Late Breaking Abstract - Antibiotic treatment in acute exacerbation of COPD: patient outcomes with amoxicillin vs. amoxicillin/clavulanic acid - Data from 38,820 outpatients

Introduction: For antibiotic treatment of Acute Exacerbations of COPD (AECOPD) GOLD recommends empirical treatment with amoxicillin/clavulanic acid (AMCL). The National guidelines in Denmark recommend either AMCL 500 mg/125 mg, TID or amoxicillin 750 mg TID (AMX). Addition of clavulanic acid offers a broader spectrum; opposite, AMX alone in a higher dose may offer more time above MIC. The aim of this study was to determine which of these regimens is associated with better outcome. Method: The Danish Registry of COPD (DrCOPD), a nationwide outpatient COPD register, were crosslinked with medication data and hospital contacts. The first prescription of AMX or AMCL after inclusion in DrCOPD was used as exposure variable. Adjusted Cox proportional hazards models were used to analyze the risk of hospitalization or death (combined) within 30 days and other endpoints. Results: For the first treatment of AECOPD 11,337 received AMX, and 27,483 patients received AMCL. AMX was associated with a decreased risk of hospitalization or death by all cause (aHR 0.77, 95% CI 0.73-0.80; p < 0.0001) and for pneumonia hospitalization or death (aHR 0.47, 95% CI 0.40-0.55; p < 0.0001) compared to AMCL. Conclusion: In AECOPD, treatment with AMX was associated with substantially better outcomes within 30 days. Reasons may include under-dosing with AMCL and residual confounding by indication.