TABLE 2.

Definitions of WRF and AKI

	Definition of WRF
GFR based definitions	Cystatin‐C based definitions	Creatinine based definitions
≥25% decrease >5 ml/min/1.73mq per year decrease	>0.3 mg/dl increase	>0.3 mg/dl increase and >25% increase >0.5 mg/dl increase 1.5x baseline >25% increase + above 2.0 mg/dl

	Definition of AKI (KDIGO)
Stages	UO component	SCr component
Stage 1	<0.5 ml/kg/h for 6–12 h	SCr 1.5–1.9x baseline over 7 days or absolute increase ≥0.3 mg/dl over 48 h
Stage 2	<0.5 ml/kg/h for ≥12 h	SCr 2.0–2.9x baseline
Stage 3	<0.3 ml/kg/h for ≥24 h or anuria for ≥12 h	SCr 3.0x baseline or increase above ≥4.0 mg/dl or RRT

Note: To calculate serum creatinine in mg/dl to μmol/L multiply with 88.4. For AKI criteria, if urine output and serum creatinine stage do not correspond to the same stage, patients are classified in the worse stage. AKI criteria have a stage 1, stage 2, and stage 3.

Abbreviations: AKI, acute kidney injury; GFR, glomerular filtration rate; KDIGO, kidney disease: improving global outcomes; RRT, renal replacement therapy; SCr, serum creatinine; UO, urine output; WRF, worsening of renal function.