title: The efficacy of sodium bicarbonate in preventing contrast-induced nephropathy in patients with pre-existing renal insufficiency: a meta-analysis.
abstract: OBJECTIVE
  The aim of this meta-analysis was to explore the efficacy of sodium bicarbonate in preventing contrast-induced nephropathy (CIN).
  
  
  METHODS
  We searched PubMed, Medline and the Cochrane Library from 1 January 2004 to 1 August 2014. The effect estimate was expressed as a pooled OR with 95% CI, using the fixed-effects or random-effects model.
  
  
  RESULTS
  20 randomised controlled trials (n=4280) were identified. Hydration with sodium bicarbonate was associated with a significant decrease in CIN among patients with pre-existing renal insufficiency (OR 0.67, 95% CI 0.47 to 0.96; p=0.027). However, moderate heterogeneity was noted across trials (I(2)=48%; p=0.008). Subgroup analyses indicated a better effect of sodium bicarbonate in studies using low-osmolar (OR 0.59, 95% CI 0.37 to 0.93; p=0.024) compared with iso-osmolar contrast agents (OR 0.76, 95% CI 0.43 to 1.34; p=0.351). The odds of CIN with sodium bicarbonate were lower in studies including only patients undergoing emergency (OR 0.16, 95% CI 0.05 to 0.51; p=0.002) compared with elective procedures (OR 0.76, 95% CI 0.54 to 1.06; p=0.105). Sodium bicarbonate was more beneficial in patients given a bolus injection before procedures (OR 0.15, 95% CI 0.04 to 0.54; p=0.004) compared with continuous infusion (OR 0.75, 95% CI 0.53 to 1.05; p=0.091). Sodium bicarbonate plus N-acetylcysteine (OR 0.17, 95% CI 0.04 to 0.79; p=0.024) was better than sodium bicarbonate alone (OR 0.71, 95% CI 0.48 to 1.03; p=0.071). The effect of sodium bicarbonate was considered greater in papers published before (OR 0.19, 95% CI 0.09 to 0.41; p=0.000) compared with after 2008 (OR 0.85, 95% CI 0.62 to 1.16; p=0.302). However, no significant differences were found in mortality (OR 0.69, 95% CI 0.36 to 1.32; p=0.263) or requirement for dialysis (OR 1.08, 95% CI 0.52 to 2.25; p=0.841).
  
  
  CONCLUSIONS
  Sodium bicarbonate is effective in preventing CIN among patients with pre-existing renal insufficiency. However, it fails to lower the risks of dialysis and mortality and therefore cannot improve the clinical prognosis of patients with CIN.
authors.affiliation: Department of Radiology, Guangdong Academy of Medical Sciences/Guangdong General Hospital, Graduate College, Guangzhou, Guangdong Province, China Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Guangdong Academy of Medical Sciences/Guangdong General Hospital, Graduate College, Guangzhou, Guangdong Province, China Southern Medical University, Guangzhou, Guangdong Province, China.
authors.forename: Long
authors.initials: L
authors.lastname: Liang
authors.affiliation: Department of Radiology, Guangdong Academy of Medical Sciences/Guangdong General Hospital, Graduate College, Guangzhou, Guangdong Province, China.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Radiology, Guangdong Academy of Medical Sciences/Guangdong General Hospital, Graduate College, Guangzhou, Guangdong Province, China.
authors.forename: Changhong
authors.initials: C
authors.lastname: Liang
authors.affiliation: Department of Radiology, Guangdong Academy of Medical Sciences/Guangdong General Hospital, Graduate College, Guangzhou, Guangdong Province, China.
authors.forename: Shuixing
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000111:Acetylcysteine / Q000627:therapeutic use; D058186:Acute Kidney Injury / Q000139:chemically induced / Q000517:prevention & control* / Q000628:therapy; D003287:Contrast Media / Q000009:adverse effects* / Q000737:chemistry; D005440:Fluid Therapy; D016166:Free Radical Scavengers / Q000627:therapeutic use; D006801:Humans; D009994:Osmolar Concentration; D016032:Randomized Controlled Trials as Topic; D006435:Renal Dialysis; D051437:Renal Insufficiency / Q000150:complications*; D017693:Sodium Bicarbonate / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D003287:Contrast Media; D016166:Free Radical Scavengers; D017693:Sodium Bicarbonate; D000111:Acetylcysteine