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A High-throughput Method for Measurement of Glomerular Filtration Rate in Conscious Mice
Published on: May 10, 2013
Estimated glomerular filtration rates are higher when creatinine-based equations are compared with a cystatin C-based
Anders O Larsson1, Michael Hultström2,3,4,5, Robert Frithiof2
1Section of Clinical Chemistry, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
Insights
Estimations of glomerular filtration rate (eGFR) using creatinine are higher than cystatin C-based eGFR in COVID-19 patients. The Cockcroft-Gault equation is not recommended for drug dosing in these critically ill patients.
Area of Science:
- Nephrology
- Critical Care Medicine
- Infectious Diseases
Background:
- Acute kidney injury (AKI) is common in Coronavirus disease 2019 (COVID-19) patients.
- Patients in intensive care units (ICUs) with COVID-19 are at high risk for AKI and drug-induced kidney injury.
- Accurate estimation of glomerular filtration rate (eGFR) is crucial for managing these patients.
Purpose of the Study:
- To compare creatinine-based eGFR equations with cystatin C-based eGFR in adult ICU patients with COVID-19.
- To evaluate the performance of different creatinine-based eGFR equations.
- To determine the most suitable eGFR estimation method for drug dosing in COVID-19 ICU patients.
Main Methods:
- Included 370 adult ICU patients with COVID-19.
- Measured serum creatinine and cystatin C levels upon ICU admission.
- Calculated eGFR using Cockcroft-Gault, MDRD (1999 and 2006), CKD-EPI, LMR, and CAPA (cystatin C-based) equations.
Main Results:
- All creatinine-based eGFR estimations were significantly higher than cystatin C-based eGFR (p < .00001).
- Median eGFR values: C-G (99 ml/min), MDRD1999 (90 ml/min), MDRD2006 (85 ml/min), CKD-EPI (91 ml/min), LMR (83 ml/min), CAPA (70 ml/min).
- The Cockcroft-Gault equation showed the largest overestimation compared to the cystatin C-based CAPA equation.
Conclusions:
- Creatinine-based eGFR equations generally overestimate renal function in COVID-19 ICU patients compared to cystatin C-based equations.
- The Cockcroft-Gault equation demonstrates the poorest performance and should be avoided for drug dosage calculations in this population.
- Cystatin C-based eGFR may provide a more accurate assessment of kidney function in critically ill COVID-19 patients.
Objectives:
Estimations of glomerular filtration rate (eGFR) are based on analyses of creatinine and cystatin C, respectively. Coronavirus disease 2019 (COVID-19) patients in the intensive care unit (ICU) often have acute kidney injury (AKI) and are at increased risk of drug-induced kidney injury. The aim of this study was to compare creatinine-based eGFR equations to cystatin C-based eGFR in ICU patients with COVID-19.
Methods:
After informed consent, we included 370 adult ICU patients with COVID-19. Creatinine and cystatin C were analyzed at admission to the ICU as part of the routine care. Creatinine-based eGFR (ml/min) was calculated using the following equations, developed in chronological order; the Cockcroft-Gault (C-G), Modified Diet in Renal Disease (MDRD)1999, MDRD 2006, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Lund-Malmö revised (LMR) equations, which were compared with eGFR calculated using the cystatin C-based Caucasian Asian Pediatric Adult (CAPA) equation.
Results:
The median eGFR when determined by C-G was 99 ml/min and interquartile range (IQR: 67 ml/min). Corresponding estimations for MDRD1999 were 90 ml/min (IQR: 54); MDRD2006: 85 ml/min (IQR: 51); CKD-EPI: 91 ml/min (IQR: 47); and for LMR 83 ml/min (IQR: 41). eGFR was calculated using cystatin C and the CAPA equation value was 70 ml/min (IQR: 38). All differences between creatinine-based eGFR versus cystatin C-based eGFR were significant (p < .00001).
Conclusions:
Estimation of GFR based on various analyses of creatinine are higher when compared with a cystatin C-based equation. The C-G equation had the worst performance and should not be used in combination with modern creatinine analysis methods for determination of drug dosage in COVID-19 patients.
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