Study design (if review, criteria of inclusion for studies)
Randomised controlled trials (RCTs). We will assess quasi-RCTs on their merit using the Cochrane risk of bias tool and if both reviewers are satisfied that the groups were similar at baseline, we will include them.
Children and adults with CF diagnosed by sweat test or genetic testing, with all stages and severity of lung disease and with or without concomitant asthma.
Long-acting inhaled bronchodilators delivered via any device and at any dose, frequency or duration. For this review the term inhaled includes the use of pressurised metered dose inhalers (MDIs) with or without a large volume spacer, dry powder devices and nebulisers. Both types of long-acting bronchodilators which have a duration of action of at least 12 hours: beta-2 agonists, e.g. salmeterol, formoterol; anticholinergics, e.g. tiotropium, aclidinium. Not considered: combined inhalers (with inhaled steroids or another bronchodilator) or short-acting bronchodilators (e.g. salbutamol, ipratropium bromide). The comparator will be an inhaled placebo, another long-acting bronchodilator (or the same drug at a different dose) or usual treatment.
Primary outcomes Change in forced expiratory volume in one second (FEV1) from baseline (litres and per cent (%) predicted). Participant-reported outcomes including quality of life (QoL) using standardised and validated QoL scores (e.g. CFQ-R (Quittner 2009)) and symptom scores (e.g. Respiratory and Systemic Symptoms Questionnaire (RSSQ), Respiratory Symptom Score (RSS) (Goss 2007)) 1 Adverse effects (especially those associated with long-acting inhaled bronchodilators i.e. for beta-2 agonists tremor, nervous tension, headache, peripheral dilatation and palpitation, increased heart rate, dry mouth, increased wheeze and shortness of breath; for anticholinergics dry mouth, gastrointestinal motility disorder (constipation and diarrhoea), nausea, gastro-oesophageal reflux disease, dysphagia, tachycardia); 2 frequency of adverse effects; 3 severity of adverse effects, e.g. mild or moderate or severe (where it has been reported).