Is a creatinine (Creatinine) level of 1.58 mg/dL and an estimated Glomerular Filtration Rate (eGFR) of 36 mL/min/1.73m^2 significant for impaired renal function?

From the Guidelines

Yes, a creatinine level of 1.58 mg/dL and an eGFR of 36 mL/min/1.73m² indicate moderate to severe kidney impairment. These values correspond to Stage 3b chronic kidney disease according to the commonly used classification system, as suggested by the National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification 1. Normal creatinine levels typically range from 0.7-1.2 mg/dL for men and 0.5-1.0 mg/dL for women, while normal eGFR is above 90 mL/min/1.73m². This level of kidney dysfunction requires medical attention and likely adjustments to medication dosages, particularly for drugs that are primarily eliminated through the kidneys, as emphasized in the guidelines 1. Some key points to consider include:

• The serum creatinine concentration is affected by factors other than GFR, such as creatinine secretion and generation and extrarenal excretion 1.
• Clinicians should not use serum creatinine concentration as the sole means to assess the level of kidney function, and should estimate GFR from prediction equations that take into account the serum creatinine concentration and some or all of the following variables: age, sex, race, and body size 1.
• Patients with this degree of renal impairment should monitor their blood pressure carefully, follow a kidney-friendly diet (typically lower in sodium, potassium, and phosphorus), and have regular follow-up appointments with a healthcare provider.
• The kidneys play a crucial role in filtering waste products, regulating electrolytes, and maintaining fluid balance in the body, so impaired function can lead to various complications if not properly managed.
• Regular monitoring of kidney function through blood tests is essential to track any progression of the disease.

From the Research

Impaired Renal Function

A creatinine level of 1.58 mg/dL and an estimated Glomerular Filtration Rate (eGFR) of 36 mL/min/1.73m^2 may indicate impaired renal function. The eGFR value is below the normal range, suggesting some level of kidney impairment.

Comparison with Study Findings

• The study 2 discusses the use of Angiotensin Converting Enzyme Inhibitors (ACEi) and Angiotensin II Receptor Antagonists (ARB) in patients with advanced Chronic Kidney Disease (CKD), but does not provide specific guidance on the significance of a creatinine level of 1.58 mg/dL and an eGFR of 36 mL/min/1.73m^2.
• Another study 3 suggests that initial increases in serum creatinine over 30% should be tolerated in the context of dual goal-directed, more aggressive Renin-Angiotensin System (RAS) inhibition and diuretic use, as this may lead to favorable long-term outcomes.
• The study 4 found that an acute increase in serum creatinine of up to 30% that stabilizes within the first 2 months of ACEi therapy is associated with long-term preservation of renal function.

Key Points

• A creatinine level of 1.58 mg/dL and an eGFR of 36 mL/min/1.73m^2 may indicate impaired renal function.
• The significance of these values should be evaluated in the context of the individual patient's overall health and medical history.
• Studies suggest that initial increases in serum creatinine should be tolerated in certain contexts, as this may lead to favorable long-term outcomes 3, 4.