Data synthesis
Due to differences in design, studies were divided into groups according to application of the reference standard: ‘Complete verification’, all participants received visual inspection of the pelvis at surgery; ‘Partial verification’, all cases received surgical confirmation but controls did not; and ‘Database/self-reporting’, cases confirmed by healthcare coding or self-reporting and controls from healthy populations not known to have endometriosis.
Statistical analysis was conducted using Stata software (version 15)31 to allow exploration of heterogeneity and statistical pooling using a bivariate random effects model and produced summary accuracy measures and summary receiver operative characteristic curves for each index test. A bivariate random effects model was applied for index tests with ≥5 contributing studies, and a univariate fixed effects model for index test with ≤4.
Index tests were assessed for performance as a ‘rule-in’ or ‘rule-out’ tool with pre-specified threshold summary accuracy of 95% sensitivity/50% specificity or 95% specificity/50% sensitivity respectively.