Harrison 2004.

Study characteristics
Methods	Randomised, placebo‐controlled, parallel‐group trial Single centre based in the UK Investigated whether doubling the dose of inhaled corticosteroid when asthma control starts to deteriorate reduces the number of participants needing prednisolone, and sought to establish effects on the severity and duration of the subsequent exacerbation Recruitment year(s) not reported 52 weeks from baseline to endpoint
Participants	Population 390 participants were randomised; 207 experienced an exacerbation and contributed to the analysis. Participants were 16 years or older; mean age was 49 years; 33% were male; 61% were non‐smokers, 36% ex‐smokers, and 3% smokers. Inclusion criteria Age ≥ 16 years; clinical diagnosis of asthma; taking an inhaled corticosteroid (100 to 2000 μg/d) on a regular basis; previous course of oral corticosteroids or doubled dose of inhaled corticosteroid in the previous 12 months for treatment or prevention of an asthma exacerbation Exclusion criteria History of smoking > 10 pack‐years; unstable asthma during a 2‐week run‐in period Baseline asthma severity See Table 2.
Interventions	Run‐in period 2‐week period whereby participants continued their usual dose of inhaled corticosteroid and recorded morning peak flow and daytime symptom scores to ensure asthma stability Study period Control arm: maintenance inhaled corticosteroid (100 to 2000 μg/d) + identical placebo inhaler for exacerbations Study arm: maintenance inhaled corticosteroid (100 to 2000 μg/d) + identical inhaler with corticosteroid to double dose of ICS for exacerbations Participants were to use study inhaler for 14 days in addition to usual treatment when peak flow or symptoms deteriorated. Other medications allowed Not specified
Outcomes	Primary outcome Proportion of participants who needed prednisolone in each group Secondary outcomes Maximum fall in peak flow Maximum increase in symptom scores Time to recovery of peak flow and symptom scores
Notes	Funding source: NHS Executive (through National Asthma Campaign) Funder role: provided critical review of the protocol but no role in study design, data collection, data analysis, data interpretation, or writing of the report Registration: not registered Ethics approval: approved by Nottingham City Hospital ethics committee Consent to participate: reports all participants provided written informed consent Trial reporting vs review analysis: study reports need for oral steroids separately for those who took their study inhaler (suitable for Analysis 1.2) and all randomised participants (suitable for Analysis 1.1)