Analysis of 24-hour ambulatory blood pressure in prehypertensive subjects

AIM: To explore the characteristics of ambulatory blood pressure monitoring (ABPM) in prehypertensive subjects. METHODS: According to resting blood pressure levels, 392 subjects were divided into three groups: normotensive group (n=82), prehypertensive group (n=183) and essential hypertensive group (n=127). A 24-h ABPM was performed in all patients. RESULTS: The 24-h BP variation coefficient of SBP (24-h SSD) in normotensive, prehypertensive and hypertensive subjects were, respectively, (14.0±2.1)%, (17.2±3.2)% and (20.5±4.6)%. The 24-h BP variation coefficient of DBP (24-h DSD) was (10.4±1.9)%, (13.1±1.9)% and (16.3±2.1)%, and the proportion of non-dipper blood pressure was 7%, 25% and 39%. SBP load (SBP-L) was (35±20)% and DBP load was (33±20)% (P<0.05, P<0.01). The rate of decrease of SBP at night (SBPF) was 13% and the rate of decrease of DBP at night (DBPF) was 11%, lower than that of the normotensive group but higher than that of the hypertensive group (P<0.01). CONCLUSION: The circadian pattern of BP significantly changed in the prehypertensive group. BP level, BP variability rate, BP load rate, and the proportion of non-dipper BP all increased, whereas SBPF and DBPF decreased.