When AST/ALT ratio was a continuous variable, AST/ALT ratio showed a negative correlation with the incidence of diabetes progressing from prediabetes in the unadjusted model (model I), for every 1 unit increase in the AST/ALT ratio, the risk of incident of diabetes in the prediabetic patients decreased by 51% (HR = 0.49, 95% CI: 0.42 to 0.56, P < 0.001). Here, GPT is linked to diabetes mellitus.