Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Prev Vet Med. 2009 Nov 15;92(3):249-55. doi: 10.1016/j.prevetmed.2009.08.019. Epub 2009 Sep 11.
Critical, systematic reviews of available diagnostic test evaluations are a meticulous approach to synthesize evidence about a diagnostic test. However, often the review finds that data quality is poor due to deficiencies in design and reporting of the test evaluations and formal statistical comparisons are discouraged. Even when only simple summary measures are appropriate, the strong correlation between sensitivity and specificity and their dependence on differences in diagnostic threshold across studies, creates the need for tools to summarise properties of the diagnostic test under investigation. This study presents summary receiver operating characteristics (SROC) analysis as a means to synthesize information from diagnostic test evaluation studies. Using data from a review of diagnostic tests for ante mortem diagnosis of paratuberculosis as an illustration, SROC and hierarchical SROC (HSROC) analysis were used to estimate overall diagnostic accuracies of antibody ELISAs for bovine paratuberculosis while accounting for covariates: the target condition (infectious or infected) used in the test evaluation (one for the evaluation of Se and one for Sp); and the type of test (serum vs. milk). The methods gave comparable results (regarding the estimated diagnostic log odds ratio), considering the small sample size and the quality of data. The SROC analysis found a difference in the performance of tests when the target condition for evaluation of Se was infected rather than infectious, suggesting that ELISAs are not suitable for detecting infected cattle. However, the SROC model does not take differences in sample size between study units into account, whereas the HSROC allows for both between and within study variation. Considering the small sample size, more credibility should be given to the results of the HSROC. For both methods the area under the (H)SROC curve was calculated and results were comparable. The conclusion is that while the SROC is simpler and easier to implement, analyse and interpret, the HSROC does have properties encourage the extra effort involved in the analysis.
对现有诊断测试评估进行严格、系统的综述是综合有关诊断测试证据的一种细致方法。然而，由于测试评估的设计和报告存在缺陷，通常审查发现数据质量较差，并且不鼓励进行正式的统计比较。即使只适合采用简单的汇总指标，灵敏度和特异性之间的强相关性及其对研究中诊断阈值差异的依赖性，也需要有工具来总结正在研究的诊断测试的特性。本研究提出了汇总受试者工作特征（SROC）分析，作为综合诊断测试评估研究信息的一种方法。使用对副结核病生前诊断的诊断测试评估综述的数据进行说明，SROC 和分层 SROC（HSROC）分析用于估计牛副结核病抗体 ELISA 的总体诊断准确性，同时考虑协变量：用于测试评估的目标条件（感染或感染）（一个用于评估 Se，一个用于评估 Sp）；和测试类型（血清与牛奶）。考虑到样本量小和数据质量，该方法（关于估计的诊断对数比值）给出了可比的结果。SROC 分析发现，当评估 Se 的目标条件为感染而非传染性时，测试的性能存在差异，这表明 ELISA 不适合检测感染的牛。然而，SROC 模型没有考虑研究单位之间样本量的差异，而 HSROC 允许考虑研究内和研究间的差异。考虑到样本量小，应更信任 HSROC 的结果。对于两种方法，均计算了（H）SROC 曲线下的面积，结果具有可比性。结论是，虽然 SROC 更简单，更易于实施、分析和解释，但 HSROC 确实具有鼓励在分析中付出额外努力的特性。
