Abstract
Objectives:The respiratory pathogen Chlamydia pneumoniae (C. pneumoniae) produces acute and chronic lung infections and is associated with asthma. Evidence for effectiveness of antichlamydial antibiotics in asthma is limited. The primary objective of this pilot study was to investigate the feasibility of performing an asthma clinical trial in practice settings where most asthma is encountered and managed. The secondary objectives were to investigate (1) whether azithromycin treatment would affect any asthma outcomes and (2) whether C. pneumoniae serology would be related to outcomes. This report presents the secondary results.Design:Randomized, placebo-controlled, blinded (participants, physicians, study personnel, data analysts), allocation-concealed parallel group clinical trial.Setting:Community-based health-care settings located in four states and one Canadian province.Participants:Adults with stable, persistent asthma.Interventions:Azithromycin (six weekly doses) or identical matching placebo, plus usual community care.Outcome Measures:Juniper Asthma Quality of Life Questionnaire (Juniper AQLQ), symptom, and medication changes from baseline (pretreatment) to 3 mo posttreatment (follow-up); C. pneumoniae IgG and IgA antibodies at baseline and follow-up.Results:Juniper AQLQ improved by 0.25 (95% confidence interval; −0.3, 0.8) units, overall asthma symptoms improved by 0.68 (0.1, 1.3) units, and rescue inhaler use decreased by 0.59 (−0.5, 1.6) daily administrations in azithromycin-treated compared to placebo-treated participants. Baseline IgA antibodies were positively associated with worsening overall asthma symptoms at follow-up (p = 0.04), but IgG was not (p = 0.63). Overall asthma symptom improvement attributable to azithromycin was 28% in high IgA participants versus 12% in low IgA participants (p for interaction = 0.27).Conclusions:Azithromycin did not improve Juniper AQLQ but appeared to improve overall asthma symptoms. Larger community-based trials of antichlamydial antibiotics for asthma are warranted.
Highlights
Chlamydia pneumoniae (C. pneumoniae) is a ubiquitous intracellular human pathogen that is reported to cause approximately 10% of community-acquired pneumonia and 5% of acute bronchitis [1]
C. pneumoniae infection has been associated with acute asthmatic bronchitis [2,3], bronchial hyperreactivity [4,5], new-onset asthma [6], chronic asthma [3,5], ‘‘infectious asthma’’ [7], and asthma severity [8,9,10]
The secondary results reported here are (1) azithromycin effects on asthma-specific quality of life (Juniper AQLQ), asthma symptoms, and rescue medication use, and (2) relationships of C. pneumoniae antibodies with these outcomes, and whether antibody levels were affected by treatment
Summary
Chlamydia pneumoniae (C. pneumoniae) is a ubiquitous intracellular human pathogen that is reported to cause approximately 10% of community-acquired pneumonia and 5% of acute bronchitis [1]. An open-label before-after trial in 48 adults with stable, persistent asthma reported that over half of participants who were treated with 3–9 wk of antibiotics, consisting mostly of azithromycin, had major lasting clinical improvement or complete remission of asthma symptoms [11]. There are very little data from clinical trials determining whether treatment with antibiotics active against C. pneumoniae has an effect on the control of asthma. What this trial shows: In this trial, the researchers randomized 45 adults who were being treated for asthma in primary care to receive either azithromycin (an antibiotic active against C. pneumoniae) or placebo, in addition to their usual asthma care. The investigators did see a significant improvement in the overall symptoms recorded by participants receiving azithromycin, as compared to placebo
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