An Introduction to Diagnostic Meta-analysis

Systematic review, and its corresponding statistical analysis, is becoming popular in the literature to assess the diagnostic accuracy of a test. When correctly performed, this research methodology provides fundamental data to inform medical decision making. This chapter reviews key concepts of the meta-analysis of diagnostic test accuracy data, dealing with the particular case in which primary studies report a pair of estimates of sensitivity and specificity. We describe the potential sources of heterogeneity unique to diagnostic test evaluation and we illustrate how to explore this heterogeneity. We distinguish two situations according to the presence or absence of inter-study variability and propose two alternative approaches to the analysis. First, simple methods for statistical pooling are described when accuracy indices of individual studies show a reasonable level of homogeneity. Second, we describe more complex and robust statistical methods that take the paired nature of the accuracy indices and their correlation into account. We end with a description of the analysis of publication bias and enumerate some software tools available to perform the analyses discussed in the chapter.