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

HRB Centre for Primary Care Research, Department of General Practice, Royal College of Surgeons in Ireland Medical School, Dublin, Ireland.
British Journal of General Practice (Impact Factor: 2.36). 10/2010; 60(579):e423-33. DOI: 10.3399/bjgp10X532422
Source: PubMed

ABSTRACT The CRB-65 score is a clinical prediction rule that grades the severity of community-acquired pneumonia in terms of 30-day mortality.
The study sought to validate CRB-65 and assess its clinical value in community and hospital settings.
Systematic review and meta-analysis of validation studies of CRB-65.
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.
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).
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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    ABSTRACT: The management of community-acquired pneumonia (CAP) continues to be a challenge, especially in older people. To enable better risk stratification, a variation of the severity scores CRB-65 and CURB-65, called CURB-age, has been suggested. We compared the association between risk groups as defined by the scores and 30-day mortality for a cohort of mainly older inpatients with CAP. We retrospectively analysed data from the CAP database from the years 2005 to 2009 of a single centre in Herne, Germany. Patient characteristics, criteria values within the severity scores CURB-65, CRB-65 and CURB-age, and 30-day mortality were assessed. We compared the association between score points and score-defined risk groups and mortality. Sensitivity and specificity with corresponding 95% CIs were calculated, and receiver operating characteristic (ROC) curve analysis was performed. Data from 559 patients were analysed (mean age 74.1 years, 55.3% male). Mortality at day 30 was 10.9%. CURB-age included more patients in the low-risk category than CRB-65 (195 vs 89), and the patient group had a lower mortality (2.6% vs 3.4%). When compared with CURB-65, CURB-age included slightly fewer patients (195 vs 214) with lower mortality (2.6% vs 4.2%). CURB-age sorted the most patients who died within 30 days into the high-risk CAP group (CURB-age, 32; CURB-65, 28; CRB-65, 9), which had the highest mortality (CURB-age, 26.4%; CURB-65, 19.4%; CRB-65, 21.4%). Advantages of CURB-age categories were depicted through ROC curve analysis (area under the curve 0.73 (95% CI 0.67 to 0.79) for CURB-age categories, 0.67 (95% CI 0.60 to 0.74) for CURB-65 categories, and 0.59 (95% CI 0.52 to 0.66) for CRB-65 categories). In comparison with CRB-65 and CURB-65, risk stratification as defined by CURB-age showed the closest association with 30-day mortality in our sample. Further prospective studies are needed to assess the potential of CURB-age for better risk prediction, especially in older patients with CAP. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to
    Postgraduate Medical Journal 01/2015; 91(1072). DOI:10.1136/postgradmedj-2014-132802 · 1.55 Impact Factor
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    ABSTRACT: Objective: Estimating calibration performance of clinical prediction rules (CPRs) in systematic reviews of validation studies is not possible when predicted values are neither published nor accessible or sufficient or no individual participant or patient data are available. Our aims were to describe a simplified approach for outcomes prediction and calibration assessment and evaluate its functionality and validity. Study design and methods: Methodological study of systematic reviews of validation studies of CPRs: a) ABCD 2 rule for prediction of 7 day stroke; and b) CRB-65 rule for prediction of 30 day mortality. Predicted outcomes in a sample validation study were computed by CPR distribution patterns (" derivation model "). As confirmation, a logistic regression model (with derivation study coefficients) was applied to CPR-based dummy variables in the validation study. Meta-analysis of validation studies provided pooled estimates of " predicted:observed " risk ratios (RRs), 95% confidence intervals (CIs), and indexes of heterogeneity (I 2) on forest plots (fixed and random effects models), with and without adjustment of intercepts. The above approach was also applied to the CRB-65 rule. Results: Our simplified method, applied to ABCD 2 rule in three risk strata (low, 0–3; intermediate , 4–5; high, 6–7 points), indicated that predictions are identical to those computed by univari-ate, CPR-based logistic regression model. Discrimination was good (c-statistics =0.61–0.82), however, calibration in some studies was low. In such cases with miscalibration, the under-prediction (RRs =0.73–0.91, 95% CIs 0.41–1.48) could be further corrected by intercept adjustment to account for incidence differences. An improvement of both heterogeneities and P-values (Hosmer-Lemeshow goodness-of-fit test) was observed. Better calibration and improved pooled RRs (0.90–1.06), with narrower 95% CIs (0.57–1.41) were achieved. Conclusion: Our results have an immediate clinical implication in situations when predicted outcomes in CPR validation studies are lacking or deficient by describing how such predictions can be obtained by everyone using the derivation study alone, without any need for highly specialized knowledge or sophisticated statistics.
    Clinical Epidemiology 04/2015; 7:267-280. DOI:10.2147/CLEP.S67632
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    ABSTRACT: Background Addition of assessment of comorbid diseases (‘D’) and oxygen saturation (‘S’) to the CRB-65 score has been recommended to improve its accuracy for risk stratification in community-acquired pneumonia (CAP). The aim of the present study was to validate the resulting DS-CRB-65 score in a large cohort of patients with CAP.MethodsA total of 4432 patients prospectively enrolled in the CAPNETZ cohort were included in the present study. Predefined endpoints were 28-day mortality, requirement for mechanical ventilation or vasopressors (MV/VS) and requirement for MV/VS or intensive care unit admission (MV/VS/ICU). Receiver operating characteristic curve analysis was used to determine the accuracy of the CRB-65 score and the addition of D (extra-pulmonary comorbidities) and S (oxygen saturation <90% or partial pressure of oxygen <8 kPa). Binary logistic regression and the method of Hanley and McNeil were used to compare the criteria.ResultsThe mortality rate was 4.0%, and 4.2% of patients required MV/VS and 6.6% required MV/VS/ICU. After multivariate analysis, D and S independently added to the CRB-65 criteria for mortality prediction, but only S improved prediction of MV/VS and MV/VS/ICU (P < 0.001 for both). The area under the curve of the CRB-65 score was significantly improved by adding D and S for all endpoints (P < 0.02). Among patients who died or required MV/VS despite a CRB-65 score of 0, 64–80% would have been identified by the DS-CRB-65 score.Conclusions The addition of assessment of oxygenation and comorbidities significantly improved the prognostic accuracy of the CRB-65 score. Consequently, the DS-CRB-65 score may have a useful role in risk stratification algorithms for CAP.This article is protected by copyright. All rights reserved.
    Journal of Internal Medicine 01/2015; DOI:10.1111/joim.12349 · 5.79 Impact Factor


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