Inhaled corticosteroids for cystic fibrosis

Background Reduction of lung inflammation is one of the goals of cystic fibrosis (CF) therapy. Inhaled corticosteroids (ICS) are often used to treat children and adults with CF. The rationale for this is their potential to reduce lung damage arising from inflammation, as well as their effect on symptomatic wheezing. It is important to establish the current level of evidence for the risks and benefits of ICS, especially in the light of their known adverse effects on growth. Objectives To assess the effectiveness of taking regular ICS, compared to not taking them, in children and adults with CF. Search strategy We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We requested information from pharmaceutical companies manufacturing inhaled corticosteroids and authors of identified trials. Date of most recent search of the Group's Trials Register: June 2008. Selection criteria Randomised or quasi-randomised trials, published and unpublished, comparing ICS to placebo or standard treatment in individuals with CF. Data collection and analysis Two independent authors assessed methodological quality of trials using established criteria and extracted data using standard pro formas. Main results Thirty citations were identified by the searches, of which 25, representing 13 trials were eligible for inclusion. These 13 trials reported the use of ICS in 506 people with CF aged between 6 and 55 years. One trial was a withdrawal study in individuals who were already taking ICS. Methodological quality was difficult to assess from published information. Inclusion criteria varied between trials, as did type and duration of treatment and timing of outcome assessments. Objective measures of airway function were reported in most trials but were often incomplete. Significant benefit has not been conclusively demonstrated. Four trials systematically documented adverse effects and growth was significantly affected in one study using high doses. Authors' conclusions Evidence from these trials is insufficient to establish whether ICS are beneficial in CF, but withdrawal in those already taking them has been shown to be safe. There is some evidence they may cause harm in terms of growth. It has not been established whether long-term use is beneficial in reducing lung inflammation, which should improve survival, but it is unlikely this will be proven conclusively in a randomised controlled trial.