Clinical value of preoperative serum calcium level in predicting deep infiltrative endometriosis among ovarian endometrioma

To evaluate preoperative serum calcium levels and their association with deep infiltrating endometriosis (DIE) in ovarian endometrioma. A retrospective, observational cohort study. A total of 2,557 women who underwent surgery for benign ovarian tumors were initially enrolled. Of these, 987 were pathologically confirmed to have endometriosis, while the remaining 1570 did not. Endometriosis (EM) group had significantly lower albumin-adjusted calcium levels than the non-EMs group (p < 0.05). Adjusted serum calcium was inversely correlated with EM risk (OR: 0.156, 95% CI: 0.061, 0.396), whereas CA 125 demonstrated a contrasting trend (OR: 1.014, 95% CI: 1.011, 1.016). A combination of adjusted calcium with CA 125 yielded a significantly great area under the curve (AUC= 0.810). EM patients with DIE were significantly younger (31.7±6.6 years) than those without DIE (34.1± 8.2 years, p < .001). The prevalence of concurrent DIE decreased with increasing age across different age groups (Gamma value = -0.181, p < .001). Multivariate logistic regression analysis revealed that adjusted serum calcium was inversely correlated with the risk of DIE among EM patients (OR=0.234, 95% CI: 0.056-0.980, p =0.047). Albumin-adjusted calcium level was lower in patients diagnosed with EM compared to those with other benign ovarian tumors. The combined use of albumin-adjusted calcium and CA125 may potentially offer enhanced diagnostic utility for EM, though further validation is required. Moreover, a lower serum level of albumin-adjusted calcium was associated with the presence of DIE among EM patients.