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Pulmonary Outcomes Associated with Long-Term Azithromycin Therapy in Cystic Fibrosis

D. Nichols, K. Odem-Davis, J. Cogen, C. Goss, C. Ren, M. Skalland, R. Somayaji, S. Heltshe

American Journal of Respiratory and Critical Care Medicine, 2020

56 citations

Abstract

Rationale: Chronic azithromycin is commonly used in cystic fibrosis based on short controlled clinical trials showing reductions in pulmonary exacerbations and improved FEV1. Long-term effects are unknown. Objectives: Examine pulmonary outcomes among chronic azithromycin users compared with matched controls over years of use and consider combined azithromycin use in cohorts using chronic inhaled tobramycin or aztreonam. Methods: This retrospective cohort study used the U.S. cystic fibrosis Foundation Patient Registry. Incident chronic azithromycin users were compared with matched controls by FEV1% predicted rate of decline and rates of intravenous antibiotic use to treat pulmonary exacerbations. Propensity score methods were utilized to address confounding by indication. Predefined sensitivity analyses based on lung function, Pseudomonas aeruginosa (PA) status, and follow-up time intervals were conducted. Measurements and Main Results: Across 3 years, FEV1% predicted per-year decline was nearly 40% less in those with PA using azithromycin compared with matched controls (slopes, −1.53 versus −2.41% predicted per yr; difference: 0.88; 95% confidence interval [CI], 0.30–1.47). This rate of decline did not differ based on azithromycin use in those without PA. Among all cohorts, use of intravenous antibiotics was no different between azithromycin users and controls. Users of inhaled tobramycin and azithromycin had FEV1% predicted per-year decline of −0.16 versus nonusers (95% CI,…

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Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence.

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