Regarding: The Effect of Hormonal Treatment on Ovarian Endometriomas: A Systematic Review and Meta-analysis

Ovarian endometrioma remains a challenging condition for clinicians and patients alike, with its diverse presentation and impact on quality of life. A recent systematic review and meta-analysis published in the Journal of Minimally Invasive Gynecology focused on the effectiveness of hormone therapy in the treatment of endometriotic cysts [ 1 Thiel PS Donders F Kobylianskii A et al. The Effect of Hormonal Treatment on Ovarian Endometriomas: A Systematic Review and Meta-Analysis. J Minim Invasive Gynecol. 2024; 31: 273-279https://doi.org/10.1016/j.jmig.2024.01.002 Abstract Full Text Full Text PDF Scopus (1) Google Scholar ]. Although this study provides valuable insights, the limitations inherent in its methodology cannot be ignored. First, the authors included a large number of studies of varying quality and design, and most of the pooled results also showed significant heterogeneity, which may have affected the precision of the study. Although sensitivity analyses were performed to account for and validate the highly heterogeneous results as much as possible, this may still not be fully convincing to the reader. The random effects model did not adequately account for the potential impact of bias on the outcome of each study and may have underestimated standard errors. Therefore, we suggest using a more powerful analytical model, the inverse variance heterogeneity model, as an alternative to the traditional random effects model. In contrast, the inverse variance heterogeneity model is better suited to deal with the high degree of heterogeneity in outcomes [ 2 Doi SA Barendregt JJ Khan S Thalib L Williams GM. Advances in the meta-analysis of heterogeneous clinical trials I: The inverse variance heterogeneity model. Contemp Clin Trials. 2015; 45: 130-138https://doi.org/10.1016/j.cct.2015.05.009 Crossref PubMed Scopus (420) Google Scholar ]. Second, the authors used the Newcastle-Ottawa scale to assess the quality of the included studies [ 3 Stang A. Critical evaluation of the Newcastle-Ottawa scale for the assessment of the quality of nonrandomized studies in meta-analyses. Eur J Epidemiol. 2010; 25: 603-605https://doi.org/10.1007/s10654-010-9491-z Crossref PubMed Scopus (11671) Google Scholar ]. However, Stang questioned the validity of this scoring tool because it tends to produce highly arbitrary results [ 4 Slim K Nini E Forestier D Kwiatkowski F Panis Y Chipponi J. Methodological index for non-randomized studies (minors): development and validation of a new instrument. ANZ J Surg. 2003; 73: 712-716https://doi.org/10.1046/j.1445-2197.2003.02748.x Crossref PubMed Scopus (4878) Google Scholar ]. Therefore, we recommend that authors use the Non-Randomized Research Methodology Index to more comprehensively assess the quality of non-randomized studies [ 5 Downs SH Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health. 1998; 52: 377-384https://doi.org/10.1136/jech.52.6.377 Crossref PubMed Scopus (6090) Google Scholar ]. Finally, the text lacks an assessment of publication bias and the level of evidence for the outcome, which is an easily overlooked but important component. Future studies need to examine the long-term effects of different hormonal treatments on patients' fertility.