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 |