Observational Studies of Inhaled Corticosteroid Effectiveness in COPD

Observational studies are important to provide evidence from real-world data on medication effects. However, appropriate study design and analysis are essential to avoid biases and ensure randomized trials with greater chances of success. The observational studies suggesting potential beneficial effects of nonrespiratory drugs to treat COPD, such as statins and beta-blockers, will also need careful review before long and expensive randomized trials are conducted.