Comment on “Red Blood Cell Indices as Predictor for Severity of Endometriosis”

Endometriosis occurs in ~10% to 15% of women of reproductive age, with a peak age between 25 and 45. Endometriosis can exist as peritoneal lesions, superficial implants, cysts, or deep infiltration, and the majority of patients with endometriosis experience chronic pelvic pain as well as fatigue, weakness, malaise, or menorrhagia. As yet, there is no clear underlying cause of endometriosis, though one theory revolves around the displacement of blood into the uterine cavity that can implant, grow, and infiltrate and thus cause co-occurring conditions such as anemia. Severe endometriosis can also affect inflammatory markers, and previous studies have reported red blood cell (RBC) indices as lower in patients with endometriosis. This study was designed to assess the correlation of RBC indices of hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW) with endometriosis severity. This was a cross-sectional retrospective study using data from Margono Regional Public Hospital between 2021 and 2024. Inclusion criteria were pre-menopausal women undergoing laparotomy for the management of benign ovarian tumors. Exclusion criteria were pregnancy, leiomyoma, pelvic inflammatory disease, tuberculosis, hematemesis/melena, endocrine disease, abnormal liver, heart disease, diabetes, kidney disease, malignancy, and autoimmune disease. Final analysis included 300 patients, with 200 having confirmed endometriosis and 100 having a confirmed diagnosis of other types of benign ovarian tumors. There were 100 patients in the endometriosis group with stage I to II disease and 100 with stage III to IV disease. The groups were similar in age, body weight, height, and BMI. The RBC indices were significantly lower in the stage III to IV endometriosis group when compared with controls or to stage I to II endometriosis, including Hb, Hct, MCV, and MCH. MCHC was not significantly different between groups, and RDW was significantly higher in the stage III-IV group compared with the others. These results indicate that RBC indices may have the potential for use as a predictor of endometriosis severity, though this needs further validation in larger and more diverse samples. These findings are consistent with previous literature showing an association between Hb, Hct, MCV, and MCH with endometriosis. Other studies also suggest a potential role of iron metabolism dysregulation in the differences seen between endometriosis patients and controls. In contrast to other RBC indices, this study also found that RDW was significantly increased in patients with severe endometriosis, also supporting the theory of iron metabolism dysregulation. Future research should attempt to validate these results in a more generalizable way as well as controlling for menstrual cycle phase and hormonal medication use that may have affected RBC indices. (Summarized from Simanjuntak J, Priyanto E, Azis MA. Red blood cell indices as predictor for severity of endometriosis. Obstet Gynecol Sci. 2025;68:519-524. doi: 10.5468/ogs.25080)