Objective To externally validate the “2021 AAGL Endometriosis Classification” staging system. Design Retrospective, diagnostic accuracy study Setting Multicentre Population or Sample Two hundred and seventy-two endometriosis patients (January 2016 - October 2021) Methods Three independent observers analysed coded surgical data to assign an AAGL surgical stage (1 to 4) as the index test, and surgical complexity level (A to D) as the reference standard. Main Outcome Measures The diagnostic accuracy of each AAGL stage to predict corresponding AAGL surgical complexity level was determined. Receiver operating characteristic curves used to determine the accuracy of cut off points used in the AAGL staging system to discriminate between surgical complexity levels. Results 272 cases were analysed. Diagnostic accuracy (sensitivity, specificity, PPV and NPV) for three observers were: stage 1 to predict level A 97.9-98.7%, 60.2-64.2%, 75.0-76.9%, and 96.3-97.5%; stage 2 to predict level B 26.1-30.4%, 93.2-95.6%, 26.3-35.3%, and 92.9-93.6%; stage 3 to predict level C 7.5-10.0%, 93.8-94.8%, 33.3-42.1%, and 70.9-71.5%; stage 4 to predict level D 90.-95.0%, 90.1-91.7% &, 41.9-47.5%, and 99.1-99.6%. For three observers AUROC for A vs B/C/D (cut-point 9) 0.75-0.88, A/B vs C/D (cut-point 16) 0.81 and A/B/C vs D (cut-point 22) 0.95-0.96. Conclusions This external validation study demonstrates that the AAGL Endometriosis Classification performs poorly overall for the prediction of surgical complexity. The results from this external validation study suggest that the system in its current form is not generalizable to all endometriosis patients and should be reviewed before its universal implementation. Funding Nil Keywords Endometriosis, staging, laparoscopy

Objectives: To determine the impact of the diagnostic test method (clinical, diagnostic imaging, or diagnostic laparoscopy) of endometriosis on the individual’s sense of control over their disease and their perceived access to social supports. Design: Retrospective cohort study. Setting: International. Population: 1,634 people aged 18-55 who had received a diagnosis of endometriosis. Methods: This study reports on data collected by the validated Endometriosis Health Profile-30 (EHP-30) section of a larger survey conducted between May and July 2020. Participants were recruited by social media platforms. Scores on the dimensions of interest were analysed with diagnostic method as the variable of interest. Diagnostic method proportionality was also assessed as a secondary outcome by geographical region. Main Outcome Measures: Scores on the dimensions of control and powerlessness and social support on the EHP-30. Results: There was a difference between control and powerlessness scores for patients that received a diagnosis via imaging (ultrasound/magnetic resonance imaging) versus clinical diagnosis (P=0.049). However, this did not reach significance when co-variates were controlled for (P=0.054). No other comparisons between diagnostic method and EHP-30 scores demonstrated a difference. There was a statistically significant (P<0.0001) difference in the rate of utilization of the various diagnostic imaging techniques between geographical regions with diagnostic imaging being relatively uncommon and surgery being the most common method of diagnosis. Conclusions: The diagnostic method of endometriosis does not appear to have a clinically significant impact on an individual’s sense of control over their disease nor their access to social supports.