title: Quality of the blood pressure phenotype in the GEnotipo, Fenotipo y Ambiente de la hipertensión arterial en UruguaY (GEFA-HT-UY) study.
abstract: BACKGROUND
  In the ongoing GEnotipo, Fenotipo y Ambiente de la HiperTensión Arterial en UruguaY (GEFA-HT-UY) study, we applied standardized epidemiological methods to determine complex phenotypes including blood pressure (BP). In this report, we present the quality control of the conventionally measured BP.
  
  
  METHODS
  Three trained observers measured BP five times consecutively in the seated position at each of two home visits and one clinic visit according to the guidelines of the European Society of Hypertension. On 1 December 2013, 4379 single BP readings in 170 participants were available for analysis.
  
  
  RESULTS
  Fewer BP readings than the five planned per contact occurred only at one home visit. Among observers, the frequency of identical consecutive readings for systolic or diastolic BP varied from 0 to 4.2%. The occurrence of odd readings ranged from 0.1 to 0.6%. Only 21.6% of the systolic and diastolic BP readings ended on zero (expected 20%). At home visits, there was a progressive decline in BP from the first to the fifth reading. The average of the five BP readings also decreased from the first to the second home visit (-5.63/-2.34 mmHg).
  
  
  CONCLUSIONS
  Our study highlighted the necessity to implement a stringent quality control of the conventionally measured BP. The procedures set up in the GEFA-HT-UY study are resulting in a well-defined BP phenotype, which is consistent with that in other population studies.
authors.affiliation: aHypertension Unit, Pathophysiology Department, Division of Nephrology bLaboratory of Clinical Pathology, School of Medicine, Hospital de Clínicas Dr Manuel Quintela, Universidad de la República, Montevideo, Uruguay cResearch Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, Studies Coordinating Centre, University of Leuven, Leuven, Belgium dDepartment of Epidemiology, Maastricht University, Maastricht, The Netherlands.
authors.forename: Leonella
authors.initials: L
authors.lastname: Luzardo
authors.forename: Mariana
authors.initials: M
authors.lastname: Sottolano
authors.forename: Inés
authors.initials: I
authors.lastname: Lujambio
authors.forename: Sebastián
authors.initials: S
authors.lastname: Robaina
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Thijs
authors.forename: Alicia
authors.initials: A
authors.lastname: da Rosa
authors.forename: Nadia
authors.initials: N
authors.lastname: Krul
authors.forename: Florencia
authors.initials: F
authors.lastname: Carusso
authors.forename: Ana C
authors.initials: AC
authors.lastname: Ríos
authors.forename: Alicia
authors.initials: A
authors.lastname: Olascoaga
authors.forename: Oscar
authors.initials: O
authors.lastname: Noboa
authors.forename: Jan A
authors.initials: JA
authors.lastname: Staessen
authors.forename: José
authors.initials: J
authors.lastname: Boggia
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011187:Posture; D011786:Quality Control