Changing thresholds and incidence of antibiotic treatment of cystic fibrosis pulmonary exacerbations, 1995-2005

Background: Increased chronic therapy use and improved cystic fibrosis (CF) patient health should be accompanied by reduced pulmonary exacerbation-associated antibiotic treatment incidence. Methods: Treatment incidence rates and associated sign/symptom scores from 1995-2005 were studied in Epidemiologic Study of CF patients by route (± IV) and age (< 6, 6-12, 13-17, ≥ 18 years). Results: Overall treatment incidence rate fell 0.0165 events/patient-year/year (P= .006); IV incidence fell 0.0179 (P< .001). Non-IV incidence increased in children ≤ 12. years (P≤ .002) while significantly decreasing in older patients. Mean IV (P= .046) and non-IV (P= .004) treatment-associated clinical scores decreased in children < 6 years. Non-IV (but not IV) clinical scores decreased in older patients. Conclusions: IV incidence fell for all ages from 1995-2005; non-IV incidence increased in patients ≤ 12 years and fell in others. Average clinical treatment thresholds fell in children < 6 years; IV thresholds were unchanged in older patients; non-IV thresholds fell for patients ≥ 13 years. Decreases in treatment incidence were likely partially offset by lower treatment thresholds.