Table 1.
Subject characteristics and candidate variables for multivariate regression models (n = 1,621).
| Variable | Mean ± SD or n (%) |
|---|---|
| Age | 66 ± 6 |
| Sex: Male | 976 (60) |
| Race: White | 1,523 (94) |
| Marital Status: Married | 1,039 (64) |
| Education: Completed High School or Higher | 1,301 (80) |
| BMI | 25 ± 4 |
| Disabled | 1,101 (68) |
| Prior Pulmonary Rehabilitation | 1,013 (62) |
| Daytime Sleepiness | 888 (55) |
| Cigarette Smoking (pack-years) | 64 ± 31 |
| Alcohol Use: Never | 628 (39) |
| Current Oral Corticosteroid Use | 535 (33) |
| Antidepressant Use | 279 (17) |
| Antianxiety Medication Use | 190 (12) |
| Oxygen Use | 1,226 (76) |
| Beck Total Score | 10 ± 6 |
| FEV1 % Predicted, After BD | 26 ± 6 |
| RV/TLC Ratio, After BD | 0.66 ± 0.08 |
| DLCO, % Predicted | 27 ± 10 |
| PaCO2 | 43 ± 6 |
| CT Emphysema Score | 16 ± 4 |
| LVEF, ≥45% | 1,566 (97) |
| MOS SF-36 PCS Score (range 8–56) | 28 ± 7 |
| MOS SF-36 MCS Score (range 12–76) | 52 ± 10 |
| SGRQ-TS (range 17–96) | 57 ± 13 |
| 6MWT Distance (m) (range 35–750) | 335 ± 98 |
| Maximal CPET Workload (W) | 33 ± 20 |
| UCSD SOBQ Total Score (range 8–120) | 66 ± 19 |
| 6MWT Borg | 5 ± 2 |
| CPET Borg | 6 ± 2 |
6MWT = 6-minute walk test; BD = bronchodilator; Beck = Beck Depression Inventory; BMI = body mass index; Borg = Borg score for breathlessness; CPET = cardiopulmonary exercise testing; CT = computed tomography; DLCO = single-breath diffusing capacity of the lung for carbon monoxide; FEV1 = forced expiratory volume in 1 second; LVEF = left ventricular ejection fraction; MCS = Mental Component Summary; MOS SF-36 = Medical Outcomes Study 36-Item Short Form; PaCO2 = partial pressure of arterial carbon dioxide; PCS = Physical Component Summary; RV = residual volume; SD = standard deviation; SGRQ-TS = St. George’s Respiratory Questionnaire total score; TLC = total lung capacity; UCSD SOBQ = University of California, San Diego Shortness of Breath Questionnaire.