Patient demographic data
| All (382) | Belfast (95) | Brompton (99) | Leicester (79) | Manchester (109) | ||
| Female (%) | 241 (63.1) | 56 (58.9) | 63 (63.6) | 45 (57.8) | 77 (70.6) | p=0.259 |
| Race, n (%) | ||||||
| White | 346 (90.6) | 95 (100) | 82 (82.8) | 64 (81.0) | 105 (96.3) | p<0.001 |
| Asian | 24 (6.3) | 0 | 9 (9.1) | 15 (19.0) | 0 | |
| African | 10 (2.6) | 0 | 7 (7.1) | 0 | 3 (2.8) | |
| Unknown | 4 (1.0) | 0 | 1 (1.0) | 0 | 3 (2.8) | |
| Age at first assessment at Difficult Asthma Service (n) | 44.9±13.7 (381) | 43.2±14.4 (95) | 43.0±13.1 (99) | 45.7±13.6 (78) | 47.5±13.4 (109) | p=0.055 |
| Age (years) at diagnosis of asthma (n) | 17 (3–35) (377) | 20 (2–39) (95) | 10 (2–27) (99) | 25 (5–43) (79) | 18 (4.25–33) (104) | p=0.019 |
| Height, m (n) | 1.66±0.096 (382) | 1.65±0.09 (95) | 1.68±1.0 (99) | 1.66±0.11 (79) | 1.65±1.0 (109) | p=0.118 |
| Weight, kg (n) | 81.2±19.9 (374) | 81.3±19.8 (95) | 83.8±18.3 (99) | 81.8±23.1 (71) | 78.3±19.2 (109) | p=0.254 |
| BMI (n) | 28 (24.3–32.4) (374) | 28 (25–34) (95) | 30 (25–32) (99) | 28.4 (24.4–34.5) (71) | 27 (24–31) (109) | p=0.291 |
| Smoking status | ||||||
| Never | 233 (61.0) | 57 (60.0) | 69 (69.7) | 50 (63.3) | 57 (52.3) | p=0.182 |
| Ex-smoker (years since stopped) | 114 (29.8) (8.97±8.15) | 27 (28.4) (11.0±9.92) | 25 (25.2) (9.64±6.72) | 24 (30.4) (10.35±8.26) | 38 (34.9) (5.55±6.35) | |
| Current smoker (%) (pack-years) | 22 (5.8) (16.12±11.62) | 9 (9.5) (16.8±13.4) | 2 (2.0) (9.0±11.3) | 5 (6.3) (16.4±15.6) | 6 (5.5) (18.2±8.01) | |
| Unknown | 13 (3.4) | 2 (2.1) | 3 (3.0) | 0 | 8 (7.3) | |
| Working status | ||||||
| Full time (%) | 151 (39.5) | 34 (35.8) | 33 (33.3) | 46 (58.2) | 38 (34.9) | p<0.001 |
| Asthma-related not working (%) | 100 (26.2) | 16 (16.8) | 40 (40.4) | 9 (11.4) | 35 (32.1) | |
| Other cause for not working (%) | 104 (27.2) | 39 (41.0) | 15 (15.2) | 22 (27.8) | 28 (25.7) | |
| Part-time working due to asthma (%) | 12 (3.1) | 0 (0) | 10 (10.1) | 0 | 2 (1.8) | |
| Part-time working due to other cause (%) | 10 (2.6) | 2 (2.1) | 1 (1.0) | 1 (1.3) | 6 (5.5) | |
| Unknown | 5 (1.3) | 4 (4.2) | 0 (0) | 1 (1.3) | 0 | |
| Work-related worsening of asthma (%) | p=0.98 | |||||
| Yes | 19 (5.0) | 4 (4.2) | 5 (5.0) | 4 (5.1) | 6 (5.5) | |
| No | 354 (92.7) | 89 (93.7) | 94 (95.0) | 69 (87.3) | 102 (93.6) | |
| Not recorded | 9 (2.3) | 2 (2.1) | 0 | 6 (7.6) | 1 (0.9) | |
Group data (mean±SD or median (IQR)) for all subjects are presented in column 2 followed by data for individual centres. Between-centre comparisons for continuous variables were made using one-way analysis of variance or Kruksal–Wallis test (for posthoc comparisons, see text) and for categorical variables using χ2 exact testing.
Significance was taken as p<0.01.
BMI, body mass index.