Subgroup analysis showed higher FGF-21 levels in patients with nonalcoholic steatohepatitis (NASH) compared to controls (SMD: 1.30; 95% CI: 0.35, 2.24; p = 0.007), but not between hepatic steatosis and controls, or hepatic steatosis and NASH. Here, FGF21 is linked to fatty liver disease.