Perspective Chapter: Metformin and its Role in Diabetic Kidney Disease and Glucose Control

Metformin is one of the most widely used and affordable medications for the management of type 2 diabetes. While metformin is best known for lowering blood sugar by reducing hepatic glucose production, research has shown that metformin may also exhibit several renoprotective effects. Diabetic kidney disease (DKD) is a leading cause of end-stage kidney failure and affects 30–40% of individuals with diabetes. This chapter focuses on the role of metformin in DKD, beyond its ability to control blood sugar levels. This explains metformin’s traditional hypoglycemic mechanisms as well as newer protective benefits, such as reducing renal inflammation, oxidative stress, and scarring. These benefits may help reduce proteinuria and loss of kidney function. The chapter also highlights how our understanding of DKD has changed, moving beyond proteinuria alone to include other signs of kidney damage. We outline the safety of metformin in people with mild-to-moderate kidney disease under careful dosage, which was previously flagged as a contraindication. We also explored how metformin fits with other kidney-protective drugs, such as SGLT2 inhibitors, GLP1 agonists, and finerenone. Finally, this chapter examines the public health impact of metformin, especially in low-resource settings, where it can be a cost-effective tool to reduce the burden of kidney disease.