Table 1.
Classification of COPDGene subjects by bone disease
| Normal (T-scoreQCT greater than −1.0) | Intermediate Bone Density (T-scoreQCT less than −1.0 and greater than −2.5) | Low Bone Density (T-scoreQCT less than −2.5) | |
|---|---|---|---|
| Number of subjects | 380 | 1,017 | 1,924 |
| Age, yr | 52.8 (6.8) | 56.3 (7.7)* | 62.3 (8.8)*† |
| Sex, % male | 31.3% | 52.5%* | 55.7%*† |
| Race, % African American | 69.7% | 44.6%* | 16.6%*† |
| BMI | 31.6 (7.3) | 29.6 (6.4)* | 27.7 (5.5)*† |
| Current smoker | 70.8% | 60.0%* | 43.4%*† |
| Pack-yr of smoking | 36.6 (22.6) | 40.3 (21.7) | 46.9 (25.6)† |
| Chronic oral steroid use | 2.5% | 1.5% | 2.7% |
| Chronic inhaled steroid use | 16.8% | 18.6%* | 27.2%* |
| Flare-up of chest trouble | 19.0% | 21.5% | 27.6%‡ |
| Treated with steroid | 13.2% | 14.4% | 18.9%‡ |
| Severe exacerbations | 10.8% | 11.1% | 12.5% |
| QCT BMD, mg/cm3 | 211.6 (25.1) | 154.2 (14.7)* | 95.1 (24.7)*† |
| FEV1, % predicted | 82.6 (20.7) | 81.5 (22.9) | 73.8 (27.2)*† |
| FVC, % predicted | 88.1 (17.3) | 88.7 (17.3) | 86.9 (18.5)‡ |
| FEV1/FVC | 0.74 (0.11) | 0.71 (0.13) | 0.64 (0.18)*† |
| COPD, % GOLD Stages 2–4 | 20.5% | 26.4%* | 42.7%*† |
| 6-min-walk distance, ft | 1,337.7 (353.6) | 1,429.5 (380.4)* | 1,407.0 (396.5) |
| Airway wall area, % segmental | 62.5 (3.45) | 61.5 (3.3)* | 60.9 (3.2)*† |
| LAA% < −950 HU (emphysema) | 2.4 (4.2) | 4.0 (7.4) | 7.1 (10.7)*† |
| Osteoporosis diagnosis | 2.6% (n = 10) | 2.9% (n = 29) | 13% (n = 251)*† |
| Treated with bisphosphonate | 0.5% (n = 2) | 0.3% (n = 3) | 2.3% (n = 45)*† |
| Coronary artery disease | 10% | 10.8% | 13.8%‡ |
| Diabetes | 14.7% | 13.2% | 11.6% |
Definition of abbreviations: BMD = bone mineral density; BMI = body mass index; COPD = chronic obstructive pulmonary disease; GOLD = Global Initiative for Chronic Obstructive Lung Disease; HU = Hounsfield units; LAA% = low attenuation area percentage; QCT = quantitative computed tomography
Values are mean and standard deviation, except where percent is shown. Boldface type indicates P < 0.05 for comparisons with normal bone density group.
*
P < 0.0001 for comparisons with normal bone density group.
†
P < 0.0001 for comparison of low bone density group with intermediate bone density group.
‡
P < 0.05 for comparison of low bone density group with intermediate bone density group.