A risk scoring model to predict renal progression associated with postcontrast acute kidney injury in chronic kidney disease patients

Postcontrast acute kidney injury (AKI) occurs more frequently in patients with lower estimated glomerular filtration rate. We hypothesized that postcontrast AKI in chronic kidney disease (CKD) patients with distinct risk factors might be associated with accelerated renal progression. We undertook this retrospective cohort study to develop and validate a risk scoring model for predicting renal progression. In a development dataset, 18,278 contrast-enhanced CT scans were performed in 9097 patients with CKD (estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m(2)) who were not undergoing dialysis. Postcontrast AKI was observed in 5.8% (1051/18,278) of all contrast-enhanced CTs with 7.6% (689/9097) of the total CKD patients. We investigated the 1-year renal outcome in 224 eligible patients. A risk scoring model was developed with multivariate regression analysis and was assessed in external validation (independent 154 patients). Among 224 patients, 70 (31.3%) patients had progression of renal dysfunction at 1 year (defined as reduction in estimated GFR ≥25% at 1 year). A risk score of 4, 4, 6, 6, 7, or 6 was assigned to diabetes, baseline estimated GFR < 45 mL/min/1.73 m(2), hypertension, repeated contrast exposure, congestive heart failure, and persistent renal injury (defined as an elevation of serum creatinine ≥25% at 3 months), respectively. An increasing risk score was associated with renal progression. Of note, persistent renal injury was more prevalent in the progression group than in the non-progression group. The AUROC of the model in the development population was 0.765. In the validation dataset, however, the discriminative power decreased (AUROC = 0.653). Our suggested model provided the risk of renal progression, aiding in predicting prognosis, counseling, and improving outcomes in CKD patients complicated by postcontrast AKI.