title: Primary care REFerral for EchocaRdiogram (REFER) in heart failure: a diagnostic accuracy study.
abstract: BACKGROUND
  Symptoms of breathlessness, fatigue, and ankle swelling are common in general practice but deciding which patients are likely to have heart failure is challenging.
  
  
  OBJECTIVE
  To evaluate the performance of a clinical decision rule (CDR), with or without N-Terminal pro-B type natriuretic peptide (NT-proBNP) assay, for identifying heart failure.
  
  
  METHODS
  Prospective, observational, diagnostic validation study of patients aged >55 years, presenting with shortness of breath, lethargy, or ankle oedema, from 28 general practices in England.
  
  
  METHODS
  The outcome was test performance of the CDR and natriuretic peptide test in determining a diagnosis of heart failure. The reference standard was an expert consensus panel of three cardiologists.
  
  
  RESULTS
  Three hundred and four participants were recruited, with 104 (34.2%; 95% confidence interval [CI] = 28.9 to 39.8) having a confirmed diagnosis of heart failure. The CDR+NT-proBNP had a sensitivity of 90.4% (95% CI = 83.0 to 95.3) and specificity 45.5% (95% CI = 38.5 to 52.7). NT-proBNP level alone with a cut-off <400 pg/ml had sensitivity 76.9% (95% CI = 67.6 to 84.6) and specificity 91.5% (95% CI = 86.7 to 95.0). At the lower cut-off of NT-proBNP <125 pg/ml, sensitivity was 94.2% (95% CI = 87.9 to 97.9) and specificity 49.0% (95% CI = 41.9 to 56.1).
  
  
  CONCLUSIONS
  At the low threshold of NT-proBNP <125 pg/ml, natriuretic peptide testing alone was better than a validated CDR+NT-proBNP in determining which patients presenting with symptoms went on to have a diagnosis of heart failure. The higher NT-proBNP threshold of 400 pg/ml may mean more than one in five patients with heart failure are not appropriately referred. Guideline natriuretic peptide thresholds may need to be revised.
authors.affiliation: Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford.
authors.forename: Clare J
authors.initials: CJ
authors.lastname: Taylor
authors.affiliation: Institute of Applied Health Research, University of Birmingham, Birmingham.
authors.forename: Andrea K
authors.initials: AK
authors.lastname: Roalfe
authors.affiliation: Institute of Applied Health Research, University of Birmingham, Birmingham.
authors.forename: Rachel
authors.initials: R
authors.lastname: Iles
authors.affiliation: Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford.
authors.forename: Fd Richard
authors.initials: FR
authors.lastname: Hobbs
authors.affiliation: Institute of Applied Health Research, University of Birmingham, Birmingham.
authors.forename: P
authors.initials: P
authors.lastname: Barton
authors.affiliation: Institute of Applied Health Research, University of Birmingham, Birmingham.
authors.forename: J
authors.initials: J
authors.lastname: Deeks
authors.affiliation: Institute of Applied Health Research, University of Birmingham, Birmingham.
authors.forename: D
authors.initials: D
authors.lastname: McCahon
authors.affiliation: Faculty of Medicine, National Heart and Lung Institute, Imperial College London.
authors.forename: M R
authors.initials: MR
authors.lastname: Cowie
authors.affiliation: Faculty of Medicine, National Heart and Lung Institute, Imperial College London.
authors.forename: G
authors.initials: G
authors.lastname: Sutton
authors.affiliation: Department of Cardiology, Sandwell and West Birmingham Hospitals, Lyndon, West Bromwich.
authors.forename: R C
authors.initials: RC
authors.lastname: Davis
authors.affiliation: Department of Public Health and Primary Care, University of Cambridge, Cambridge.
authors.forename: J
authors.initials: J
authors.lastname: Mant
authors.affiliation: Department of Cardiology, King's College Hospital, London.
authors.forename: T
authors.initials: T
authors.lastname: McDonagh
authors.affiliation: School of Health Sciences, Nottingham.
authors.forename: L
authors.initials: L
authors.lastname: Tait
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002985:Clinical Protocols; D004417:Dyspnea; D004562:Electrocardiography; D004739:England; D005221:Fatigue; D005260:Female; D006333:Heart Failure / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011320:Primary Health Care; D011446:Prospective Studies; D012372:ROC Curve; D012017:Referral and Consultation; D012107:Research Design
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain
keywords: clinical decision rule; diagnostic; echocardiography; general practice; heart failure; natriuretic peptide