Assessing and Managing Kidney Function with Jardiance

Introduction to Kidney Function Assessment

• The American College of Cardiology recommends using cystatin C to assess kidney function, as it is independent of muscle mass, making it particularly reliable for detecting true kidney dysfunction 1, 2
• A cystatin C level of 3.16 mg/L is approximately 4 times the reference value, suggesting eGFR is likely well below 30 mL/min/1.73 m² and possibly approaching 15-20 mL/min/1.73 m² (Stage 4-5 CKD) 3, 4

Calculating eGFR

• The European Society of Cardiology recommends calculating eGFR using both creatinine and cystatin C to obtain the most accurate assessment 1, 2
• The combined equation (eGFRcreat-cys) has 94.9% accuracy within 30% of measured GFR 1, 5

Investigating Causes of Elevated Cystatin C

• The American Heart Association suggests checking thyroid function (TSH), as hypothyroidism increases cystatin C independent of GFR 2, 5
• Assessing for active smoking and reviewing corticosteroid use are also recommended, as they can affect cystatin C levels 2, 5

Assessing for Intrinsic Kidney Disease

• The European Heart Journal recommends obtaining urinalysis with microscopy and spot urine albumin-to-creatinine ratio to assess for intrinsic kidney disease 4, 2
• Albuminuria >300 mg/g indicates significant kidney damage and cumulative risk with reduced eGFR 3

Alternative Management Strategies

• The American College of Cardiology recommends focusing on blood pressure control targeting <130/80 mmHg for cardiovascular risk reduction if eGFR confirms <20 mL/min/1.73 m² 2
• Consider nephrology referral for advanced CKD management and potential renal replacement therapy planning 3

Monitoring and Avoiding Pitfalls

• The European Society of Cardiology recommends monitoring kidney function every 3-6 months in patients with eGFR 30-45 mL/min/1.73 m² (Stage 3b CKD) 3
• Do not rely solely on serum creatinine in patients with low muscle mass, as it may underestimate kidney dysfunction 4, 1