A Comparison of the Systems for the Identification of Postoperative Acute Kidney Injury in Pediatric Cardiac Patients

Background

The pediatric-modified Risk, Injury, Failure and Loss, and End-Stage (pRIFLE) criteria and a different but conceptually similar system termed Acute Kidney Injury Network (AKIN) were created to standardize the definition of acute kidney injury (AKI) in children. Kidney Disease: Improving Global Outcomes (KDIGO) currently recommends a combination of AKIN and pRIFLE in AKI. This study aimed to compare the three classifications for predicting AKI in pediatric patients undergoing cardiac operations.

Methods

We analyzed the prospectively collected data of 1,489 consecutive pediatric patients undergoing cardiac operations between January 2004 and December 2008. AKI presence and severity was assessed for each classification using the change in serum creatinine and estimated creatinine clearance levels calculated by the Schwartz equation.

Results

AKI was present in 285 (20%), 481 (34%), and 409 (29%) patients according to the AKIN, pRIFLE, and KDIGO systems, respectively. The KDIGO classification categorized 121 patients (8%) who were placed in the AKIN 0 category, whereas the pRIFLE system categorized 74 (5%) in KDIGO 0 and 200 (14%) in AKIN 0 stages as having an AKI. The overall mortality rate was 3.9%. The KDIGO stage III (odds ratio [OR], 18.8; 95% confidence interval [CI], 9.6 to 36.6, p < 0.001), the AKIN stage III (OR, 38.3; 95% CI, 20.6 to 70.9, p < 0.001), and pRIFLE failure group (OR, 13.6, 95% CI, 7 to 26.3; p < 0.001) were associated with increased mortality.

Conclusions

The pRIFLE system was the most sensitive test in detecting AKI, and this was especially so in the infant age group and also in the early identification of AKI in low-risk patients. The AKIN system was more specific and detected mostly high-risk patients across all age groups. The KDIGO classification system fell between pRIFLE and AKIN in performance. All three had increasing severity of AKI associated with mortality.