INS and diabetic kidney disease: Metformin is known to enhance insulin sensitivity and inhibit hepatic gluconeogenesis, but in the context of diabetic kidney disease (DKD), the multifactorial pathophysiology—glomerular injury, inflammation, oxidative stress, and fibrosis—may limit metformin’s impact on markers such as serum creatinine unless dosing or duration are sufficient to affect these pathways [21,22].