Management of Type 2 Diabetes with Reduced Kidney Function

First-Line Therapy

The American Diabetes Association and the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend discontinuing metformin at a GFR of 30 ml/min/1.73m² due to increased risk of lactic acidosis 1, 2, 3
At GFR 30-44 ml/min/1.73m², the dose of metformin should be reduced to half the maximum recommended dose, but at GFR 31, discontinuation is safest 2, 1
The FDA revised metformin labeling to reflect safety only down to eGFR ≥30 ml/min/1.73m² 4
SGLT2 inhibitors should be continued even at GFR 31 ml/min/1.73m² for their cardiovascular and kidney protective benefits, despite reduced glucose-lowering efficacy 2, 1, 5
Do not initiate SGLT2 inhibitors if GFR <30 ml/min/1.73m² for glycemic control, but if already on therapy, continue as long as well-tolerated and kidney replacement therapy is not imminent 5, 3
Dapagliflozin is specifically approved for use at 10 mg once daily with eGFR 25 to <45 ml/min/1.73m² 6

Long-acting GLP-1 receptor agonists (dulaglutide, liraglutide, or injectable semaglutide) are the preferred add-on agents when glycemic targets are not met with SGLT2 inhibitors alone 1, 6, 3
These agents have demonstrated cardiovascular benefits and can be used safely down to eGFR 15 ml/min/1.73m² 7, 5
Dulaglutide requires no dose adjustment and can be used at 0.75-1.5 mg once weekly with eGFR >15 ml/min/1.73m² 1
Liraglutide showed significantly greater MACE risk reduction in patients with eGFR <60 ml/min/1.73m² compared to those with higher eGFR 6

Linagliptin requires no dose adjustment in renal impairment and can be added if GLP-1 receptor agonists are not tolerated or affordable 3
DPP-4 inhibitors are less preferred than GLP-1 receptor agonists due to lack of cardiovascular outcome benefits 1, 6
Insulin is always an option at any level of kidney function, including GFR 31 ml/min/1.73m² 2, 1
Reduce insulin doses by 25% or more when GFR <45 ml/min/1.73m² due to decreased insulin clearance and increased hypoglycemia risk 3

Glyburide is NOT recommended due to high hypoglycemia risk in renal impairment 6
Pioglitazone requires no dose adjustment but causes fluid retention and is contraindicated in heart failure 6
Use thiazolidinediones only if other options are not feasible 1

The risk of hypoglycemia increases substantially at GFR <45 ml/min/1.73m² due to decreased renal gluconeogenesis and reduced clearance of insulin and oral agents 3
Continuous glucose monitoring may be beneficial when HbA1c becomes unreliable in advanced CKD 3
If the patient is on insulin or sulfonylureas and meeting glycemic targets, reduce or withdraw these medications when adding SGLT2 inhibitors to prevent hypoglycemia 5
Initiate or continue ACE inhibitor or ARB if hypertension and albuminuria are present, with careful monitoring of potassium and creatinine 8, 3
Statin therapy is recommended regardless of baseline lipid levels to reduce cardiovascular risk 3
Monitor eGFR at least every 3-6 months when GFR is 30-44 ml/min/1.73m² 2, 1
Monitor vitamin B12 if metformin was used long-term before discontinuation 4, 1