Table 2.
Baseline Characteristics of Subjects with Asthma by Tertile of Paraspinous Muscle Density
| Male |
Female |
|||||||
|---|---|---|---|---|---|---|---|---|
| First Tertile (>48 HU) |
Second Tertile (42–48 HU) | Third Tertile (<42 HU) | First Tertile (>46.4 HU) |
Second Tertile (38.2–46.4 HU) | Third Tertile (<38.2 HU) | |||
| Characteristic | (n = 24) | (n = 25) | (n = 24) | P Value | (n = 48) | (n = 49) | (n = 49) | P Value |
| Age at baseline, yr* | 42.0 ± 13.7 | 43.6 ± 16.1 | 54.3 ± 10.2 | 0.005 | 41.0 ± 12.3 | 48.5 ± 13.5 | 52.8 ± 12.9 | <0.001 |
| Body mass index, kg/m2* | 27.6 ± 4.8 | 29.4 ± 5.2 | 36.1 ± 6.9 | <0.001 | 29.9 ± 7.8 | 32.2 ± 8.0 | 39.0 ± 10.3 | <0.001 |
| Body surface area, m2* | 2.04 ± 0.18 | 2.07 ± 0.23 | 2.26 ± 0.25 | 0.002 | 1.86 ± 0.23 | 1.90 ± 0.24 | 2.02 ± 0.26 | 0.005 |
| Asthma duration, yr* | 29.6 ± 17.0 | 29.9 ± 13.7 | 29.3 ± 18.4 | 0.99 | 23.7 ± 12.9 | 28.1 ± 13.7 | 29.6 ± 15.2 | 0.10 |
| Baseline exacerbations in prior 6 mo† | 0 (0–2) | 1 (0–3) | 0 (0–1) | 0.66 | 1 (0–3) | 1 (0–3) | 1 (0–3) | 0.79 |
| Severe asthma‡ | 13 (54.2) | 20 (80.0) | 20 (83.3) | 0.05 | 27 (56.3) | 33 (67.3) | 35 (71.4) | 0.27 |
| Number of controller medications† | 2 (1–3) | 2 (2–3) | 3 (2–4) | 0.03 | 3 (2–3) | 2 (2–3) | 3 (2–3) | 0.66 |
| Maintenance oral corticosteroid use‡ | 1 (4.2) | 4 (16.0) | 7 (29.2) | 0.07 | 5 (10.4) | 10 (20.4) | 7 (14.3) | 0.38 |
| ACT score* | 17.0 ± 5.4 | 16.6 ± 4.2 | 14.9 ± 5.6 | 0.31 | 17.0 ± 4.8 | 17.2 ± 4.9 | 15.5 ± 5.3 | 0.21 |
| Pre-BD FEV1% predicted* | 66.7 ± 21.9 | 66.2 ± 18.4 | 63.7 ± 16.5 | 0.84 | 80.0 ± 20.0 | 77.119.9 | 70.9 ± 18.8 | 0.07 |
| CT airway volume, mm3* | 11,666 ± 2,867 | 10,521 ± 2,767 | 9,737 ± 2,560 | 0.06 | 9,000 ± 3,096 | 9,085 ± 2,292 | 7,452 ± 2,652 | 0.004 |
| CT airway volume, BSA adjusted, mm3*§ | 1,087 ± 2,836 | −80 ± 2,682 | −1,003 ± 2,542 | 0.03 | 540 ± 3,092 | 595 ± 2,277 | −1,124 ± 2,637 | 0.002 |
Definition of abbreviations: ACT = Asthma Control Test; BD = bronchodilator; BSA = body surface area; CT = computed tomography; HU = Hounsfield units; PSMD = paraspinous muscle density.
*
Distribution for continuous measures is mean ± SD.
†
Distribution for ordinal measures is median (interquartile range).
‡
Distribution for categorical measures is n (%)
§
BSA-adjusted airway volume represents the value above or below the expected airway volume for BSA (residual from a linear model).