Table 3.

Planned subgroup analyses and justification

Subgroup of primary interest	Justification
Surgical patients (defined by admission to a surgical team)	Risk of underdocumentation (reference)
Subjects with baseline creatinine<1.0 mg/L	AKI occurs when creatinine in ‘normal range’
Subjects with baseline creatinine<0.5 mg/L	AKI occurs when creatinine in ‘normal range’
Females	Lower rate of creatinine increase after AKI (reference)
African Americans	Higher rate of creatinine increase after AKI (reference)
Elderly (age>65, age>70 and age>75)	Lower rate of creatinine increase after AKI (reference)
Subjects in an intensive care unit at the time of the alert	AKI may be overlooked in the setting of multiple clinical problems
Subjects who enter the study based on a 50% increase in creatinine vs. a 0.3 mg/L increase in creatinine vs both	Clinicians may be less likely to recognise a 0.3 mg/L change vs a 50% change