O69 Modeling H. influenzae treatment response and progression in patients with COPD as they progress between acute exacerbation of chronic bronchitis (AECB) and community acquired pneumonia (CAP)

Abstract

Objective: Previously we presented a progression model for AECB and CAP patients infected with S. pneumoniae (SP) that identified chronic obstructive lung disease (COPD) severity and area under the inhibitory curve (AUIC) to be significantly associated with progression to CAP. For this analysis, we sought to determine if similar disease progression risk would be observed in patients infected with H. influenzae (HI). Methods: 3,885 patients with lower respiratory tract infection and COPD were identified. Patients were stratified according to GOLD-like grouping (GLG) and analyzed by pathogen, AUIC and COPD severity for progression. The relative impacts of GLG and AUIC on progression were modeled using multivariate logistic regression. Results: By organism, progression to CAP was clearly apparent in patients infected with SP (80.6%), and less so with HI (19.4%). Other sputum isolates mimicked HI progression (8.2%) while if a culture was taken but no growth was found, progression was similar to SP (86.7%). Lack of antibiotic (AUIC = 0) resulted in the greatest progression (42.9%; p 0.05), while in antibiotic treated cases, AUIC 100 (0%) was associated with no progression to CAP, while those with AUIC < 100 did experience progression, but at a higher frequency (4.8%) than AUIC = 0. Conclusions: HI is not associated with the same risk of progression in AECB as observed with SP. Conversely, when cultures were taken but did not yield organism growth, progression frequency was similar to culture proven SP. Frequency of progression increased with GLG severity in most pathogens, and achieving AUIC 100 can attenuate progression, regardless of GLG. Thus, treatment with an active antibiotic is a good strategy to protect patients with AECB, even those with less virulent organisms such as HI.