The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

TITLE: IS THE FAT FREE MASS RELATED TO THE CHANGE IN OXYGEN UPTAKE FROM BASELINE TO PEAK OF EXERCISE IN DIFFERENT RESPIRATORY DISEASES?

Russell Sabbag1, Luis Torre-Bouscoulet1, Sohail Qadir1, Felipe Cortopassi1, Nelson Gomez1, Marshall Krashin1, Victor Pinto-Plata1, Bartolome R. Celli1



Background: Fat free mass (FMM) has been recognized as a predictor of exercise capacity in healthy subjects as well as in patients with chronic obstructive pulmonary disease (COPD); however, little is known about the association between FFM and the change in oxygen uptake (from baseline to peak of exercise) in respiratory diseases other than COPD. Those associations are explored.

Methods:
We examined 60 consecutive incremental cardiopulmonary exercise tests (CPET) performed in patients referred to a single respiratory physiology laboratory in a tertiary care hospital. Anthropometric parameters and body composition (Bodystat 1500 v 2/02 , Bodystat Limited, British Isles) were measured in all patients. CPETs were performed following ATS/ACCP standards. We analyzed the relation between FFM (Kg) with the change of oxygen uptake (VO2) from baseline to peak and with work load (Watts). Subjects were classified into one of six groups according to the final CPET diagnosis. Group 1 (n=11), normal; group 2 (n=19), airway diseases (asthma, COPD, bronchiectasis, smoke inhalation); group 3 (n=7), coronary artery disease; group 4 (n=5), interstitial lung diseases; group 5 (n=9), lung cancer; group 6 (n=9), other (esophageal cancer, amyloidosis, sarcoidosis, multiple sclerosis). The strength of the association was explored calculating the Spearman's correlation coefficient (rs).

Results:
The entire group was formed by 26 female and 34 male with mean age of 58 ± 13 y, body mass index 29.1 ± 5.4 Kg/m2, FFM 57 ± 14 Kg, FEV1 77±23%, FVC 87±21%, FEV1/FVC 68±13%, TLC 94±18%, baseline VO2 0.306±0.079 L, VO2 at peak of exercise 1.504±0.584 L, delta VO2 baseline to peak 1.204±0.563 L, work achieved 110±45 Watts. Statistically significant correlations between fat free mass and change in oxygen uptake were observed in group 1 with rs of 0.97 (p<0.0001) and group 2 with rs of 0.77 (p=0.0001). When we explored the association between fat free mass and work load (Watts) similar results were found with rs of 0.84 (p=0.001) in group 1 and rs of 0.78 (p=0.005) in group 2. There were no associations between FFM and VO2 for any of the other groups.

Conclusion:
In this preliminary report, FFM was found to be a predictor of oxygen uptake change from baseline to peak of exercise and work load only in patients with airway diseases as well as in normal subjects. Our results underline the heterogeneous nature of the physiological or pathophysiological factors involved in exercise capacity.