Table 3.

Validation of AKI billing codes compared with AKI based on Kidney Disease Improving Global Outcomes (KDIGO) creatinine criteria and KDIGO combined creatinine and urine output criteria

AKI DefinitionAKIcraAKIcrbAKIcr_uopb
Data sourceChart reviewElectronic medical recordElectronic medical record
Sample size (n)54619701839
Billing code AKI
 Events (n)233361609
 Sensitivity (%)17.4 (11.6 to 23.1)17.2 (13.2 to 21.2)11.7 (8.8 to 14.5)
 Specificity (%)99.6 (99.3 to 99.9)98.5 (97.9 to 99.1)98.9 (98.2 to 99.5)
 PPV (%)92.0 (85.9 to 98.2)72.1 (62.4 to 81.8)83.5 (75.4 to 91.7)
 NPV (%)81.8 (76.5 to 87.2)84.1 (82.2 to 86.1)69.3 (66.9 to 71.7)
  • Ranges in parentheses are 95% confidence intervals. AKIcr, AKI by the creatinine-based criteria; AKIcr_uop, AKI by the creatinine- or urine output–based criteria; PPV, positive predictive value; NPV, negative predictive value.

  • a Validation measures are weighted for probability sampling.

  • b Washington County site only, 2002–2008.