A study analyzing the prevalence and incidence of bronchiectasis in the United States found that both are substantially higher than previously reported, and the number of cases has been growing steadily since 2001.

Despite the availability of non-invasive and effective diagnostic technologies following the advent of high-resolution computed tomography (HRCT), researchers believe that bronchiectasis continues to be underdiagnosed in the U.S. And while recent studies in the U.K. and South Korea have suggested that bronchiectasis is more common than previously thought, no similar studies had been undertaken in the U.S.

In the study, “Prevalence and incidence of noncystic fibrosis bronchiectasis among US adults in 2013,” published in the journal Chronic Respiratory Disease, researchers sought a clearer picture of bronchiectasis diagnosis in U.S. clinical practice.

The team used data from 33.2 million adults in the “MarketScan Database,” a large healthcare repository of medical claims from a large number of private U.S. health plans. Of those, 31,122 were found to have been diagnosed with bronchiectasis in 2013. Patients had a mean age of 68.

The most common comorbidities of bronchiectasis were chronic obstructive pulmonary disease (52%), acute bronchitis (38%), post-inflammatory fibrosis (14%), and genetic disorders (10%).

The overall prevalence of bronchiectasis was estimated at 139 cases per 100,000 U.S. adults. The prevalence was higher in women than men, at 180 per 100,000 and 95 per 100,000, respectively.

Prevalence also was found to be associated with age, increasing from 7 per 100,000 in patients aged 18-34 to 812 per 100,000 in patients 75 and older.

Annual bronchiectasis incidence, which is the number of patients newly diagnosed in 2013, was estimated at 29 cases per 100,000. Again, this was higher in women than in men (34 per 100,000 compared with 23 per 100,000, respectively) and increased with age, from 2 per 100,000 in people aged 18-34 to 154 per 100,000 in people 75 and older.

The results indicate that the prevalence of bronchiectasis in the U.S. is much higher than previously thought.

A previous study had reported a prevalence of 52.3 adult cases per 100,000, corresponding to 110,000 adults of all ages with bronchiectasis in the U.S.

Taken together, the results of the current study estimated the number of adults with bronchiectasis in the U.S. to be between 340,000 and 522,000, with 70,000 adults diagnosed every year.

Furthermore, the team found that the diagnosis of bronchiectasis has been growing steadily since 2001 at an annual rate of 8%.

“Taken collectively, this study indicates that the prevalence and incidence of bronchiectasis is substantially higher than previously reported, underscoring the importance of diligent surveillance and attentive treatment for this condition,” the research team stated.