in the ambulatory blood pressure room of

Jiangsu Province Hospital of Chinese Medicine from January to December 2022 were enrolled， and according to their outpatient blood pressure measurements， 24-hour ambulatory blood pressure monitoring and follow-up survey results， the MH， essential hypertension （EH） and normal blood pressure groups were classified， with 50 cases in each group. The general data， office blood pressure and 24-hour ambulatory blood pressure monitoring data were collected. The circadian rhythm of blood pressure including 24-hour average systolic blood pressure （24h SBP）， daytime average systolic blood pressure （d SBP）， nighttime average systolic blood pressure （n SBP）， 24-hour average diastolic blood pressure （24h DBP）， daytime average diastolic blood pressure （d DBP）， and nighttime average diastolic blood pressure （n DBP） were compared among the groups， and the nighttime blood pressure dipping percentage was calculated. The type of circadian rhythm was determined based on the nighttime blood pressure dipping percentage. The variability of blood pressure including 24h SBP standard deviation （24h SBP-SD）， d SBP standard deviation （dSBP-SD）， n SBP standard deviation （nSBP-SD）， 24h DBP standard deviation （24h DBP-SD）， d DBP standard deviation （dDBP-SD）， and n DBP standard deviation （nDBP-SD） were compared among groups， and the corresponding coefficient of variation （CV）， that is， 24h SBP-CV， d SBP-CV， n SBP-CV， 24h DBP-CV， d DBP-CV and n DBP-CV， were calculated. Based on the 24-hour ambulatory blood pressure monitoring results， the twelve two-hour average SBP and DBP in each group were calculated and compared. Simultaneously， patients with EH were divided into g

rades 1， 2， and 3 for further stratified analysis.

Results

2

The age of the MH group was significantly higher than that of the EH group and the normal blood pressure group （

P

＜0.01）. The body mass index （BMI） and the proportion of smoking and alcohol consumption in the MH group and the EH group were significantly higher than those in the normal blood pressure group （

P

＜0.05 or

P

＜0.01）. In the normal blood pressure group， there were 49 dipper patterns （98.0%） and one non-dipper pattern （2.0%）； in the MH group， there were two dipper patterns （4.0%）， 29 non-dipper patterns （58.0%） and 19 reverse-dipper patterns （38.0%）； in the EH group， there were 20 dipper patterns （40.0%）， 23 non-dipper patterns （46.0%） and seven reverse-dipper patterns （14.0%）. Compared to the normal blood pressure group， the groups of MH and EH had significantly decreased proportion of dipper pattern and increased proportion of non-dipper and reverse-dipper pattern （

P

＜0.01）； the proportion of dipper pattern in the MH group was lower than that in the EH group， while the proportion of reverse-dipper pattern was higher （

P

＜0.01）. Compared to those in the normal blood pressure group， n SBP and n DBP in the MH group， as well as the the average SBP and average DBP at Zi hour （子时， 23：00-1：00）， Chou hour （丑时， 1：00-3：00）， Yin hour （寅时， 3：00-5：00）， Mao hour （卯时， 5：00-7：00） and average SBP at Hai hour （亥时， 21：00-23：00） in the MH group increased，while the average DBP at Si hour （巳时， 9：00-11：00） decreased （

P

＜0.01）； 24h SBP， 24h DBP， d SBP， d DBP， n SBP， and n DBP，d SBP-SD， n SBP-SD，n DBP-SD increased， as well as the average SBP and average DBP at twelve two-hour periods increased in the EH group，while the 24h SBP-CV， 24h DBP-CV，and d DBP-CV in the EH group decreased（

P

＜0.05 or

P

＜0.01）. The EH group had higher 24h SBP， 24h DBP， d SBP， d DBP， n SBP， n DBP， 24h DBP-SD and n DBP-SD ， as well as higher av

erage SBP and DBP at all twelve two-hour periods， and lower d DBP-CV than the MH group（

P

＜0.05 or

P

＜0.01）. The EH group had 18 cases of grade 1 （36.0％）， 19 cases of grade 2 （38.0％） and 13 cases of grade 3 （26.0％）， with no significant differences among groups （

P

＞0.05）.

Conclusion

2

The circadian rhythm of blood pressure in MH patients are mostly non-dipper and reverse-dipper patterns， and the abnormal elevation of blood pressure is obvious at Zi hour， Chou hour， Yin hour and Mao hour （23：00-7：00）.