What glucose management should be implemented for a 72-year-old patient with diabetic foot infection, type 2 diabetes, hypertension, and stage three chronic kidney disease (CKD) with impaired renal function, currently on metformin and glipizide (sulfonylurea)?

From the Guidelines

For this 72-year-old patient with diabetic foot infection, type 2 diabetes, hypertension, and stage three CKD, the glucose management should be modified immediately by discontinuing metformin and glipizide and starting insulin glargine 12 units daily and Humalog four units three times daily with meals. This approach is based on the most recent and highest quality study 1, which provides guidance on diabetes management in chronic kidney disease. Given the patient's impaired renal function (creatinine 2.3) and acute illness, metformin should be discontinued due to the risk of lactic acidosis, as recommended by 1 and 1. Glipizide can be discontinued due to the increased hypoglycemia risk in elderly patients with kidney disease, as noted in 1. Initiating insulin therapy with basal-bolus insulin is recommended to manage hyperglycemia during the infection, with blood glucose targets less stringent than for younger patients, aiming for fasting glucose of 100-180 mg/dL and postprandial levels below 200 mg/dL, with an HbA1c target of 7.5-8.0% 1. Regular monitoring of renal function, electrolytes, and blood glucose is essential, with frequent adjustments to the regimen as the infection resolves and the patient's condition stabilizes. Some key points to consider in this patient's management include:

• Avoiding hypoglycemia and symptomatic hyperglycemia, as recommended by 1
• Considering the use of DPP-4 inhibitors like linagliptin, which requires no dose adjustment in kidney disease, as noted in 1
• Monitoring for signs of lactic acidosis and adjusting the treatment regimen accordingly, as recommended by 1 and 1
• Adjusting the dose of glargine and Humalog based on the patient's glucose levels and kidney function, as recommended by 1.

From the FDA Drug Label

Metformin hydrochloride tablets are contraindicated in patients with an eGFR less than 30 mL/min/1.73 m^2 Initiation of metformin hydrochloride tablets is not recommended in patients with eGFR between 30 to 45 mL/min/1.73 m^2

The patient has stage three chronic kidney disease with a creatinine of 2.3, which likely corresponds to an eGFR below 45 mL/min/1.73 m^2. Given this renal impairment, the risk of metformin accumulation and metformin-associated lactic acidosis increases. Therefore, discontinuing metformin is recommended. For glucose management, considering the patient's type 2 diabetes and renal impairment, insulin therapy may be a suitable alternative. A possible regimen could be insulin GLARGINE 12 units daily and Humalog four units three times daily with meals or sliding scale insulin Lispro every six hours, but the exact dosing should be determined by the patient's healthcare provider based on their individual needs and response to therapy 2.

From the Research

Glucose Management for Diabetic Foot Infection

The patient in question has a diabetic foot infection, type 2 diabetes, hypertension, and stage three chronic kidney disease (CKD) with impaired renal function, currently on metformin and glipizide. Considering the patient's condition, the following glucose management options should be evaluated:

• Continuing metformin and glipizide: However, given the patient's stage three CKD, metformin may need to be used with caution or avoided due to the risk of lactic acidosis 3.
• Discontinuing metformin and continuing glipizide: This option may be considered, but sulfonylureas like glipizide can be continued at adjusted doses until an advanced stage of CKD, subject to strict monitoring 4.
• Discontinuing metformin and glipizide and starting Lantis 12 units daily: There is no evidence to support the use of Lantis in this specific context.
• Discontinuing metformin and glipizide and starting insulin GLARGINE 12 units daily and Humalog four units three times daily with meals: This option may be considered, as intensive glycemic control can improve wound healing in patients with diabetic foot ulcers 5, 6.
• Discontinuing metformin and glipizide and starting insulin glargine GLARGINE 12 units daily and sliding scale insulin Lispro every six hours: This option may also be considered, as it allows for flexible blood glucose management.

Considerations for Glucose Management

When managing glucose levels in patients with diabetic foot infections and CKD, the following considerations should be taken into account:

• The risk of lactic acidosis associated with metformin use in patients with CKD 7, 3.
• The importance of strict blood glucose control to promote wound healing 5, 6.
• The need for regular monitoring of blood glucose levels, renal function, and other comorbidities 4.
• The potential benefits of insulin therapy in achieving tight glycemic control and promoting wound healing 5, 6.