In fact, the type of inflammation seen in patients with both asthma and bronchiectasis might render them insensitive to typical asthma treatment, and testing bronchiectasis-type antibiotics in this group of patients might be a better approach, researchers suggested.
The study, “Investigation of bronchiectasis in severe uncontrolled asthma,” appeared in the Clinical Respiratory Journal.
Researchers recruited 40 patients — 28 women and 12 men — who had asthma for an average of 16.5 years. All were being treated with a combination of an inhaled corticosteroid and a long-acting beta-2 agonist, and 40 percent were also taking a leukotriene receptor blocker.
Despite treatment, all patients had uncontrolled disease, characterized by cough, wheezing, chest tightness and breathing difficulties.
Using high-resolution computed tomography, the research team found bronchiectasis in 27 of the 40 patients, or 67.5 percent of the group.
Earlier studies have suggested that asthma might cause bronchiectasis. Except for asthma, researchers could not find any specific cause of bronchiectasis in any of the patients.
Sputum tests showed that 22.5 percent of patients had airway bacterial infections, most commonly with Pseudomonas aeruginosa and Haemophilus influenzae. All patients with bacterial infections also had bronchiectasis.
Interestingly, patients with bronchiectasis also consumed more antibiotics. In fact, the more extensive the bronchiectasis was, the more antibiotics a patient used. Those with lung infections also had worse bronchiectasis and used more antibiotics.
Researchers calculated the severity of asthma using the asthma control test. Lower scores — indicating more uncontrolled asthma — were linked to more common asthma exacerbations and a more extensive use of corticosteroids. In addition, lower asthma control scores and bronchiectasis extent were not related to results in lung function tests.
Nevertheless, researchers said it is important to diagnose the presence of bronchiectasis in asthma patients, as the two conditions might need different treatment approaches.
Asthma typically involves inflammation caused by eosinophil immune cells, which respond to treatment with corticosteroids. Bronchiectasis, on the other hand, mainly involves neutrophil immune cells, which do not react to corticosteroid treatment in the same way. Doctors instead use a type of antibiotics called macrolides in bronchiectasis patients.
The findings raise the issue of whether a subgroup of asthma patients with neutrophil-based inflammation would respond better to treatment with these antibiotics — a question that should be explored in future research, the team said.