What is the management strategy for patients with community-acquired pneumonia based on the CRB-65 (Confusion, Respiratory rate, Blood pressure, 65 years of age) score?

From the Guidelines

The CRB-65 score is a crucial tool for guiding management decisions in patients with community-acquired pneumonia, with a score of 0 indicating low risk, 1-2 indicating intermediate risk, and 3-4 indicating high risk of mortality, as outlined in the NICE guidance 1. The CRB-65 score is calculated by assigning one point each for confusion, respiratory rate ≥30 breaths/minute, systolic blood pressure <90mmHg or diastolic ≤60mmHg, and age ≥65 years.

• Patients with a score of 0 can typically be managed as outpatients with oral antibiotics such as amoxicillin 1g three times daily for 5-7 days, or doxycycline 100mg twice daily if penicillin-allergic.
• Those with a score of 1-2 require careful clinical judgment, with some needing hospital admission for intravenous antibiotics (typically a beta-lactam plus a macrolide such as ceftriaxone 2g daily plus azithromycin 500mg daily).
• Patients scoring 3-4 should be hospitalized immediately, often requiring intensive care assessment and broader-spectrum antibiotics like piperacillin-tazobactam 4.5g every 6-8 hours plus a respiratory fluoroquinolone. This approach stratifies mortality risk and helps determine appropriate treatment intensity, with higher scores correlating with increased mortality risk and need for more aggressive intervention, as supported by the Infectious Diseases Society of America/American Thoracic Society consensus guidelines 1. Key considerations in management include:
• Clinical judgment is essential in assessing a patient's risk of severe disease, particularly in face-to-face clinical situations 1.
• Point-of-care C reactive protein (CRP) tests can inform prescribing decisions, with cut-off values of 20 and 100 mg/L being useful in guiding antibiotic therapy 1.
• The presence of influenza does not rule out bacterial co-infection, and viral testing results should not solely guide antibiotic prescribing decisions 1.

From the Research

Management Strategy for Patients with Community-Acquired Pneumonia based on CRB-65 Score

The CRB-65 score is a clinical prediction rule that grades the severity of community-acquired pneumonia in terms of 30-day mortality. The management strategy for patients with community-acquired pneumonia based on the CRB-65 score is as follows:

• Assessment of Severity: The CRB-65 score is used to assess the severity of community-acquired pneumonia, which helps decide hospitalization and type of treatment 2.
• Hospitalization: Patients with a CRB-65 score of 1 have a relatively small mortality rate and can be managed as outpatients, while those with a score of 2 or more may require hospitalization 2, 3.
• Antibiotic Treatment: The recommended treatment for patients with severe CAP (CRB-65 score 2) is penicillin G in most situations, while combination therapy with cefotaxime/macrolide or penicillin G/fluoroquinolone is recommended for critically ill patients (CRB-65 score 3-4) 3.
• Microbiological Investigation: A thorough microbiological investigation should be undertaken in all patients, including blood cultures, respiratory tract sampling, and urine antigens, with the addition of extensive sampling for more uncommon respiratory pathogens in the case of severe disease 3.
• Prevention Measures: Recommended measures for the prevention of CAP include vaccination for influenza and pneumococci, as well as smoking cessation 3.

CRB-65 Score and Mortality Risk

The CRB-65 score has an acceptable ability to classify mortality risk in elderly patients with CAP, with a direct association between the CRB-65 score and 30-day mortality 2.

• Mortality Risk: Patients with a CRB-65 score of 1 have a relatively small mortality rate, while those with a score of 2 or more have a higher mortality risk 2, 4.
• Predictive Value: The CRB-65 score has a modest value for predicting in-hospital and 30-day mortality, with a c statistic of 0.68 at both time points 4.

Limitations and Future Directions

While the CRB-65 score is a useful tool for assessing the severity of community-acquired pneumonia, it has some limitations, including over-prediction of 30-day mortality in community settings 5.

• Future Studies: Further studies are needed to validate the CRB-65 score in different populations and settings, and to explore its use in combination with other clinical prediction rules or biomarkers 6.