Endometriosis Fertility Index for predicting non-assisted reproductive technology pregnancy after endometriosis surgery: a systematic review and meta-analysis

Background Results of studies that have assessed the accuracy of the Endometriosis Fertility Index (EFI) for predicting non-assisted reproductive technology (ART) pregnancy are inconsistent. Objective We intended to evaluate the accuracy of EFI for the prediction of non-ART pregnancy. Search strategy Embase, Medline, Scopus and Web of Science were searched up to 5 October 2019. Selection criteria We included studies that used EFI to predict non-ART pregnancy in women with surgically documented endometriosis. Data collection and analysis A total of 5547 studies were identified, from which we included 17 studies on 4598 women in the meta-analysis. Eight studies were classified as good quality, and the rest were considered to be of fair quality. Only five (29.41%) studies used appropriate approaches to account for potential confounders. Pooled effect sizes with corresponding 95% CI were calculated using random-effects model. Main results The cumulative non-ART pregnancy rate at 36 months was 10% (95% CI: 3, 16%; P < 0.001) for women with an EFI of 0-2, which significantly increased to 69% (95% CI: 58, 79%; P < 0.001) for women with an EFI of 9-10. Compared with women with an EFI of 3-4 (18%, 95% CI: 12, 24%; P < 0.001), the combined cumulative non-ART pregnancy rates were 44% (95% CI: 26, 63%; P < 0.001) for women with an EFT of 5-6 and 55% (95% CI: 47, 64%; P < 0.001) for women with an EFI of 7-8. Paired comparison by the chi-square test showed a significant difference between all categories (P < 0.001). The odds ratio (OR) for EFI was 1.33 (95% CI: 1.17, 1.49, P < 0.001) and the summary area under the curve (AUC) was 72% (95% CI: 65, 80%, P < 0.001). Conclusion The current findings highlighted the good performance of the EFI score in predicting the non-ART pregnancy rate. However, these findings should be considered with caution because of the substantial heterogeneity between studies. Tweetable abstract Review findings show the merits of Endometriosis Fertility Index as having a prognostic ability for non-assisted reproductive technology pregnancy.