Characterization of the “frequent exacerbator phenotype” in bronchiectasis

Rationale: Exacerbations are key events in the natural history of bronchiectasis, but clinical predictors and outcomes of patients with frequently exacerbating disease are not well described. Objectives: To establish if there is a “frequent exacerbator phenotype” in bronchiectasis and the impact of exacerbations on long-term clinical outcomes. Methods: We studied patients with bronchiectasis enrolled from 10 clinical centers in Europe and Israel, with up to 5 years of follow-up. Patients were categorized by baseline exacerbation frequency (zero, one, two, or three or more per year). The repeatability of exacerbation status was assessed, as well as the independent impact of exacerbation history on hospitalizations, quality of life, and mortality. Measurements and Main Results: A total of 2,572 patients were included. Frequent exacerbations were the strongest predictor of future exacerbation frequency, suggesting a consistent phenotype.

The incident rate ratios for future exacerbations were 1.73 (95% confidence interval [CI], 1.47-2.02; P, 0.0001) for one exacerbation per year, 3.14 (95% CI, 2.70-3.66; P, 0.0001) for two exacerbations, and 5.97 (95% CI, 5.27-6.78; P, 0.0001) for patients with three or more exacerbations per year at baseline. Additional independent predictors of future exacerbation frequency were Haemophilus influenzae and Pseudomonas aeruginosa infection, FEV₁, radiological severity of disease, and coexisting chronic obstructive pulmonary disease. Patients with frequently exacerbating disease had worse quality of life and were more likely to be hospitalized during followup. Mortality over up to 5 years of follow-up increased with increasing exacerbation frequency. Conclusions: The frequent exacerbator phenotype in bronchiectasis is consistent over time and shows high disease severity, poor quality of life, and increased mortality during follow-up.