Chest
Volume 132, Issue 1, July 2007, Pages 164-169
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ORIGINAL RESEARCH
COPD
Body Mass and Fat-Free Mass Indices in COPD: Relation With Variables Expressing Disease Severity

https://doi.org/10.1378/chest.06-2789Get rights and content

Background:

COPD primarily affects the lungs but also produces systemic consequences that are not reflected by the recent staging according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. Body mass index (BMI) and fat-free mass index (FFMI) represent different aspects of nutrition abnormalities in COPD. We investigated whether BMI and FFMI could be related to parameters expressing airflow obstruction and limitation, exercise capacity, airway inflammation, and quality of life, and whether they would reflect the GOLD staging of the disease.

Methods:

One hundred patients with clinically stable COPD equally classified into the five stages of the disease were evaluated for BMI, FFMI (measured by bioelectrical impedance analysis), airway obstruction and hyperinflation (FEV1, FEV1/FVC, inspiratory capacity), exercise capacity (6-min walk distance [6MWD], Borg scale before and after 6MWD]), chronic dyspnea using the Medical Research Council (MRC) scale, airway inflammation (sputum differential cell counts, leukotriene B4 in supernatant), and quality of life (emotional part of the chronic respiratory disease questionnaire).

Results:

6MWD was significantly associated with both BMI and FFMI values, while FFMI additionally presented significant correlations with MRC scale, percentage of predicted FEV1, and FEV1/FVC ratio. No association was observed between the two nutritional indexes. BMI was not statistically different among patients in the five stages of COPD, while FFMI reflected the staging of the disease, presenting the highest values in stage 0.

Conclusions:

Nutritional status is mainly related to exercise capacity. FFMI seems to be more accurate in expressing variables of disease severity, as well as the current staging compared to BMI.

Section snippets

Patients

Four hundred twenty clinically stable COPD patients, all current smokers, were screened through the outpatient clinic of Veterans Hospital during a period of 1 year in order to select 100 patients and to form similar groups of each stage of the GOLD classification.8 Inclusion criteria were medication according to the stage of their disease, no self-reported asthma or reversibility > 12% of airway obstruction after administration of a β2-agonist, and no participation to a rehabilitation program

Correlations

Patient Characteristics are summarized in Table 1. Correlation data for the whole study group are summarized in Table 2. Briefly, BMI was weakly correlated with exercise capacity as assessed by 6MWD (Fig 1, left, A). FFMI presented significant correlations with 6MWD (Fig 1, right, B), MRC dyspnea, and airway obstruction and limitation as assessed with FEV1/FVC ratio and FEV1%pred, respectively. Stepwise linear regression analysis showed that 6MWD and MRC were the best predictors of FFMI,

Discussion

Our study, which included COPD patients with a wide range of severity, shows that FFMI provides information beyond BMI regarding variables expressing disease severity and exercise capacity, and should be considered in the routine assessment of patients with COPD. FFMI seems to be more accurate in predicting the recent staging of the disease compared to BMI.

Our study showed that FFMI values were higher in those stages where no or minimal airflow limitation and obstruction exists. The above

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  • Cited by (0)

    This work was performed at the Department of Pneumonology, Veterans Hospital of Athens, Greece.

    The authors have no conflicts of interest to disclose.

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