Ruiz-Gonzalez et al developed a bedside predictive model and scoring system to evaluate patients with community-acquired pneumonia. The goal is to identify the probable etiology for the pneumonia, with selection of initial empiric therapy. The authors are from the University Hospital of Lleida in Catalonia, Spain.
Diagnostic groups:
(1) virus-like: viral, Chlamydia pneumoniae, Mycoplasma pneumoniae, Coxiella burnetii
(2) bacterial: Streptococcus pneumoniae, Hemophilus influenzae, Streptococcus viridans, Streptococcus pyogenes, Enterococcus faecium
(3) unknown etiology (? everything else)
Parameters:
(1) age and/or comorbidity
(2) onset
(3) WBC count
Co-morbidities in patients:
(1) chronic bronchitis
(2) HIV infection
(3) chronic heart failure
(4) malignancy
(5) chronic liver disease
(6) diabetes mellitus
(7) stroke
(8) dementia
where:
• Other comorbid conditions (immunodeficiency, immunosuppression, splenectomy, etc.) were not listed.
|
Parameter
|
Odds Ratio
|
95% CI
|
|
age or comorbidity
|
6.9
|
2 – 23
|
|
abrupt onset
|
31
|
6 – 150
|
|
abnormal WBC count
|
2
|
0.6 – 7.0
|
|
Parameter
|
Finding
|
Points
|
|
age or comorbidity
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age > 65 years, OR >= 1 comorbidities present
|
3
|
|
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age <= 65 AND no comorbidities
|
0
|
|
onset
|
abrupt
|
5
|
|
|
not abrupt
|
0
|
|
WBC count
|
leukocytosis (>= 11,000 per µL)
|
2
|
|
|
normal WBC count (4,001 – 10,999 per µL)
|
0
|
|
|
leukopenia (<= 4,000 per µL)
|
2
|
bedside score =
= SUM(points for all 3 parameters)
Interpretation:
• minimum score: 0
• maximum score: 10
• The higher the score, the more likely that the patient has a bacterial pneumonia.
Different cut-off points for different goals:
(1) maximal sensitivity for bacterial pneumonia: >= 5
(2) maximal specificity for bacterial pneumonia: = 10
(3) maximal specificity for virus-like pneumonia: <= 3
|
Diagnostic Goal
|
Sensitivity (95% CI)
|
Specificity (95% CI)
|
|
maximal sensitivity for bacterial pneumonia
|
89% (78 - 96%)
|
63% (54 – 81%
|
|
maximal specificity for bacterial pneumonia
|
57% (40 – 74%)
|
94% (86 – 100%)
|
|
virus-like pneumonia
|
63% (48 – 77%)
|
89% (78 – 100%)
|
The area under the ROC curve was 0.84.
Limitations:
• This may apply to patients from the general population. I would not expect it to work as well in patients with highly specialized needs or risk factors (transplants, etc.).
• The differential is between bacterial and virus-like pneumonias, while fungal pneumonias are not represented.
