Table 4.
Patient characteristics according to the total actual usage score (3 groups only including patients with valid physical activity measurement by actigraph, n=140); data are expressed as mean (SD) unless stated otherwise. P value indicates differences between the 3 actual usage groups.
| Variables | Low actual usage, <47% of usage (n=47) | Medium actual usage, 47% to 75% of usage (n=46) | High actual usage, >75% of usage (n=47) | P value |
| Age in years, mean (SD) | 66 (8) | 66 (9) | 65 (8) | .76 |
| Gender (male), n (%) | 31 (66) | 29 (63) | 29 (62) | .91 |
| BMIa in kg per m2, mean (SD) | 27.5 (5.3) | 27.6 (6.5) | 26.0 (4.3) | .34 |
| FEV1b predicted percentage, mean (SD) | 54.4 (20.3) | 55.2 (19.5) | 53.5 (21.6) | .92 |
| 6MWDc (m), mean (SD) | 431 (106) | 432 (105) | 454 (107) | .50 |
| 6MWD predicted percentage, mean (SD) | 69 (17) | 69 (17) | 72 (16) | .61 |
| CATd score, median (p25-p75)e | 14 (7-19) | 13 (6-19) | 12 (7-21) | .94 |
| QFf (kg), mean (SD) | 32.0 (10.8) | 30.0 (12.9) | 31.1 (9.4) | .73 |
| PAg (steps per day) median (p25-p75) | 4369 (2868-5672) | 3850 (2380-6108) | 4540 (2940-6731) | .49 |
aBMI: body mass index.
bFEV1: forced expiratory volume in 1 second.
c6MWD: 6-minute walking distance; 6MWD was missing in 2 patients.
dCAT: chronic obstructive pulmonary disease (COPD) assessment test.
e25th and 75th percentiles (P25-P75).
fQF: quadriceps force; QF was not measured in 2 centers and QF was missing in 27 patients.
gPA: physical activity; valid PA measurements was present in 140 patients.