Inhaled antibiotics for long-term therapy in cystic fibrosis

Background Inhaled antibiotics are commonly used to treat persistent airway infection that contributes to lung damage in people with cystic fibrosis (CF). Objectives To examine the evidence that inhaled antibiotic treatment in people with CF reduces frequency of exacerbations of infection, and improves lung function, quality of life and survival. To examine adverse effects of inhaled antibiotic treatment. Search strategy Trials were identified from the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register. Last search: 31 January 2011. Selection criteria Trials were selected if inhaled antibiotic treatment was used for at least four weeks in people with CF, treatment allocation was randomised or quasi-randomised, and there was a control group (either placebo, no placebo or another inhaled antibiotic). Data collection and analysis Two authors independently selected trials, judged the risk of bias and extracted data from these trials. Main results The searches identified 176 citations to 78 trials. Nineteen trials, with 1724 participants, met the inclusion criteria. Adequate meta-analysis was not possible because of the variability of study design and reporting of results. Seventeen trials with 1562 participants compared an inhaled antibiotic with placebo or usual treatment for a duration between 1 and 32 months. Inhaled tobramycin was studied in eight trials. Lung function (measured as forced expired volume in one second) was higher and exacerbations of lung infection (by different measures) were less in the antibiotic-treated group. Resistance to antibiotics increased more in the antibiotic-treated group than in placebo group when results were reported. No auditory or renal impairment was found; analysis showed tinnitus, voice alteration, hemoptysis and cough were more frequent with tobramycin than placebo. One trial, compared tobramycin with colistin in 115 participants, after one month the mean difference in forced expiratory volume at one second was 6.33 (95% confidence interval 0.04 to 12.70) favouring tobramycin. Authors' conclusions Inhaled antibiotic treatment probably improves lung function and reduces exacerbation rate, but a pooled estimate of the level of benefit is not possible. The best evidence is for inhaled tobramycin. More evidence, from trials of longer duration, is needed to determine whether this benefit is maintained and to determine the significance of development of antibiotic-resistant organisms.