title: Validity of self-reported hypertension is inversely associated with the level of education in Brazilian individuals.
abstract: BACKGROUND
  Self-reported hypertension is an important piece of information for public health that is available in epidemiological studies. For proper use of this information, such studies should be validated.
  
  
  OBJECTIVE
  To validate self-reported hypertension and associated factors in adults and elderly individuals in São Paulo, Brazil.
  
  
  METHODS
  Participants were selected from the sample of a population-based cross-sectional health survey carried out in São Paulo (ISA Capital-2008). Their age was 20 years or older, they were from both genders, and had their blood pressure measured (n = 535). Hypertension was defined as blood pressure > 140/90 mmHg and/or use of medication for hypertension. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa coefficient were calculated. Poisson regression was used to identify factors associated with sensitivity of self-reported hypertension.
  
  
  RESULTS
  Sensitivity of self-reported hypertension was 71.1% (95%CI: 64.8 to 76.9), specificity 80.5% (95%CI: 75.6 to 84.8), PPV 73.7% (95%CI: 67.4 to 79.3), and NPV 78.5% (95%CI: 73.5 to 82.9). There was moderate agreement between self-reported hypertension and hypertension as diagnosed by blood pressure measurement (kappa = 0.52, 95%CI: 0.45 to 0.59). Body mass index and level of education were independently associated with sensitivity (body mass index > 25 kg/m²: PR = 1.42, 95% CI: 1.15 to 1.76; schooling > 9 years: PR = 0.71 95%CI: 0.54-0.94).
  
  
  CONCLUSIONS
  Self-reported hypertension was shown to be valid in adults and the elderly in the city of São Paulo, and is thus an appropriate indicator for the surveillance of hypertension prevalence in the absence of blood pressure measurement. Overweight was positively associated with validity of self-reported hypertension. Further studies are needed to elucidate the inverse association between the validity of self-reported hypertension and level of education.
authors.affiliation: Departamento de Nutrição, Faculdade de Saúde Pública da Universidade de São Paulo, São Paulo, SP, Brasil. sorayaselem@gmail.com
authors.forename: Soraya Sant'Ana de Castro
authors.initials: SS
authors.lastname: Selem
authors.forename: Michele Alessandra
authors.initials: MA
authors.lastname: Castro
authors.forename: Chester Luiz Galvão
authors.initials: CL
authors.lastname: César
authors.forename: Dirce Maria Lobo
authors.initials: DM
authors.lastname: Marchioni
authors.forename: Regina Mara
authors.initials: RM
authors.lastname: Fisberg
mesh_terms: D000328:Adult; D017677:Age Distribution; D018660:Blood Pressure Monitoring, Ambulatory; D001938:Brazil; D004522:Educational Status; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D057566:Self Report; D017678:Sex Distribution; D055815:Young Adult