May O, Arildsen H, Damsgaard E M
Department of Cardiology, Odense University Hospital, Denmark.
Blood Press. 1998 May;7(2):103-8. doi: 10.1080/080370598437475.
The aim of this study was to compare the nocturnal fall in BP parameters calculated from individually defined periods of day and night to values computed from collectively fixed day/night definitions. Day and night periods were defined according to 3 different methods: (i) the individually defined time of getting up and going to bed obtained from participant diaries (MethodIND); (ii) the mean time of rising and retiring in the group (MethodMEAN); and (iii) a daytime period from 07.00-22.00 h as recommended by The Scientific Committee (Method722). The ambulatory BP was recorded every 30 min over 24 h. One hundred and eighty-seven persons aged 40-66 years participated. With MethodIND, the BP load, systolic, diastolic and mean BPs were higher in the daytime and lower in the night-time compared to the results using Method722 and MethodMEAN. The nocturnal BP fall using MethodIND was larger than the fall calculated from every possible fixed division in the period from 3 h before till 3 h after the group mean time of getting up and going to bed (p < 0.001). The lowest frequency of non-dipping, defined as a nightly fall in systolic and diastolic BP below 10%, was observed using MethodIND (10%). Compared to MethodIND, 11% were misclassified as non-dippers by Method722 and 8% by MethodMEAN. We conclude that the diurnal blood pressure variation based on individually defined periods of day and night is larger than the variation based on any collectively fixed day/night definition. It is recommended that assessment of the nocturnal change in BP be based on individually defined periods of day and night.
本研究的目的是比较根据个体定义的白天和夜间时段计算得出的血压参数夜间下降值与根据共同固定的昼夜定义计算得出的值。昼夜时段根据3种不同方法定义：（i）从参与者日记中获取的个体定义的起床和就寝时间（方法IND）；（ii）组内起床和就寝的平均时间（方法MEAN）；以及（iii）科学委员会建议的07:00 - 22:00时段作为白天（方法722）。动态血压每30分钟记录一次，持续24小时。187名年龄在40 - 66岁的人参与了研究。与使用方法722和方法MEAN的结果相比，采用方法IND时，白天的血压负荷、收缩压、舒张压和平均血压较高，夜间较低。使用方法IND计算的夜间血压下降幅度大于从起床和就寝组平均时间前3小时至后3小时期间任何可能的固定划分计算得出的下降幅度（p < 0.001）。采用方法IND观察到非勺型血压（定义为夜间收缩压和舒张压下降低于10%）的频率最低（10%）。与方法IND相比，方法722将11%误分类为非勺型血压，方法MEAN将8%误分类为非勺型血压。我们得出结论，基于个体定义的昼夜时段的昼夜血压变化大于基于任何共同固定的昼夜定义的变化。建议基于个体定义的昼夜时段评估血压的夜间变化。
