Ambulatory treatment of acute exacerbations of chronic bronchitis (AECB) is associated with a high risk for relapse. Risk factors for relapse are older age and prior medical history. Relapse rates have differed among antibiotic classes. This study considers whether there were differences in relapse rates for the treatment of AECB between the advanced macrolide antibiotics, clarithromcyin extended release (ER) and azithromycin.
Retrospective cohort analysis of visits for AECB using medical record review. Patients with a diagnostic code for chronic obstructive pulmonary disease (COPD) and bronchitis treated with clarithromycin-ER or azithromycin were evaluated. A logistic regression model was used to control for demographic characteristics, severity of infection, smoking history, caridiopulmonary diseases, and season.
A total of 187 unique patients accounted for 252 episodes of AECB (127 episodes for clarithromcyin ER and 125 for Azithromycin). The groups differed only in that patients treated with clarithromycin-ER tended to be older (mean ages 52.5 +/− 14.3 vs 49.1 +/− 14.2 years, respectively, p=0.053) and patients treated with azithromycin were more likely to have a prior history of COPD (13/125 vs. 4/127, respectively, p=0.025). Of the total observations the overall relapse rate was 4% (2.3% for clarithromycin-ER and 5.6% for azithromycin). When controlling for other factors, patients treated with azithromycin were 8.8 times more likely to fail than were patients treated with clarithromycin-ER (p=0.02). Black and Hispanic were twice as likely to fail than were White patients (p=0.008).CONCLUSIONS: The use of advanced generation macrolide antibiotics (i.e., clarithromycin-ER, azithromycin) demonstrated a low relapse rate in patients presenting with AECB. Patients treated with clarithromycin-ER, were shown to have a significantly lower relapse rate than were patients treated with azithromycin. Racial differences may also be a predictive factor for relapse.
Decreased relapses may decrease hospitalizations, provide longer time between AECB episodes requiring drug therapy and lower mean total costs for those patients treated with clarithromycin-ER compared to azithromycin.
R.S. Castaldo, Abbott Laboratories, grant monies, Industry.