title: Reference values for self-recorded blood pressure: a meta-analysis of summary data.
abstract: BACKGROUND
  The widespread clinical use of self-recorded blood pressure measurement is limited by the lack of generally accepted reference values. The purpose of this study was therefore to perform a meta-analysis of summary data in an attempt to determine an operational threshold for self-recorded blood pressures. STUDIES AND METHODS: Seventeen studies, including a total of 5422 subjects, were reviewed. Eight of these 17 studies included both normotensive and untreated hypertensive subjects, while the other 9 reports included normotensive subjects only. Within each study an operational cutoff point between normotension and hypertension was derived by means of the mean+2 SDs and the 95th percentiles of the self-recorded blood pressure in normotensive subjects. These 2 methods were contrasted with 2 other techniques that have been applied in the literature to calculate (1) the self-recorded pressures equivalent to a conventional pressure of 140 mm Hg systolic and 90 mm Hg diastolic by means of regression analysis and (2) the self-recorded blood pressures at the percentiles corresponding to a conventional pressure of 140/90 mm Hg. The latter 2 methods were applied in untreated subjects not selected on the basis of their blood pressure.
  
  
  RESULTS
  With weighting for the number of subjects included in the various studies, the self-recorded blood pressure averaged 115/71 mm Hg in normotensive persons and 119/74 mm Hg in untreated subjects not selected on the basis of their blood pressure. The reference values for self-recorded blood pressures determined by the mean+2 SDs (137/89 mm Hg) or the 95th percentile (135/86 mm Hg) of the distribution in normotensive subjects were concordant within 2/3 mm Hg, whereas the cutoff points derived with the regression and percentile methods were considerably lower, ie, 125/79 and 129/84 mm Hg, respectively.
  
  
  CONCLUSIONS
  Until the relationship between self-recorded pressure and the incidence of cardiovascular morbidity and mortality is further clarified by prospective studies, a mean self-recorded blood pressure above 135 mm Hg systolic or 85 mm Hg diastolic may be considered hypertensive.
authors.affiliation: Department of Molecular and Cardiovascular Research, University of Leuven, Belgium. Lutgarde.Thijs@med.kuleuven.ac.be
authors.forename: L
authors.initials: L
authors.lastname: Thijs
authors.forename: J A
authors.initials: JA
authors.lastname: Staessen
authors.forename: H
authors.initials: H
authors.lastname: Celis
authors.forename: R
authors.initials: R
authors.lastname: de Gaudemaris
authors.forename: Y
authors.initials: Y
authors.lastname: Imai
authors.forename: S
authors.initials: S
authors.lastname: Julius
authors.forename: R
authors.initials: R
authors.lastname: Fagard
mesh_terms: D001795:Blood Pressure Determination / Q000009:adverse effects; D018660:Blood Pressure Monitoring, Ambulatory; D003937:Diagnosis, Differential; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000209:etiology; D012016:Reference Values; D012648:Self Care