Hermida R C, Fernández J R
Bioengineering and Chronobiology Laboratories, E.T.S.I. Telecommunicación, University of Vigo, Campus Universitario, Spain.
Biomed Instrum Technol. 1996 May-Jun;30(3):257-66.
Hypertension is an important risk factor for strokes, heart attacks, and other vascular diseases. Pharmacologic treatment of high blood pressure reduces the incidence of these complications and prolongs life, so there is a strong incentive to identify and treat individuals with high blood pressure. The development of automatic instrumentation for noninvasive and ambulatory blood pressure monitoring makes it possible to follow the time course of blood pressure variations continuously in healthy peer groups to be used as a reference standard as well as in potentially hypertensive subjects. For clinical applications, tolerance intervals should be substituted, whenever possible for prediction limits. When only hybrid data (time series of data collected from a group of subjects) are available, such a tolerance interval can be difficult to determine following a parametric approach similar to the procedure used for the computation of prediction intervals when consideration of both within-subject and among-subjects variances is wanted. The authors have developed a nonparametric method for the computation of such tolerance intervals. Because the method is based on bootstrap techniques, it does not require the assumption of normality or symmetry in the data and is thus more appropriate when dealing with small samples. The method was used to establish time-qualified reference limits for series of blood pressure and heart rate values monitored automatically in healthy individuals of both genders. The use of these tolerance intervals may eliminate many false-positive and false-negative diagnoses that might be obtained when relying on time-unspecified single samples. These limits can serve as a reference for comparisons of a given subject's blood pressure series over time, yielding nonparametric measures of extent and timing of any blood pressure excess or deficit. Such indices can then be used for an objective and positive definition of health, for the screening and diagnosis of disease, and for gauging responses to treatment.
高血压是中风、心脏病发作及其他血管疾病的重要风险因素。高血压的药物治疗可降低这些并发症的发生率并延长寿命，因此，识别和治疗高血压患者具有强烈的动机。用于无创和动态血压监测的自动仪器的发展，使得在健康同龄人组中连续跟踪血压变化的时间过程成为可能，这些健康同龄人组可作为参考标准，也可用于潜在高血压患者。对于临床应用，应尽可能用容许区间替代预测限。当只有混合数据（从一组受试者收集的数据的时间序列）可用时，若要同时考虑受试者内和受试者间的方差，按照类似于计算预测区间的参数方法来确定这样的容许区间可能会很困难。作者们开发了一种计算此类容许区间的非参数方法。由于该方法基于自助法技术，它不需要数据呈正态分布或对称的假设，因此在处理小样本时更合适。该方法用于为自动监测的健康男女的血压和心率值系列建立时间限定的参考限。使用这些容许区间可以消除许多依赖未指定时间的单个样本时可能出现的假阳性和假阴性诊断。这些限值可作为比较给定受试者随时间变化的血压系列的参考，得出任何血压过高或过低的程度和时间的非参数测量值。这样的指标可用于对健康进行客观和积极的定义、疾病的筛查和诊断以及衡量治疗反应。
