title: Sex-specific versus overall cut points for a high sensitivity troponin I assay in predicting 1-year outcomes in emergency patients presenting with chest pain.
abstract: OBJECTIVE
  To evaluate the incidence of major adverse cardiac events (MACE) at 1 year in emergency department (ED) patients with possible acute coronary syndromes, stratified by high sensitivity troponin (hs-cTnI) concentrations using sex-specific cut points compared with overall cut points.
  
  
  METHODS
  In a multicentre observational study of 2841 patients, presentation hs-cTnI concentrations were categorised using sex-specific (women 16 ng/L; men 34 ng/L) and overall (26 ng/L) cut points. The primary outcome was MACE occurring within 1 year of presentation. Patients with hs-cTnI values concentrations within these categories were reported by sex and 1-year MACE. Net reclassification improvement (NRI) was computed to measure the change in prediction after altering the hs-cTnI cut points, and was calculated separately for events and non-events.
  
  
  RESULTS
  Application of sex-specific 99th percentile cut points rather than the overall cut point of 26 ng/L, reclassified 25 females from having a non-elevated troponin to having an elevated troponin, and 29 males from having an elevated troponin value to having a non-elevated troponin value on presentation. Of these, 7 (28.0%) females and 12 (41.4%) males had a 1-year MACE. There was no reclassification improvement for those with or without 1-year MACE (NRIevents=-1.5%, 95% CI -4.0% to 1.1%; NRInon-events -0.04%, 95% CI -0.5% to 0.4%).
  
  
  CONCLUSIONS
  Sex-specific cut points improve the identification of women but not men at risk for 1-year MACE. The net-effect across the whole ED population with possible cardiac chest pain is minimal. Lowering the clinical cut point for both sexes may be appropriate for prognostic purposes.
  
  
  BACKGROUND
  ISRCTN No. 21109279, ACTRN12609000283279.
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia School of Medicine, The University of Queensland, Brisbane, Queensland, Australia School of Public Health, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Louise
authors.initials: L
authors.lastname: Cullen
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia School of Medicine, The University of Queensland, Brisbane, Queensland, Australia School of Public Health, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Jaimi H
authors.initials: JH
authors.lastname: Greenslade
authors.affiliation: Emergency Department, Southmead Hospital, Bristol, UK.
authors.forename: Edward W
authors.initials: EW
authors.lastname: Carlton
authors.affiliation: Department of Emergency Medicine, Christchurch Hospital, Christchurch, New Zealand.
authors.forename: Martin
authors.initials: M
authors.lastname: Than
authors.affiliation: Emergency Care Foundation, Christchurch Hospital, Christchurch, New Zealand.
authors.forename: John W
authors.initials: JW
authors.lastname: Pickering
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.
authors.forename: Ariel
authors.initials: A
authors.lastname: Ho
authors.affiliation: School of Medicine, The University of Queensland, Brisbane, Queensland, Australia Department of Cardiology, Sunshine Coast Hospital and Health Services, University of the Sunshine Coast, Nambour, Australia.
authors.forename: Kim
authors.initials: K
authors.lastname: Greaves
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Berndt
authors.affiliation: Emergency Department, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Body
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.
authors.forename: Kimberley
authors.initials: K
authors.lastname: Ryan
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.
authors.forename: William A
authors.initials: WA
authors.lastname: Parsonage
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000401:mortality; D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D002637:Chest Pain / Q000097:blood / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009026:Mortality; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D012737:Sex Factors; D020107:Troponin T / Q000097:blood*
chemical_list: D020107:Troponin T