Chatellier G, Dutrey-Dupagne C, Vaur L, Zannad F, Genes N,
Elkik F, Menard J
Home self blood pressure measurement in general practice: the
Am J Hypert
(Jul) 29:644-652 1996
Although self home blood pressure monitoring is widely employed in
clinical hypertension practice, the exact value and limitations of
such a practice are not well studied. These authors wanted to assess
the feasibility and practical value of self measured home BP, and
office BP in a clinical trial in a French population.
The study design is an open label one based in General Practice
involving 1710 patients with essential hypertension. After an initial
2 week washout of current antihypertensive therapy, subjects with
diastolic BP between 95 to 115 mmHg were given trandolapril 2mg in the
morning for 4 weeks. Office BP and self measured BP was performed to
assess response to therapy. Home BP was planned during the last 4 days
of the washout and also of the final week of treatment. The home BP
device used in this study uses an oscillometric method and is also
able to record BP and print values. The authors analyzed compliance
with taking the home BP, and also compared home BP to office BP levels
at baseline and after treatment with Trandolapril.
Compliance with taking home BP readings was only fair with 25% of
subjects not taking any readings, and only 36% of all subjects taking
the full complement of expected home readings. There were no good
identifiers of compliance with home self BP measurement. A distinct
digit preference for 0 and 5 was found among the physicians' office BP
readings. The performance of 6 readings at home achieved most of the
reduction of the standard deviation seen with the entire set of home
readings. As expected home BP was significantly lower than office BP
by 13/8 ñ 15/10 mmHg. Large differences were seen between the two
methods especially at lower BP values. Office BP declined more with
treatment than home BP.
Comment: Although the authors are optimistic about the
use of home BP in the evaluation and treatment of hypertension, only
36% of all subjects performed all expected readings. Perhaps a period
of education about anticipated value of the home BP would have
improved compliance. Doctors continue to show observer bias in
recording BP, a problem which has to be constantly guarded against.
Home BP devices however are notoriously unreliable and should be
calibrated at time of purchase against a mercury sphygmomanometer.
Further work is necessary before home BP can substitute for office BP
or ambulatory BP in clinical work or clinical research trials.
(George Mansoor, M.D., University of Connecticut)