title: Meta-analysis: effectiveness of drugs for preventing contrast-induced nephropathy.
abstract: BACKGROUND
  N-Acetylcysteine, theophylline, and other agents have shown inconsistent results in reducing contrast-induced nephropathy.
  
  
  OBJECTIVE
  To determine the effect of these agents on preventing nephropathy.
  
  
  METHODS
  Relevant randomized, controlled trials were identified by computerized searches in MEDLINE (from 1966 through 3 November 2006), EMBASE (1980 through November 2006), PubMed, Web of Knowledge (Current Contents Connect, Web of Science, BIOSIS Previews, and ISI Proceedings for the latest 5 years), and the Cochrane Library databases (up to November 2006). Databases were searched for studies in English, Spanish, French, Italian, and German.
  
  
  METHODS
  Randomized, controlled trials that administered N-acetylcysteine, theophylline, fenoldopam, dopamine, iloprost, statin, furosemide, or mannitol to a treatment group; used intravenous iodinated contrast; defined contrast-induced nephropathy explicitly; and reported sufficient data to construct a 2 x 2 table of the primary effect measure.
  
  
  METHODS
  Abstracted information included patient characteristics, type of contrast media and dose, periprocedural hydration, definition of contrast-induced nephropathy, and prophylactic agent dose and route.
  
  
  RESULTS
  In the 41 studies included, N-acetylcysteine (relative risk, 0.62 [95% CI, 0.44 to 0.88]) and theophylline (relative risk, 0.49 [CI, 0.23 to 1.06]) reduced the risk for contrast-induced nephropathy more than saline alone, whereas furosemide increased it (relative risk, 3.27 [CI, 1.48 to 7.26]). The remaining agents did not significantly affect risk. Significant subgroup heterogeneity was present only for N-acetylcysteine. No publication bias was discerned.
  
  
  CONCLUSIONS
  All trials evaluated the surrogate end point of contrast-induced nephropathy as the primary outcome. The lack of a statistically significant renoprotective effect of theophylline may result from insufficient data or study heterogeneity. True study quality remains uncertain.
  
  
  CONCLUSIONS
  N-acetylcysteine is more renoprotective than hydration alone. Theophylline may also reduce risk for contrast-induced nephropathy, although the detected association was not significant. Our data support the administration of N-acetylcysteine prophylaxis, particularly in high-risk patients, given its low cost, availability, and few side effects.
authors.affiliation: Department of Radiology, Division of Cardiothoracic Imaging, University of Michigan and Veteran Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan 48109, USA
authors.forename: Aine M
authors.initials: AM
authors.lastname: Kelly
authors.forename: Ben
authors.initials: B
authors.lastname: Dwamena
authors.forename: Paul
authors.initials: P
authors.lastname: Cronin
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Bernstein
authors.forename: Ruth C
authors.initials: RC
authors.lastname: Carlos
mesh_terms: D000111:Acetylcysteine / Q000627:therapeutic use; D058186:Acute Kidney Injury / Q000139:chemically induced* / Q000517:prevention & control*; D001205:Ascorbic Acid / Q000627:therapeutic use; D001639:Bicarbonates / Q000627:therapeutic use; D002986:Clinical Trials as Topic / Q000592:standards; D003287:Contrast Media / Q000009:adverse effects*; D005665:Furosemide / Q000009:adverse effects; D020011:Protective Agents / Q000627:therapeutic use*; D012107:Research Design / Q000592:standards; D013806:Theophylline / Q000627:therapeutic use
chemical_list: D001639:Bicarbonates; D003287:Contrast Media; D020011:Protective Agents; D005665:Furosemide; D013806:Theophylline; D001205:Ascorbic Acid; D000111:Acetylcysteine