Predictors of COPD Exacerbation Reduction in Response to Daily Azithromycin Therapy.
Am J Respir Crit Care Med. 2014 Apr 29;
Authors: Han MK, Tayob N, Murray S, Dransfield MT, Washko G, Scanlon PD, Criner GJ, Casaburi R, Connett J, Lazarus SC, Albert R, Woodruff P, Martinez FJ
Background: Daily azithromycin decreases acute exacerbations of chronic obstructive pulmonary disease (AECOPD), but long-term side effects are unknown. We sought to identify the types of exacerbations most likely to be reduced and clinical subgroups most likely to benefit from azithromycin 250 mg daily added to usual care. Methods: Enrollment criteria included irreversible airflow limitation and AECOPD requiring corticosteroids, ED visit or hospitalization in the prior year or use of supplemental oxygen. Recurrent events and cumulative incidence analyses compared treatment received for AECOPD by randomization group, stratified by subgroups of interest. Cox proportional hazards models estimated treatment effects in subgroups adjusted for age, gender, smoking status, FEV1% predicted, concomitant COPD medications and oxygen use. Findings: Azithromycin was most effective in reducing AECOPD requiring both antibiotic and steroid treatment (n=1,113; cumulative incidence analysis p=0.0002; recurrent events analysis p=0.002). No difference in treatment response by gender (p=0.75), presence of chronic bronchitis (p=0.19), concomitant inhaled therapy (p=0.29) or supplemental oxygen use (p=0.23) was observed. Older age and milder GOLD stage were associated with better treatment response (p=0.02 and 0.04 respectively). A significant interaction between treatment and current smoking was seen (p=0.03) and azithromycin did not reduce exacerbations in current smokers [HR=0.99 (95% CI 0.71, 1.38; p=0.95)]. Interpretation: Azithromycin is most effective in preventing AECOPD requiring both antibiotic and steroid treatment. Adjusting for confounders, we saw no difference in efficacy by gender, history of chronic bronchitis, oxygen use or concomitant COPD therapy. Greater efficacy was seen in older patients and milder GOLD stages. We found little evidence of treatment effect among current smokers.
PMID: 24779680 [PubMed - as supplied by publisher]