The use of ambulatory blood pressure monitoring to improve the accuracy and reduce the numbers of subjects in clinical trials of antihypertensive agents

J. Conway, J. Johnston, A. Coats, Virend Somers, P. Sleight

Research output: Contribution to journalArticle

149 Scopus citations


A low-cost ambulatory blood pressure measuring device has been developed from a commercially available stationary apparatus. The device, which has been compared for accuracy with a mercury manometer, has functioned satisfactorily as an ambulatory monitor for 4 years. To minimize errors, blood pressure readings were made in the sitting position at half-hourly intervals over the waking day. The utility of the device in clinical trials has been investigated. On repeated readings no placebo effect on blood pressure was detectable and the mean difference between two readings in 42 subjects was 1.9/-0.33 mmHg. The standard deviation of the difference were 8.1/5.6 mmHg. This should make it possible to detect differences of 8/5 mmHg between two treatments in about 16 subjects. There was no detectable tendency for blood pressure to change during the day but the variability between readings was substantially increased if the observation periods were reduced to 4 h.

Original languageEnglish (US)
Pages (from-to)111-116
Number of pages6
JournalJournal of Hypertension
Issue number2
StatePublished - 1988
Externally publishedYes


ASJC Scopus subject areas

  • Endocrinology
  • Internal Medicine

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