SYSTEMATIC REVIEW OF THE COMPARATIVE EFFECTIVENESS OF INHALED CORTICOSTEROIDS FOR THE TREATMENT OF PERSISTENT ASTHMA

Purpose: To assess the comparative effectiveness of inhaled corticosteroids (ICSs) for the treatment of adults and children with persistent asthma.

 Methods:  We searched Medline, the Cochrane database, and the International Pharmaceutical Abstracts (1990 through April 2008), using terms for included drugs, indications, and study designs. We also reviewed dossiers provided by pharmaceutical companies.  We included studies of subjects with persistent asthma that compared the efficacy or effectiveness of ICSs: beclomethasone, budesonide, flunisolide, fluticasone, triamcinolone, and mometasone. We included head-to-head randomized controlled trials (RCTs) of at least 6 weeks duration and systematic reviews.  Outcomes of interest included control of symptoms, rescue medication use, exacerbations, quality of life, healthcare utilization, and mortality.

 Two reviewers independently assessed abstracts and full-text articles to identify included studies. Disagreements were resolved by consensus.  We used a structured data abstraction form to ensure consistency in appraisal for each study.  Trained reviewers abstracted data and assessed the methodologic quality (internal validity) of studies using predefined criteria based on the U.S. Preventive Services Task Force and the National Health Service Centre for Reviews and Dissemination (U.K.) criteria.  Meta-analyses were conducted for outcomes reported by a sufficient number of studies which were homogeneous enough to justify combining their results. Otherwise, the data were summarized qualitatively. Random effects models were used for the estimation of pooled effects.  We rated the overall strength of evidence (insufficient, low, moderate, or high) using standard methods from the Evidence-based Practice Centers’ Guide for Conducting Comparative Effectiveness Reviews.

 Results: We found 30 head-to-head RCTs (4 in children) and two systematic reviews comparing one ICS to another that met inclusion criteria.  Trial duration ranged from 6 to 52 weeks.  The most commonly compared medications were beclomethasone vs fluticasone (9 RCTs) and budesonide vs fluticasone (6 RCTs).  We found no trials meeting our criteria for three of the comparisons (beclomethasone vs flunisolide, flunisolide vs mometasone, and flunisolide vs triamcinolone).  Overall, we found no significant differences between ICSs in their ability to control asthma symptoms and reduce rescue medication use (moderate strength of evidence).  Data were limited for other outcomes.

 Conclusion: Efficacy studies provide moderate evidence that ICSs do not differ in their ability to control asthma symptoms and reduce the need for additional rescue medication at equipotent doses administered through comparable delivery devices.