<![CDATA[Background: Coronary heart disease involves chronic lipid burden and acute inflammation; troponin I is central to diagnosing myocardial injury. Objective: This study evaluated whether the neutrophil-to-lymphocyte ratio (NLR) and low-density lipoprotein (LDL) cholesterol differed by admission troponin I status and characterized each marker's discrimination for this threshold. Methods: This cross-sectional study used de-identified data from 38 coronary heart disease patients at a tertiary hospital in Central Java, Indonesia (January-December 2025). The first admission troponin I value was classified as below (<50 ng/L) or at/above (≥50 ng/L) the hospital's clinical decision threshold for a conventional troponin I assay. NLR and LDL were compared between groups, with separate ROC analyses. Results: Mean NLR was higher in the at/above-threshold group than the below-threshold group (4.21 ± 1.10 vs 2.28 ± 0.67; p < 0.001), whereas mean LDL did not differ significantly (103.47 ± 32.69 vs 106.32 ± 32.79 mg/dL; p = 0.791). NLR showed within-sample discrimination for at/above-threshold troponin I (AUC 0.798, 95% CI 0.640-0.955; p = 0.002); an exploratory, data-derived threshold of ≥2.92 yielded 84.2% sensitivity and 89.5% specificity. LDL showed no discrimination beyond chance (AUC 0.478, 95% CI 0.290-0.665; p = 0.815). Conclusion: NLR was higher at/above the local decision threshold and showed fair within-sample discrimination, whereas LDL did not. Because ROC curves were not formally compared and the NLR threshold was derived in the same cohort, these findings are exploratory. NLR warrants validation as a potential adjunctive inflammatory marker but should not replace or delay guideline-recommended troponin testing.]]>
