On the same day, body composition was also assessed by whole-body DEXA scanning, which was conducted by a medical radiology technician certified by the Brazilian Society of Clinical Densitometry. Measurements were taken ten minutes after the patients had been positioned in orthostatic position, in order to minimize errors caused by acute changes in body fluid distribution.ĭata on total body composition-body fat percentage, muscle mass, and bone mass-were collected. The measurement of body composition variables by the eight-contact electrode BIA system was performed as per the instructions of the manufacturer and as recommended by Kyle et al. The metal platform is attached to a force transducer for the measurement of weight, and the eight contact electrodes are connected to a digital circuit. That body composition monitor operates at 50 kHz and contains eight contact electrodes, two pairs of electrodes being coupled to a metal platform for the feet and two pairs for hand grasping. Weight and body composition variables were measured with a household segmental body composition monitor (BC-558 Ironman Tanita Corp., Tokyo, Japan). Height was measured with a wall-mounted stadiometer (Standard Sanny, São Bernardo do Campo, Brazil) in accordance with the standardization proposed by Gordon et al. All participants gave written informed consent.ĭuring the assessment of nutritional status, the individuals remained barefoot and unadorned, wearing only an apron. The study was approved by the Research Ethics Committees of the Universidade do Estado de Santa Catarina and the Universidade Federal de Santa Catarina (Protocol numbers 85/2010 and 865.2010, respectively). A total of 17 clinically stable COPD patients (14 men) from public or private pulmonary outpatient clinics agreed to participate in the study. Exclusion criteria were current smoking and presence of associated diseases, such as cardiomyopathy, musculoskeletal diseases, cancer, tuberculosis, or asthma. Of both genders, who had a smoking history ≥ 20 pack-years, had been clinically stable four weeks prior to study entry, and were ≥ 40 years of age.
The study sample was selected by convenience and included COPD patients classified as the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages 2, 3, or 4 (presence of a post-bronchodilator FEV 1/FVC ratio < 0.70 and FEV 1 < 80% of the predicted value), This was a cross-sectional study conducted between July and December of 2011. Thereby, the objective of the present study was to investigate the validity of an eight-contact electrode BIA system within a household scale for assessing whole body composition in COPD patients, using DEXA as the standard method. In those patients, factors other than age contribute to muscle atrophy, such as disuse, inflammation, oxidative stress, hypoxemia, hypercapnia, low levels of anabolic hormones or growth factors, impaired energy balance, corticosteroid use, and vitamin D deficiency. However, to the best of our knowledge, the assessment of body composition using this system has yet to be studied in patients with COPD. The measurement of lean mass (LM) by an eight-contact electrode BIA system has already been validated against DEXA in people ranging in age from 6 to 64 years.Īdditionally, this simple, practical, and convenient system was used in an epidemiological study in which FFM and FFM index were determined in men and women of white ethnicity ranging from 45 to 69 years of age. The BIA system, which is based on differential opposition to the electrical current among body tissues, has been used to assess body composition in COPD patients in various studies.
In comparison with DEXA, conventional bioelectrical impedance analysis (BIA) system, with four adhesive gel electrodes, has satisfactory clinical accuracy in estimating body composition in patients with COPD. This system distinguishes the body composition in three compartments by a difference in the attenuation of X-rays among body tissues. The use of dual-energy X-ray absorptiometry (DEXA) is recommended to assess body composition in COPD patients. Than does BMI in those patients, justifying the routine assessment of their body composition. The fat-free mass (FFM) index, however, seems to be a stronger predictor of mortality It is known that body mass index (BMI) is related to the number of hospitalizationsįor acute exacerbation in patients with COPD, with an impact on mortality. Weight loss and depletion of muscle mass are common systemic manifestations in COPDĪnd have been associated with the disease prognosis.
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