The Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Am J Hypertens. 2011 Jul;24(7):789-95. doi: 10.1038/ajh.2011.48. Epub 2011 Mar 31.
As groups of African descent may have higher nocturnal blood pressure (BP) for a given day BP than other ethnic groups, we ascertained whether this translates into differences in conventional (CBP) and 24-h ambulatory (ABP) BP control at a community level.
Ambulatory 24-h, day and night BP (model 90207; SpaceLabs, Issaquah, WA) and CBP (mean of five values) control rates were determined in 689 randomly selected participants (>16 years) of African ancestry in South Africa. Target organ effects were determined from urinary microalbumin-to-creatinine ratios (ACR) and aortic pulse wave velocity (PWV, applanation tonometry).
Of the participants 45.7% were hypertensive and 22.6% were receiving antihypertensive medication. More participants had uncontrolled BP at night (34.0%) than during the day (22.6%, P < 0.0001). Uncontrolled CBP was noted in 37.2% of participants, while a much lower proportion had uncontrolled ABP (24.1%) (P < 0.0001). Marked differences in the proportion of hypertensive participants with uncontrolled CBP and ABP were noted (treated: CBP = 62.2%, ABP = 33.3%, P < 0.0001; all: CBP = 81.3%, ABP = 44.4%, P < 0.0001). These differences were accounted for by a high prevalence of isolated increases in CBP (white-coat effects) (treated = 35.9%; all = 39.4%). Indeed, after censoring data from participants with white-coat effects, similar CBP and ABP control rates were noted. Participants with white-coat effects had similar ACR and PWV values as participants with normal ABP and CBP.
In communities of African descent, despite worse BP control at night than during the day, a high prevalence of white-coat effects translates into a striking underestimation of BP control in hypertensives when employing CBP rather than ABP measurements.
由于非洲裔人群的夜间血压（BP）相对于其他族裔人群而言，在一天内的血压可能更高，因此我们确定了这是否会导致社区层面常规血压（CBP）和 24 小时动态血压（ABP）控制方面的差异。
在南非，我们对 689 名随机选择的具有非洲血统的（年龄大于 16 岁）参与者进行了 24 小时动态、日间和夜间血压（模型 90207；SpaceLabs，艾萨夸，华盛顿州）和 CBP（五次测量的平均值）控制率的检测。通过尿微量白蛋白与肌酐比值（ACR）和主动脉脉搏波速度（PWV，平板测压法）来确定靶器官的影响。
参与者中 45.7%患有高血压，22.6%正在服用抗高血压药物。与白天相比，更多的参与者夜间血压未得到控制（34.0% vs. 22.6%，P<0.0001）。37.2%的参与者存在 CBP 未得到控制，而 ABP 未得到控制的比例要低得多（24.1%）（P<0.0001）。患有高血压的参与者中，CBP 和 ABP 未得到控制的比例存在显著差异（治疗组：CBP=62.2%，ABP=33.3%，P<0.0001；所有组：CBP=81.3%，ABP=44.4%，P<0.0001）。这归因于 CBP（白大衣效应）单纯升高的高患病率（治疗组=35.9%；所有组=39.4%）。事实上，在对具有白大衣效应的参与者的数据进行删节后，注意到类似的 CBP 和 ABP 控制率。具有白大衣效应的参与者的 ACR 和 PWV 值与 ABP 和 CBP 正常的参与者相似。
在非洲裔人群的社区中，尽管夜间血压控制比白天差，但白大衣效应的高患病率会导致在使用 CBP 而非 ABP 测量时，对高血压患者的血压控制情况产生惊人的低估。
