Xu J, Xu X, Shen B, et al. - In order to assess long-term results of cardiac surgery associated acute kidney injury (CSA-AKI), researchers compared five different definitions of renal recovery. Between April 2009 and April 2013, individuals who had cardiac surgery were enlisted and divided into acute kidney injury (AKI) and non-AKI groups. Five criteria for complete renal recovery were compared: Acute Renal Failure Trial Network (ATN): serum creatinine (SCr) at discharge returned to within baseline SCr + 0.5 mg/dL; Acute Dialysis Quality Initiative (ADQI): returned to within 50% above baseline SCr; Pannu: returned to within 25% above baseline SCr; Kidney Disease: Improving Global Outcomes (KDIGO): eGFR at discharge ≥ 60 mL/min/1.73 m²; Bucaloiu: returned to ≥ 90% baseline estimated glomerular filtration rate (eGFR). Data reported that the complete recovery rate for ATN, ADQI, Pannu, KDIGO and Bucaloiu were 84.60%, 82.49%, 60.49%, 68.60% and 46.32%. ADQI or ATN-equivalent criteria may overestimate the extent of renal recovery, on the other hand, equivalent criteria for KDIGO, Pannu and Bucaloiu may be more suitable for clinical use. The study results showed that SCr at baseline discharge > 30% or > 0.4 mg/dL, or eGFR < 70% of baseline resulted in significant 3-year major adverse event incidence differences, which could serve as an indication for new definitions of renal recovery.