Red blood cell indices as predictor for severity of endometriosis

Endometriosis is the presence of endometrial tissue outside of the uterine cavity. Certain markers have been used to evaluate the severity of endometriosis. This study aimed to explore the correlation between red blood cell (RBC) indices and the severity of endometriosis. This was a cross-sectional study including 200 patients with endometriosis (stage I-II and stage III-IV groups) and 100 patients with other benign ovarian tumors who underwent laparotomy at the Department of Obstetrics and Gynaecology, Margono Regional Public Hospital, between 2021 and 2024. Blood tests were evaluated before surgery, and the severity of endometriosis was determined during surgery using the revised American Society for Reproductive Medicine classification. Among the obtained RBC indices, mean hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) values were significantly lower in subjects with stage III-IV endometriosis than in those with stage I-II endometriosis and the control group (P=0.000, P =0.000, P=0.006, and P=0.010, respectively). The mean red cell distribution width (RDW) was significantly higher in the stage III-IV group than in the stage I-II and control groups (P=0.000). In addition, univariate analysis indicated that lower preoperative RBC indices (Hb ≤11.9 g/dL, Hct ≤37.1%, MCV ≤82.6 fL, MCH ≤26.6 pg) and higher RDW (≥14.9%) were independent risk factors for stage III/IV endometriosis. Lower RBC indices, including pre-operative Hb, Hct, MCV, and MCH, were significantly associated with the severity of endometriosis, which is potentially caused by dysregulation of iron metabolism and inflammation.