title: Clinical features of patients isolated for suspected Ebola virus disease at Connaught Hospital, Freetown, Sierra Leone: a retrospective cohort study.
abstract: BACKGROUND
  The size of the west African Ebola virus disease outbreak led to the urgent establishment of Ebola holding unit facilities for isolation and diagnostic testing of patients with suspected Ebola virus disease. Following the onset of the outbreak in Sierra Leone, patients presenting to Connaught Hospital in Freetown were screened for suspected Ebola virus disease on arrival and, if necessary, were admitted to the on-site Ebola holding unit. Since demand for beds in this unit greatly exceeded capacity, we aimed to improve the selection of patients with suspected Ebola virus disease for admission by identifying presenting clinical characteristics that were predictive of a confirmed diagnosis.
  
  
  METHODS
  In this retrospective cohort study, we recorded the presenting clinical characteristics of suspected Ebola virus disease cases admitted to Connaught Hospital's Ebola holding unit. Patients were subsequently classified as confirmed Ebola virus disease cases or non-cases according to the result of Ebola virus reverse-transcriptase PCR (EBOV RT-PCR) testing. The sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio of every clinical characteristic were calculated, to estimate the diagnostic accuracy and predictive value of each clinical characteristic for confirmed Ebola virus disease.
  
  
  RESULTS
  Between May 29, 2014, and Dec 8, 2014, 850 patients with suspected Ebola virus disease were admitted to the holding unit, of whom 724 had an EBOV RT-PCR result recorded and were included in the analysis. In 464 (64%) of these patients, a diagnosis of Ebola virus disease was confirmed. Fever or history of fever (n=599, 83%), intense fatigue or weakness (n=495, 68%), vomiting or nausea (n=365, 50%), and diarrhoea (n=294, 41%) were the most common presenting symptoms in suspected cases. Presentation with intense fatigue, confusion, conjunctivitis, hiccups, diarrhea, or vomiting was associated with increased likelihood of confirmed Ebola virus disease. Three or more of these symptoms in combination increased the probability of Ebola virus disease by 3·2-fold (95% CI 2·3-4·4), but the sensitivity of this strategy for Ebola virus disease diagnosis was low. In a subgroup analysis, 15 (9%) of 161 confirmed Ebola virus disease cases reported neither a history of fever nor a risk factor for Ebola virus disease exposure.
  
  
  CONCLUSIONS
  Discrimination of Ebola virus disease cases from patients without the disease is a major challenge in an outbreak and needs rapid diagnostic testing. Suspected Ebola virus disease case definitions that rely on history of fever and risk factors for Ebola virus disease exposure do not have sufficient sensitivity to identify all cases of the disease.
  
  
  BACKGROUND
  None.
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK. Electronic address: marta.lado@kcl.ac.uk.
authors.forename: Marta
authors.initials: M
authors.lastname: Lado
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK; Department of Infectious Diseases and Immunity, Imperial College London, London, UK; Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Naomi F
authors.initials: NF
authors.lastname: Walker
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Baker
authors.affiliation: Public Health, Epidemiology & Biostatistics, University of Birmingham, Birmingham, UK.
authors.forename: Shamil
authors.initials: S
authors.lastname: Haroon
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK; The Hospital for Tropical Diseases, University College London Hospitals, London, UK.
authors.forename: Colin S
authors.initials: CS
authors.lastname: Brown
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Youkee
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Studd
authors.affiliation: College of Medicine and Allied Health Sciences, University of Sierra Leone, Freetown, Sierra Leone.
authors.forename: Quaanan
authors.initials: Q
authors.lastname: Kessete
authors.affiliation: Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: Rishma
authors.initials: R
authors.lastname: Maini
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK; Division of Infectious Diseases and HIV Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Tom
authors.initials: T
authors.lastname: Boyles
authors.affiliation: Connaught Hospital, Freetown, Sierra Leone; Ministry of Health and Sanitation, Freetown, Sierra Leone.
authors.forename: Eva
authors.initials: E
authors.lastname: Hanciles
authors.affiliation: Ministry of Health and Sanitation, Freetown, Sierra Leone.
authors.forename: Alie
authors.initials: A
authors.lastname: Wurie
authors.affiliation: Connaught Hospital, Freetown, Sierra Leone; Ministry of Health and Sanitation, Freetown, Sierra Leone; Department of Surgery, College of Medicine and Allied Health Sciences, University of Sierra Leone, Freetown, Sierra Leone.
authors.forename: Thaim B
authors.initials: TB
authors.lastname: Kamara
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK.
authors.forename: Oliver
authors.initials: O
authors.lastname: Johnson
authors.affiliation: King's Sierra Leone Health Partnership, King's Centre for Global Health, King's Health Partners and King's College London, London, UK.
authors.forename: Andrew J M
authors.initials: AJM
authors.lastname: Leather
mesh_terms: D000328:Adult; D003221:Confusion / Q000821:virology; D003236:Conjunctivitis, Viral / Q000821:virology; D003967:Diarrhea / Q000821:virology; D029043:Ebolavirus / Q000302:isolation & purification; D005221:Fatigue / Q000821:virology; D005260:Female; D005334:Fever / Q000821:virology; D019142:Hemorrhagic Fever, Ebola / Q000150:complications* / Q000175:diagnosis*; D006606:Hiccup / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009325:Nausea / Q000821:virology; D010356:Patient Isolation; D018579:Patient Selection; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012807:Sierra Leone; D014839:Vomiting / Q000821:virology; D055815:Young Adult