Table 5.

Improvement in AUC and NRI as a result of adding first postoperative ACR to different clinical and biomarker predictive models

ModelAged 1 mo–<2 yr at SurgeryAged ≥2 yr at Surgery
Stage 1 or Higher AKIaStage 2 or 3 AKIaStage 1 or Higher AKIa
AUC (SEM)NRI (SEM)AUC (SEM)NRI (SEM)AUC (SEM)NRI (SEM)
P Value by Adding ACRbP ValueP Value by Adding ACRP ValueP Value by Adding ACRP Value
Clinical model alonec0.71 (0.04)0.75 (0.04)0.79 (0.04)
ACR alone0.57 (0.05)0.63 (0.05)0.63 (0.05)
Clinical model + ACR0.72 (0.04) 0.310.26 (0.17) 0.120.79 (0.04) 0.130.34 (0.20) 0.080.82 (0.04) 0.170.30 (0.18) 0.10
Clinical model + CysC0.77 (0.04)0.81 (0.04)0.84 (0.03)
Clinical model + CysC + ACR0.78 (0.04) 0.670.24 (0.17) 0.160.83 (0.04) 0.500.33 (0.20) 0.090.87 (0.03) 0.140.48 (0.19) 0.01
Clinical model + biomarkers0.72 (0.04)0.78 (0.04)0.81 (0.04)
Clinical model + biomarkers + ACR0.73 (0.04) 0.420.18 (0.17) 0.270.80 (0.04) 0.260.10 (0.20) 0.610.84 (0.04) 0.360.22 (0.18) 0.22
Clinical model + biomarkers/creatinined0.72 (0.04)0.78 (0.04)0.83 (0.04)
Clinical model + biomarkers/creatinine + ACRd0.73 (0.04) 0.360.27 (0.17) 0.110.80 (0.04) 0.420.41 (0.20) 0.040.84 (0.04) 0.450.20 (0.18) 0.27
Clinical model + CysC + biomarkers0.79 (0.04)0.82 (0.04)0.86 (0.03)
Clinical model + CysC + biomarkers + ACR0.80 (0.04) 0.460.22 (0.17) 0.210.84 (0.04) 0.410.22 (0.20) 0.280.88 (0.03) 0.460.39 (0.19) 0.03
Clinical model + CysC + biomarkers/creatinined0.77 (0.04)0.82 (0.04)0.87 (0.03)
Clinical model + CysC + biomarkers/creatinine + ACRd0.79 (0.04) 0.270.26 (0.17) 0.130.84 (0.04) 0.340.22 (0.20) 0.280.88 (0.03) 0.640.28 (0.19) 0.13
  • AUC, area under the curve; NRI, net reclassification improvement; ACR, albumin/creatinine ratio; CysC, serum cystatin C; urine biomarkers, urinary neutrophil gelatinase-associated lipocalin and urine IL-18; RACHS-1, risk adjustment for congenital heart surgery-1; eGFR, estimated GFR.

  • a The outcomes were stage 1 AKI and stage 2 AKI in the group aged ≤2 years, and stage 1 AKI in the group aged >2 years (too few events for analysis of stage 2 AKI as the outcome). “Stage 1 or higher AKI” includes participants with AKI stages 2 or 3.

  • b P values are only included in cells with ACR added to the previous model. For example, AUC or NRI for the clinical model + CysC does not include a P value; the model with clinical model + CysC + ACR includes a P value, which denotes whether addition of ACR led to a significant increase in AUC and NRI, relative to the previous model.

  • c The clinical predictive model includes age (continuous in the group aged ≤2 years; categorized as 2–<6 versus ≥6 years in the group aged >2 years), sex, white (versus nonwhite), elective versus urgent surgery, RACHS-1 score ≥3 versus <3, preoperative eGFR percentile, study site, and cardiopulmonary bypass time (< versus ≥120 minutes).

  • d These prediction models utilize urine biomarkers normalized to urine creatinine concentrations. The other models including urine biomarkers utilize nonurine creatinine normalized values (i.e., concentration values).