Table 1 KDIGO-based acute kidney injury criteria for this study (as described in [20])

Index AKI episode (lasting up to 90 days in duration)

Serum creatinine ≥1.5 times higher than the median of all creatinine values 8-90 days ago; or 91–365 days ago if no tests between 8 and 90 days;

or serum creatinine ≥1.5 times higher than the lowest creatinine within 7 days;

or serum creatinine >26 μmol/L higher than the lowest creatinine within 48 h

Prior AKI episode

Any episode occurring 91-1095 days prior to index episode