Endometriosis fertility index score maybe more accurate for predicting the outcomes of in vitrofertilisation than r-AFS classification in women with endometriosis

Background Endometriosis is a common disease. The most widely used staging system of endometriosis is the revised American Fertility Society classification (r-AFS classification) which has limited predictive ability for pregnancy after surgery. The endometriosis fertility index (EFI) is used to predict fecundity after endometriosis surgery. This diagnostic accuracy study was designed to compare the predictive value of the EFI with that of the r-AFS classification for IVF outcomes in patients with endometriosis. Methods 199 women with endometriosis receiving IVF treatment after surgery were analysis. The EFI score and r-AFS classification in their ability to predict these IVF outcomes were compared in the same population. ROC curves were used to analyse the predictive values of the EFI and r-AFS indices for clinical pregnancy, and their accuracies were evaluated by sensitivity, specificity, and the Youden's index. Results The Area Under the Curve (AUC) of the EFI score (AUC = 0.641, Standard Error(SE) = 0.039, P = 0.001, 95% CI = 0.564-0.717, cut-off score = 6) was significantly larger than that of the r-AFS classification (AUC = 0.445, SE = 0.041, P = 0.184, and 95% CI = 0.364-0.526). The antral follicle count, oestradiol level on day of hCG, number of oocytes retrieved, number of oocytes fertilised, and number of cleaved embryos in the greater than or equal to 6 EFI score group was greater than that of the lower than or equal to 5 EFI score group, and the dose of gonadotropin of the greater than or equal to 6 EFI score group were less than that in the lower than or equal to 5 EFI score group. Implantation rate, clinical pregnancy rate, and cumulative pregnancy rate in the greater than or equal to 6 EFI score group were higher than in the lower than or equal to 5 EFI score group. Conclusions It suggests that the EFI has more predictive power for IVF outcomes in endometriosis patients than the r-AFS classification. The clinical pregnancy rate was higher in patients with EFI greater than or equal to 6 score than with EFI lower than or equal to 5 score. Keywords: Endometriosis fertility index (EFI), Revised American Fertility Society (r-AFS) classification, Endometriosis, In vitro fertilization (IVF), Clinical pregnancy rate