What is the best approach to managing diabetes in a patient with diastolic heart failure and severe pulmonary hypertension who is currently taking Lantus (insulin glargine), Janumet (sitagliptin and metformin), and Glipizide (glyburide)?

Management of Diabetes in a Patient with Diastolic Heart Failure and Severe Pulmonary Hypertension

Discontinue glipizide (sulfonylurea) immediately and avoid thiazolidinediones entirely, continue metformin only if heart failure is stable with normal renal function, maintain insulin glargine (Lantus) as the safest backbone therapy, and strongly consider adding an SGLT2 inhibitor which provides cardiovascular and heart failure benefits in this high-risk population. 1

Immediate Medication Adjustments

Discontinue Glipizide (Sulfonylurea)

• Sulfonylureas should be eliminated from the regimen as they offer no cardiovascular benefit and increase hypoglycemia risk, particularly problematic in patients with heart failure where hypoglycemic episodes can precipitate decompensation. 2, 3
• While sulfonylureas are not explicitly contraindicated in heart failure, they provide no mortality or morbidity benefit and represent suboptimal therapeutic choice when superior alternatives exist. 3, 4

Metformin (Janumet Component) - Conditional Continuation

• Metformin may be continued only if the patient has stable congestive heart failure with normal renal function. 1
• Metformin must be avoided if the patient is unstable or hospitalized with heart failure. 1
• Given the severe pulmonary hypertension and diastolic heart failure, carefully assess volume status and renal function before continuing metformin. 5, 3
• Monitor for lactic acidosis risk, particularly if renal function deteriorates or if the patient develops acute decompensation. 5

Sitagliptin (Janumet Component) - Exercise Caution

• DPP-4 inhibitors show overall neutral cardiovascular outcomes, though saxagliptin specifically has been associated with increased heart failure hospitalization risk. 3
• Sitagliptin appears safer than saxagliptin in heart failure populations, but offers no cardiovascular benefit. 3
• Consider discontinuation in favor of medications with proven heart failure benefits. 3

Insulin Glargine (Lantus) - Continue as Foundation

• Insulin remains the safest antihyperglycemic agent in patients with symptomatic heart failure and should be maintained. 1, 6
• Insulin does not cause fluid retention or worsen heart failure outcomes. 1
• Titrate doses carefully to avoid hypoglycemia, which can be particularly dangerous in this population. 2

Strongly Recommended Addition

SGLT2 Inhibitors - Priority Addition

• Add empagliflozin, dapagliflozin, or canagliflozin to reduce heart failure hospitalization risk and improve cardiovascular mortality. 1, 7
• SGLT2 inhibitors provide cardiovascular benefits independent of glycemic control and are now considered foundational therapy in patients with diabetes and heart failure. 1, 7
• These agents reduce fluid overload through mild diuretic effect, which is particularly beneficial in diastolic heart failure with pulmonary hypertension. 7
• Monitor renal function, as efficacy may be reduced in advanced chronic kidney disease. 7

Absolute Contraindications

Thiazolidinediones (TZDs) - Never Use

• Thiazolidinediones are contraindicated in patients with symptomatic heart failure (NYHA class III-IV). 1
• TZDs cause dose-related fluid retention and can precipitate or exacerbate heart failure, particularly when combined with insulin. 1
• Even in NYHA class I-II symptoms, TZDs should be avoided given this patient's severe pulmonary hypertension. 1

Heart Failure-Specific Diabetes Management

Optimize Underlying Cardiac Conditions

• Aggressive volume management with diuretics is essential to reduce left ventricular filling pressures and pulmonary venous congestion. 8
• Blood pressure control with ACE inhibitors or ARBs is crucial to prevent and potentially reverse left ventricular hypertrophy underlying diastolic dysfunction. 1, 8
• The pulmonary hypertension in this patient is secondary to diastolic heart failure (Group 2 PH), requiring treatment of the underlying left heart disease rather than pulmonary arterial hypertension-specific medications. 8

Glycemic Targets in Heart Failure

• Optimize glucose control to reduce progression of both cardiac and renal complications. 1
• Avoid overly aggressive glycemic targets that increase hypoglycemia risk, as hypoglycemic episodes can precipitate heart failure decompensation. 1
• Hyperinsulinemia from insulin resistance may promote cardiac and vascular hypertrophy, potentially hastening heart failure progression. 1

Monitoring Requirements

Renal Function Surveillance

• Monitor creatinine and estimated glomerular filtration rate closely, as both heart failure and diabetes increase chronic kidney disease risk. 7, 5
• Adjust metformin dosing or discontinue if renal function deteriorates (eGFR <30 mL/min/1.73m²). 5
• SGLT2 inhibitors require renal function monitoring but can be continued at lower eGFR thresholds than metformin. 7

Volume Status Assessment

• Monitor for signs of fluid retention or worsening heart failure with any medication changes. 1, 8
• Assess weight, edema, dyspnea, and orthopnea at each visit. 8
• Brain natriuretic peptide levels may help detect subtle cardiac function deterioration. 9

Multidisciplinary Coordination

Team-Based Approach

• Coordinate care between cardiology, endocrinology, and primary care to optimize both heart failure and diabetes management. 1
• Pharmacist involvement can identify drug therapy-related issues, particularly drug-drug interactions and contraindications common in this complex population. 4
• The complexity of managing multiple comorbidities requires clear communication across disciplines to avoid therapeutic conflicts. 1

Common Pitfalls to Avoid

• Do not continue sulfonylureas simply because they are "not contraindicated" - they offer no benefit and increase hypoglycemia risk in a vulnerable population. 3, 4
• Do not withhold metformin reflexively in all heart failure patients - it is safe in stable heart failure with normal renal function and should only be avoided in unstable or hospitalized patients. 1
• Do not use pulmonary arterial hypertension-specific medications for this patient's Group 2 pulmonary hypertension, as they are contraindicated and potentially harmful. 8
• Do not overlook SGLT2 inhibitors - these represent the most important therapeutic advance for patients with diabetes and heart failure and should be prioritized. 1, 7