title: Can a novel clinical risk score improve pneumonia prediction in acute stroke care? A UK multicenter cohort study.
abstract: BACKGROUND
  Pneumonia frequently complicates stroke and has a major impact on outcome. We derived and internally validated a simple clinical risk score for predicting stroke-associated pneumonia (SAP), and compared the performance with an existing score (A(2)DS(2)).
  
  
  RESULTS
  We extracted data for patients with ischemic stroke or intracerebral hemorrhage from the Sentinel Stroke National Audit Programme multicenter UK registry. The data were randomly allocated into derivation (n=11 551) and validation (n=11 648) samples. A multivariable logistic regression model was fitted to the derivation data to predict SAP in the first 7 days of admission. The characteristics of the score were evaluated using receiver operating characteristics (discrimination) and by plotting predicted versus observed SAP frequency in deciles of risk (calibration). Prevalence of SAP was 6.7% overall. The final 22-point score (ISAN: prestroke Independence [modified Rankin scale], Sex, Age, National Institutes of Health Stroke Scale) exhibited good discrimination in the ischemic stroke derivation (C-statistic 0.79; 95% CI 0.77 to 0.81) and validation (C-statistic 0.78; 95% CI 0.76 to 0.80) samples. It was well calibrated in ischemic stroke and was further classified into meaningful risk groups (low 0 to 5, medium 6 to 10, high 11 to 14, and very high ≥15) associated with SAP frequencies of 1.6%, 4.9%, 12.6%, and 26.4%, respectively, in the validation sample. Discrimination for both scores was similar, although they performed less well in the intracerebral hemorrhage patients with an apparent ceiling effect.
  
  
  CONCLUSIONS
  The ISAN score is a simple tool for predicting SAP in clinical practice. External validation is required in ischemic and hemorrhagic stroke cohorts.
authors.affiliation: Stroke and Vascular Research Centre, Institute of Cardiovascular Sciences, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK (C.J.S., P.J.T.) Greater Manchester Comprehensive Stroke Centre, Department of Medical Neurosciences, Salford Royal NHS Foundation Trust, Salford, UK (C.J.S., P.J.T.).
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Smith
authors.affiliation: Division of Health and Social Care Research, King's College London, UK (B.D.B., C.A.W., A.G.R.).
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Bray
authors.affiliation: Royal College of Physicians, London, UK (A.H.).
authors.forename: Alex
authors.initials: A
authors.lastname: Hoffman
authors.affiliation: Centre for Stroke Research Berlin, Charité Universitätsmedizin Berlin, Germany (A.M.).
authors.forename: Andreas
authors.initials: A
authors.lastname: Meisel
authors.affiliation: Institute of Clinical Epidemiology and Biometry, University of Würzburg; Comprehensive Heart Failure Center, University of Würzburg; Clinical Trial Center, University Hospital Würzburg, Germany (P.U.H.).
authors.forename: Peter U
authors.initials: PU
authors.lastname: Heuschmann
authors.affiliation: Division of Health and Social Care Research, King's College London, UK (B.D.B., C.A.W., A.G.R.) National Institute for Health Research Comprehensive Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK (C.A.W., A.G.R.).
authors.forename: Charles D A
authors.initials: CD
authors.lastname: Wolfe
authors.affiliation: Stroke and Vascular Research Centre, Institute of Cardiovascular Sciences, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK (C.J.S., P.J.T.) Greater Manchester Comprehensive Stroke Centre, Department of Medical Neurosciences, Salford Royal NHS Foundation Trust, Salford, UK (C.J.S., P.J.T.).
authors.forename: Pippa J
authors.initials: PJ
authors.lastname: Tyrrell
authors.affiliation: Division of Health and Social Care Research, King's College London, UK (B.D.B., C.A.W., A.G.R.) National Institute for Health Research Comprehensive Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK (C.A.W., A.G.R.).
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Rudd
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011014:Pneumonia / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012042:Registries; D015203:Reproducibility of Results; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D020521:Stroke / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D016019:Survival Analysis; D016896:Treatment Outcome; D006113:United Kingdom
keywords: clinical risk score; pneumonia; stroke, acute; stroke‐associated pneumonia