Plasma Cystatin C as a Marker of Acute-on-Chronic Liver Failure and 28-Day Mortality in Patients With Acutely Decompensated Liver Cirrhosis: A Prospective Observational Study.

BACKGROUND

Acute decompensation of cirrhosis carries a 28-day mortality of 1.9%, rising to nearly 30% with acute-on-chronic liver failure (ACLF), in which renal failure is the most frequent and most ominous organ failure. Serum creatinine overestimates glomerular filtration rate in cirrhosis. Plasma cystatin C may better reflect renal function and prognosis, but Indian data are scarce. We assessed cystatin C as a marker of ACLF and 28-day mortality in acutely decompensated cirrhosis.

METHODS

In this prospective observational cohort study, 100 adults with acutely decompensated cirrhosis were enrolled over 18 months. We performed clinical assessments and standard investigations, and measured plasma cystatin C by nephelometric immunoassay within 48 hours of admission. Participants were followed for ACLF and 28-day mortality. Cystatin C, Child-Turcotte-Pugh (CTP), and Model for End-Stage Liver Disease (MELD) scores were compared as predictors of mortality by receiver operating characteristic (ROC) curve analysis.

RESULTS

ACLF developed in 41 participants (41%), and 44 (44%) died within 28 days. Mean plasma cystatin C was higher in non-survivors than survivors (5.49±4.70 vs 2.06±1.54 mg/L; p<0.001) but did not differ by ACLF status (p=0.271). Cystatin C predicted 28-day mortality with AUROC 0.781 (95% CI 0.688-0.874); a cut-off ≥2.5 mg/L gave 73% sensitivity and 75% specificity, outperforming CTP (0.506) and MELD (0.508) scores (p<0.001).

CONCLUSIONS

Plasma cystatin C rose in patients who died within 28 days and predicted short-term mortality better than CTP or MELD scores, although it did not discriminate ACLF status. Cystatin C may serve as a simple, reproducible adjunct for prognostication in decompensated cirrhosis; larger multicentric studies are needed to validate this cut-off.