Table 1.
Participant characteristics by quartile of serum TRAIL level. Continuous variables are summarized as median (IQR).
| 1st/L006Fwest Quartile | 2nd Quartile | 3rd Quartile | 4th/Highest Quartile | p | |
|---|---|---|---|---|---|
| n (%) | 119 (25.1) | 118 (24.9) | 119 (25.1) | 118 (24.9) | |
| Serum TRAIL, pg/ml | 54.0 (45.3; 59.5) | 77.6 (73.2; 81.9) | 98.7 (91.6; 104.6) | 130.6 (122.6; 153.2) | |
| Age, years | 68.0 (62.0; 72.0) | 64.0 (60.0; 69.0) | 64.0 (60.0; 69.0) | 64.5 (61.0; 70.0) | 0.005 |
| Male (%) | 49 (41.2) | 51 (43.2) | 55 (46.2) | 72 (61.0) | 0.002 |
| Caucasian (%) | 115 (96.6) | 110 (93.2) | 113 (95.0) | 110 (93.2) | 0.37 |
| BMI, kg/m2 | 28.0 (25.1; 30.0) | 27.8 (24.9; 31.4) | 28.0 (24.8; 31.4) | 27.6 (25.1; 31.6) | 0.22 |
| Current smoking (%) | 45 (37.8) | 57 (48.3) | 52 (43.7) | 62 (52.5) | 0.053 |
| Pack years of smoking | 52.0 (40.0; 75.0) | 45.0 (30.0; 60.0) | 45.0 (33.8; 63.0) | 48.0 (35.0; 75.2) | 0.04 |
| FEV1, % predicted | 79.1 (22.4) | 86.1 (18.3) | 85.7 (19.7) | 82.6 (19.6) | 0.20 |
| FEV1/FVC | 63.8 (13.3) | 68.8 (11.5) | 68.5 (12.1) | 67.7 (12.4) | 0.10 |
| Shuttle walk distance, ft | 403.3 (144.8) | 446.8 (137.4) | 450.3 (139.6) | 409.3 (138.6) | 0.70 |
| Unscheduled visits (%)* | 4.2 | 7.6 | 8.4 | 9.3 | 0.46 |
| Systolic BP, mm Hg | 132.0 (125.0; 144.0) | 134.0 (121.0; 145.0) | 130.0 (120.0; 144.0) | 129.0 (118.0; 143.0) | 0.05 |
| Diastolic BP, mm Hg | 76.0 (69.0; 82.0) | 77.0 (69.0; 82.0) | 74.0 (69.0; 80.0) | 75.0 (68.0; 81.0) | 0.21 |
| Hypertension (%) | 64 (54.2) | 62 (53.9) | 62 (52.5) | 56 (47.9) | 0.32 |
| Diabetes mellitus (%) | 14 (11.9) | 13 (11.4) | 10 (8.5) | 8 (6.9) | 0.15 |
| Hyperlipidemia (%) | 74 (63.2) | 63 (54.8) | 59 (49.6) | 65 (56.0) | 0.19 |
| hs-CRP, mg/L | 1.0 (0.4; 3.7) | 1.1 (0.4; 2.1) | 1.2 (0.5; 2.4) | 1.3 (0.5; 2.6) | 0.62 |
| IL-6, pg/mL | 1.4 (0.9; 2.0) | 1.1 (0.8; 1.7) | 1.2 (0.9; 1.9) | 1.3 (0.8; 2.3) | 0.29 |
| TNF-α, pg/mL | 1.6 (1.4; 2.1) | 1.7 (1.4; 2.4) | 1.8 (1.3; 2.4) | 1.9 (1.4; 2.6) | 0.24 |
*
Defined as an unscheduled visit to a physician or emergency room for respiratory difficulty in the six months prior to enrollment.