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: 2.29). 10/2010; 60(579):e423-33. DOI: 10.3399/bjgp10X532422
Source: PubMed


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.

Download full-text


Available from: Borislav D Dimitrov
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In community-acquired pneumonia, severity assessment tools, such as CRB65, CURB65 and Pneumonia Severity Index (PSI), have been promoted to increase the proportion of patients treated in the community. The prognostic accuracy of these scores is established in hospitalized patients, but less is known about their use in out-patients. We aimed to study the accuracy of these severity tools to predict mortality in patients managed as out-patients. We performed a systematic review and meta-analysis according to MOOSE guidelines. From 1980 to 2010, we identified 13 studies reporting prognostic information for the CRB65, CURB65 and PSI severity scores in out-patients (either exclusively managed in the community or discharged from an emergency department <24 h after admission). Two reviewers independently collected data and assessed study quality. Performance characteristics across the studies were pooled using a random-effects model. Relationships between sensitivity and specificity were plotted using summary receiver operator characteristic curves (sROC). Out-patient mortality ranged from 0% to 3.5%. Four studies were identified for CRB65, 2 for CURB65 and 10 for PSI. Mortality was low for out-patients in the low-risk CRB65 classes [CRB65 0 or 1: mortality occurred in 3 of 1494 patients (0.2%)] but higher in CRB65 Groups 2-4 [mortality 13 of 154 patients (8.4%)]. Similarly, mortality was low in PSI Classes I-III [mortality 8 of 3655 patients (0.2%)] managed as out-patients but higher in Classes IV and V [mortality 32 of 317 patients (10.1%)]. CRB65 showed pooled sensitivity of 81% (54-96%), pooled specificity of 91% (90-93%) and the area under the sROC was 0.91 [standard error (SE) 0.05]. For PSI, pooled sensitivity was 92% (64-100%), pooled specificity was 90% (89-91%) and area under the sROC was 0.92 (SE 0.03). There were insufficient studies to analyse CURB65. The limited data available suggest that CRB65 and PSI can identify groups of patients at low risk of mortality that can be safely managed in the community.
    Preview · Article · Jul 2011 · QJM: monthly journal of the Association of Physicians
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To explore the potential use of the CRB-65 rule (based on Confusion, Respiratory rate, Blood pressure and age >65 years) in adults with lower respiratory tract infection (LRTI) in primary care. Primary care clinicians in 13 European countries recorded antibiotic treatment and clinical features for adults with LRTI. Patients recorded daily symptoms. Multilevel regression models determined the association between an elevated CRB-65 score and prolonged moderately severe symptoms, hospitalisation, and time to recovery. Sensitivity analyses used zero imputation. Respiratory rate and blood pressure were recorded in 22.7% and 31.9% of patients, respectively. A total of 2,690 patients completed symptom diaries. The CRB-65 could be calculated for 339 (12.6%). A score of >1 was not significantly associated with prolonged moderately severe symptoms (odds ratio (OR) 0.42, 95% CI 0.04 to 4.19) or hospitalisations (OR 3.12, 95% CI 0.16 to 60.24), but was associated with prolonged time to self-reported recovery when using zero imputation (hazard ratio (HR) 0.75, 95% CI 0.64 to 0.88). Respiratory rate and blood pressure are infrequently measured in adults with LRTI. We found no evidence to support using the CRB-65 rule in the assessment of LRTI in primary care. However, it is unclear whether it is of value if used only in patients where the primary care clinician suspects pneumonia.
    Full-text · Article · Sep 2011 · Primary care respiratory journal: journal of the General Practice Airways Group
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study compares the ability of the Pneumonia Severity Index (PSI) and the British Thoracic Society CURB-65 and CRB-65 rules in predicting short-term mortality among elderly patients with community-acquired pneumonia (CAP). It is a population-based study including all people over 65 years old with a radiographically confirmed CAP in the region of Tarragona (Spain) between 2002 and 2008. Treatment setting and clinical variables were considered for each patient. PSI, CURB-65 and CRB-65 scores were calculated at the moment of diagnosis and 30-day mortality was considered as a main dependent variable. The rules were compared based on sensitivity, specificity and area under the receiver operating characteristic curve (AUC). Of the total 590 CAP cases, mortality rate was 13.6% (15.3% in hospitalised and 1.4% in outpatient cases; p = 0.001). Mortality increased with increasing PSI score (None in class II, 6,9% in class III, 14,4% in class IV and 29,5% in class V), CURB-65 score (7.5%, 14.5%, 26.7%, 53.3% and 100% for scores 1,2,3,4 and 5 respectively) and CRB-65 score (6.6%, 26.1%, 40.5% and 50% for scores 1,2,3 and 4 respectively). The three rules performed too similarly to predict 30-day mortality, with a ROC area of 0.727 [95% confidence interval (CI): 0.67-0.79] for the PSI, 0.672 (95% CI: 0.61-0.74) for the CURB-65, and 0.719 (95% CI: 0.65-0.78) for the CRB-65. Our data shows that the analysed rules perform equally well among elderly people with CAP which supports the recommendation for using the simplified CRB-65 severity score among elderly patients in primary care or emergency visits.
    No preview · Article · Sep 2011 · International Journal of Clinical Practice
Show more