Clinical and Safety Outcomes of Long-Term Azithromycin Therapy in Severe COPD Beyond the First Year of Treatment

Background Exacerbations of COPD (ECOPD) are a major cause of mortality and morbidity. Continuous cyclic azithromycin (CC-A) reduces the exacerbation rate, but it is unknown whether it remains effective and safe beyond the first year. Methods This study was a retrospective analysis of patients with severe COPD (Global Initiative for Chronic Obstructive Lung Disease grade D) with ≥ 4 moderate to severe ECOPD who received CC-A (500 mg three times per week) as add-on therapy. Patients treated over 24 months were considered long-term continuous cyclic azithromycin (LT-CC-A) users, and ECOPD, hospitalizations, and length of hospital stays during the first, second, and third years were compared with the previous 12 months. Microbiologic monitoring, assessment of macrolide resistance, and analysis of side effects were maintained throughout the study period. Results A total of 109 patients with severe COPD treated with CC-A (39 for ≥ 24 months) comprised the LT-CC-A group (35.8%). This group presented average reductions in ECOPD from baseline of 56.2% at 12 months, 70% at 24 months, and 41% at 36 months, paralleled by respective reductions in hospitalizations of 62.6%, 75.8%, and 39.8%. ECOPD due to common microorganisms fell by 12.5% and 17.3% at 12 and 24 months of LT-CC-A, respectively, with a 50% increase in macrolide resistance. Pseudomonas aeruginosa ECOPD rose by 7.2% and 13.1% at these two time points. CC-A therapy was well tolerated with few side effects: digestive disorders in the short term (7.1%) and hearing loss in the long term (5.1%). Conclusions LT-CC-A therapy over a 24- to 36-month period in patients with COPD (Global Initiative for Chronic Obstructive Lung Disease grade D) achieved sustained reductions in ECOPD and hospitalizations of > 50% with few adverse events, although macrolide resistance increased.