There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
To stratify COPD patients presenting with an acute exacerbation on the basis of sputum
color and to relate this to the isolation and viable numbers of bacteria recovered
on culture.
Open, longitudinal study of sputum characteristics and acute-phase proteins.
Patients presenting to primary-care physicians in the United Kingdom. Patients were
followed up as outpatients in specialist clinic.
One hundred twenty-one patients with acute exacerbations of COPD were assessed together
with a single sputum sample on the day of presentation (89 of whom produced a satisfactory
sputum sample for analysis). One hundred nine patients were assessed 2 months later
when they had returned to their stable clinical state.
The expectoration of green, purulent sputum was taken as the primary indication for
antibiotic therapy, whereas white or clear sputum was not considered representative
of a bacterial episode and the need for antibiotic therapy.
A positive bacterial culture was obtained from 84% of patients sputum if it was purulent
on presentation compared with only 38% if it was mucoid (p < 0.0001). When restudied
in the stable clinical state, the incidence of a positive bacterial culture was similar
for both groups (38% and 41%, respectively). C-reactive protein concentrations were
significantly raised (p < 0.0001) if the sputum was purulent (median, 4.5 mg/L; interquartile
range [IQR], 6. 2 to 35.8). In the stable clinical state, sputum color improved significantly
in the group who presented with purulent sputum from a median color number of 4.0
(IQR, 4.0 to 5.0) to 3.0 (IQR, 2.0 to 4. 0; p < 0.0001), and this was associated with
a fall in median C-reactive protein level to 2.7 mg/L (IQR, 1.0 to 6.6; p < 0.0001).
The presence of green (purulent) sputum was 94.4% sensitive and 77.0% specific for
the yield of a high bacterial load and indicates a clear subset of patient episodes
identified at presentation that is likely to benefit most from antibiotic therapy.
All patients who produced white (mucoid) sputum during the acute exacerbation improved
without antibiotic therapy, and sputum characteristics remained the same even when
the patients had returned to their stable clinical state.