Supplementary file 1_Cross-sectional associations and incremental discrimination of inflammatory and lipid-derived indices for prevalent coronary heart disease in type 2 diabetes.docx

Median SII was 649 × 10⁹/L in participants with CHD and 522 × 10⁹/L in those without CHD (P < 0.001). The adjusted OR for SII was 2.37 (95% CI, 1.91–2.93) for Q4 versus Q1 and 1.46 (95% CI, 1.36–1.58) per 1-SD increase. The association was nonlinear (P for nonlinearity < 0.001), with no interaction by sex, age, BMI, or hypertension.

The optimism-corrected AUC increased from 0.729 to 0.744 after adding SII (ΔAUC = 0.015, P < 0.001); corrected AUCs were 0.744 for PIV and 0.745 for SIRI. Paired comparisons showed no statistically significant difference between the SII-augmented model and either the PIV-augmented model (P = 0.964) or the SIRI-augmented model (P = 0.717). The SII model showed a cross-validated AUC of 0.742, Brier score of 0.188, ICI of 0.017, and calibration slope of 0.963.</p>Conclusion<p>Several indices were associated with prevalent CHD, without consistent evidence that SII was superior.</p>