KRT18 and metabolic disease: FGF-21 is elevated in patients with NAFLD and correlates with the severity of liver inflammation in NAFLD.FGF-21 is also increased in obesity, metabolic syndrome, and insulin resistance. Hence, it could be used as a biomarker for the diagnosis of metabolic disorders.FGF-21 is associated with markers of liver inflammation, such as M30 fragment (a caspase-cleaved fragment of cytokeratin 18) and plasminogen activator inhibitor-1 (PAI-1).