title: The obesity paradox in stable chronic heart failure does not persist after matching for indicators of disease severity and confounders.
abstract: OBJECTIVE
  To verify whether controlling for indicators of disease severity and confounders represents a solution to the obesity paradox in chronic heart failure (CHF).
  
  
  RESULTS
  From a cohort of 1790 patients, we formed 230 nested matched triplets by individually matching patients with body mass index (BMI) > 30 kg/m(2) (Group 3), BMI 20-24.9 k/m(2) (Group 1) and BMI 25-29.9 kg/m(2) (Group 2), according to NT-proBNP, age, sex, and NYHA class (triplet = one matched patient from each group). Although in the pre-matching cohort, BMI group was a significant univariable prognostic indicator, it did not retain significance [heart rate (HR): 0.91, 95% CI: 0.78-1.05, chi(2): 1.67] when controlled for group propensities as covariates. Furthermore, in the matched cohort, 1-year mortality and 3-year mortality did not differ significantly. Here, BMI again failed to reach statistical significance for prognosis, either as a continuous or categorical variable, whether crude or adjusted. This result was confirmed in the patients not selected for matching. NT-proBNP, however, remained statistically significant (log(NT-proBNP): HR: 1.49, 95% CI: 1.13-1.97, chi(2): 7.82) after multivariable adjustment.
  
  
  CONCLUSIONS
  The obesity paradox does not appear to persist in a matched setting with respect to indicators of disease severity and other confounders. NT-proBNP remains an independent prognostic indicator of adverse outcome irrespective of obesity status.
authors.affiliation: Department of Cardiology, Angiology, Pulmonology, University of Heidelberg, Heidelberg, Germany. lutz.frankenstein@med.uni-heidelberg.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Frankenstein
authors.forename: Christian
authors.initials: C
authors.lastname: Zugck
authors.forename: Manfred
authors.initials: M
authors.lastname: Nelles
authors.forename: Dieter
authors.initials: D
authors.lastname: Schellberg
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Katus
authors.forename: B Andrew
authors.initials: BA
authors.lastname: Remppis
mesh_terms: D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D009765:Obesity / Q000150:complications*; D010446:Peptide Fragments / Q000097:blood; D011379:Prognosis; D012044:Regression Analysis
chemical_list: D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain