title: Reverse epidemiology in different stages of heart failure.
abstract: BACKGROUND
  In heart failure (HF), traditional cardiovascular risk factors (RF) as body mass index (BMI), total cholesterol (TC) and systolic blood pressure (SBP) are associated with better survival. It is unknown at which time point along the disease continuum the adverse impact of these RF ceases and may 'start to reverse'. We analyzed the distribution of RF and their association with survival across HF stages.
  
  
  METHODS
  We pooled data from four cohort studies from the German Competence Network HF. Employing ACC/AHA-criteria, patients were allocated to stage A (n=218), B (n=1324), C1 (i.e., New York Heart Association [NYHA] classes I & II; n=1134), and C2+D (NYHA III & IV; n=639).
  
  
  RESULTS
  With increasing HF severity median age increased (63/67/67/70 years), whereas the proportion of females (56/52/37/35%), median BMI (26.1/28.8/27.7/26.6 kg/m(2)), TC (212/204/191/172 mg/dl), and SBP (140/148/130/120 mmHg) decreased (P<0.001 for trend for all). In the total cohort, higher levels of all RF were associated with better survival, even after extensive adjustment for multiple confounders. If analyses were stratified, however, a higher RF burden predicted better survival only in clinically symptomatic patients: hazard ratio (HR) per +2 kg/m(2) BMI 0.91 (95% confidence interval 0.88; 0.95); per +10 mg/dl TC 0.93 (0.92; 0.95); per +5 mmHg SBP 0.94 (0.92; 0.95).
  
  
  CONCLUSIONS
  In this well-characterized sample of patients representing the entire HF continuum, reverse associations were only consistently observed in symptomatic HF stages. Our data indicate that the phenomenon of a "reverse epidemiology" in HF is subject to significant selection bias in less advanced disease.
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Güder
authors.affiliation: Institute of Clinical Epidemiology and Biometry, University of Würzburg, Würzburg, Germany; Clinical Trial Center Würzburg, University Hospital Würzburg, Würzburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Gelbrich
authors.affiliation: Department of Cardiology, University Hospital of Göttingen, Göttingen, Germany; Department of Internal Medicine - Cardiology, Charité University Hospital Berlin, Campus Virchow Klinikum, Berlin Germany.
authors.forename: F
authors.initials: F
authors.lastname: Edelmann
authors.affiliation: Department of Cardiology, University Hospital of Göttingen, Göttingen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Wachter
authors.affiliation: Department of Internal Medicine - Cardiology, Charité University Hospital Berlin, Campus Virchow Klinikum, Berlin Germany; Deutsches Herzzentrum, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Pieske
authors.affiliation: Department of Cardiology, University Hospital Marburg, Marburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Pankuweit
authors.affiliation: Department of Cardiology, University Hospital Marburg, Marburg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Maisch
authors.affiliation: Clinical Trial Centre Leipzig - KKS, University of Leipzig, Leipzig, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Prettin
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Brenner
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Morbach
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany; Department of Cardiology, Hannover Medical School, Hannover, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Berliner
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany; Department of Cardiology, Kerckhoff Klinik Bad Nauheim, Bad Nauheim, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Deubner
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Ertl
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany.
authors.forename: C E
authors.initials: CE
authors.lastname: Angermann
authors.affiliation: Department of Medicine I - Cardiology, University of Würzburg, Comprehensive Heart Failure Center & University Hospital Würzburg, Würzburg, Germany. Electronic address: stoerk_s@ukw.de.
authors.forename: S
authors.initials: S
authors.lastname: Störk
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
keywords: AHA/ACC stages of heart failure; Prognosis; Reverse epidemiology