What is the optimal management for a type 2 diabetic adult with improved HbA1c on Farxiga (dapagliflozin), impaired renal function, proteinuria, and significant glycosuria, on metformin, lisinopril, aspirin, simvastatin, and restarting Lantus (insulin glargine)?

Optimal Management Strategy for This Patient

Continue Farxiga 10 mg, metformin 1000 mg BID, lisinopril, aspirin, and simvastatin, and restart Lantus 20 units at bedtime with aggressive titration to target fasting glucose <130 mg/dL, while closely monitoring renal function given the improved but still impaired GFR. 1, 2

Current Clinical Assessment

Your patient demonstrates significant improvement but inadequate glycemic control with several concerning features:

• HbA1c 10.7% remains far above target of <7.0%, though improved from 14.7% 1, 2
• Fasting glucose 200 mg/dL indicates inadequate basal insulin coverage (target <130 mg/dL) 2
• GFR improved from 44 to 59 mL/min represents stage 3a CKD, which affects medication dosing 3
• Proteinuria 2+ and glycosuria 3+ reflect ongoing diabetic nephropathy and severe hyperglycemia 4, 5

Critical Medication Considerations for Farxiga at GFR 59

Farxiga can be continued at 10 mg with GFR 59 mL/min, but requires close monitoring:

• Dapagliflozin is contraindicated when GFR falls below 45 mL/min for glycemic control, though it can be continued for heart failure/CKD indications down to GFR 25 mL/min 6, 3
• At GFR 59 mL/min, dapagliflozin's glucose-lowering efficacy is reduced but still present, and it provides important cardiovascular and renal protective benefits 7, 5
• Small transient reductions in eGFR occur early with dapagliflozin but typically return to near baseline by week 24 and remain stable long-term 8
• Monitor renal function every 3 months given the borderline GFR and proteinuria 2, 3

Insulin Initiation and Titration Strategy

Restarting Lantus 20 units is appropriate, but requires aggressive titration:

• Starting dose of 20 units is reasonable (alternatively 0.1-0.2 units/kg/day) 2
• Titrate by 4 units every 3 days until fasting glucose consistently reaches <130 mg/dL without hypoglycemia 2
• With HbA1c >10%, more aggressive starting doses of 0.3-0.5 units/kg/day total daily insulin may be considered 2
• Continue metformin as the foundation of therapy—it reduces insulin requirements and provides cardiovascular benefits 1, 2

Expected Outcomes and Timeline

With this regimen, expect:

• HbA1c reduction of approximately 2-3% over 3 months with optimized basal insulin 2
• Fasting glucose should reach target <130 mg/dL within 2-4 weeks of proper titration 2
• Reassess HbA1c in 3 months—if still >7%, further intensification will be needed 1, 2

Next Steps if HbA1c Remains >7% at 3 Months

If glycemic targets are not achieved after 3-6 months despite optimized basal insulin:

• Add a GLP-1 receptor agonist as the preferred next agent—provides HbA1c reduction of 0.6-0.8%, causes weight loss rather than weight gain, and has minimal hypoglycemia risk 1, 2
• GLP-1 receptor agonists can be used with GFR >30 mL/min (liraglutide, dulaglutide, albiglutide require no dose adjustment in stages 2-3 CKD) 3
• Alternatively, add prandial insulin before the largest meal, starting with 4 units or 10% of basal dose 2

Critical Monitoring Parameters

Essential monitoring to prevent complications:

• Renal function (eGFR, creatinine) every 3 months—if GFR falls below 45 mL/min, discontinue Farxiga for glycemic indication 6, 3
• Metformin requires dose reduction if GFR falls below 45 mL/min and should be discontinued if GFR <30 mL/min 2
• Monitor for genital infections (more common with SGLT2 inhibitors) and hypoglycemia (with insulin titration) 7, 5
• Check for diabetic ketoacidosis symptoms (rare but more common with SGLT2 inhibitors, especially when combined with insulin) 7

Important Caveats

Key pitfalls to avoid:

• Do not delay insulin titration—waiting beyond 3 months at HbA1c >10% significantly increases complication risk 2
• Do not stop Farxiga prematurely—the improved GFR from 44 to 59 mL/min suggests renal benefit, and cardiovascular protection is independent of glycemic control 7, 5
• Avoid overbasalization—if basal insulin exceeds 0.5 units/kg/day without achieving target, add prandial coverage or GLP-1 receptor agonist rather than continuing to increase basal dose 2
• The 3+ glycosuria will persist until better glycemic control is achieved (renal threshold ~180 mg/dL), but this is expected and not harmful 4, 9