Infection & Sepsis Risk score Strong evidence Clinical review pending v1.0.0

CURB-65 Pneumonia Severity Score

How severe is this community-acquired pneumonia, and where should it be treated?

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About this tool

Five-item score estimating 30-day mortality in community-acquired pneumonia to guide site of care.

Intended use

Adults with community-acquired pneumonia.

Outcome

All-cause mortality

Time horizon

30 days

Derivation population

UK, New Zealand and Netherlands hospital cohorts.

Limitations

Does not include oxygenation or comorbidities.
Less validated in older and immunocompromised patients.

Clinical problems

Pneumonia and sepsis

Evidence

Evidence level

Strong evidence

Derived and externally validated in multiple cohorts (including prospective studies) and incorporated into major clinical guidelines. Methodology

Guideline status

Used in British Thoracic Society CAP guidance; the 2019 ATS/IDSA guideline prefers PSI.

Validation studies

Derivation and validation (Lim 2003)

1,068 patientsProspective

30-day mortality by score: 0, 0.7%; 1, 2.1%; 2, 9.2%; 3, 14.5%; 4, 40%; 5, 57%.

Evidence summaries for this tool are awaiting independent clinical review. Statistics are shown only where they could be attributed to a specific publication.

References

Original publicationLim WS, van der Eerden MM, Laing R, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax 2003;58:377-382. Find on PubMed (opens in a new tab)
GuidelineMetlay JP, Waterer GW, Long AC, et al. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the ATS and IDSA. Am J Respir Crit Care Med 2019;200:e45-e67. Find on PubMed (opens in a new tab)

Version history

Version	Formula	Effective	Reviewer	Changes
v1.0.0	Lim 2003	2026-10-03	—	Initial implementation with reference test vectors.

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Clinical decision support only. Interpret results in the context of the individual patient and current guidance; HumanPulse does not replace professional medical judgment.