Clarifying the concept of chronic kidney disease for non-nephrologists

Area of Science:

• Nephrology
• Internal Medicine
• Clinical Epidemiology

Background:

• Chronic kidney disease (CKD) encompasses a broader spectrum than chronic renal insufficiency, including early stages with preserved function.
• Even with normal estimated glomerular filtration rate (eGFR) (≥60 mL/min/1.73 m²), CKD diagnosis requires additional criteria beyond eGFR.
• Misconceptions regarding CKD diagnosis and the distinction between GFR and creatinine clearance are prevalent in clinical practice.

Purpose of the Study:

• To clarify the definition and staging of CKD for non-nephrologists.
• To address common misunderstandings regarding CKD diagnosis, particularly in early stages.
• To highlight the potential negative consequences of misdiagnosing CKD.

Main Methods:

• Review and commentary on the current understanding and diagnostic criteria for CKD.
• Analysis of a clinical trial illustrating common diagnostic errors.
• Explanation of the difference between estimated glomerular filtration rate (eGFR) and creatinine clearance.

Main Results:

• A decreased eGFR (<60 mL/min/1.73 m²) persisting for >3 months is diagnostic of CKD.
• When eGFR is ≥60 mL/min/1.73 m², additional criteria are necessary for CKD diagnosis.
• Estimating creatinine clearance can overestimate eGFR, leading to diagnostic inaccuracies.

Conclusions:

• Accurate CKD diagnosis is essential to prevent patient harm (e.g., insurance issues) and medical confusion.
• Understanding the nuances of CKD staging, especially with preserved eGFR, is critical for appropriate patient management.
• Distinguishing between GFR and creatinine clearance is fundamental for correct CKD assessment.