GPT and diabetes mellitus: Both univariate (OR = 2.25, 95% CI: 1.51–3.34, P < .001) and multivariable logistic regression analyses (adjusted for confounding factors) showed that the risk of DR increased by 36% when the AST/ALT ratio increased by 1 standard deviation (SD) (OR = 1.36, 95% CI: 1.16–1.59, P < .001), and 29.3% was mediated by the duration of diabetes.