In a patient with an A1c of 10.2% on basal NPH insulin 30 U daily plus a medium‑dose sliding‑scale of regular insulin, an eGFR of ~67 mL/min/1.73 m², hypertension and prior myocardial infarction, what additional antidiabetic medication should be added?

Add an SGLT2 Inhibitor with Proven Cardiovascular Benefit to the Current Insulin Regimen

For this patient with type 2 diabetes, A1c 10.2%, prior myocardial infarction, hypertension, and eGFR 67 mL/min/1.73 m², empagliflozin 10 mg daily should be added immediately to the current NPH and regular insulin regimen, independent of A1c level, because of established cardiovascular disease. 1

---

Rationale: Prioritize Cardiovascular and Renal Protection

SGLT2 Inhibitors Are Guideline-Mandated in This Clinical Context

• In patients with type 2 diabetes and established atherosclerotic cardiovascular disease (prior MI qualifies), an SGLT2 inhibitor or GLP-1 receptor agonist with demonstrated cardiovascular benefit is recommended as part of the glucose-lowering regimen independent of A1c and independent of metformin use. 1
• Empagliflozin, canagliflozin, and dapagliflozin have all shown statistically significant reductions in cardiovascular events in large randomized controlled trials enrolling patients with established ASCVD or high cardiovascular risk. 1
• More than 70% of patients in these cardiovascular outcomes trials were already on metformin at baseline, demonstrating that SGLT2 inhibitors provide additive benefit on top of existing therapy. 1

Renal Function Supports SGLT2 Inhibitor Use

• This patient's eGFR of 67 mL/min/1.73 m² is well above the threshold for initiating empagliflozin (eGFR ≥20 mL/min/1.73 m²), making it both safe and indicated. 2
• SGLT2 inhibitors are specifically recommended for patients with chronic kidney disease as part of the glucose-lowering regimen. 1
• In patients with acute myocardial infarction and type 2 diabetes, empagliflozin prevented kidney functional decline, especially in those with baseline eGFR ≥60 mL/min/1.73 m². 3
• Early administration of SGLT2 inhibitors in post-MI patients with diabetes is considered desirable for renal protection. 3

Glycemic Benefit Without Hypoglycemia Risk

• SGLT2 inhibitors lower A1c by approximately 0.7–1.0% when added to existing therapy. 1
• Empagliflozin does not increase hypoglycemia risk when used as monotherapy or in combination with metformin, but hypoglycemia incidence increases when combined with insulin or sulfonylureas. 2
• In this patient already on insulin, close glucose monitoring is required, and insulin doses may need reduction by 10–20% after starting empagliflozin to prevent hypoglycemia. 4, 5

---

Practical Implementation

Starting Empagliflozin

• Begin empagliflozin 10 mg once daily in the morning. 2
• The 10 mg dose is appropriate for initiation; the dose can be increased to 25 mg daily if additional glycemic control is needed and the medication is well tolerated. 2
• Empagliflozin can be taken with or without food. 2

Insulin Dose Adjustment Protocol

• On the day empagliflozin is started, reduce the total daily insulin dose by approximately 10–20% to mitigate hypoglycemia risk. 4, 5
• For this patient on NPH 30 units daily plus sliding-scale regular insulin, consider reducing NPH to 24–27 units daily initially. 4
• Monitor fasting glucose daily for the first 1–2 weeks; if fasting glucose remains ≥180 mg/dL, increase NPH by 2–4 units every 3 days until fasting glucose reaches 80–130 mg/dL. 4, 6
• If fasting glucose falls below 70 mg/dL, reduce NPH immediately by 10–20%. 4, 6

Monitoring Requirements

• Check fasting glucose daily during the first 2–3 weeks after starting empagliflozin. 4, 5
• Monitor for signs of volume depletion (dizziness, orthostatic hypotension), especially in patients on diuretics for hypertension. 2
• Educate the patient on recognizing and treating hypoglycemia (15 g fast-acting carbohydrate for glucose <70 mg/dL). 4
• Reassess A1c in 3 months; if A1c remains >8%, consider further intensification of the insulin regimen (adding prandial insulin) or adding a GLP-1 receptor agonist. 1, 4, 5

