Objectives: To determine the effect of age, severity of
lung disease, severity and frequency of exacerbation, steroid use,
choice of an antibiotic, and the presence of comorbidity on the outcome
of treatment for an acute exacerbation of COPD.
Design: A retrospective chart analysis over 24 months.
Setting: A university Veterans Affairs medical center.
Patients: Outpatients with COPD who were treated with an
antibiotic over a period of 24 months for an acute exacerbation of
Methods: Severity of an acute exacerbation of
COPD was defined using the criteria of Anthonisen et al: increased
dyspnea, increased sputum volume, and increased sputum purulence.
Severity of lung disease was stratified based on FEV1
percent predicted using American Thoracic Society guidelines
(stage I, FEV1 ≥ 50%; stage II, FEV1 35 to
49%; stage III, FEV1 < 35%). Treatment outcome was
judged successful when the patient had no return visit in 4 weeks for a
respiratory problem. Failure was defined as a return visit for
persistent respiratory symptoms that required a change of an antibiotic
in < 4 weeks.
Results: One-hundred seven patients
with COPD (mean age ± SD, 66.9 ± 9.5 years) experienced 232
exacerbations over 24 months. First-line antibiotics
(trimethoprim-sulfamethoxazole, ampicillin/amoxicillin, and
erythromycin) were used to treat 78% of all exacerbations. Treatment
failure was noted in 12.1% of first exacerbations and 14.7% of all
exacerbations, with more than half the failures requiring
hospitalization. Host factors that were independently associated with
treatment failure included the following: FEV1 < 35%
(46.4% vs 22.4%; p = 0.047), use of home oxygen (60.7% vs 15.6%;
p < 0.0001), frequency of exacerbation (3.8 ± 2.0 vs
1.6 ± 0.91; p < 0.001), history of previous pneumonia (64.3% vs
35.1 p < 0.007), history of sinusitis (28.6% vs 8.8%;
p < 0.009) and use of maintenance steroids (32.1% vs 15.2%
p = 0.052). Using stepwise logistic regression analysis to identify
the top independent variables, the use of home oxygen (p = 0.0002)
and frequency of exacerbation (p < 0.0001) correctly classified
failures in 83.3% of the patients. Surprisingly, age, the choice of an
antibiotic, and the presence of any one or more comorbidity did not
affect the treatment outcome.
Conclusion: The results
of our study suggest that patient host factors and not antibiotic
choice may determine treatment outcome. Prospective studies in
appropriately stratified patients are needed to validate these