Preoperative Short-Term Calorie Restriction for Prevention of Acute Kidney Injury After Cardiac Surgery: A Randomized, Controlled, Open-Label, Pilot Trial

J Am Heart Assoc. 2018 Mar 13;7(6):e008181. doi: 10.1161/JAHA.117.008181.


Background: Acute kidney injury is a frequent complication after cardiac surgery and is associated with adverse outcomes. Although short-term calorie restriction (CR) has proven protective in rodent models of acute kidney injury, similar effects have not yet been demonstrated in humans.

Methods and results: CR_KCH (Effect of a Preoperative Calorie Restriction on Renal Function After Cardiac Surgery) is a randomized controlled trial in patients scheduled for cardiac surgery. Patients were randomly assigned to receive either a formula diet containing 60% of the daily energy requirement (CR group) or ad libitum food (control group) for 7 days before surgery. In total, 82 patients were enrolled between April 16, 2012, and February 5, 2015. There was no between-group difference in the primary end point of median serum creatinine increment after 24 hours (control group: 0.0 mg/dL [-0.1 - (+0.2) mg/dL]; CR group: 0.0 mg/dL [-0.2 - (+0.2) mg/dL]; P=0.39). CR prevented a rise in median creatinine at 48 hours (control group: +0.1 mg/dL [0.0 - 0.3 mg/dL]; CR group: -0.1 mg/dL [-0.2 - (+0.1) mg/dL]; P=0.03), with most pronounced effects observed in male patients and patients with a body mass index >25. This benefit persisted until discharge: Median creatinine decreased by 0.1 mg/dL (-0.2 - 0.0 mg/dL) in the CR group, whereas it increased by 0.1 mg/dL (0.0 - 0.3 mg/dL; P=0.0006) in the control group. Incidence of acute kidney injury was reduced by 5.8% (41.7% in the CR group compared with 47.5% in the control group). Safety-related events did not differ between groups.

Conclusions: Despite disappointing results with respect to creatinine rise within the first 24 hours, the benefits observed at later time points and the subgroup analyses suggest the protective potential of short-term CR in patients at risk for acute kidney injury, warranting further investigation.

Clinical trial registration: URL: Unique identifier: NCT01534364.

Keywords: acute kidney injury; calorie restriction; cardiac surgery; dietary restriction; preconditioning.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury / diagnosis
  • Acute Kidney Injury / etiology
  • Acute Kidney Injury / prevention & control*
  • Aged
  • Biomarkers / blood
  • Caloric Restriction* / adverse effects
  • Cardiac Surgical Procedures / adverse effects*
  • Creatinine / blood
  • Female
  • Germany
  • Humans
  • Male
  • Middle Aged
  • Pilot Projects
  • Preoperative Care / adverse effects
  • Preoperative Care / methods*
  • Prospective Studies
  • Protective Factors
  • Risk Factors
  • Time Factors
  • Treatment Outcome


  • Biomarkers
  • Creatinine

Associated data