GPT and type 2 diabetes mellitus: This study demonstrated that the AST/ALT ratio was significantly increased in patients with T2DM combined with osteopenia/osteoporosis, suggesting that the AST/ALT ratio may serve as a useful and reliable biomarker of osteopenia/osteoporosis and emphasizing that more attention should be paid to T2DM patients with the high AST/ALT ratio to further prevent and reduce the occurrence of osteopenia/osteoporosis and related adverse health outcome.