What is the clinical significance of a patient's impaired fasting glucose (glucose 118 mg/dL), normal urea nitrogen (BUN) and creatinine levels, low estimated glomerular filtration rate (eGFR) (58 mL/min/1.73m2), and other normal electrolyte and liver function tests?

From the Guidelines

Your glucose level of 118 mg/dL is elevated, indicating prediabetes, and your eGFR is slightly below normal, suggesting mild kidney function impairment. Given these findings, it is crucial to address both the elevated glucose level and the reduced eGFR to prevent further decline in kidney function and reduce the risk of developing type 2 diabetes. The most recent and highest quality study 1 emphasizes the importance of early detection and management of diabetic kidney disease, highlighting the benefits of newer classes of glucose-lowering agents such as sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists in reducing the risk of kidney disease progression and cardiovascular events.

Key Findings and Recommendations:

• Elevated Glucose Level: The glucose level of 118 mg/dL is above the normal range of 65-99 mg/dL, consistent with prediabetes. This should be confirmed with follow-up testing.
• Mild Kidney Function Impairment: The eGFR of 58 mL/min/1.73m² is slightly below the normal threshold of 60, indicating mild kidney function impairment.
• Lifestyle Modifications: Lifestyle changes including diet modifications, regular exercise, and weight management are recommended to address the prediabetic state and improve kidney function.
• Periodic Monitoring: Regular monitoring of kidney function is essential to prevent further decline.
• Hydration and Sodium Intake: Staying well-hydrated and limiting sodium intake may also be beneficial for kidney health.

Management Approach:

Based on the guidelines from the Kidney Disease: Improving Global Outcomes (KDIGO) 1, an individualized approach to managing prediabetes and mild kidney function impairment is recommended. This includes:

• Glycemic Monitoring: Using hemoglobin A1c (HbA1c) to monitor glycemic control, with individualized targets ranging from <6.5% to <8.0% for patients with diabetes and CKD not treated with dialysis.
• Glucose-Lowering Therapies: Considering the use of metformin and SGLT2 inhibitors as first-line treatments for patients with type 2 diabetes and CKD, given their benefits in reducing the risk of kidney disease progression and cardiovascular events.
• Lifestyle Interventions: Maintaining a protein intake of 0.8 g/kg/day, limiting sodium intake to <2 g/day, and undertaking moderate-intensity physical activity for at least 150 minutes per week.

By following these recommendations and guidelines, it is possible to effectively manage prediabetes and mild kidney function impairment, reducing the risk of progression to type 2 diabetes and further kidney disease.

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. Obtain an eGFR at least annually in all patients taking metformin hydrochloride tablets.

The patient's eGFR is 58 mL/min/1.73m2, which is low but not contraindicated. However, the patient's eGFR is close to the threshold of 60 mL/min/1.73m2, and caution should be exercised when considering metformin therapy. It is recommended to monitor the patient's renal function more frequently and assess the benefit and risk of continuing therapy. 2

From the Research

Glucose Levels and Prediabetes

• A glucose value of 118 mg/dL is higher than the normal fasting reference interval of 65-99 mg/dL, but not high enough to be classified as diabetes.
• According to the provided information, a glucose value between 100 and 125 mg/dL is consistent with prediabetes and should be confirmed with a follow-up test 3, 4.
• The American Diabetes Association (ADA) recommends using hemoglobin A1c (HbA1c) as a diagnostic tool for diabetes and prediabetes, with a threshold of 5.7% for prediabetes and 6.5% for diabetes 5, 6.

Diagnostic Tests for Diabetes and Prediabetes

• The oral glucose tolerance test (OGTT) is considered the gold standard for diagnosing diabetes and prediabetes, but it has some limitations, such as requiring fasting and a 2-hour glucose measurement 7.
• HbA1c is a widely used diagnostic tool, but its performance can be affected by various factors, such as hemoglobin variants and red blood cell turnover 3, 5.
• Fasting plasma glucose (FPG) is another diagnostic test, but its agreement with OGTT and HbA1c can be low, especially in certain populations, such as obese individuals 4, 6.

Renal Function and Electrolyte Levels

• The provided lab results show normal levels of urea nitrogen (BUN), creatinine, sodium, potassium, chloride, carbon dioxide, and calcium.
• The estimated glomerular filtration rate (eGFR) is slightly low at 58 mL/min/1.73m2, which may indicate some degree of kidney impairment.
• The BUN/creatinine ratio is within the normal range, which suggests that the kidney function is not severely impaired.