J Crit Care. 2020 Jul 8;59:201-206. doi: 10.1016/j.jcrc.2020.07.005. Online ahead of print.
PURPOSE: Estimating renal function by serum creatinine after critical illness is a challenging problem. However, the role of cystatin C for estimation of the renal function in survivors of critical illness is unknown. We aimed to compare the performance of serum cystatin C- and serum creatinine-based eGFR against a reference GFR using 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) in survivors of critical illness.
MATERIAL AND METHODS: Survivors of critical illness with stable hemodynamics and renal functions were recruited. Their serum creatinine and cystatin C levels were measured. eGFR were calculated by using various equations: 1)CKD-EPI SCysC; 2) Thai eGFR SCysC; 3)CKD-EPI SCr; 4)Thai eGFR SCr; 5)MDRD Caucasian SCr; 6)CKD-EPI SCr-SCysC. The 99mTc-DTPA plasma clearance was used as a standard eGFR.
RESULTS: Forty-two patients were included. The bias (median percentage difference) between standard GFR and SCysC-based eGFR were 41.97% (95%CI 33.1% to 48.5%) for CKD-EPI SCysC and 31.72% (95%CI 21.1% to 34.9%) for Thai eGFR SCysC. While, the bias between standard GFR and SCr-based eGFR were -11.37 (95%CI -20.9 to 1.6) for CKD-EPI SCr, -18.30 (95%CI -26.3 to -10.6) for Thai eGFR SCr, and -27.17 (-43.7 to -19.1) for MDRD Caucasian SCr.
CONCLUSION: In survivors of critical illness, we demonstrated limitations of estimating GFR by both currently available SCysC and SCr-based equations. Therefore, further studies are still needed to develop better eGFR equations.