Levels of physical activity and predictors of mortality in COPD.

OBJECTIVE: To compare the Body mass index, airway Obstruction, Dyspnea, and E xercise capacity (BODE) index scores and its individual components between COPD patients with and without severe physical inactivity, as well as to correlate the number of steps/day with scores of physical activity questionnaires, age, and the BODE index (including its components).

METHODS: We included 30 patients, who were evaluated for body composition, pulmonary function (FEV1), perception of dyspnea (modified Medical Research Council scale), and exercise capacity (six-minute walk distance [6MWD]). The patients also completed the International Physical Activity Questionnaire (IPAQ), short version, and the modified Baecke questionnaire (mBQ). The level of physical activity was assessed by the number of steps/day (as determined by pedometer), using the cut-off of 4,580 steps/day to form two groups: no severe physical inactivity (SPI-) and severe physical inactivity (SPI+). We used the Mann-Whitney test or t-test, as well as Pearson's or Spearman's correlation tests, in the statistical analysis.

RESULTS: In comparison with the SPI- group, the SPI+ group showed more advanced age, higher mBQ scores (leisure domain), lower 6MWD (in m and % of predicted), and lower IPAQ scores (metabolic equivalent-walk/week domain and total). The IPAQ scores showed weak correlations with steps/day (r = 0.399), age (r = -0.459), and 6MWD-in m (r = 0.446) and in % of predicted (r = 0.422).

CONCLUSIONS: In our sample, the cut-off of 4,580 steps/day was not sensitive enough to identify differences between the groups when compared with the predictors of mortality. The IPAQ, short version score correlated with steps/day.