Oral antimicrobial use in outpatient cystic fibrosis pulmonary exacerbation management: a single-center experience

Introduction: Cystic fibrosis (CF) pulmonary disease is characterized by intermittent episodes of acute lung symptoms known as pulmonary exacerbations. While exacerbations are classically treated with parenteral antimicrobials, oral antibiotics are often used in mild cases. Objectives: We determined how often management progressed to intravenous (IV) therapy. We also examined multiple courses of oral antimicrobials within one exacerbation, and identified patient factors associated with unsuccessful treatment. Methods: We performed a retrospective chart audit of oral antibiotic use in CF patients, from March 2009 through March 2010, for 'mild' CF exacerbations. Results: Administration of a single vs multiple courses of oral antibiotics for treatment of 'mild' CF exacerbation avoided progression to IV therapy 79.8% and 50.0% of the time, respectively. Overall, oral antibiotics circumvented the need for IV therapy 73.8% of the time. Using multi-variant analysis, we found multiple patient characteristics to be independent risk factors for oral antibiotic failure including a history of pseudomonas infection [odds ratio (OR) 2.13, confidence interval (CI) 1.29-3.54], CF-related diabetes (OR 1.85, CI 1.00-3.41), allergic Bronchopulmonary aspergillosis (OR 3.81, CI 1.38-10.56), low socioeconomic status (OR 1.67, CI 1.04-2.67), and calculated baseline forced expiratory volume in 1 s (FEV1) < 75% of predicted prior to an acute exacerbation (OR 1.93, CI 1.20-3.08). Decline in FEV1 > 10%, weight for age, body mass index, distance from the CF center and gender were not significant. Conclusion: Our observations suggest that one course of oral antimicrobials is frequently effective in outpatient CF pulmonary exacerbations but exacerbations requiring more than one course of oral antibiotics are likely to require IV therapy.