---

Additional Considerations

Metformin Should Be Added Unless Contraindicated

• Metformin is the preferred initial pharmacologic agent for type 2 diabetes and should be continued as long as tolerated and not contraindicated. 1
• In this patient with eGFR 67 mL/min/1.73 m² (CKD stage 2), metformin is safe and should be started at 500 mg twice daily with meals, titrating up to 1000 mg twice daily (2000 mg total) as tolerated. 1
• Metformin reduces total insulin requirements by 20–30% and provides complementary glucose-lowering effects. 4, 5
• Metformin should not be discontinued when insulin is added unless contraindicated, as this leads to higher insulin requirements and greater weight gain. 4, 5

Transition from Sliding-Scale to Scheduled Insulin

• Sliding-scale insulin as monotherapy is strongly discouraged and ineffective for long-term glycemic management. 1, 4
• This patient's current regimen of NPH 30 units daily plus sliding-scale regular insulin is suboptimal for an A1c of 10.2%. 4
• Consider transitioning to a basal-bolus regimen: increase NPH to 40–50 units daily (or switch to insulin glargine for more predictable action), and add scheduled prandial insulin (4 units regular or rapid-acting insulin before each meal) rather than relying on sliding-scale corrections. 4, 6
• Basal-bolus therapy achieves mean glucose <140 mg/dL in approximately 68% of patients versus 38% with sliding-scale insulin alone. 4

GLP-1 Receptor Agonist as an Alternative or Addition

• If cost is not prohibitive and the patient can tolerate injections, a GLP-1 receptor agonist (liraglutide, semaglutide, or dulaglutide) with demonstrated cardiovascular benefit is an alternative or addition to SGLT2 inhibitors. 1
• GLP-1 receptor agonists are preferred to insulin intensification when possible because they provide comparable or better A1c reduction with lower hypoglycemia risk and weight loss rather than weight gain. 1
• In patients with type 2 diabetes and established ASCVD, both SGLT2 inhibitors and GLP-1 receptor agonists can be used together for maximal cardiovascular and renal protection. 1

---

Common Pitfalls to Avoid

• Do not delay adding an SGLT2 inhibitor in patients with established cardiovascular disease; this is a guideline-mandated recommendation independent of A1c. 1
• Do not continue sliding-scale insulin as the sole prandial coverage when A1c is 10.2%; scheduled prandial insulin is required for adequate glycemic control. 4
• Do not increase basal insulin beyond 0.5 units/kg/day (approximately 40–50 units for most adults) without adding prandial insulin, as this leads to "over-basalization" with increased hypoglycemia risk and suboptimal control. 4, 6
• Do not withhold metformin in patients with eGFR ≥30 mL/min/1.73 m² unless there are specific contraindications (e.g., acute infection, tissue hypoxia, contrast administration). 7
• Do not ignore the increased risk of genital mycotic infections and urinary tract infections with SGLT2 inhibitors; counsel patients on hygiene and early recognition of symptoms. 2

---

Expected Clinical Outcomes

• With the addition of empagliflozin 10 mg daily to the current regimen, expect an A1c reduction of approximately 0.7–1.0%, bringing A1c from 10.2% to approximately 9.2–9.5%. 1
• Further intensification of insulin therapy (transitioning to basal-bolus) can achieve an additional 1.5–2.0% A1c reduction, potentially bringing A1c to <8% within 3–6 months. 4, 5
• Cardiovascular outcomes trials demonstrate that SGLT2 inhibitors reduce the risk of major adverse cardiovascular events (cardiovascular death, nonfatal MI, nonfatal stroke) in patients with established ASCVD. 1
• Empagliflozin also reduces the risk of heart failure hospitalization, which is particularly relevant in patients with prior MI. 1