Table 2. Baseline characteristics by BMI categories.
| <21 kg/m2 (n = 24) | 21–25 kg/m2 (n = 31) | 25–30 kg/m2 (n = 26) | >30 kg/m2 (n = 13) | |
| Men (%) | 50 | 45 | 77*+ | 85*+ |
| Age (years) | 57.2 (7.8) | 59.5 (9.1) | 66.3 (8.7)†+ | 56.8 (8.8)# |
| FEV1 (L) | 1.25 (0.61) | 1.37 (0.52) | 1.54 (0.64) | 1.59 (0.44) |
| FEV1 (% predicted) | 44.8 (19.9) | 51.7 (18.3) | 56.9 (20.1) | 50.5 (15.1) |
| FEV1/FVC (%) | 39.2 (14.7) | 41.0 (11.1) | 44.3 (13.4) | 48.5 (12.0) |
| TLCO (%) | 53.3 (18.6) | 54.4 (19.3) | 57.3 (20.4) | 61.1 (19.0) |
| PaO2 (kPa)* | 9.79 (1.41) | 9.65 (1.05) | 9.77 (1.17) | 9.85 (1.56) |
| PaCO2 (kPa) | 5.33 (0.92) | 5.14 (0.56) | 5.11 (0.53) | 5.34 (0.62) |
| SaO2 (%) | 94.7 (3.2) | 95.4 (1.6) | 95.4 (1.5) | 95.3 (1.8) |
| GOLD stage I/II/III/IV (n) | 1/6/6/11 | 1/14/13/3 | 2/11/11/2 | 1/5/6/1 |
| MRC grade 1/2/3/4/5 (n) | 3/5/9/4/3 | 2/10/11/5/3 | 1/9/10/3/3 | 1/4/6/1/1 |
| BODE score (points) | 4.2 (2.0) | 2.4 (1.4)† | 2.4 (2.0)† | 2.5 (1.5)† |
| Body weight (kg)** | 52.6 (7.9) | 64.9 (7.7)† | 76.7 (11.0)†+ | 99.7 (7.8)†+# |
| Height (cm) | 167.0 (9.2) | 167.7 (9.7) | 168.5 (10.5) | 172.4 (8.6) |
| Body mass index (kg/m2) | 18.8 (1.7) | 23.0 (1.0)† | 26.9 (1.4)†+ | 33.7 (3.6)†+# |
| FFM (kg) | 39.0 (5.4) | 42.9 (5.7) | 48.5 (8.8)†+ | 59.3 (6.7)†+# |
| FFMI (kg/m2) | 14.0 (1.2) | 15.2 (1.3)† | 17.0 (1.6)†+ | 20.0 (1.5)†+# |
| Women <15 kg/m2 (%) | 75.0 | 76.5 | 16.7 | 0.0 |
| Men <16 kg/m2 (%) | 91.7 | 71.4 | 20.0 | 0.0 |
| Charlson CMI (points) | 1.7 (0.9) | 1.9 (1.1) | 2.5 (1.8) | 2.1 (1.9) |
| Charlson CMI 2 (points) | 3.0 (1.5) | 3.4 (1.8) | 4.8 (2.2)† | 3.4 (2.6) |
| ≥1 co-morbidities (%) | 57.6 | 55.6 | 56.7 | 53 |
| 6MWD (m) | 487 (111) | 500 (96) | 483 (114) | 485 (108) |
| Peak VO2 (mL/min) | 1009 (306) | 1172 (330) | 1290 (343)† | 1458 (374)† |
| Peak VO2 (mL/min/kg BW) | 19.2 (4.9) | 18.0 (4.3) | 16.8 (3.6) | 14.6 (3.7)† |
| Peak VO2 (mL/min/kg FFM) | 25.7 (6.1) | 27.3 (6.5) | 26.7 (5.2) | 24.7 (6.1) |
| Peak VE (L) | 42.6 (11.2) | 45.7 (15.6) | 50.6 (15.3) | 53.8 (14.1) |
| Peak VE (% MVV) | 96.9 (31.3) | 83.5 (17.5) | 91.5 (29.0) | 88.0 (25.4) |
| Peak HR (bpm) | 130 (17.8) | 137 (19.8) | 130 (19.4) | 131 (25.5) |
| Peak HR (% max HR) | 80.1 (10.8) | 85.2 (10.3) | 84.7 (12.5) | 79.8 (12.6) |
| Borg dyspnoea (points) | 6.5 (2.5) | 7.2 (2.0) | 6.2 (1.7) | 6.2 (2.4) |
| Borg fatigue (points) | 5.6 (2.5) | 6.4 (2.6) | 5.6 (1.6) | 5.6 (2.0) |
Results are presented as mean (standard deviation). FEV1 = forced expiratory volume in the first second; L = litre; FVC = forced vital capacity; kg = kilogram; kg/m2 = kilogram per squared meters; Charlson CMI = Charlson co-morbidity index [19]; Charlson CMI 2 = Charlson age comorbidity index [20]; 6MWD = six-minute walking distance; VO2 = oxygen uptake; mL = millilitre; min = minute; BW = body weight; FFM = fat free mass; VE = minute ventilation; MVV = maximum voluntary ventilation; HR = heart rate; bpm = beats per minute. *1 kPa = 7.5 mm Hg; **1 kilogram = 2.2046 pounds; †p<0.05 vs. <21 kg/m2 +p<0.05 vs. 21–25 kg/m2 #p<0.05 vs. 25–30 kg/m2.