Fasting plasma lactate: A diagnosis and staging biomarker with superior performance in adult nonalcoholic fatty liver disease

Abstract Purpose: For the assessment and staging of metabolic diseases such as obesity and type 2 diabetes mellitus (T2DM), fasting plasma lactate (FPL) has been a useful marker. However, it has never been used to evaluate nonalcoholic fatty liver disease (NAFLD). Since NAFLD is one of the significant metabolic syndromes, we investigated whether FPL can be used as a biomarker for diagnosing and staging NAFLD. Methods: A total of 102 patients who were diagnosed with NAFLD and 100 healthy control between October 2018 and September 2019 were enrolled in our study. We determined the levels of FPL, total cholesterol(TC), triglycerides (TG), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting plasma glucose (FPG), fasting insulin(FINS), and homeostasis model assessment of insulin resistance (HOMA-IR). We performedreceiver operating characteristic (ROC) analysis to evaluate their diagnostic performance. Results: In NAFLD patients, we found FPL, ALT, AST, TG, FPG, FINS, and HOMA-IR levels to be elevated while HDL-C level was reduced (P < 0.05). FPL, FPG, FINS, and HOMA-IR levels were higher in mild NAFLD patients than moderate to severe ones (P < 0.05). For NAFLD diagnosis and staging, the areas under the ROC curve (AUC) of FPL were 0.973 and 0.999, making it clearly (P < 0.05) superior to other biomarkers.For diagnosing and staging NAFLD, the cutoff value of1.285 mmol/L and 2.370 mmol/L for FPL had the highest validity, respectively. The sensitivity, specificity, negative likelihood ratio (LR-), and positive likelihood ratio (LR+) were 87.25%, 98.00%, 0.13, and 43.63 for the diagnosis cutoff value and. 92.19%, 97.37%, 0.08, and 35.05 for staging, respectively.In addition, for NAFLD patients, FPL positively correlated with TG, FPG, FINS, and HOMA-IR (P < 0.05).Conclusion: Thus, in adult NAFLD, FPL can be used as a diagnosis and staging biomarker with superior performance.