Table 1.
Characteristics of all 1206 patients at baselinea.
| Characteristics | Income ≥US$30,000 (N = 563) |
Income ≤US$30,000 (N = 643) |
p Value |
|---|---|---|---|
| Medical treatment | 52.0% | 49.1% | 0.3153 |
| Sex, male | 65.4% | 57.5% | 0.0054 |
| Age, mean (SD) (years) | 67.2 (5.5) | 65.6 (6.6) | 0.0001 |
| Married | 83.3% | 48.5% | <0.0001 |
| Lonelyb | 5.5% | 10.1% | 0.0031 |
| Smoking pack years | 65.4 (29.3) | 63.6 (32.6) | 0.0826 |
| Post BD FEV1% pred, mean (SD) | 26.8 (7.1) | 26.6 (7.2) | 0.3947 |
| 6MWD in feet, mean (SD) | 1250.7 (314.8) | 1171.7 (306.8) | <0.0001 |
| Maximum load (watts), mean (SD)c | 41.6 (22.7) | 36.8 (20.4) | 0.0001 |
| Total days in hospital, mean (SD) | 3.0 (7.8) | 3.3 (7.6) | 0.3840 |
| Any days in hospital, yes | 31.7% | 33.8% | 0.4620 |
| Total visits to ER, mean (SD) | 0.6 (1.1) | 0.7 (1.3) | 0.5015 |
| Any visit to ER, yes | 37.5% | 39.7% | 0.4659 |
| Follow-up status, deadd | 39.4% | 41.7% | 0.4278 |
| MRC Dyspnea Scale | 0.0058 | ||
| 0 | 1.4% | 1.6% | |
| 1 | 0.2% | 0.5% | |
| 2 | 29.2% | 22.1% | |
| 3 | 23.5% | 19.9% | |
| 4 | 45.7% | 55.9% | |
| Education beyond high school | 62.9% | 35.1% | <0.0001 |
N: sample; SD: standard deviation; Post BD FEV1% pred: postbronchodilator forced expiratory volume in 1 second % predicted; ER: emergency department; MRC scale: Medical Research Council Dyspnea Scale; 6MWD: 6-minute walk distance. Every value in italics <0.05 denotes significance (standard practice).
a Base-line measurements were obtained after rehabilitation but before randomization.
bLoneliness was measured by asking subjects “Do you feel lonely or socially isolated now or in the last 3 days?” An answer was either “yes” or “no.”20
c Maximum load (watts) was chosen to measure exercise capacity during CPET.
d The follow-up period was 2 years.