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The abnormalities of blood pressure (BP) nocturnal decline have been found to be predictive for carotid plaque and lacunar infarction in patients with hypertension. In this study, BP dipping patterns in postmenopausal females with hypertension was investigated.
The nocturnal decline of systolic BP (SBP) was evaluated using 24 hours ambulatory BP monitoring (ABPM). The hypertensive patients were excluded if they (1) were <45 or >90 years old; (2) were under antihypertensive treatment; (3) had a BP over 160/100 mmHg; (4) were night workers; (5) had acute stroke or myocardial infarction within the past 6 months; (6) had sleep apnea syndrome; (7) were diagnosed as secondary hypertension; (8) could not tolerate the ABPM; (9) had other chronic diseases. In this study, the circadian decline rate of SBP fluctuating from 10% to 20% was considered as BP dipping pattern. Nondipper (0% to 10% SBP fall) and reverse dipper (SBP nocturnal rise) were also investigated. The distribution of three circadian BP patterns (dipper, nondipper, reverse dipper) among postmenopausal females with different menopause age was analyzed using chi-squared test. Multivariate logistic regression analyses were applied to explore the relationship between the relevant variable and ABPM result. P-values <0.05 were considered statistically significant for all analyses.
A total of 163 hypertensive patients including 18 dippers (11.0%), 87 non-dippers (53.4%) and 58 reverse-dippers (35.6%) were eventually involved in our study. The prevalence of reverse-dipper BP pattern was 32.3% in females with menopause age of 40s and 40% at 50s. There was significant difference (p=0.016) in menopause age between reverse dippers (48.6±3.6) and dippers (45.8±6.0). Furthermore, after multivariate logistic regression analysis, menopause age was shown to be an independent risk factor for BP reverse dipping (Odds ratio [OR] 1.148; 95%CI 1.020-1.292; p=0.020). Moreover, menopause age was negatively correlated with the decline rate of nocturnal SBP (r=-0.159; p<0.05) and DBP (r=-0.161; p<0.05).
Our study suggested that the menopause age might serve as an independent risk factor for reverse-dipper BP pattern in postmenopausal females with hypertension.