Study objectives: To determine the concentration of
exhaled H2O2 in patients with bronchiectasis,
and to study the relationship between levels of exhaled
H2O2, extent of disease, symptoms score,
spirometry, and cellular composition obtained from induced sputum;
furthermore, to account for possible confounding effects of inhaled
corticosteroids (ICS) usage, long-term oral antibiotic treatment, and
chronic colonization with Pseudomonas aeruginosa.
Design: Cross-sectional study.
Thirty patients with steady-state bronchiectasis.
Results: Mean (95% confidence interval [CI]) exhaled
H2O2 levels were significantly elevated in
patients with bronchiectasis compared to normal subjects: 1.1 (0.87 to
1.29) μM vs 0.3 (0.19 to 0.36) μM, respectively (p < 0.0001).
Patients treated with ICS had similar values as steroid-naïve
patients. The group of patients with P aeruginosa
colonization showed a significantly increased concentration of
H2O2 compared to the group without P
aeruginosa colonization. Patients receiving long-term oral
antibiotic treatment had significantly higher values of
H2O2 compared to those not receiving
antibiotics. There was a significant positive correlation between
H2O2 and either the percentage of neutrophils
in induced sputum or the extent of the disease as defined by
high-resolution CT. A significant negative correlation was found
between H2O2 and FEV1 percent
predicted. Finally, there was a significant positive correlation
between H2O2 and the symptoms score.
Conclusions: Patients with bronchiectasis in stable
condition showed increased levels of exhaled
H2O2. The above-mentioned levels were not
decreased either by ICS or long-term oral antibiotic treatment, but
were significantly affected by chronic colonization with P
aeruginosa. H2O2 levels could be an
indirect index of neutrophilic inflammation, impairment of lung
function, and extension and severity of the disease.