The prevalence and incidence of bronchiectasis are not known accurately. Prevalence has been estimated to be from 0.013 cases per 100 000 population in 1954 in the UK and 0.5 per 100 000 in Finland in 1998, to 4 per 100 000 in people aged 18–34 years, rising to 272 per 100 000 in over those over 75 years of age in the USA in 2005. In New Zealand, the reported prevalence is 3.7 per 100 000 population but this varies according to ethnicity. Bronchiectasis is particularly common in children of Pacific Island descent compared with European children. In a sample of 5% of Medicare data in the USA, the 8-year period prevalence of bronchiectasis was 1106 cases per 100 000 population, and in this study the prevalence of bronchiectasis increased by about 8.7% per year of life. This report also suggested a higher prevalence in Asian- compared to African- and European-Americans.
In Europe, age-standardised hospital admission rates vary from less than 2 to more than 6 per 100 000 population (figure 1). This is lower than the estimated average annual age-adjusted hospitalisation rate in a US study, which found 16.5 hospitalisations per 100 000 population and an increase of 2.4% among men and 3.0% among women between 1993 and 2006. In the US study, women and people aged > 80 years had the highest rate of bronchiectasis-associated hospitalisations. The differences between the USA and Europe perhaps reflect the quality of available data.
Prognosis in people with bronchiectasis is not clear, but it is definitely related to lung function and the presence of infection, particularly Pseudomonas aeruginosa. A study from the UK suggests that the number of deaths due to bronchiectasis is increasing at 3% per year.