Baseline demographics
| Variable | Overall (n=729) | Neither (n=194) | Muscle (n=137) | Cardiovascular (n=154) | Both (n=132) |
| Age (years) | 67 (8) | 66 (7)*** | 63 (8)*** | 70 (7)*** | 70 (7)*** |
| Gender (% male) | 60.6 | 58.3 | 54.7 | 67.5 | 62.9 |
| Smoking history (total pack years) | 47 (28) | 45 (27) | 47 (26) | 51 (31) | 47 (28) |
| BMI (kg / m2) | 27.3 (5.8) | 26.3 (4.9)** | 26.9 (5.6) | 27.1 (4.9) | 28.3 (6.5)* |
| Fat-free mass (kg) | 51.0 (11.1) | 49.7 (10.6) | 50.1 (11.2) | 51.9 (10.5) | 52.2 (11.9) |
| CAT score (0–40) | 20 (0–40) | 17 (0–38)*** | 22 (1–39)** | 19 (3–40) | 21.5 (6–40)* |
| SGRQ total score | 51.4 (22.3) | 44.2 (21.2)*** | 57.4 (21.5)*** | 47.7 (22.5)* | 55.8 (20.5)* |
| FEV1 (L) | 1.34 (0.53) | 1.50 (0.52)*** | 1.31 (0.53) | 1.32 (0.50) | 1.26 (0.50) |
| FEV1 (% predicted) | 52.2 (16.1) | 57.4 (14.2)*** | 49.4 (16.3)* | 51.8 (16.4) | 50.5 (15.8) |
| FEV1/FVC | 0.48 (0.13) | 0.49 (0.12) | 0.48 (0.13) | 0.47 (0.12) | 0.49 (0.13) |
| Muscle indices | |||||
| QMVC (kg) | 30.6 (11.5) | 36.1 (10.1) | 23.4 (7.9) | 36.7 (10.7) | 22.7 (8.2) |
| QMVC (% predicted) | 68.2 (20.7) | 81.4 (15.3) | 51.5 (12.0) | 82.2 (14.9) | 50.2 (12.9) |
| SPPB total score | 10 (1–12) | 11 (3–12)*** | 10 (3–12) | 11 (4–12)** | 9 (2–12)*** |
| 6MWD (m) | 345 (130) | 404 (104)*** | 338 (129) | 361 (125) | 282 (132)*** |
| Cardiovascular indices | |||||
| Supine MAP (mm Hg) | 98 (12) | 96 (11)* | 95 (10)*** | 100 (10)* | 100 (11)* |
| aPWV (m/s) | 10.3 (2.6) | 8.3 (1.1) | 8.3 (1.1) | 12.2 (2.0) | 12.7 (1.9) |
| Inflammatory markers | |||||
| Fibrinogen (g/dL) | 3.49 (0.86) | 3.44 (0.95) | 3.41 (0.76) | 3.49 (0.78) | 3.52 (0.90) |
| hsCRP (mg/L) | 6.57 (12.1) | 7.45 (19.7) | 6.11 (8.13) | 5.63 (6.95) | 6.365 (6.55) |
| WCC (×109/L) | 7.50 (2.16) | 7.32 (2.15) | 7.19 (2.18) | 7.42 (1.95) | 7.70 (2.38) |
| Comorbidities | |||||
| Exacerbations per year | 1.9 (2.1) | 1.71 (1.8) | 2.2 (2.0)* | 1.81 (2.34) | 2.2 (2.3)* |
| Diabetes (%) | 11.4 | 6.3 | 7.2 | 10.4 | 18.3** |
| Antihypertensive therapy (%) | 35.9 | 31.4 | 28.9 | 39.0 | 43.9* |
| Cholesterol-lowering therapy (%) | 32.6 | 22.8 | 28.5 | 37.9** | 43.8*** |
| Previous myocardial infarction (%) | 7.9 | 6.3 | 6.6 | 9.1 | 9.2 |
Baseline demographics for overall cohort (n=729) and phenotypic groups. Values expressed as mean (SD) for continuous variables and median (range) for discrete variables. The ‘Neither’ group (n=194) represents subjects with neither elevated aPWV nor skeletal muscle weakness. The ‘Muscle’ group (n=137) represents subjects with skeletal muscle weakness alone. The ‘Cardiovascular’ group (n=154) represents subjects with cardiovascular manifestation, defined as elevated aPWV, alone, and the ‘Both’ group (n=132) contains subjects demonstrating both skeletal muscle weakness and elevated aPWV. Skeletal muscle weakness according to predicted QMVC based on equations developed by Seymour et al 2 and elevated aPWV defined as >10 m/s.
↵*P<0.05, **P<0.01, ***P<0.001 for significant differences across groups. For continuous variables, the P value represents differences between overall mean and group mean. For ordinal and binary variables, the P value represents differences between the ‘Neither’ group and the remaining groups. Adjustments have not been made for multiple comparisons.
6MWD, 6 min walk distance; aPWV, aortic pulse wave velocity; BMI, body mass index; CAT, COPD Assessment Test; hsCRP, high-sensitivity C reactive protein; MAP, mean arterial pressure; QMVC, quadriceps maximal volitional contraction; SGRQ, St George’s Respiratory Questionnaire; SPPB, short physical performance battery; WCC, white cell count.