Reference values for self-recorded blood pressure: a meta-analysis of summary data.
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.
Thijs
L
L
Department of Molecular and Cardiovascular Research, University of Leuven, Belgium. Lutgarde.Thijs@med.kuleuven.ac.be
Staessen
J A
JA
Celis
H
H
de Gaudemaris
R
R
Imai
Y
Y
Julius
S
S
Fagard
R
R
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