In contrast to creatinine, cystatin C consistently associated with long-term mortality, identifying patients at both high and low risk, and better correlated with follow-up renal function. Conversely, lower creatinine relative to cystatin C appeared to confer adverse prognosis, confounding creatinine interpretation in isolation. Cystatin C warrants further investigation as a more meaningful measure of renal function after critical illness.

Plasma NGAL can help clinicians to identify bacterial infections in critically ill patients.

No abstract

Decreased glomerular filtration rate (GFR) is linked to poor survival. The predictive value of creatinine estimated GFR (eGFR) and cystatin C eGFR in critically ill patients may differ substantially, but has been less studied. This study compares long-term mortality risk prediction by eGFR using a creatinine equation (CKD-EPI), a cystatin C equation (CAPA) and a combined creatinine/cystatin C equation (CKD-EPI), in 22,488 patients treated in intensive care at three University Hospitals in Sweden, between 2004 and 2015. Patients were analysed for both creatinine and cystatin C on the same blood sample tube at admission, using accredited laboratory methods. During follow-up (median 5.1 years) 8401 (37%) patients died. Reduced eGFR was significantly associated with death by all eGFR-equations in Cox regression models. However, patients reclassified to a lower GFR-category by using the cystatin C-based equation, as compared to the creatinine-based equation, had significantly higher mortality risk compared to the referent patients not reclassified. The cystatin C equation increased C-statistics for death prediction (p < 0.001 vs. creatinine, p = 0.013 vs. combined equation). In conclusion, this data favours the sole cystatin C equation rather than the creatinine or combined equations when estimating GFR for risk prediction purposes in critically ill patients.