Diagnostic Utility of Hematologic Inflammatory Indices and Serum Cytokeratin-18 (M65) for predicting Ultrasonography-confirmed Nonalcoholic Fatty Liver Disease in Adults with Type 2 Diabetes Mellitus

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is highly prevalent among patients with type 2 diabetes mellitus (T2DM). OBJECTIVE: To determine the utility of neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), and cytokeratin-18 (CK-18) (M65) in predicting T2DM patients with NAFLD. METHODS: This single-center, hospital-based, analytical, and cross-sectional study (January-June 2025) enrolled adults aged 30-60 years with established T2DM and ultrasound-confirmed NAFLD (n = 44) or absence of NAFLD (n = 44). RESULTS: Among 88 participants (44 T2DM+NAFLD and 44 T2DM without NAFLD), patient with NAFLD has longer duration of diabetes mellitus compared to diabetes mellitus without NAFLD (10.5 ± 4.2 vs. 7.8 ± 3.6 years; P = 0.002). Adiposity and blood pressure (BP) were higher (body mass inde × 29.8 ± 3.3 vs. 22.9 ± 1.9 kg/m2; waist 93.4 ± 16.1 vs. 80.8 ± 16.5 cm; systolic BP/diastolic BP 138.9/84.1 vs. 131.3/74.5 mmHg; all P < 0.001). Glycemic control was poorer (fasting blood glucose 197.7 ± 53.2 vs. 171.2 ± 20.7 mg/dL; P = 0.003; glycated hemoglobin 13.5 ± 2.9 vs. 8.9% ±2.3%; P < 0.001) with higher insulin. The NAFLD group also had higher aspartate transaminase/alanine transaminase and gamma-glutamyl transferase and higher inflammation (C-reactive protein [CRP] 0.62 ± 0.28 vs. 0.38 ± 0.22 mg/dL; P < 0.001), with higher NLR and lower LMR/PLR. CK-18 (M65) was higher (472.8 ± 155.6 vs. 318.6 ± 118.9 U/L; P < 0.001), as were fatty liver index (FLI) and aspartate aminotransferase-to-platelet ratio index (APRI). CK-18 (M65) showed excellent receiver operating characteristic performance (area under the curve [AUC] 0.955; >300 U/L: 90.9% sensitivity, 81.8% specificity), outperforming APRI (AUC 0.816) and FLI (AUC 0.789). Lipids were atherogenic (TC 240.0 vs. 182.6; low density lipoprotein 170.4 vs. 125.0 mg/dL; P < 0.001). CRP AUC 0.756; NLR AUC 0.669 overall. CONCLUSION: CK-18 (M65) demonstrated excellent accuracy for predicting NAFLD among patients with T2DM, whereas NLR, LMR, and PLR showed only modest discriminatory performance.