From the Guidelines
eGFR and serum creatinine are limited in predicting acute kidney injury (AKI) in acute heart failure patients due to their delayed rise and numerous non-renal factors affecting their specificity. While they are widely available and routinely used clinical markers, their limitations as predictive tools must be acknowledged 1. Serum creatinine rises relatively late in the course of kidney injury, typically 24-48 hours after the initial insult, making it a delayed marker rather than a predictive one. eGFR, which is calculated from creatinine, inherits these same limitations.
Limitations of eGFR and Serum Creatinine
- Affected by numerous non-renal factors including age, muscle mass, diet, and medications, reducing their specificity 1
- Delayed rise in serum creatinine, typically 24-48 hours after the initial insult 1
- eGFR was developed and validated in populations with steady or slowly declining renal function, making it less reliable for acute changes in renal function 1
Clinical Context and Newer Biomarkers
- Clinicians should consider clinical context, hemodynamic parameters, and when available, newer biomarkers like NGAL, KIM-1, and cystatin C for better prediction of AKI in acute heart failure 1
- Serial measurements rather than single values provide more useful information about kidney function trajectory in acute heart failure patients 1
- A patient-based monitoring regimen should be developed, considering both medication and individual risk factors, to minimize risk of WRF and AKI in vulnerable patients 1
Pros and Cons of eGFR and Serum Creatinine
- Pros: universal availability, established reference ranges, and familiarity among clinicians
- Cons: limited predictive value, delayed rise, and affected by non-renal factors
- In practice, clinicians should not rely solely on creatinine or eGFR for AKI prediction, but rather use a combination of clinical context, hemodynamic parameters, and newer biomarkers to guide decision-making 1
From the Research
Prediction of AKI in Acute Heart Failure
- eGFR and serum creatinine are commonly used to predict Acute Kidney Injury (AKI) in acute heart failure, but their accuracy is limited 2.
- A study found that serum creatinine- and cystatin C-based estimates of glomerular filtration rate (GFR) provided only moderate correlation with measured GFR in patients with acute heart failure 2.
- The incidence of AKI in acute heart failure is approximately 33% 3, and it is more common in patients with chronic kidney disease 4, 5.
Pros of Using eGFR and Serum Creatinine
- eGFR and serum creatinine are widely available and easily measurable 4, 5.
- They can provide a general indication of kidney function and help identify patients at risk of AKI 3.
- Monitoring eGFR and serum creatinine can help detect changes in kidney function over time 4, 5.
Cons of Using eGFR and Serum Creatinine
- They may not accurately reflect changes in kidney function in acute heart failure 2.
- Serum creatinine- and cystatin C-based estimates of GFR may be misleading in acute heart failure 2.
- A single measurement of eGFR or serum creatinine may not be sufficient to predict AKI, and serial measurements may be needed 6.
- The use of eGFR and serum creatinine may not account for other factors that can affect kidney function, such as renal venous congestion 5.
Other Factors to Consider
- Diabetes, hypertension, history of chronic kidney disease, and age are predictor factors for AKI in heart failure patients 3.
- The RIFLE classification can predict all-cause and cardiac mortality in both AKI and acute-on-chronic kidney injury (ACKI) 4.
- Renal venous congestion due to increased right-sided heart pressures in acute heart failure is a major cause of kidney dysfunction 5.