Are outcomes the same with all dry powder inhalers?

Most clinicians and patients would intuitively say that the inhaler device used influences the outcome achieved in asthma. However, it is important to have objective evidence to support or refute this view. Systematic reviews have suggested that there is no difference in clinical effectiveness between dry powder inhalers and metered-dose inhalers. However, the studies included in the review were randomised clinical trials and not studies based on real-life clinical practice. In the real world, the efficacy of products as determined in a specified and well-monitored population is only one aspect of product performance--patient characteristics and behaviour are critical. Observational studies in real-world primary care settings suggest that the choice of inhaler device has an important impact on asthma outcomes. The IMS Mediplus database has now been used to compare outcomes among patients receiving initial maintenance therapy with beclometasone dipropionate administered via different dry powder inhalers. Patients using the DISKHALER dry powder inhaler used significantly less short-acting beta(2)-agonist than those using the ROTAHALER dry powder inhaler. This suggests a difference in the level of asthma control with the different devices, even when the same chemical entity is delivered. Real-world studies suggest, therefore, that outcomes are not always the same with all dry powder inhalers. This indicates the need for further studies to investigate the impact of inhaler device choice and the impact of switching between devices.