Background: Non-dipping (ND), defined as a \<10% decrease in blood pressure (BP) during sleep, is an independent significant predictor of cardiovascular outcome in hypertensive patients. A few anti-hypertensive medications, including angiotensin receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs), may normalize dipping if administered at night. Chinese data are scarce and there are no prospective studies on cardiovascular outcomes in Chinese patients. Aim: To determine if the bedtime administration of ACEIs and ARBs is more effective at normalizing ND than morning administration. As a pilot project, the feasibility of recruiting hypertension patients in primary care for ambulatory blood pressure monitoring (ABPM) and conducting a clinical trial will be evaluated such that future larger randomized trials can be planned to determine treatments for ND. Method: Fifty patients diagnosed with essential hypertension who are receiving either ACEIs or ARBs and diagnosed with ND will be randomized to take ACEIs or ARBs either early morning or before bedtime. A follow-up 48-hour ABPM will be performed after 4-6 weeks to examine post-treatment changes in BP and ND status. Outcome: The primary outcome of this proposed study is the proportion of ND at 6 weeks; secondary outcomes will include (i) mean awake and asleep SBP/DBP of 48-hour duration (ii) feasibility of this pilot study will be assessed by recruitment and dropout rates during the study period. Potential: This pilot study will provide the basis for a future larger randomized controlled study to further examine the treatment for ND in primary care.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
4
To take the ACEis or ARBs before bedtime instead of in the morning
Lek Yuen Clinic
Hong Kong, Hong Kong
proportion of non-dipping in each group as measured by ambulatory BP machines(ABPM)
the ABPM - An ApneABP (Meditech, Hungary) will be used in the study. non-dipping is defined as lack of more than 10% drop in SBP during sleep when compared to awake BP. The sleep duration and time are defined by actigraphy (Actigraph, model GT9X-BT)
Time frame: 6 weeks
mean awake and asleep SBP/DBP of 48-hour duration as assessed by ABPM
Time frame: 6 weeks
feasibility of the intervention as assessed by dropout rate
The trial is deemed feasible and a larger similar study can be conducted if: (i) ≤30% of ND patients drop out from the study
Time frame: 1 year (assessed after the whole study)
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