GPT and diabetes mellitus: To elucidate the association between ALB levels and DR risk, curve fitting analyses, as illustrated in Fig. 2, were conducted, adjusting for confounders such as age, sex, BMI, duration of diabetes, smoking status, FBG, HbA1c, lipid profile (total cholesterol and triglycerides), liver enzymes (AST and ALT), and comorbidities like fatty liver disease, diabetic nephropathy, and diabetic peripheral neuropathy.