Inhaled bronchodilators for cystic fibrosis
Abstract
Background
Recurrent wheeze and breathlessness are common in people with cystic fibrosis, and bronchodilators are commonly prescribed. Despite their wide‐scale and often long‐term use, there is limited objective evidence about their efficacy in cystic fibrosis (CF).
Objectives
To evaluate the effectiveness of inhaled bronchodilators in people with CF.
Search methods
We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic databases searches, and handsearches of relevant journals and abstract books of conference proceedings.
Latest search of the Group's Trials Register: 09 September 2010.
Selection criteria
Randomised or quasi‐randomised trials comparing inhaled bronchodilators to placebo or another inhaled bronchodilator in people with CF, diagnosed clinically and by sweat or genetic testing and at all stages and severity of lung disease.
Data collection and analysis
The authors independently extracted data and assessed trial quality. A trial's primary author was contacted for any missing data where possible. Data were grouped into classes of bronchodilator and, for each class, into short‐term effects (less than one week) and long‐term effects (greater to or equal to one week).
Main results
The search identified 66 references; eighteen trials (total of 369 participants) were suitable for inclusion. All but two of the trials were cross‐over in design; a meta‐analysis was not possible. There were varied conclusions from the different trials reflecting their heterogeneity. Compared to placebo, short‐acting beta‐2 agonists increased forced expiratory volume at one second (FEV1) in the short term in three out of five trials, and in the long‐term increased peak expiratory flow rate in individuals who had been shown to have bronchial hyperreactivity, bronchodilator responsiveness or both. Compared to placebo, long‐acting beta‐2 agonists increased FEV1 and forced expiratory flow between 25% and 75% of expiratory flow in the short term in participants known to have bronchodilator responsiveness, but produced inconsistent results in long‐term trials. Short acting‐anticholinergics had no consistent effect on lung function tests in either the short or the long term. We found no published trials of fenoterol, formoterol or tiotropium.
Authors' conclusions
It was not possible to determine fully the effectiveness of inhaled bronchodilators in CF as a meta‐analysis was not possible. However, short and long‐acting beta‐2 agonists can be beneficial both in the short and long term in individuals with demonstrable bronchodilator responsiveness or bronchial hyper‐responsiveness. As we found no evidence, the use of fenoterol, formoterol or tiotropium in CF cannot be supported.
PICOs
Plain language summary
Inhaled drugs to open up the airways of people with cystic fibrosis
People with cystic fibrosis are often given drugs to open up their airways when they are breathless or wheezy. The drugs are given either by metered dose inhalers or nebulisers. We looked at how well these drugs worked in both children and adults. We included 18 trials in the review. Some of these used beta‐2 agonist bronchodilators and some used anticholinergic bronchodilators. Data for both long‐acting and short‐acting versions of both drug classes were collected. The results were split into short‐term effects (less than one week) and long‐term effects (one week or longer). The studies were too varied to allow results to be combined. Both short‐acting and long‐acting beta‐2 agonists improved lung function in the short‐term, but only in those people whose airways were found to be sensitive to the bronchodilator after their first dose. Results were not consistent in the long‐term. It is reasonable to suggest that a long‐term trial of inhaled bronchodilators be considered before their long‐term use is recommended. Further large trials are needed to make clear the benefits of these drugs.
