Pneumonia Scores

A number of pneumonia severity scores have been described in the literature. In Australia CURB and SMART-COP are the most commonly used, however you will also see CURB-65 and PSI referred to in the literature. It is important not to use these scores in isolation as none of these are 100% sensitive. A safer approach is to consider the whole patient, their clinical stability, individual risk factors for severe disease and social factors that could lead to failure of management in the community.

CURB-65

Clinical prediction rule recommended by the British Thoracic Society that has been validated for predicting mortality in community acquired pneumonia and therefore helps predict inpatient vs outpatient treatment.

Each risk factor scores one point with a maximum score of 5.

Confusion of new onset

Urea > 7 mmol/L

Respiratory rate >30/min or greater

Blood pressure

Age >65 years

The risk of death at 30 days increases as the score increases:

0 - 0.7%

1 - 3.2%

2 - 13.0%

3 - 17.0%

4 - 41.5%

5 - 57.0%

Disposition recommendations based on score:

0-1: Treat as an outpatient

2-3: Consider a short stay in hospital or watch very closely as an outpatient

4-5: Requires hospitalisation, consider ICU admission

Pneumonia Severity Index (PSI)

This is a more complex scoring system which stratifies patients into low, moderate or high risk, advocating outpatient treatment for those in the low risk group.

A patient can only be in the low risk group if they satisfy the following criteria:

• Age <50, AND

• No malignancy, CCF, cerebrovascular, renal or liver disease, AND

• Normal mental state, AND

• Satisfactory vital signs: HR90 mmHg, temp 35-40C

CORB and SMART-COP

Recent Australian studies have developed severity scoring systems (e.g. CORB, SMART-COP) that are based on predictors of requirement for intensive respiratory or inotrope support, in addition to mortality. The CORB score is simpler and does not rely on investigation results however it is less sensitive than SMART-COP.

CORB

Confusion (acute)

Oxygen saturation 90% or less

Respiratory rate > 30 breaths per minute

Blood pressure

'Severe CAP' is defined as the presence of at least two of these features and has a sensitivity of 81% and specificity of 68% for predicting need for IRVS.

SMART-COP

Systolic BP < 90 mmHg (2 points)

Multilobe infiltrate (1 point)

Albumin < 35g/L

RR (age adjusted < 50yrs > 25/min, > 50 yrs> 30/min) (1 point)

Tachycardia > 125 bmp (1 point)

Confusion (acute onset) (1 point)

Oxygenation (age adjusted: SpO2 < 93%, PaO2 < 70 mmHg, PF <333 mmHg) (2 points)

pH < 7.35 (2 points)

Scoring:

0 - 2 points: Low risk ( < 2% 30 day mortality)

3 - 4 points: Moderate risk (5- 13% 30 day mortality)

5 - 6 points: High risk (11 - 18% 30 day mortality)

7 or more points: Very high risk (33% 30 day mortality)

In the Australian Community-Acquired Pneumonia Study (ACAPS) cohort, the accuracy for predicting patients who required IRVS (a SMART-COP score of 3 or more points) was a sensitivity of 92%, specificity of 62%.