GDF15 and primary biliary cholangitis: Likewise, another case-control study found that the levels of GDF-15 were significantly higher in non-cirrhotic primary biliary cholangitis (PBC) patients than in healthy controls, along with a higher expression of total bilirubin (TBIL) and direct bilirubin (DBIL) (Li et al., 2020), the typical markers of cholestasis, showing the notable role of GDF-15 as a risk predictor for cholestasis and cholelithiasis.