Table 1.
Baseline subject characteristics.a
| Characteristic | Total (N = 93) | Event (N = 46) | No event (N = 47) | Between group (p valueb) |
|---|---|---|---|---|
| Age (years) | 69 ± 8 | 70 ± 10 | 69 ± 6 | 0.49 |
| Male (sex) | 91 (97.9) | 45 (97.8) | 46 (97.9) | 0.99c |
| Race (White) | 85 (91.4) | 42 (91.3) | 43 (91.5) | 1.0c |
| BMI (kg/m2) | 29 ± 5.3 | 28.5 ± 4.7 | 29.5 ± 5.9 | 0.33 |
| Pack-years | 61.5 ± 40.9 | 60.8 ± 42 | 62.2 ± 40.3 | 0.73d |
| Current smoker | 33 (35.5) | 18 (39.1) | 15 (31.9) | 0.47 |
| Current oxygen use | 22 (23.7) | 8 (17.4) | 14 (29.8) | 0.16 |
| Prior pulmonary rehabilitation | 11 (11.8) | 4 (8.7) | 7 (14.9) | 0.52c |
| Baseline daily step count | 3127 ± 1830 | 3437 ± 1995 | 2824 ± 1618 | 0.13d |
| FEV1 (L) | 1.86 ± 0.6 | 1.8 ± 0.6 | 1.9 ± 0.7 | 0.34d |
| FEV1% predicted | 62.7 ± 22.3 | 61.9 ± 20.8 | 63.4 ± 24 | 0.88d |
| GOLD stage | 0.55c | |||
| I | 18 (19.4) | 10 (21.7) | 8 (17.0) | |
| II | 50 (53.8) | 25 (54.4) | 25 (53.2) | |
| III | 19 (20.4) | 7 (15.2) | 12 (25.5) | |
| IV | 6 (6.5) | 4 (8.7) | 2 (4.3) | |
| Comorbidities | ||||
| CAD | 19 (20.4) | 11 (23.9) | 8 (17) | 0.41 |
| Hypertension | 51 (54.8) | 24 (52.2) | 27 (57.5) | 0.61 |
| CHF | 5 (5.4) | 1 (2.2) | 4 (8.5) | 0.36c |
| Arthritis | 36 (38.7) | 14 (30.4) | 22 (46.8) | 0.105 |
| Diabetes | 22 (23.7) | 8 (17.4) | 14 (29.8) | 0.16 |
| Depression | 34 (36.6) | 19 (41.3) | 15 (31.9) | 0.35 |
| Back pain | 38 (40.9) | 22 (47.8) | 16 (34) | 0.18 |
| 6MWT distance (m) | 390 ± 82 | 384 ± 86 | 396 ± 77 | 0.49 |
| SGRQ-TS | 34 ± 16 | 37 ± 16 | 31 ± 16 | 0.05 |
| MMRC dyspnea score | 0.21 | |||
| 0–2 | 70 (75.3) | 32 (69.6) | 38 (80.9) | |
| 3–4 | 23 (24.7) | 14 (30.4) | 9 (19.2) | |
| BDI-II depression score | 8.9 ± 9.3 | 10.7 ± 9.6 | 7.2 ± 8.8 | 0.03d |
| AE in the past year | 15 (16.1) | 11 (23.9) | 4 (8.5) | 0.05c |
| Hospitalized for any reason in past year | 10 (10.8) | 6 (13) | 4 (8.5) | 0.52c |
BMI: body mass index; FEV1: forced expiratory volume in one second; GOLD: global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease; CAD: coronary artery disease; CHF: congestive heart failure; 6MWT: 6-minute walk test; SGRQ-TS: St. George’s Respiratory Questionnaire-Total Score; MMRC: Modified Medical Research Council; AE: acute exacerbation; SD: standard deviation.
a Values are means ± SD or frequency (percentages).
b Unpaired t-test for continuous and χ 2 test for categorical variables, unless otherwise noted.
c Fisher’s exact test.
d Wilcoxon rank-sum test.