What does impaired renal function indicate?

From the Guidelines

Impaired renal function indicates a significant risk of chronic kidney disease (CKD) and acute kidney injury (AKI), which can lead to severe health consequences, including cardiovascular disease, hospitalization, and mortality 1.

Key Indicators of Impaired Renal Function

• Estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 1
• Albuminuria ≥ 30 mg/g 1
• Serum creatinine increase by 50% from baseline within 7 days 1
• Absolute increase in creatinine by 26.5 μmol/L over 48 hours 1

Stages of Chronic Kidney Disease

• Stage 1-5, with Stage 5 indicating kidney failure 1

Risk Factors for Impaired Renal Function

• Hypertension and diabetes are the predominant risk factors for CKD 1
• Heart failure can also lead to impaired renal function 1

Importance of Early Detection and Monitoring

• Early detection and treatment of impaired renal function can prevent or delay adverse outcomes 1
• Regular monitoring of renal function can help clinicians intervene at an early stage to reduce the risk of progression to kidney failure 1

From the Research

Impaired Renal Function Indicators

Impaired renal function can be indicated by various factors, including:

• Elevations in levels of blood urea nitrogen and/or serum creatinine, although these do not necessarily indicate structural renal disease 2
• Decreased glomerular filtration rates (GFR) with normal range serum creatinine values, making recognition of renal dysfunction more difficult 3
• Increased serum creatinine levels, which can occur with age and are associated with decreased creatinine clearance 3
• Decreased creatinine clearance, which can be estimated using various formulas such as the Cockcroft-Gault formula, MDRD formula, and body surface formula 3

Association with Mortality and Morbidity

Impaired renal function is associated with:

• Increased risk of cardiovascular mortality, even in individuals with mild renal insufficiency 4
• Adverse outcomes, including mortality, readmission, and functional decline in patients hospitalized for heart failure 5
• Higher risk of death, with larger creatinine elevations predicting the highest risk 5

Renal Function Classification

Renal function can be classified using various criteria, including:

• Glomerular filtration rate (GFR) estimated by the MDRD formula, which classifies chronic renal failure into different stages 6
• RIFLE (risk, injury, failure, loss and end-stage renal disease) and AKIN (acute renal injury network) criteria, which define the severity of acute renal injury 6
• Novel criteria based on estimated GFR measurements, which propose definitions for the reversibility of renal impairment, including renal complete response, partial response, and minor response 6