Determinants of bronchodilator reversibility in subjects with asthma
| ΔFEV1 | ΔFVC | |||
| ≥12% | ≥12% + 200 mL | ≥10.5% | ≥10.5% + 320 mL | |
| Age per 10 years | 0.90 (0.82–0.99) | 0.82 (0.75–0.91) | 1.23 (1.11–1.37) | 1.08 (0.96–1.22) |
| Female | 1.19 (0.95–1.50) | 0.99 (0.79–1.25) | 1.19 (0.91–1.54) | 0.72 (0.55–0.95) |
| Smoking history | ||||
| Never-smoker | 1 | 1 | 1 | 1 |
| Ex-smoker | 0.96 (0.74–1.24) | 1.01 (0.78–1.31) | 1.05 (0.79–1.41) | 1.15 (0.84–1.57) |
| Current smoker | 0.75 (0.55–1.01) | 0.78 (0.57–1.06) | 1.06 (0.76–1.06) | 1.08 (0.75–1.06) |
| BMI kg·m−2 | ||||
| <20 | 0.60 (0.37–0.97) | 0.51 (0.31–0.85) | 0.61 (0.36–1.06) | 0.60 (0.33–1.06) |
| 20–25 | 1 | 1 | 1 | 1 |
| >25–30 | 0.98 (0.75–1.29) | 1.06 (0.81–1.40) | 1.10 (0.80–1.52) | 1.06 (0.76–1.48) |
| >30 | 1.06 (0.81–1.38) | 1.06 (0.81–1.40) | 1.31 (0.96–1.79) | 1.17 (0.84–1.64) |
| Wheeze | 1.33 (1.02–1.73) | 1.36 (1.04–1.79) | 1.42 (1.04–1.92) | 1.19 (0.86–1.64) |
| Wheeze and breathlessness | 1.17 (0.94–1.46) | 1.16 (0.93–1.45) | 1.10 (0.85–1.42) | 1.02 (0.78–1.33) |
| Wheeze not having a cold | 1.05 (0.84–1.31) | 1.10 (0.88–1.38) | 1.16 (0.90–1.49) | 1.08 (0.82–1.42) |
| Nocturnal chest tightness | 1.32 (0.93–1.86) | 1.35 (0.6–1.91) | 2.31 (1.50–3.55) | 2.25 (1.44–3.52) |
| Breathless at rest | 1.28 (0.89–1.86) | 1.28 (0.88–1.86) | 1.48 (0.95–2.31) | 1.65 (1.04–2.60) |
| Breathless after effort | 0.92 (0.64–1.31) | 0.87 (0.61–1.24) | 1.08 (0.70–1.68) | 1.32 (0.83–2.10) |
| Nocturnal breathlessness | 1.14 (0.79–1.66) | 1.12 (0.77–1.63) | 1.19 (0.76–1.88) | 1.25 (0.78–1.99) |
| Nocturnal cough | 0.84 (0.59–1.20) | 0.82 (0.58–1.17) | 0.64 (0.42–0.98) | 0.59 (0.38–0.93) |
| Chronic cough | 0.74 (0.59–0.92) | 0.71 (0.57–0.88) | 0.86 (0.67–1.10) | 0.96 (0.74–1.25) |
| Chronic bronchitis | 0.85 (0.67–1.09) | 0.90 (0.76–0.92) | 1.15 (0.88–1.50) | 1.12 (0.84–1.50) |
| Asthma attacks in past 3 months | ||||
| 0 | 1 | 1 | 1 | 1 |
| 1 | 1.13 (0.70–1.82) | 1.15 (0.72–1.86) | 1.42 (0.80–2.52) | 1.38 (0.75–2.53) |
| ≥2 | 0.92 (0.59–1.44) | 0.85 (0.54–1.33) | 1.03 (0.60–1.75) | 1.13 (0.66–1.96) |
| Nasal allergy | 1.15 (0.79–1.66) | 1.12 (0.77–1.62) | 0.84 (0.54–1.29) | 0.79 (0.50–1.25) |
| IgE sensitisation | ||||
| Pollen | 1.80 (1.22–2.67) | 1.54 (1.03–2.31) | 1.44 (0.90–2.29) | 1.57 (0.94–2.60) |
| Mite | 1.91 (1.30–2.81) | 2.00 (1.36–2.93) | 1.58 (0.99–2.53) | 1.69 (1.04–2.76) |
| Pets | 1.56 (1.04–2.34) | 1.82 (1.23–2.69) | 1.60 (0.98–2.59) | 1.29 (0.80–2.11) |
| Any | 2.19 (1.37–3.51) | 1.36 (1.04–1.79) | 1.57 (0.93–2.64) | 1.42 (0.82–2.45) |
| Total IgE per log unit | 1.50 (1.12–2.03) | 1.53 (1.13–2.06) | 0.94 (0.65–1.36) | 1.01 (0.68–1.49) |
| FeNO per log unit | 5.27 (2.47–11.3) | 5.02 (2.36–10.7) | 3.61 (1.48–8.82) | 3.80 (1.49–9.64) |
| Pre-bronchodilator FEV1 % pred | 0.94 (0.93–0.95) | 0.95 (0.95–0.96) | 0.94 (0.94–0.95) | 0.97 (0.96–0.98) |
| Pre-bronchodilator FVC % pred | 0.96 (0.95–0.97) | 0.97 (0.96–0.98) | 0.94 (0.93–0.95) | 0.96 (0.96–0.97) |
Data are presented as OR (95% CI), adjusted by sex, age, body mass index (BMI), smoking, pre-bronchodilator forced expiratory volume in 1 s (FEV1) and study. Statistically significant associations are presented in bold. FVC: forced vital capacity; FeNO: exhaled nitric oxide fraction.