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.