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Review
. 2010 Oct;60(579):e423-33.
doi: 10.3399/bjgp10X532422.

Validity of British Thoracic Society guidance (the CRB-65 rule) for predicting the severity of pneumonia in general practice: systematic review and meta-analysis

Maggie McNally  1 , James Curtain, Kirsty K O'Brien, Borislav D Dimitrov, Tom Fahey
Affiliations
Review

Validity of British Thoracic Society guidance (the CRB-65 rule) for predicting the severity of pneumonia in general practice: systematic review and meta-analysis

Maggie McNally et al. Br J Gen Pract. 2010 Oct.

Abstract

Background: The CRB-65 score is a clinical prediction rule that grades the severity of community-acquired pneumonia in terms of 30-day mortality.

Aim: The study sought to validate CRB-65 and assess its clinical value in community and hospital settings.

Design of study: Systematic review and meta-analysis of validation studies of CRB-65.

Method: Medline (1966 to June 2009), Embase (1988 to November 2008), British Nursing Index (BNI) and PsychINFO were searched, using a diagnostic accuracy search filter combined with subject-specific terms. The derived (index) rule was used as a predictive model and applied to all validation studies. Comparison was made between the observed and predicted number of deaths stratified by risk group (low, intermediate, and high) and setting of care (community or hospital). Pooled results are presented as risk ratios (RRs) in terms of over-prediction (RR>1) or under-prediction (RR<1) of 30-day mortality.

Results: Fourteen validation studies totalling 397 875 patients are included. CRB-65 performs well in hospitalised patients, particularly in those classified as intermediate (RR 0.91, 95% confidence interval [CI] = 0.71 to 1.17) or high risk (RR 1.01, 95% CI = 0.87 to 1.16). In community settings, CRB-65 over-predicts the probability of 30-day mortality across all strata of predicted risk, low (RR 9.41, 95% CI = 1.75 to 50.66), intermediate (RR 4.84, 95% CI = 2.61 to 8.69), and high (RR 1.58, 95% CI = 0.59 to 4.19).

Conclusion: CRB-65 performs well in stratifying severity of pneumonia and resultant 30-day mortality in hospital settings. In community settings, CRB-65 appears to over-predict the probability of 30-day mortality across all strata of predicted risk. Caution is needed when applying CRB-65 to patients in general practice.

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Figures

Figure 1
Figure 1
Severity assessment by the CRB-65 in terms of risk strata and subsequent management strategy for patients with suspected community-acquired pneumonia.,
Figure 2
Figure 2
Selection of studies for inclusion in the meta-analysis.
Figure 3
Figure 3
Summary diagram of the quality assessment of the included studies.
Figure 4
Figure 4
Low-risk group (score = 0) predicted and observed deaths in community and hospital settings.
Figure 5
Figure 5
Intermediate-risk group (score = 1 or 2) predicted and observed deaths in community and hospital settings.
Figure 6
Figure 6
High-risk group (score = 3 or 4) predicted and observed deaths in community and hospital settings.
Appendix 1
Appendix 1
Funnel plot with 95% confidence limits for existence of publication bias in the meta-analysis.
See this image and copyright information in PMC

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