Persistent serum creatinine increase following contrast-induced acute kidney injury

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) may led to both a transient and a persistent serum creatinine (sCr) increase. OBJECTIVES: To assess whether serum cystatin C (sCyC) and urine and serum neutrophil gelatinase-associated lipocalin (uNGAL, sNGAL) are useful in the early identification of persistent sCr increase following CI-AKI. METHODS: One hundred and eighteen patients who developed CI-AKI were included into the study. Persistent sCr elevation was defined as a persistent increase >=0.3 mg dL-1 at 1 month after contrast media (CM) administration. RESULTS: sCr levels recovered in 87 patients (74%; Transient group), whereas a persistent elevation of sCr was observed in the remaining 31 patients (26%; Persistent group). By multivariable logistic regression analysis, independent predictors of persistent sCr increase were insulin therapy, uNGAL at 48 hr and absolute sCr difference between 48 and 72 hr. On the contrary, sCyC assessment did not help in the early identification of this subset of patients. By receiver operating curve analysis, the best cutoff values for predicting persistent sCr increase were uNGAL >=0.50 ng dL-1 at 48 hr, and the absolute sCr increase >=0.20 mg dL-1 between 48 and 72 hr. CONCLUSIONS: uNGAL >=0.50 ng dL-1 at 48 hr and absolute sCr increase >=0.20 mg dL-1 between 48 and 72 hr but not sCyC are useful in the early identification of patients developing persistent sCr increase after CM administration.