A new study to be published in the Annals of Allergy, Asthma & Immunology suggests that bronchiectasis occurs in almost half of patients with severe asthma and is associated with more frequent hospitalizations, concomitant gastroesophageal reflux disease (GERD), hypersensitivity to NSAIDs, and higher blood eosinophil levels.
While only 5% to 10% of all asthma cases are classified as severe, severe asthma disproportionately contributes to asthma-related health care costs. Treatment of comorbidities can go a long way in preventing poor disease control.
Bronchiectasis, or the permanent enlargement of parts of the airways, has been described as a comorbidity of asthma. Then again, asthma has been described as one of the many causes of bronchiectasis. Both asthma severity and bronchiectasis have been associated with sensitization to fungi, including Alternaria spp, Cladosporium spp, and Aspergillus spp.
Prior research has shown that bronchiectasis is present in anywhere from 17.5% to 80% of asthma cases.
This retrospective study was led by Isabel Coman, MD, of the Hospital Universitario La Paz in Madrid, Spain. The team aimed to determine the prevalence of bronchiectasis in patients with severe asthma and to examine the outcomes in this patient population.
Data were collected from patients with severe or uncontrolled asthma at the Hospital Universitatio La Paz between 2010 and 2013. Diagnosis was confirmed via bronchodilator response testing or methacholine bronchial provocation testing.
Patients underwent skin prick testing to determine sensitization to local pollens, dust mites, cockroaches, fungi, and pet dander. All patients underwent measurement of total serum IgE levels and specific IgE levels for aeroallergens and fungi.
High-resolution computed tomodensitography of the thorax, as well as basic hematology, serum levels of eosinophilic cationic protein (ECP), and serum antineutrophil cytoplasmic antibody levels were also performed in all patients.
Data from 184 patients were analyzed. More than 90% were on Global Initiative for Asthma treatment steps 4 and 5. Almost half (47%) had bronchiectasis. Patients with bronchiectasis were more likely to be older than those without, and they were also more likely to have GERD and be intolerant to NSAIDs.
Those with bronchiectasis had significantly higher blood eosinophil and serum ECP levels. IgE levels were comparable between groups.
Conversely, those with bronchiectasis were less likely to have atopic dermatitis than those without. There was also no difference in the likelihood of sensitization to common aeroallergens and fungi.
During the year prior to the study period, 97% of patients with bronchiectasis and 90% of those without bronchiectasis had at least one asthma exacerbation; exacerbation averages were similar between groups (3.45 vs 3.39, respectively).
However, patients with bronchiectasis were more likely to have been hospitalized due to an exacerbation in that same period. The association remained significant for GERD and NSAID intolerance after a multiple logistical regression analysis was performed.
In general, the prevalence of bronchiectasis in patients with any form of asthma is quite low, but it rises markedly in patients with severe asthma. The combined presence of both pathologies is associated with an increased risk of exacerbation, hospitalization, and chronic respiratory failure.
“It is difficult to determine whether the severity of asthma in subjects with coexistent bronchiectasis is due to the presence of bronchiectasis, or if the presence of bronchiectasis is a manifestation of the asthma itself,” the authors wrote. “The higher levels of blood eosinophils and eosinophil cationic protein we observed in patients with coexistent bronchiectasis seems to suggest the latter.”