Limited Incremental Value of Six Haemogram-Derived Inflammatory Indices for Detecting Endometrial Carcinoma and Intraepithelial Neoplasia in Abnormal Uterine Bleeding: A Case–Control Study

Background/Objectives: Haemogram-derived inflammatory indices are proposed as inexpensive markers of endometrial neoplasia, but almost all supporting evidence is prognostic, from women already known to have carcinoma. We compared six indices head-to-head and asked whether any improved discrimination beyond a clinical model of age, menopausal status, endometrial thickness and metabolic comorbidity. Methods: In this single-centre retrospective case–control study, all women with endometrial intraepithelial neoplasia (EIN) or uterine malignancy on curettage for abnormal uterine bleeding (January 2021–June 2026) were identified (136 cases); 272 benign controls were drawn at a fixed 1:2 ratio. Indices were recalculated de novo from raw differential counts. Each log-transformed index was added singly to the fixed model; the likelihood-ratio test was the primary test and the change in C-statistic (ΔC) the effect measure, with ΔC ≥ 0.02 taken as clinically relevant, and performance was internally validated by bootstrapping and cross-validation. Results: Cases were 93 carcinomas and 43 EINs. Age (AUC 0.792, 95% CI 0.744–0.841) and endometrial thickness (0.749, 0.697–0.800) discriminated better than any index; SIRI was best (0.621, 0.564–0.678) and PLR did not discriminate (0.510). The clinical model reached a C-statistic of 0.882 (0.844–0.919), inflated by design; optimism-corrected calibration slope 0.963. No index remained significant after adjustment (smallest p = 0.141); the largest ΔC was +0.0042 (−0.0027 to +0.0111). The six log-indices are algebraically dependent, so the joint model used an identifiable four-index basis; it added +0.0064 (χ24 = 4.48, p = 0.345), an increment that vanished on validation (optimism-corrected −0.0001; cross-validated +0.0010, −0.0076 to +0.0097). Accuracy at the Youden cut-off was 83.5% (clinical) and 81.7–84.2% (index models). Twelve sensitivity analyses agreed. Conclusions: None of the six indices provided detectable incremental discrimination once age, menopausal status and endometrial thickness were accounted for; their univariable associations reflect the clinical profile of affected women rather than an independent biological signal.