The relationship between body mass index/body composition and survival in patients with heart failure.

PURPOSE The purpose of this review was to summarize the literature on the relationship between obesity and survival in persons with heart failure (HF). In particular, the article examines the ways in which studies define body size/composition (body mass index [BMI], body composition, weight, cachexia, fluid retention, or albumin) and the relationship of BMI and survival after controlling for factors such as HF severity, etiology of the HF, gender, race, age, and/or time since HF diagnosis. DATA SOURCES The keywords heart failure and body mass index, heart failure and obesity, and heart failure and body composition were indexed in PubMed. Articles published from 1999 to 2006 that used multivariate analyses to examine the relationship between obesity and survival in persons with HF were included in the review. CONCLUSIONS BMI is the standard most often used for measuring body weight in patients with HF. Yet, BMI does not address other major components of body weight (fat, lean body mass, and fluid) that may factor into the mortality of patients with HF. Four of the six studies reviewed reported a positive relationship between obesity and improved survival. However, the studies are limited by design, with the majority being cross-sectional. Furthermore, most of the data were collected through secondary data analysis from patient records in the 1990s, before contemporary HF treatment was used. IMPLICATIONS FOR PRACTICE Until further research solidifies a clear association between higher BMIs and improved survival in patients with HF, nurse practitioners and others should continue to counsel their patients with HF who are overweight to lose weight. Assessing BMI alone as a predictor of survival for patients with HF may be misleading and should be performed in the context of other factors. Moreover, care should be taken in managing patients with HF who are cachexic because these patients have a worrisome prognosis.