title: Sodium bicarbonate for the prevention of contrast induced-acute kidney injury: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Infusion of sodium bicarbonate has been suggested as a preventative strategy but reports are conflicting on its efficacy. The aim of this study was to assess the effectiveness of hydration with sodium bicarbonate for the prevention of contrast-induced acute kidney injury (CI-AKI).
  
  
  METHODS
  Medline, EMBASE, Cochrane library, and the Internet were searched for randomized controlled trials comparing hydration between sodium bicarbonate and chloride for the prevention of CI-AKI between 1966 and November 2008. Fourteen trials that included 2290 patients were identified. There was significant heterogeneity between studies (P heterogeneity = 0.02; I(2) = 47.8%), which was largely accounted for by trial size (P = 0.016). Trials were therefore classified by size.
  
  
  RESULTS
  Three trials were categorized as large (n = 1145) and 12 as small (n = 1145). Among the large trials, the incidence of CI-AKI for sodium bicarbonate and sodium chloride was 10.7 and 12.5%, respectively; the relative risk (RR) [95% confidence interval (CI)] was 0.85 (0.63 to 1.16) without evidence of heterogeneity (P = 0.89, I(2) = 0%). The pooled RR (95% CI) among the 12 small trials was 0.50 (0.27 to 0.93) with significant between-trial heterogeneity (P = 0.01; I(2) = 56%). The small trials were more likely to be of lower methodological quality.
  
  
  CONCLUSIONS
  A significant clinical and statistical heterogeneity was observed that was largely explained by trial size and published status. Among the large randomized trials there was no evidence of benefit for hydration with sodium bicarbonate compared with sodium chloride for the prevention of CI-AKI. The benefit of sodium bicarbonate was limited to small trials of lower methodological quality.
authors.affiliation: Center for Interventional Vascular Therapy, Columbia University Medical Center, New York, NY 10032, USA. SBrar@cvri.org
authors.forename: Somjot S
authors.initials: SS
authors.lastname: Brar
authors.forename: Swapnil
authors.initials: S
authors.lastname: Hiremath
authors.forename: George
authors.initials: G
authors.lastname: Dangas
authors.forename: Roxana
authors.initials: R
authors.lastname: Mehran
authors.forename: Simerjeet K
authors.initials: SK
authors.lastname: Brar
authors.forename: Martin B
authors.initials: MB
authors.lastname: Leon
mesh_terms: D000208:Acute Disease; D003287:Contrast Media / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D006801:Humans; D007668:Kidney / Q000187:drug effects*; D017594:Publication Bias; D016032:Randomized Controlled Trials as Topic; D017582:Renal Replacement Therapy; D012306:Risk; D017693:Sodium Bicarbonate / Q000627:therapeutic use*
chemical_list: D003287:Contrast Media; D017693:Sodium Bicarbonate; D003404:Creatinine