title: Evaluation of the importance of fever with respect to dengue prognosis according to the 2009 WHO classification: a retrospective study.
abstract: The 2009 revised World Health Organization (WHO) guidelines for dengue describe fever as the core symptom. Accordingly, the diagnosis of non-febrile patients is complicated. The aim of this study was to evaluate the importance of fever in patients with dengue according to the 2009 revised WHO classification.
  
  
  
  In this study, we assessed 30,670 dengue cases using enzyme-linked immunosorbent assay, detection of the non-structural protein 1, or polymerase chain reaction for diagnostic confirmation. Fisher's exact test was used to evaluate associations between fever and related clinical manifestations. The Mann-Whitney U test was used to assess the association of dengue classification with fever and time to treatment. The effects of fever and time to treatment on the risk of progression were analyzed using an ordinal logistic regression to stereotype the model.
  
  
  
  Disease classification was found to associate significantly with both fever and time to treatment (both P < 0.001). Non-febrile patients were nearly four-fold more likely to exhibit "dengue without warning signs" than "severe dengue" (odds ratio [OR] = 3.74; 95% confidence interval [CI]: 3.20-4.36). Patients who received treatment within 7 days were twice as likely to have "dengue without warning signs" as opposed to "severe dengue" when compared to those who waited >7 days (OR = 2.23; 95% CI: 1.78-2.80). However, this difference was negligible in the multivariate analysis (OR = 1.02; 95% CI: 0.98-1.07).
  
  
  
  Fever is a risk factor for disease progression in patients with dengue. However, non-febrile patients should not be neglected because this may delay treatment and could lead to more severe disease.
authors.affiliation: Faculdade de Medicina, União das Faculdades dos Grandes Lagos, São José do Rio Preto, São Paulo, Brazil.
authors.forename: Caroline
authors.initials: C
authors.lastname: Tukasan
authors.affiliation: Faculdade de Medicina, União das Faculdades dos Grandes Lagos, São José do Rio Preto, São Paulo, Brazil.
authors.forename: Nathália Barbosa
authors.initials: NB
authors.lastname: Furlan
authors.affiliation: Laboratório de Pesquisas em Virologia, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, São Paulo, Brazil.
authors.forename: Cássia Fernanda
authors.initials: CF
authors.lastname: Estofolete
authors.affiliation: Laboratório de Pesquisas em Virologia, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, São Paulo, Brazil. mnogueira@famerp.br.
authors.forename: Maurício Lacerda
authors.initials: ML
authors.lastname: Nogueira
authors.affiliation: Faculdade de Medicina, União das Faculdades dos Grandes Lagos, São José do Rio Preto, São Paulo, Brazil. natalss@gmail.com.|Laboratório de Pesquisas em Virologia, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, São Paulo, Brazil. natalss@gmail.com.|Laboratório de Modelagens Matemática e Estatística em Medicina, Faculdade de Medicina, União das Faculdades dos Grandes Lagos, São José do Rio Preto, São Paulo, Brazil. natalss@gmail.com.
authors.forename: Natal Santos
authors.initials: NS
authors.lastname: da Silva
mesh_terms: D000293:Adolescent; D000328:Adult; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005334:Fever / Q000150:complications* / Q000401:mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D019595:Severe Dengue / Q000150:complications* / Q000175:diagnosis* / Q000401:mortality; D012720:Severity of Illness Index; D014944:World Health Organization; D055815:Young Adult
keywords: Dengue epidemiology; Dengue fever; Severe dengue; WHO 2009 classification