Serum Cystatin C for Prediction of Dialysis Requirement or Death in Acute Kidney Injury: A Comparative Study

Serum cystatin C level stratified by Acute Physiology and Chronic Health Evaluation II (APACHE II) score quartiles. P = 0.004 by means of analysis of variance test. Box plots show 25th, 50th (median), and 75th percentiles. Conversion factor for serum cystatin C in mg/L to nmol/L, ×74.9.

Restrictive cubic spline shows the unadjusted relationship (with 95% confidence bands) of (A) serum cystatin C (P = 0.004), (B) serum creatinine (P = 0.04), and (C) serum urea nitrogen levels (P = 0.005), and (D) urine output (P = 0.002) at enrollment with predicted probability of dialysis therapy requirement or in-hospital death. For each spline, P for linearity test is greater than 0.10, suggesting no deviation from linearity. Vertical lines show the spike-histogram of the variable shown on the x-axis. Conversion factors for units: serum cystatin C in mg/L to nmol/L, ×74.9; serum creatinine in mg/dL to μmol/L, ×88.4; serum urea nitrogen in mg/dL to mmol/L, ×0.357.