De relatie tussen de concentratie amoxicilline in sputum en de opnameduur bij gehospitaliseerde COPD-patiënten

Objective and design: Little is known about the excretion of amoxicillin into sputum of COPD patients. Theoretically, to be effective the amoxicillin concentration in sputum should be higher than the Minimal Inhibiting Concentration (MIC) of the bacterial pathogen. The objective of this prospective cohort (pilot) trial was to investigate the relation between amoxicillin concentration in sputum and length of hospitalisation in COPD patients.

Methods: COPD inpatients with an exacerbation, treated with amoxicillin + clavulanic acid, were included. Concentrations of amoxicillin in sputum and plasma and clinical parameters were measured.

Results: 23 Patients were included in the primary analysis. Eight patients had a concentration in sputum above MIC (2 mg/l). The mean length of hospitalisation for patients with concentrations below MIC was 11.5 days; for patients with concentrations above MIC the mean length was 8.5 days (p = 0.06). C-reactive protein (CRP) at baseline and the decrease in CRP over time showed a relation with concentration in sputum (p = 0.02, respectively p = 0.07). However, no significant relation with length of hospitalisation was found. The concentration of interleukin 8, leucocytes and cell counts in sputum, GOLD-classification, microbiological culture, route of administration, age and sex showed no relation with amoxicillin concentration in sputum or length of hospitalisation (p > 0.10).

Conclusion: There are indications that a higher concentration of amoxicillin in sputum reduces length of hospitalisation by 3 days in patients with a concentration above 2 mg/l. Only 8 of 23 patients had a concentration above MIC.