Estimates of sensitivity and specificity can be biased when reporting the results of the second test in a screening trial conducted in series.
Estimates of sensitivity and specificity can be biased when reporting the results of the second test in a screening trial conducted in series.
复制标题
DOI：
10.1186/1471-2288-10-3
复制
发表时间：
2010-01-11
影响因子：
4
通讯作者：
Glueck DH
中科院分区：
文献类型：
--
作者：
Ringham BM;Alonzo TA;Grunwald GK;Glueck DH
癌症筛查可以降低癌症死亡率，因为早期发现可以成功治疗其他致命疾病。有多种试验设计用于找到最佳筛选试验。在系列筛选试验设计中，进行第二次试验的决定是基于第一次试验的结果。因此，第二次测试的诊断准确性的估计是有条件的，并且可能不同于无条件估计。当一些病例由于不完全的疾病状态确定而被错误地归类为非病例时，问题进一步复杂化。对于系列设计，我们假设只有在第一次试验结果为阴性时才进行第二次筛选试验。我们推导出公式的条件灵敏度和特异性的第二次测试中存在的差异验证偏差。为了比较，我们还推导出一个单一的测试设计的灵敏度和特异性的公式，有和没有差分验证偏差。系列设计和差分验证偏倚对敏感性和特异性的估计都有很强的影响。在单次检验和系列设计中，差异验证偏倚夸大了敏感性和特异性的估计。一般而言，对于串联设计，膨胀小于单个试验设计所观察到的膨胀。偏倚的程度取决于疾病流行率、错误分类病例的比例以及病例检测结果之间的相关性。随着疾病患病率的增加，观察到的条件敏感性不受影响。然而，在观察到的条件特异性中，存在越来越多的向上偏倚。随着正确分类病例的比例增加，观察到的条件敏感性和特异性的向上偏倚降低。随着两种筛选试验之间的一致性变得更强，观察到的条件敏感性的向上偏倚降低，而特异性偏倚增加。在系列设计中，第二次检验的敏感性和特异性估计值是条件估计值。必须始终在试验设计和研究人群的背景下描述这些估计值，以防止误导性比较。此外，这些估计值可能因疾病状态确定不完整而存在偏倚。
Cancer screening reduces cancer mortality when early detection allows successful treatment of otherwise fatal disease. There are a variety of trial designs used to find the best screening test. In a series screening trial design, the decision to conduct the second test is based on the results of the first test. Thus, the estimates of diagnostic accuracy for the second test are conditional, and may differ from unconditional estimates. The problem is further complicated when some cases are misclassified as non-cases due to incomplete disease status ascertainment. For a series design, we assume that the second screening test is conducted only if the first test had negative results. We derive formulae for the conditional sensitivity and specificity of the second test in the presence of differential verification bias. For comparison, we also derive formulae for the sensitivity and specificity for a single test design, both with and without differential verification bias. Both the series design and differential verification bias have strong effects on estimates of sensitivity and specificity. In both the single test and series designs, differential verification bias inflates estimates of sensitivity and specificity. In general, for the series design, the inflation is smaller than that observed for a single test design. The degree of bias depends on disease prevalence, the proportion of misclassified cases, and on the correlation between the test results for cases. As disease prevalence increases, the observed conditional sensitivity is unaffected. However, there is an increasing upward bias in observed conditional specificity. As the proportion of correctly classified cases increases, the upward bias in observed conditional sensitivity and specificity decreases. As the agreement between the two screening tests becomes stronger, the upward bias in observed conditional sensitivity decreases, while the specificity bias increases. In a series design, estimates of sensitivity and specificity for the second test are conditional estimates. These estimates must always be described in context of the design of the trial, and the study population, to prevent misleading comparisons. In addition, these estimates may be biased by incomplete disease status ascertainment.
登录
查看更多内容
影响因子：
120.7
作者：
Bluemke, DA;Gatsonis, CA;Schnall, MD
通讯作者：
Schnall, MD
影响因子：
158.5
作者：
Pisano, ED;Gatsonis, C;Rebner, M
通讯作者：
Rebner, M
影响因子：
2.1
作者：
Thompson, ML
通讯作者：
Thompson, ML
影响因子：
1.9
作者：
LAU, T
通讯作者：
LAU, T
影响因子：
158.5
作者：
Elmore, G;Barton, MB;Fletcher, SW
通讯作者：
Fletcher, SW