title: Validation of self reported diagnosis of hypertension in a cohort of university graduates in Spain.
abstract: BACKGROUND
  The search for risk factors of hypertension requires the study of large populations. Sometimes, the only feasible way of studying these populations is to rely on self-reported data of the outcome. The objective of this study was to evaluate validity of self-reported diagnosis of hypertension in a cohort of university graduates in Spain.
  
  
  METHODS
  The Seguimiento Universidad de Navarra (SUN) Study is a cohort of more than 15,000 university graduates in Spain. We selected a random sample of 79 cohort participants who reported a diagnosis of hypertension and 48 participants who did not report such diagnosis (76% participation proportion). Then, we compared information on the self-reported diagnosis of hypertension and hypertension status as assessed through two personal blood pressure measurements and an interview. Additionally, we compared self-reported and measured blood pressure levels with intraclass correlation coefficients and the survival-agreement plot.
  
  
  RESULTS
  From those 79 reporting a diagnosis of hypertension, 65 (82.3%, 95% CI 72.8-92.8) were confirmed through conventional measurement of blood pressure and the interview. From those 48 that did not report a diagnosis of hypertension, 41 (85.4%, 95% CI 72.4-89.1) were confirmed as non hypertensives. Results were similar among men and women, but were worse for overweight and obese individuals, and for those with a family history of hypertension. The agreement between self-reported and measured blood pressure levels (as a continuous variable), as estimated by the intraclass correlation coefficient, was 0.35 for both systolic and diastolic blood pressure.
  
  
  CONCLUSIONS
  Self-reported hypertension among highly educated participants in a cohort study is a relatively valid tool to assess the hypertensive status of participants. However, the investigators should be cautious when using self-reported blood pressure values.
authors.affiliation: Department of Preventive Medicine and Public Health, University of Navarra, Pamplona, Spain. aalogut@alumni.unav.es
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Beunza
authors.forename: Miguel
authors.initials: M
authors.lastname: Delgado-Rodríguez
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Martínez-González
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001795:Blood Pressure Determination / Q000592:standards*; D015331:Cohort Studies; D038441:Diet, Mediterranean; D004522:Educational Status; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012648:Self Care / Q000592:standards*; D013030:Spain / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014495:Universities