CURB-65 Pneumonia Severity Score
CURB-65 is a 5-item clinical prediction rule for severity (and site-of-care decisions) in community-acquired pneumonia (CAP) using 1 point for each criterion: confusion, urea, respiratory rate, blood pressure, and age ≥65 years. [1], eGuideline/IDSA Bundle
CURB-65 Criteria Definition (1 Point Each)
Each criterion is assessed at presentation. [1], eGuideline/IDSA Bundle
- Confusion (C): new onset disorientation or inability to provide appropriate information (commonly operationalized as a mental status deficit). [1], eGuideline/IDSA Bundle
- Urea (U): blood urea nitrogen (BUN) >20 mg/dL (corresponding to urea >7 mmol/L). [1], eGuideline/IDSA Bundle
- Respiratory rate (R): ≥30 breaths/min. [1], eGuideline/IDSA Bundle
- Blood pressure (B): systolic <90 mm Hg or diastolic ≤60 mm Hg. [1], eGuideline/IDSA Bundle
- Age (65): age ≥65 years. [1], eGuideline/IDSA Bundle
Scoring Method and Interpretation
CURB-65 score is the sum of positive criteria (range 0–5). eGuideline/IDSA Bundle
| CURB-65 score | Reported 30-day mortality (%) | Typical site-of-care implication |
|---|---|---|
| 0 | 0.6 | Low risk; consider home treatment |
| 1 | 2.7 | Low risk; consider home treatment |
| 2 | 6.8 | Admit to ward |
| 3 | 14.0 | Severe pneumonia; hospitalize |
| 4–5 | 27.8 | Severe pneumonia; hospitalize and consider intensive care |
eGuideline/IDSA Bundle
Treatment-Site Application Framework
CURB-65 is applied at initial presentation to support decisions about home management vs inpatient admission and whether intensive care-level evaluation may be needed. eGuideline/IDSA Bundle
- Score 0–1: typically managed as low risk, with consideration of outpatient treatment. eGuideline/IDSA Bundle
- Score 2: ward admission is typical. eGuideline/IDSA Bundle
- Score 3: hospitalization is typical. eGuideline/IDSA Bundle
- Score 4–5: hospitalization with consideration of intensive care is typical. eGuideline/IDSA Bundle
Important Clarifications and Nuances
CURB-65 is a prognostic/triage tool for CAP severity at presentation. eGuideline/IDSA Bundle
- CURB-65 is not a substitute for clinical judgment for suspected sepsis, hypoxemic respiratory failure, or inability to safely manage at home. eGuideline/IDSA Bundle
- The “urea” criterion is operationalized as BUN >20 mg/dL in common score tables. [1], eGuideline/IDSA Bundle
Common Pitfalls to Avoid
- Using a single abnormal vital sign without totaling criteria: each component should be assessed and the CURB-65 score should be calculated from 0–5. eGuideline/IDSA Bundle
- Overreliance for disposition: CURB-65 supports site-of-care decisions, but disposition should incorporate overall clinical status and feasibility of outpatient care. eGuideline/IDSA Bundle
Target Outcomes of Scoring
CURB-65 is used to estimate near-term risk and to align site of care with severity, reflecting progressively higher reported 30-day mortality with increasing score. eGuideline/IDSA Bundle