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

Objective: To evaluate preoperative serum calcium levels and their association with deep infiltrating endometriosis (DIE) in ovarian endometrioma.

Design: A retrospective, observational cohort study.

Participants: 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.

Result: Endometriosis (EM) group had significantly lower albumin-adjusted calcium levels than the non-EMs group ( < 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, < .001). The prevalence of concurrent DIE decreased with increasing age across different age groups (Gamma value = -0.181, < .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, =0.047).

Conclusion: 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.