Treatment costs associated with community-acquired pneumonia by community level of antimicrobial resistance

Introduction: The aim is to quantify community-acquired pneumonia (CAP) treatment outcomes and costs from a managed care perspective by the level of macrolide resistance corresponding to the metropolitan statistical area (MSA) where patients lived. Materials and methods: A retrospective analysis was conducted using the i3 Magnify database (05/2000-05/2005) and the Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin (PROTEKT) database. Continuously enrolled patients aged 18 years and older residing in MSAs with PROTEKT data that had an outpatient CAP-related ICD-9 code and with one antibiotic pharmacy claim within 7 days were included. Patients were excluded for having a prior condition or drug treatment that could mimic CAP or precipitate infections, or for recent hospitalizations. Treatment costs by the level of resistance in the patient's MSA, by treatment outcome and by initial treatment were measured and adjusted for differences in baseline patient characteristics. Results: The final study included 9446 CAP cases (average age of 47.6 years, 52.2% male). The majority (56.1%) resided in an MSA with macrolide resistance rates of < 25%. Treatment success rates were 82.5% and 80.5% for MSAs with resistance levels being < 25% and >= 25%, respectively (P < 0.001). Treatment failure resulting in hospitalization was higher in resistance areas >= 25% at 13.1% versus 8.0% in areas with resistance < 25% (P < 0.001). Average adjusted treatment costs were 33% higher for those treated in areas with resistance levels >= 25% than for those treated in areas where resistance was < 25%. Treatment success was associated with average adjusted costs that were 58% less than those whose initial treatment failed, controlling for level resistance (P < 0.001). Conclusions: This study observed an association between community-level macrolide resistance and treatment and economic outcomes. Treatment failure costs were higher for CAP patients treated in areas with macrolide resistance rates >= 25% than for those treated in areas where resistance was <= 25%.