Randomised controlled clinical trials on the effects of inhaled corticosteroids in patients with corticosteroid naive asthma
| Study | Major outcome measures | Mean baseline BHR (range of doses applied) | Mean baseline FEV1 | Effects on BHR (inhaled corticosteroid vs. control)* | Effects on lung function (inhaled corticosteroid vs. control) | Effects on symptoms, β2 agonists and bronchial epithelium/eosinophils (inhaled corticosteroids vs. control) |
|---|---|---|---|---|---|---|
| Ryan55 | PC20 histamine | 0.5 mg/ml histamine (0.0125–16) | 3.18 l | +0.44 DD (p = 0.14) | FEV1 = | No data |
| Baets56 | PD20 histamine/HDM | 50 μg histamine (10–1280) | 90%pred | +1.55 DD (p<0.001) | FEV1+ (97%), morning PEF+ (20 l/min) | Symptoms =, β2 agonists − |
| Kerrebijn57 | PD20 methacholine | 38 μg methacholine (10–1280) | 95%pred | +2.33 DD (p<0.001) | FEV1 = | Symptoms = |
| Bel58 | PC20 methacholine, max airway narrowing methacholine | 3.6 mg/ml methacholine (0.25–256) | 94%pred | +0.65 DD (p = 0.23) | FEV1= | No data |
| Fuller59 | PD35histamine/bradykinin | 0.28 μmol histamine (0.06–16) | 89%pred | +1.00 DD (p = 0.21) | FEV1=, PEF+ (35–50 l/min) | Symptoms = |
| Laitinen60 | PC15 histamine, FEV1, PEF, symptoms, biopsy: bronchial epithelium, inflammatory cells mucosa | 2.9 mg/ml histamine (1.0–32) | 89%pred | +0.70 DD (p = 0.25) | FEV1 =, PEF+ (50 l/min) | Symptoms =, β2 agonists =, structure airway epithelium +, lymphocytes −, eosinophils − |
| Haahtela61 | PC15 histamine, FEV1, PEF, symptoms, β agonists | 7.0 mg/ml histamine (1.0–32) | 86%pred | +1.10 DD (p<0.001) | FEV1 =, PEF+ (30 l/min) | Symptoms −, β2 agonists − |
| O’Connor62 | PC20methacholine/MBS/AMP | 1.4 mg/ml methacholine (0.125–32) | 96%pred | +1.17 DD (p = 0.009) | FEV1= | No data |
| Evans63 | Peripheral blood eosinophils, PC20 methacholine | 0.13–2.23 mg/ml methacholine (0.125–32) | 96%pred | +0.88 DD (p<0.001) | No data | No data about symptoms/β2 agonists, eosinophils − |
| Vathenen64 | PD20 histamine, FEV1, PEF, symptoms, β agonists | 0.37 μmol histamine (0.03–32) | 95%pred | +2.40 DD (p = 0.003) | FEV1+ (98%), PEF+ (40 l/min) | Symptoms −, β2 agonists − |
| Wiebicke65 | PC100 sRaw histamine/methacholine, PV75 sRaw hypervent/So 2 | 0.2 mg/ml histamine (0.01–8.0) | 90%pred | +0.64 DD (histamine or methacholine) (p = 0.28) | No data | No data |
BHR = bronchial hyperresponsiveness; DD = doubling dose; FEV1 = forced expiratory volume in one second; PEF = peak expiratory flow; sRaw = specific airways resistance; So 2 = oxygen saturation; PC20, PD20 = concentration or dose of provocative agent required to produce a fall in FEV1 of 20% or more.; HDM = house dust mite. According to effects of inhaled corticosteroids versus control group on lung function and symptoms, ‘+’ or ‘−’ means statistically significant increase or decrease (p<0.05), ‘=’ means no statistically significant difference. * See fig 1.