ORIGINAL ARTICLE
Association Between Direct Measures of Body Composition and Prognostic Factors in Chronic Heart Failure

https://doi.org/10.4065/mcp.2010.0103Get rights and content

OBJECTIVE

To explore the covariate-adjusted associations between body composition (percent body fat and lean body mass) and prognostic factors for mortality in patients with chronic heart failure (CHF) (nutritional status, N-terminal pro-B-type natriuretic peptide [NT-proBNP], quality of life, exercise capacity, and C-reactive protein).

PATIENTS AND METHODS

Between June 2008 and July 2009, we directly measured body composition using dual energy x-ray absorptiometry in 140 patients with systolic and/or diastolic heart failure. We compared body composition and CHF prognostic factors across body fat reference ranges and body mass index (BMI) categories. Multiple linear regression models were created to examine the independent associations between body composition and CHF prognostic factors; we contrasted these with models that used BMI.

RESULTS

Use of BMI misclassified body fat status in 51 patients (41%). Body mass index was correlated with both lean body mass (r=0.72) and percent body fat (r=0.67). Lean body mass significantly increased with increasing BMI but not with percent body fat. Body mass index was significantly associated with lower NT-proBNP and lower exercise capacity. In contrast, higher percent body fat was associated with a higher serum prealbumin level, lower exercise capacity, and increased C-reactive protein level; lean body mass was inversely associated with NT-proBNP and positively associated with hand-grip strength.

CONCLUSION

When BMI is divided into fat and lean mass components, a higher lean body mass and/or lower fat mass is independently associated with factors that are prognostically advantageous in CHF. Body mass index may not be a good indicator of adiposity and may in fact be a better surrogate for lean body mass in this population.

Section snippets

PATIENTS AND METHODS

Between June 2008 and July 2009, 140 consecutive patients with CHF (systolic and/or diastolic) were recruited from the University of Alberta Heart Function Clinic, Edmonton, Alberta, Canada, a tertiary care clinic staffed by a multidisciplinary team of physicians, specialized nurses, pharmacists, dieticians, and social workers. Patients 18 years or older who were able to give informed consent, who had heart failure diagnosed on the basis of Framingham Heart Study criteria,9 and who were deemed

RESULTS

Of the 221 consecutive eligible patients approached, 140 consented to participate. Reasons for refusal included lack of time, poor noncardiac health, lack of transportation to attend appointments, and unwillingness to undergo x-ray exposure.

Mean age of the cohort was 63 years, 103 (74%) of the patients were male, and 126 (90%) were white. When categorizedaccording to directly measured body fat, 39, 39, and 62 patients were in the low-normal, overweight, and obese body fat groups, respectively (

DISCUSSION

In this cross-sectional study, we found that increasing BMI was significantly associated with lower NT-proBNP levels and lower exercise capacity. However, when directly measuring body composition, we found significant associations between increasing body fat and unfavorable changes in prognostic factors, such as higher inflammation and lower exercise capacity, whereas increasing lean mass was associated with favorable changes, such as better hand-grip strength and lower NT-proBNP levels. To our

CONCLUSION

In this study of patients with CHF in whom body composition was directly measured, using BMI as the measure of body fat lead to misclassification of 41% of patients with CHF. Directly measured body composition was also found to be more closely linked to indicators of prognosis in patients with CHF than BMI. Significant associations were found between increasing body fat and unfavorable changes in certain important CHF prognostic factors, whereas increasing lean body mass was associated with

Acknowledgments

We sincerely thank the study participants, the University of Alberta Heart Function Clinic staff for their support of this study, and Mark Little, Melissa Stafford, Aga Andrzejewska, and Kinga Walter for their assistance with the DEXA scans.

REFERENCES (33)

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This study was funded by the University of Alberta Hospital Foundation.

Dr Oreopoulos is supported by a Doctoral Research Award from the Heart and Stroke Foundation of Canada. Dr Johnson holds a Canada Research Chair, and Dr Ezekowitz and Dr Norris hold New Investigator Awards, all from the Canadian Institutes of Health Research. Dr Ezekowitz, Dr McAlister, Dr Norris, and Dr Johnson are supported by the Alberta Heritage Foundation for Medical Research. Dr McAlister is also supported by the Patient Health Management Chair at the University of Alberta. Dr Kalantar-Zadeh is supported by research grants from the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, an American Heart Association grant in aid, and a philanthropic grant from Mr Harold Simmons. Dr Fonarow is supported by the Ahmanson Foundation (Los Angeles, CA) and holds the Eliot Corday Chair in Cardiovascular Medicine and Science.

This study was presented at Cardiac Sciences Research Day; June 11, 2010; Edmonton, Alberta, Canada.

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