Should basal insulin be initiated in a 63‑year‑old Black woman with type 2 diabetes, estimated glomerular filtration rate 16 mL/min/1.73 m², currently taking dapagliflozin 10 mg and a four‑times‑daily sliding‑scale insulin regimen after discontinuing Actos (pioglitazone)?

Should Basal Insulin Be Started?

Yes, basal insulin should be initiated immediately in this patient, and dapagliflozin must be discontinued because it is contraindicated at eGFR 16 mL/min/1.73 m².

Critical Medication Safety Issue: Discontinue Dapagliflozin

• Dapagliflozin is not recommended for initiation when eGFR <25 mL/min/1.73 m² and should be stopped at eGFR 16 mL/min/1.73 m² because glucose-lowering efficacy is lost and the patient is approaching dialysis 1.
• Although dapagliflozin may be continued for cardiovascular/renal protection when eGFR falls below 25 mL/min/1.73 m² if already established on therapy, at eGFR 16 mL/min/1.73 m² the patient is in advanced CKD stage 5 and the drug provides minimal benefit while increasing risks of volume depletion and ketoacidosis 1, 2.
• The 2019 AHA/HFSA guidelines explicitly state that dapagliflozin is contraindicated with eGFR <30 mL/min/1.73 m² for glycemic control 3.

Why Basal Insulin Is Mandatory

• Sliding-scale insulin alone (four times daily) is inadequate therapy and does not address basal hyperglycemia—this patient requires structured basal-bolus or at minimum basal insulin to achieve glycemic control 4.
• At eGFR 16 mL/min/1.73 m², insulin is the only glucose-lowering agent that remains fully effective regardless of renal function and requires no contraindication based on kidney disease 1, 4, 2.
• Sliding-scale coverage is reactive rather than proactive and leads to glycemic variability, increased hypoglycemia risk, and poor long-term outcomes 4.

Recommended Basal Insulin Regimen

• Start basal insulin (NPH, glargine, detemir, or degludec) at 0.1–0.2 units/kg/day as a single evening dose, with the understanding that insulin clearance is reduced in advanced CKD and doses may need to be lower than in patients with normal renal function 4, 2.
• Continue correctional (sliding-scale) insulin with meals but transition to a structured regimen that includes basal insulin to cover fasting and between-meal glucose 4.
• For a 63-year-old patient, if body weight is approximately 70–80 kg, start with 7–10 units of basal insulin at bedtime and titrate based on fasting glucose 4.

Monitoring and Dose Adjustment

• Check fasting glucose daily and titrate basal insulin by 2–4 units every 3 days until fasting glucose is 80–130 mg/dL 4.
• Monitor for hypoglycemia closely because insulin clearance is impaired at eGFR 16 mL/min/1.73 m², and doses may need to be reduced by 25–50% compared to patients with normal renal function 4, 2.
• Re-check eGFR every 3–6 months and adjust insulin doses as renal function changes 1, 4.

Alternative Glucose-Lowering Options at eGFR 16 mL/min/1.73 m²

• GLP-1 receptor agonists (semaglutide, dulaglutide, liraglutide) can be used without dose adjustment even at eGFR 15–29 mL/min/1.73 m² and provide cardiovascular protection with lower hypoglycemia risk than insulin alone 4.
• If additional glycemic control is needed beyond basal insulin, consider adding a GLP-1 receptor agonist rather than increasing insulin doses, as this combination reduces hypoglycemia risk and may provide weight and cardiovascular benefits 4.
• DPP-4 inhibitors such as linagliptin require no dose adjustment at any eGFR level but lack the robust cardiovascular and renal benefits of GLP-1 receptor agonists 3, 4.

Why Other Agents Are Not Appropriate

• Metformin is absolutely contraindicated at eGFR <30 mL/min/1.73 m² due to risk of lactic acidosis 4.
• Sulfonylureas (e.g., gliclazide, glipizide) should not be used at eGFR 16 mL/min/1.73 m² because they are renally cleared, cause prolonged hypoglycemia in advanced CKD, and provide no cardiovascular or renal protection 4.
• Pioglitazone (Actos) was appropriately discontinued because thiazolidinediones cause fluid retention and are contraindicated in advanced CKD and heart failure 3.

Common Pitfalls to Avoid

• Do not continue dapagliflozin at eGFR 16 mL/min/1.73 m² solely because it was previously prescribed—the drug is ineffective for glycemic control and poses safety risks at this level of renal function 1, 2.
• Do not rely on sliding-scale insulin alone—this approach is reactive and leads to poor glycemic control and increased hypoglycemia 4.
• Do not use standard insulin dosing algorithms without accounting for reduced clearance in advanced CKD—start with lower doses and titrate cautiously 4, 2.
• Do not add sulfonylureas or other renally cleared oral agents in an attempt to avoid insulin—these drugs are unsafe at eGFR 16 mL/min/1.73 m² 4.

Clinical Decision Algorithm

1. Stop dapagliflozin immediately (contraindicated at eGFR 16 mL/min/1.73 m²) 1, 2.
2. Initiate basal insulin at 0.1–0.2 units/kg/day (approximately 7–10 units at bedtime for a 70–80 kg patient) 4.
3. Continue sliding-scale insulin with meals but transition to a structured basal-bolus regimen if needed 4.
4. Monitor fasting glucose daily and titrate basal insulin by 2–4 units every 3 days until fasting glucose is 80–130 mg/dL 4.
5. If additional glycemic control is needed, add a GLP-1 receptor agonist (e.g., semaglutide, dulaglutide) rather than increasing insulin doses excessively 4.
6. Re-check eGFR every 3–6 months and adjust therapy as renal function changes 1, 4.