European Journal of Heart Failure Advance Access originally published online on November 3, 2009
European Journal of Heart Failure 2009 11(12):1189-1194; doi:10.1093/eurjhf/hfp150
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The obesity paradox in stable chronic heart failure does not persist after matching for indicators of disease severity and confounders
1 Department of Cardiology, Angiology, Pulmonology, University of Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
2 Department of Psychosomatic and General Internal Medicine, University of Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
* Corresponding author. Tel: +49 6221 56 3 8895, Fax: +49 6221 56 6547, Email: lutz.frankenstein{at}med.uni-heidelberg.de
| Abstract |
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Aims: To verify whether controlling for indicators of disease severity and confounders represents a solution to the obesity paradox in chronic heart failure (CHF).
Methods and results: From a cohort of 1790 patients, we formed 230 nested matched triplets by individually matching patients with body mass index (BMI) > 30 kg/m2 (Group 3), BMI 20–24.9 k/m2 (Group 1) and BMI 25–29.9 kg/m2 (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,
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,
2: 7.82) after multivariable adjustment.
Conclusion: 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.
Key Words: Obesity Heart failure Natriuretic peptides Survival Obesity paradox
Received May 27, 2009; Revised September 16, 2009; Accepted October 2, 2009