What is the recommended treatment for a patient with pneumonia who meets the Curb 65 (Confusion, Urea, Respiratory rate, Blood pressure, 65 years of age) criteria?

CURB-65 Guided Pneumonia Management

Patients with pneumonia and CURB-65 scores of 0-1 should receive outpatient treatment with oral antibiotics (amoxicillin 1g three times daily or doxycycline 100mg twice daily for healthy adults without comorbidities), scores of 2 require hospitalization or intensive home care, and scores ≥3 mandate hospital admission with prompt ICU evaluation. 1, 2

Understanding CURB-65 Scoring

CURB-65 assigns one point for each of the following criteria 1, 2:

• Confusion (mental test score <8, or new disorientation in person, place, or time)
• Urea >7 mmol/L (or >19 mg/dL)
• Respiratory rate ≥30 breaths/minute
• Blood pressure (systolic <90 mmHg or diastolic ≤60 mmHg)
• Age ≥65 years

Risk Stratification and Mortality

The mortality risk increases directly with score 1, 2, 3:

• Score 0: 0.7% mortality
• Score 1: 2.1% mortality
• Score 2: 9.2% mortality
• Score 3: 14.5% mortality
• Score 4: 40% mortality
• Score 5: 57% mortality

Treatment Algorithm by CURB-65 Score

CURB-65 Score 0-1 (Low Risk: <3% Mortality)

Outpatient treatment is appropriate for most patients. 1, 2

For healthy adults without comorbidities: 1

• Amoxicillin 1g three times daily, OR
• Doxycycline 100mg twice daily

For adults with comorbidities (COPD, diabetes, heart disease, etc.): 1

• Combination therapy with amoxicillin/clavulanate or cephalosporin PLUS macrolide

Consider hospitalization despite low scores if: 1, 2

• Inability to maintain oral intake
• Homelessness or lack of social support
• Severe psychiatric illness
• Injection drug abuse
• Failure of prior adequate outpatient antibiotic therapy
• Important comorbidities not captured by CURB-65 (e.g., HIV)

CURB-65 Score 2 (Intermediate Risk: 9.2% Mortality)

Hospitalization or intensive in-home health services are required. 4, 1, 2 This decision requires clinical judgment, as these patients face significantly elevated mortality risk and require active intervention for physiologic derangements. 1

Additional assessment tools to guide decision: 4

• Point-of-care C-reactive protein (CRP) testing can help inform antibiotic decisions
• CRP >100 mg/L supports immediate antibiotics
• CRP 20-100 mg/L: consider back-up antibiotic prescription
• CRP <20 mg/L: do not routinely offer antibiotics

CURB-65 Score ≥3 (High Risk: 14.5-57% Mortality)

Hospital admission with prompt evaluation for ICU care is mandatory. 4, 1, 2

Specific ICU criteria (regardless of CURB-65 score): 3

• Septic shock requiring vasopressors
• Acute respiratory failure requiring intubation and mechanical ventilation
• Persisting hypoxia with PaO₂ <8 kPa despite maximal oxygen
• Progressive hypercapnia
• Severe acidosis (pH <7.26)

Consider ICU/HDU transfer for patients with: 4, 3

• CURB-65 score of 4 or 5
• Primary viral pneumonia
• Bilateral lung infiltrates on chest radiography
• ≥3 minor criteria: respiratory rate ≥30/min, PaO₂/FiO₂ ratio ≤250, multilobar infiltrates, confusion, uremia, leukopenia, thrombocytopenia, hypothermia, or hypotension requiring aggressive fluid resuscitation

Critical Pitfalls and Limitations

CURB-65 may underestimate severity in young patients (<65 years) with severe respiratory failure who lack age points despite significant physiologic derangement. 1, 2, 3 These patients may require hospitalization or ICU care despite low scores.

CURB-65 performs poorly for ICU triage decisions (sensitivity only 78.4% for predicting critical care interventions). 1, 5 The IDSA/ATS severe CAP criteria should be used instead for ICU admission decisions. 1, 2

Elderly patients with multiple stable comorbidities may have falsely elevated CURB-65 scores without true severity. 2, 3

Bilateral chest x-ray changes indicating primary viral pneumonia should be managed as severe pneumonia regardless of CURB-65 score. 4

Monitoring and Follow-Up

Clinical improvement should be expected within 3 days. 1, 3 Patients should contact their physician if no improvement occurs. 1

Reassess for treatment failure, resistant organisms, or complications if fever persists beyond 72 hours. 1

Repeat chest x-ray at approximately 6 weeks if respiratory symptoms or signs persist, or where there is higher risk of underlying malignancy (especially smokers and those over 50 years). 4

Implementation Best Practices

Use CURB-65 as an adjunct to clinical judgment, not as the sole determinant for site-of-care decisions. 2, 3 The tool should be implemented as part of a systematic pneumonia care bundle including pulse oximetry and point-of-care lactate. 1, 3

The simplified CRB-65 variant (omitting urea measurement) can be used in outpatient settings where laboratory testing is unavailable, with a score range of 0-4. 2, 3