Serum Cys C predicts acute kidney injury in patients with acute pancreatitis: A retrospective study

We investigated the value of the serum cystatin C level as a potential predictor of acute kidney injury (AKI) in patients with acute pancreatitis (AP). We retrospectively examined patients diagnosed with AP between January 2013 and December 2018. Patients were categorized into two groups based on their serum cystatin C levels after admission: the normal (n-Cys C group) and high serum cystatin C levels groups (h-Cys C group). Patients in the h-Cys C group demonstrated serum cystatin C levels ≥1.05 mg/L. Demographic parameters, laboratory data, and AP severity were compared between the two groups. Receiver operating curve (ROC) analysis was used to evaluate the efficacy of serum cystatin C in predicting persistent AKI. A total of 379 patients with AP were enrolled: 319 in the n-Cys C group and 60 in the h-Cys C group. Serum cystatin C levels were significantly higher in patients with severe acute pancreatitis (SAP) compared to moderate acute pancreatitis (MAP) (P< 0.05). The h-Cys C group had a higher BISAP score (P < 0.001). Incidences of organ failure and SAP were significantly higher in the h-Cys C group (P < 0.05). ROC analysis indicated that a serum cystatin C cutoff point of 1.055 mg/L optimally predicted persistent AKI (AUC = 0.711). For internal validation, we selected 545 AP patients, treated at our center from 2019 to 2022, including 54 AKI patients. ROC analysis in this validation group yielded a sensitivity of 100% and specificity of 90.9% (AUC = 0.916, 95% CI: 0.894–0.937). Elevated serum cystatin C levels are sensitive indicators of adverse AKI prognosis in AP patients. The cystatin C level at admission can reflect a patient's initial renal function status.