Risk Stratification

The following systems are recommended:


The BTS adopted the CURB-65 scoring system in 2004 as it is easy to use (being a single step system compared to previous multi-step systems) and it is clinically useful in determining the disposition of patients.

The BTS classifies patients scoring 3 or more are as having severe pneumonia and recommends that these patients are admitted urgently.

Hospital treatment should be considered for those scoring 2 but outpatient management is acceptable in selected cases. Most patients with CAP who have CURB-65 scores of 0 or 1 can be managed in the community.

CURB-65 Score

Score one point each for these components:

  • Confusion (new onset disorientation in time, place or person) or an AMT score of (≤8/10)
  • Urea: >7 mmol/l
  • Respiratory rate: ≥ 30/min
  • Blood pressure: low blood pressure (systolic BP <90 mm Hg or diastolic BP ≤60 mm Hg)
  • Age: ≥65 years

Mortalaity ranges

CURB-65 score 0 1 2 3 4 5
30-day mortality (%) 0.7 3.2 13 17 41.5 57

Abbreviated mental test (AMT) Score

Patients with new confusion (disorientation in time, place or person) secondary to pneumonia are stratified by the CURB-65 system into a higher mortality risk group than those that are not confused.

It is not uncommon to meet confused patients that have been brought by ambulance from care homes into the ED and be unsure whether their confusion is old or new. In this situation a score of 8 or less on the AMT score is substituted for confusion in the CURB-65 score.

Abbreviated mental test score [6]

(correct answer=1 point, max. score 10)

Time (nearest hour)
Address (repeat now and at end of test)
Name of this place
Identify two persons e.g. doctor, nurse etc
Date of birth
Date of First World War
Name of present monarch
Count backwards from 20 to 1


Confusion (new onset disorientation in time, place or person) OR an AMT score of (≤ 8/10) scores 1 point on the CURB-65 score.

Other factors suggesting a need for admission

The vast majority of patients with a CURB-65 score of 0 or 1 can be discharged. However, the BTS considers additional factors that are adversely related to prognosis to be important in deciding whether patients require in-patient treatment or not, irrespective of their CURB-65 score. These include:

  • Hypoxaemia (SaO2 <94% or PaO2 <8 kPa) regard¬less of FiO2
  • Bilateral or multi-lobe involvement on the chest radiograph
  • Presence of a co-existing disease e.g. congestive cardiac failure, chronic renal failure
  • Age over 50 years

Some elderly patients with no adverse factors (other than age) will require admission solely for social reasons.

Learning bite

The CURB-65 score should not be used in isolation to risk stratify patients.