Department of Public Health, Epidemiology and Biostatistics, University of Birmingham, Birmingham, UK.
J Hum Hypertens. 2010 Oct;24(10):631-8. doi: 10.1038/jhh.2009.114. Epub 2010 Jan 7.
This simulation study investigates the effects of within-individual variability in estimated cardiovascular risk on categorization of patients as high risk. Published estimates of within-individual blood pressure and cholesterol variability were used to generate blood pressure and cholesterol levels for hypothetical subjects at a range of ages. These were used to calculate the estimated cardiovascular risk of each individual. The relationship between an individual's mean cardiovascular risk and within-individual coefficient of variation for cardiovascular risk was determined. Using the derived relationship, mean cardiovascular risk and within-individual variation in risk was calculated for 5018 adults from a population health survey. From this, was determined their probability of being classified as high risk (>20% 10-year cardiovascular risk) and the test characteristics of risk estimation at a range of ages. Within-individual variability in cardiovascular risk and potential for misclassification are both greater in lower-risk populations. At age 35-44 years, the positive predictive value of a diagnosis of high risk is 0.61 (95% confidence interval (CI): 0.59-0.64), and at age 65-74 years, it is 0.94 (95% CI: 0.91-0.96). About 39% of adults under 45 years diagnosed as high risk are not at high risk. Cardiovascular risk assessment should be targeted at high-risk populations.
本模拟研究调查了个体内心血管风险估计的变异性对高风险患者分类的影响。使用已发表的个体内血压和胆固醇变异性估计值，为一系列不同年龄的假设对象生成血压和胆固醇水平。这些水平用于计算每个个体的估计心血管风险。确定了个体平均心血管风险与心血管风险个体内变异系数之间的关系。使用得出的关系，为来自一项人群健康调查的 5018 名成年人计算了平均心血管风险和风险的个体内变异。由此确定了他们被归类为高风险（>20%的 10 年心血管风险）的概率，以及在不同年龄段进行风险估计的测试特征。心血管风险的个体内变异性和潜在的分类错误在低风险人群中都更大。在 35-44 岁年龄组，高危诊断的阳性预测值为 0.61（95%置信区间（CI）：0.59-0.64），而在 65-74 岁年龄组，阳性预测值为 0.94（95%CI：0.91-0.96）。大约 39%的45 岁以下被诊断为高风险的成年人并非处于高风险。心血管风险评估应针对高风险人群。
