Of our 100 patients only 45% had radiographic pneumonia.
This is in line with a primary-care based study by
Blaeuer et al.,[21] but differs from the results presented
by Vugt et al., who found radiographic pneumonia in
57% of patients with clinically suspected pneumonia.[22]
Our main finding was that the physician’s degree of
suspicion was strongly associated with the presence of a
new infiltrate on CXR. In particular, a high degree of
suspicion for pneumonia corresponds well with a
positive CXR. To our knowledge, this has not been
shown before. Of the other investigated anamnestic,
clinical, or laboratory variables only CRP, rales, and body
temperature were positively associated with CXR. Of
note is that current smoking was negatively associated
with CXR in the adjusted models. We believe this is an
effect of unhealthy selection out of exposure in the
study population, as the prevalence of current smokers
is lower in the study population than in a normal
Swedish population. The odds ratio in this setting should
not be confused with evaluation of smoking as a risk
factor for new infiltrate