Table 4.

AKI events identified by billing codes, serum creatinine, and combined creatinine and urine output criteria: stage (by creatinine criteria) and presence of oliguria

Variable	Billing Code AKI	AKIcr	AKIcr_uop
Stage (by creatinine criteria) (%)
No AKI	27.9	–a	43.0
Stage 1 AKI	20.9	62.3	35.3
Stage 2 AKI	16.3	18.0	10.2
Stage 3 AKI	34.9	19.7	11.5
Urine output <20 ml/hr×24 hr (%)
Oliguria	47.2	31.7	61.1

Electronic medical record sample; staging is based solely on serum creatinine criteria. AKI_cr, AKI by the creatinine-based criteria; AKI_{cr_uop}, AKI by creatinine- or urine output–based criteria.

^a0% by definition.