title: Clinical exacerbations as a surrogate end point in heart failure research.
abstract: BACKGROUND
  We examined the utility of an index of clinical exacerbations of heart failure (HF) as a surrogate measure of outcome for use in modestly sized clinical trials and observational studies.
  
  
  METHODS
  Electronic records of 189 outpatients with HF in a US Veterans Affairs Medical Center were examined over a 2- to 3-year period. Data collected included patient characteristics, clinical exacerbations of HF, hospitalizations, and deaths. Subsets of patient were also assessed for HF-related level of functioning.
  
  
  RESULTS
  Episodes of clinical exacerbation could be detected reliably (kappa = .83). An index of episodes (number of episodes divided by the time in years) was associated with lower quality of life, higher functional class, increased rate of HF hospitalization, poorer exercise tolerance, and up to 30% increased risk of mortality across 2 years.
  
  
  CONCLUSIONS
  The index of HF exacerbations is potentially a useful surrogate end point for use in clinical HF research.
authors.affiliation: Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Sayers
authors.forename: Barbara
authors.initials: B
authors.lastname: Riegel
authors.forename: Lee R
authors.initials: LR
authors.lastname: Goldberg
authors.forename: James C
authors.initials: JC
authors.lastname: Coyne
authors.forename: Frederick F
authors.initials: FF
authors.lastname: Samaha
mesh_terms: D015415:Biomarkers; D035843:Biomedical Research; D017079:Exercise Tolerance; D005260:Female; D006306:Health Surveys; D006333:Heart Failure / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D006760:Hospitalization; D006787:Hospitals, Veterans; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012720:Severity of Illness Index; D018434:Sickness Impact Profile; D013318:Stroke Volume; D011795:Surveys and Questionnaires; D014481:United States
chemical_list: D015415:Biomarkers