Estimates of glomerular filtration rate based on creatinine and cystatin C equations in critically ill patients: eGFR creatinine and cystatin C in ICU

• Main Authors: Kakar, Sohaila, Md Ralib, Azrina, Mohammad Aidid, Edre, Abd Rahim, Shahir Asraf, Mat Nor, Mohd Basri
• Format: Article
• Language: English
• Published: Journal of Clinical and Translational Nephrology 2022
• Subjects: R Medicine (General)
• Online Access: http://irep.iium.edu.my/99827/2/99827_Estimates%20of%20glomerular%20filtration%20rate.pdf; http://irep.iium.edu.my/99827/; https://jctn.msn.org.my/index.php/ejournal
• Institution: Universiti Islam Antarabangsa Malaysia

Introduction: Accurate assessment of renal function in the critically ill is important for the diagnostic and prognostic utility to guide clinical management. It is usually estimated from various estimate glomerular filtration rate (eGFR) equations. We evaluated eGFR based on Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation using serum creatinine (Cr), Cystatin C (CysC), and its combination, against 24-hour creatinine clearance (CrCl). We aimed to find the most accurate, precise, and less biased equation for GFR estimation. Methods: Critically ill patients, older than 18 years who stayed longer than 24 hours were included in the study. Urinary creatinine, serum Cr, and CysC were measured at three-time points (8, 24, and 72 hours). We then compared eGFR from Cr (eGFRCr), CysC (eGFRCysC) and combined CKD-EPI (eGFRCr-CysC) to the measured 24-hour CrCl. Results: A total of 43 patients were recruited. eGFRCr had the highest correlation to CrCl, with correlation of 0.81 and 0.73 at 24 and 72 hours, respectively, and was the most precise and accurate equation compared to eGFRCysC and eGFRCr-CysC at all-time points. The bias was lowest for eGFRCysC equation. The Area Under Curve of eGFRCr in diagnosing acute kidney injury (AKI) was 0.93 and 0.84 at 24 and 72 hours, respectively. Neither the eGFR equations nor CrCl played a role in the prediction of in-hospital mortality. Conclusion: eGFRCr had the highest correlation to CrCl and was the most accurate and precise equation, however, eGFRCysC had lowest bias. Most of the equations contributed to the diagnosis of AKI. However, none on contributed to the prediction of in-hospital mortality.