title: Renal impairment and outcomes in heart failure: systematic review and meta-analysis.
abstract: OBJECTIVE
  We estimated the prevalence of renal impairment in heart failure (HF) patients and the magnitude of associated mortality risk using a systematic review of published studies.
  
  
  BACKGROUND
  Renal impairment in HF patients is associated with excess mortality, although precise risk estimates are unclear.
  
  
  METHODS
  A systematic search of MEDLINE (through May 2005) identified 16 studies characterizing the association between renal impairment and mortality in 80,098 hospitalized and non-hospitalized HF patients. All-cause mortality risks associated with any renal impairment (creatinine >1.0 mg/dl, creatinine clearance [CrCl] or estimated glomerular filtration rate [eGFR] <90 ml/min, or cystatin-C >1.03 mg/dl) and moderate to severe impairment (creatinine > or =1.5, CrCl or eGFR <53, or cystatin-C > or =1.56) were estimated using fixed-effects meta-analysis.
  
  
  RESULTS
  A total of 63% of patients had any renal impairment, and 29% had moderate to severe impairment. After follow-up > or =1 year, 38% of patients with any renal impairment and 51% with moderate to severe impairment died versus 24% without impairment. Adjusted all-cause mortality was increased for patients with any impairment (hazard ratio [HR] = 1.56; 95% confidence interval [CI] 1.53 to 1.60, p < 0.001) and moderate to severe impairment (HR = 2.31; 95% CI 2.18 to 2.44, p < 0.001). Mortality worsened incrementally across the range of renal function, with 15% (95% CI 14% to 17%) increased risk for every 0.5 mg/dl increase in creatinine and 7% (95% CI 4% to 10%) increased risk for every 10 ml/min decrease in eGFR.
  
  
  CONCLUSIONS
  Renal impairment is common among HF patients and confers excess mortality. Renal function should be considered in risk stratification and evaluation of therapeutic strategies for HF patients.
authors.affiliation: Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Grace L
authors.initials: GL
authors.lastname: Smith
authors.forename: Judith H
authors.initials: JH
authors.lastname: Lichtman
authors.forename: Michael B
authors.initials: MB
authors.lastname: Bracken
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlipak
authors.forename: Christopher O
authors.initials: CO
authors.lastname: Phillips
authors.forename: Paul
authors.initials: P
authors.lastname: DiCapua
authors.forename: Harlan M
authors.initials: HM
authors.lastname: Krumholz
mesh_terms: D003404:Creatinine / Q000097:blood; D015891:Cystatins / Q000097:blood; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000097:blood / Q000401:mortality*; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors
chemical_list: D015891:Cystatins; D003404:Creatinine