Should a patient with type 2 diabetes (T2D), impaired renal function, significant proteinuria, and a left ventricular ejection fraction (LVEF) of 60-65%, who is on an insulin pump, continue taking a Sodium-Glucose Linked Transporter 2 (SGLT-2) inhibitor?

Should a Patient on an Insulin Pump Continue SGLT-2 Inhibitors?

Yes, patients with type 2 diabetes on an insulin pump should absolutely continue SGLT-2 inhibitors, as these medications provide critical kidney and cardiovascular protection that is independent of their glucose-lowering effects. 1

Primary Rationale: Organ Protection Beyond Glucose Control

The fundamental principle here is that SGLT-2 inhibitors are recommended for kidney and cardiovascular protection, not primarily for glucose management. 1 This is why guidelines explicitly state that SGLT-2 inhibitors can be added to any current glucose-lowering regimen, including insulin pumps. 1

Key Evidence Supporting Continuation:

• SGLT-2 inhibitors reduce all-cause mortality by 15% (RR 0.85,95% CI 0.78-0.94) and cardiovascular death by 17% (RR 0.83,95% CI 0.74-0.93) in patients with type 2 diabetes and CKD, regardless of other glucose-lowering therapies. 2

• Kidney failure risk is reduced by 30% (RR 0.70,95% CI 0.62-0.79) with SGLT-2 inhibitor use, representing a class 1A recommendation—the strongest level of evidence. 1, 2

• Hospital admission for heart failure decreases by 30% (RR 0.70,95% CI 0.62-0.79), which is particularly relevant given this patient's preserved LVEF of 60-65% and proteinuria indicating cardiovascular risk. 2

Specific Considerations for This Patient Profile

Renal Protection with Impaired Function:

• With impaired renal function and significant proteinuria, this patient has clear indications for SGLT-2 inhibitor therapy regardless of glucose control status. 1

• SGLT-2 inhibitors should be initiated or continued in patients with eGFR ≥20 mL/min/1.73 m², and once started, can be continued even if eGFR falls below this threshold. 1

• The medications reduce glomerular hyperfiltration through tubuloglomerular feedback, decreasing intraglomerular pressure and protecting the filtration barrier—mechanisms completely independent of insulin therapy. 3, 4, 5

Cardiovascular Protection:

• Despite preserved LVEF (60-65%), the presence of proteinuria and renal impairment places this patient at substantially elevated cardiovascular risk. 1

• SGLT-2 inhibitors reduce 3-point MACE (RR 0.89,95% CI 0.81-0.98) and 4-point MACE (RR 0.82,95% CI 0.70-0.96). 2

Critical Safety Considerations with Insulin Pump Use

Diabetic Ketoacidosis Risk Management:

Patients with type 2 diabetes requiring insulin are at particular risk for euglycemic ketoacidosis when taking SGLT-2 inhibitors. 1 This is the primary concern when combining these therapies.

Mitigation strategies include:

• Maintain at least low-dose basal insulin at all times—never discontinue basal insulin completely even if glucose levels are well-controlled. 1

• Temporarily withhold SGLT-2 inhibitors during acute illness, prolonged fasting, surgery, or critical medical illness when ketosis risk increases. 1

• Monitor blood or urine ketones during sick days, not just glucose levels, as ketoacidosis can occur with minimal glucose elevation. 1

• Educate the patient to discontinue SGLT-2 inhibitors and seek immediate medical attention if signs, symptoms, or biochemical evidence of ketoacidosis develop. 1

Hypoglycemia Considerations:

• SGLT-2 inhibitors actually reduce hypoglycemia risk (RR 0.93,95% CI 0.89-0.98) and severe hypoglycemia requiring assistance (RR 0.75,95% CI 0.65-0.88) compared to placebo. 2

• With an HbA1c of 5.4% (if applicable to this patient), insulin pump settings may need adjustment downward to prevent hypoglycemia when SGLT-2 inhibitors are added, but this does not contraindicate their use. 6

• Background insulin therapy adjustment is generally not required when initiating SGLT-2 inhibitors, but follow-up to reassess glycemia is important. 1

Volume Status Monitoring:

• Assess for volume depletion risk, particularly if the patient is on concurrent diuretics or has tenuous volume status. 1

• Consider reducing thiazide or loop diuretic doses before SGLT-2 inhibitor initiation if volume depletion is a concern. 1

• Educate patients about symptoms of volume depletion and low blood pressure. 1

Practical Implementation Algorithm

Step 1: Confirm Eligibility

• eGFR ≥20 mL/min/1.73 m²? → Yes, continue/initiate SGLT-2 inhibitor 1
• Normal serum potassium? → Proceed 1

Step 2: Select Appropriate Agent

• Prioritize agents with proven kidney or cardiovascular benefits: canagliflozin, dapagliflozin, or empagliflozin. 1
• Adjust dosing based on eGFR per package insert guidelines, though kidney and cardiovascular benefits persist even at reduced doses. 1

Step 3: Patient Education

• Never stop basal insulin completely 1
• Withhold SGLT-2 inhibitor during illness, fasting, or surgery 1
• Monitor ketones during sick days, not just glucose 1
• Recognize ketoacidosis symptoms: nausea, vomiting, abdominal pain, fatigue, dyspnea 1

Step 4: Monitoring Schedule

• eGFR within 2-4 weeks after initiation, then every 3-6 months 1
• Expect and accept a reversible acute dip in eGFR—this is not a reason to discontinue therapy 1
• Volume status assessment at follow-up 1
• Ketone monitoring capability during acute illness 1

Common Pitfalls to Avoid

• Do not discontinue SGLT-2 inhibitors solely because glucose control is excellent on insulin pump therapy—the primary indication is organ protection, not glucose lowering. 1

• Do not stop SGLT-2 inhibitors if eGFR drops below initiation threshold—continuation is recommended unless dialysis is initiated or the medication is not tolerated. 1

• Do not ignore the reversible eGFR dip that occurs with initiation—this represents hemodynamic changes that are actually protective long-term. 1, 7

• Do not fail to educate about ketoacidosis risk—this is the most serious complication when combining SGLT-2 inhibitors with insulin therapy. 1