The less severely affected randomized group of the trial did not exhibit significant effects attributable to azithromycin. The more severely affected OL cohort demonstrated significant, and large, azithromycin treatment effects for asthma symptoms, asthma quality of life, and asthma control (P < .05 for both groups; number needed to treat [NNT] = 3) that persisted during the posttreatment observation period.
There is no direct evidence that the benefit of azithromycin in asthma is limited to patients who have positive infection biomarkers.
Comment: The authors concluded: “Pending further randomized trials and given the relative safety of azithromycin and the significant disease burden from severe, refractory asthma, prescribing prolonged azithromycin therapy to patients with uncontrolled asthma may be considered by managing clinicians, particularly for patients who have failed to respond to conventional treatment and as an alternative to instituting immunomodulatory agents.”15
Before-and-after trial. Forty-six patients with moderate or severe chronic, persistent, stable asthma were selected as a cohort unlikely to experience spontaneous remission (ie, patients in exacerbation were excluded) (Level 2 study: prospective cohort).17 Subjects were treated for a median of 4 weeks (range, 3 to 9 weeks) with oral doxycycline, 100 mg bid; azithromycin, 1000 mg, once weekly; or erythromycin, 1000 mg/d in divided doses. Average duration of posttreatment follow-up was 6 months. All subjects were positive for antibodies to Chlamydia pneumoniae.
Four patients with diagnosed acuteC pneumoniae respiratory infection developed chronic asthma, which disappeared in each case after treatment. Of the other 42 seroreactive patients who were treated a mean of 6 years after they developed chronic asthma, 21 had either complete remission of asthma symptoms (n = 3) or major persistent clinical improvement (n = 18). Clinical improvement was more likely to occur in patients with early disease (P = .01) and before development of fixed airway obstruction (P < .01).
These results are consistent with the hypothesis that chronic infection of the lower respiratory tract contributes to the development and progression of asthma.17 Although clinical improvement was more likely in early asthma compared with asthma with fixed airway obstruction, improvement was nevertheless noted in the latter group.
