Prevention of contrast-induced acute kidney injury: is simple oral hydration similar to intravenous? A systematic review of the evidence

PLoS One. 2013;8(3):e60009. doi: 10.1371/journal.pone.0060009. Epub 2013 Mar 26.


Background: Pre-procedural intravenous fluid administration is an effective prophylaxis measure for contrast-induced acute kidney injury. For logistical ease, the oral route is an alternative to the intravenous. The objective of this study was to compare the efficacy of the oral to the intravenous route in prevention of contrast-induced acute kidney injury.

Study design: A systematic review and meta-analysis of randomised trials with a stratified analysis and metaregression. Databases included MEDLINE (1950 to November 23 2011), EMBASE (1947 to week 47 2011), Cochrane CENTRAL (3(rd) quarter 2011). Two reviewers identified relevant trials and abstracted data. SETTINGS AND POPULATION: Trials including patients undergoing a contrast enhanced procedure.

Selection criteria: Randomised controlled trial; adult (>18 years) population; comparison of oral versus intravenous volume expansion.

Intervention: Oral route of volume expansion compared to the intravenous route.

Outcomes: Any measure of acute kidney injury, need for renal replacement therapy, hospitalization and death.

Results: Six trials including 513 patients met inclusion criteria. The summary odds ratio was 1.19 (95% CI 0.46, 3.10, p = 0.73) suggesting no difference between the two routes of volume expansion. There was significant heterogeneity (Cochran's Q = 11.65, p = 0.04; I(2) = 57). In the stratified analysis, inclusion of the five studies with a prespecified oral volume expansion protocol resulted in a shift towards oral volume expansion (OR 0.75, 95% CI 0.37, 1.50, p = 0.42) and also resolved the heterogeneity (Q = 3.19, P = 0.53; I(2) = 0).

Limitations: Small number of studies identified; lack of hard clinical outcomes.

Conclusion: The oral route may be as effective as the intravenous route for volume expansion for contrast-induced acute kidney injury prevention. Adequately powered trials with hard endpoints should be done given the potential advantages of oral (e.g. reduced patient burden and cost) over intravenous volume expansion.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Acute Kidney Injury / chemically induced*
  • Acute Kidney Injury / prevention & control*
  • Administration, Intravenous
  • Administration, Oral
  • Contrast Media / administration & dosage*
  • Contrast Media / adverse effects*
  • Humans


  • Contrast Media

Grant support

This study was not directly funded by any source. However, SH and AA are supported by research salary awards from the Department of Medicine, The Ottawa Hospital and the University of Ottawa. GK is supported by a University of Ottawa Chair in Clinical Transplantation Research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.