Evaluation of five different renal recovery definitions for estimation of long-term outcomes of cardiac surgery associated acute kidney injury

BMC Nephrol. 2019 Nov 21;20(1):427. doi: 10.1186/s12882-019-1613-6.


Background: The commonly used recommended criteria for renal recovery are not unequivocal. This study compared five different definitions of renal recovery in order to evaluate long-term outcomes of cardiac surgery associated acute kidney injury (CSA-AKI).

Methods: Patients who underwent cardiac surgery between April 2009 and April 2013 were enrolled and divided into acute kidney injury (AKI) and non-AKI groups. The primary endpoint was 3-year major adverse events (MAEs) including death, new dialysis and progressive chronic kidney disease (CKD). We compared five criteria for complete renal recovery: 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). Multivariate regression analysis was used to compare risk factors for 3-year MAEs.

Results: The rate of complete recovery for ATN, ADQI, Pannu, KDIGO and Bucaloiu were 84.60% (n = 1242), 82.49% (n = 1211), 60.49% (n = 888), 68.60% (n = 1007) and 46.32% (n = 680). After adjusting for confounding factors, AKI with complete renal recovery was a risk factor for 3-year MAEs (OR: 1.69, 95% CI: 1.20-2.38, P < 0.05; OR: 1.45, 95% CI: 1.03-2.04, P < 0.05) according to ATN and ADQI criteria, but not for KDIGO, Pannu and Bucaloiu criteria. We found that relative to patients who recovered to within 0% baseline SCr or recovered to ≥100% baseline eGFR, the threshold values at which significant differences in 3-year MAEs were observed were > 30% or > 0.4 mg/dL above baseline SCr or < 70% of baseline eGFR.

Conclusions: ADQI or ATN-equivalent criteria may overestimate the extent of renal recovery, while KDIGO, Pannu and Bucaloiu equivalent criteria may be more appropriate for clinical use. Our analyses revealed that SCr at discharge > 30% or > 0.4 mg/dL of baseline, or eGFR < 70% of baseline led to significant 3-year MAE incidence differences, which may serve as hints for new definitions of renal recovery.

Keywords: Acute kidney injury; Cardiac surgery; Long-term outcome; Renal recovery.

Publication types

  • Comparative Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury* / blood
  • Acute Kidney Injury* / complications
  • Acute Kidney Injury* / mortality
  • Acute Kidney Injury* / physiopathology
  • Biomarkers / blood
  • Cardiac Surgical Procedures* / classification
  • Creatinine / blood*
  • Disease Progression
  • Female
  • Glomerular Filtration Rate* / physiology
  • Hospital Mortality
  • Humans
  • Kidney
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Recovery of Function*
  • Regression Analysis
  • Renal Insufficiency, Chronic / blood
  • Renal Insufficiency, Chronic / etiology*
  • Retrospective Studies
  • Risk Factors
  • Survival Rate
  • Treatment Outcome


  • Biomarkers
  • Creatinine