It's long been known in the pediatric cystic fibrosis population that exacerbations accelerate decline of lung function. de Boer et al show that exacerbations are just as bad or worse in adults. Following 446 adults with CF in Ontario for 3 years, those with >2 exacerbations per year had a hazard ratio of 4.05 for death or lung transplantation during the study, after controlling for confounders. Thorax 2011;66:680-685.