Management of Diabetes with Chronic Kidney Disease

Initial Assessment and Treatment

The American Diabetes Association and the Kidney Disease: Improving Global Outcomes (KDIGO) guideline recommend discontinuing metformin immediately when the estimated glomerular filtration rate (eGFR) is less than 30 mL/min/1.73m² due to the risk of lactic acidosis 1, 2.
For patients with an eGFR of 30 mL/min/1.73m² or greater, the American Heart Association and the American College of Cardiology recommend adding a sodium-glucose cotransporter 2 (SGLT2) inhibitor as a Grade 1A recommendation for patients with diabetes and chronic kidney disease (CKD) 1, 2, 3.
SGLT2 inhibitors provide cardiorenal protection independent of glycemic control and should be prioritized over other glucose-lowering agents 1, 2, 3.

If the eGFR is less than 30 mL/min/1.73m², the European Association for the Study of Diabetes recommends adding insulin as the primary glucose-lowering agent since both metformin and SGLT2 inhibitors are contraindicated at this level of renal function 1, 2.
Consider adding a glucagon-like peptide-1 (GLP-1) receptor agonist for additional glycemic control and cardiovascular benefits if the eGFR is greater than 15 mL/min/1.73m² 1, 2, 3.

The National Kidney Foundation recommends monitoring eGFR every 3-6 months in patients with CKD 1, 2, 4, 5.
If an SGLT2 inhibitor is started, temporarily withhold the medication during prolonged fasting, surgery, or critical illness due to increased ketoacidosis risk 3.
Monitor for volume depletion, especially in the first few weeks of SGLT2 inhibitor therapy 1, 2.

Do not continue metformin at any dose when the eGFR is less than 30 mL/min/1.73m², as this is a hard contraindication 1, 2.
Do not delay SGLT2 inhibitor initiation if the eGFR is 30 mL/min/1.73m² or greater, as the cardiorenal benefits are independent of glycemic control and should be started immediately 1, 2, 3.

Elevated BUN disproportionate to creatinine may indicate dehydration or volume depletion rather than true renal dysfunction, which changes management, in patients with type 2 diabetes 6
Monitor electrolytes (sodium, potassium, chloride, bicarbonate, calcium, magnesium, phosphate) alongside renal function in patients with type 2 diabetes 7
Significant renal dysfunction (creatinine >221 μmol/L [>2.5 mg/dL] or eGFR <30 mL/min/1.73m²) may be worsened by diuretics, and thiazide diuretics may not be effective, according to the European Journal of Heart Failure 8
Loop diuretics are preferred over thiazides when eGFR <30 mL/min/1.73m², as recommended by the European Journal of Heart Failure 8
Monitor renal function and electrolytes 1-2 weeks after diuretic initiation or dose increase, in patients with type 2 diabetes and renal impairment 8