title: Internal and external validation of a model to predict adverse outcomes in patients with left-sided infective endocarditis.
abstract: BACKGROUND
  Early identification of prognostic factors is essential to improve the grim prognosis associated with left-sided infective endocarditis. This group identified three independent risk factors obtained within 72 h of admission, (Staphylococcus aureus, heart failure and periannular complications) for inhospital mortality or urgent surgery in a series of 317 patients diagnosed at five tertiary centres (derivation sample). A stratification score was constructed for the test cohort by a simple arithmetic sum of the number of variables present. The goal was to validate this model internally and externally in a prospective manner with two different cohorts of patients.
  
  
  METHODS
  The appropriateness of the model was tested prospectively on predicting events in two cohorts of patients with left-sided endocarditis: internally with the 263 consecutive patients diagnosed at the same centres where the model was derived (internal validation sample), and externally with 264 patients admitted at another hospital (external validation sample).
  
  
  RESULTS
  The discriminatory power of the model, expressed as the area under the receiver operating characteristic curve was similar between derivation and both validation samples (internal 0.67 vs 0.68, p=0.79; external 0.67 vs p=0.74, p=0.09). There was a progressive, significant pattern of increasing event rates as the risk stratification score increased in both validation cohorts (p<0.001 by χ² for trend).
  
  
  CONCLUSIONS
  The early risk stratification model derived, based on variables obtained within 72 h of admission, is applicable to different populations with left-sided endocarditis. A simple bedside assessment tool is provided to clinicians that identifies patients at high risk of having an adverse event.
authors.affiliation: Instituto de Ciencias del Corazón (ICICOR), Hospital Clínico Universitario, C/ Ramón y Cajal 3, 47005 Valladolid, Spain. javihouston@yahoo.es
authors.forename: Javier
authors.initials: J
authors.lastname: López
authors.forename: Nuria
authors.initials: N
authors.lastname: Fernández-Hidalgo
authors.forename: Ana
authors.initials: A
authors.lastname: Revilla
authors.forename: Isidre
authors.initials: I
authors.lastname: Vilacosta
authors.forename: Pilar
authors.initials: P
authors.lastname: Tornos
authors.forename: Benito
authors.initials: B
authors.lastname: Almirante
authors.forename: Teresa
authors.initials: T
authors.lastname: Sevilla
authors.forename: Itziar
authors.initials: I
authors.lastname: Gómez
authors.forename: Eduardo
authors.initials: E
authors.lastname: Pozo
authors.forename: Cristina
authors.initials: C
authors.lastname: Sarriá
authors.forename: José Alberto
authors.initials: JA
authors.lastname: San Román
mesh_terms: D000328:Adult; D000368:Aged; D006348:Cardiac Surgical Procedures; D016009:Chi-Square Distribution; D004696:Endocarditis / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology / Q000401:mortality / Q000601:surgery; D006305:Health Status Indicators; D006333:Heart Failure / Q000382:microbiology / Q000401:mortality; D017052:Hospital Mortality; D006785:Hospitals, University; D006801:Humans; D007297:Inpatients; D016015:Logistic Models; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013030:Spain; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013997:Time Factors