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Q In a Japanese population, is self measured home blood pressure (BP) or clinic BP measured by healthcare professionals accurate for predicting the risk of a stroke or transient ischaemic attack (TIA)?
Clinical impact ratings GP/FP/Primary care ★★★★★☆☆ IM/Ambulatory care ★★★★★☆☆ Neurology ★★★★★☆☆
METHODS
Design:
a cohort of Japanese people followed up for a mean of 10.6 years (maximum of 13.9 y)
Setting:
A rural community (Ohasama town) in Japan.
Participants:
1702 participants ⩾40 years of age (mean age 61 y, 61% women) who were followed up for the first onset of a stroke or TIA.
Description of prediction guide:
in line with the Joint National Committee 7 criteria, participants were classified into groups 1–4 on the basis of either home or clinic BP (table). Groups 2, 3, and 4 were further divided into 2 subgroups (a and b): those without and with cardiovascular risk factors (eg, diabetes mellitus, smoking, hypercholesterolaemia, or history of cardiovascular disease), respectively. Risk of first stroke or TIA in each of these groups was estimated using the Cox proportional hazards model after adjusting for age and sex.
Self measured home blood pressure (HBP) v “clinic” blood pressure (CBP) measured by healthcare professionals for predicting the risk of stroke at a mean follow up of 10.6 years*
Outcomes:
incidence of a first stroke or TIA confirmed by hospital records.
MAIN RESULTS
8.3% of participants had a stroke or TIA. The table shows hazard ratios for groups 2–4 compared with group 1.
CONCLUSION
In a Japanese population, self measured home blood pressure was more consistent than “clinic” blood pressure for predicting the risk of stroke or transient ischeamic attacks.
Commentary
Many studies have confirmed that home BP readings are generally 8–12 mm Hg lower for systolic and 4–6 mm Hg lower for diastolic compared with office readings. Ambulatory BP monitoring (ABPM) further showed an association between the common occurrence of white coat hypertension and an intermediate cardiovascular risk relative to patients with normal BP and those with sustained elevations. Both home BP and ABPM provide more data by which to judge BP control than episodic clinic visits.1 Home BP determinations carry some cautions for implementation and interpretation.2,3 Morning readings offer useful correlates to circadian variation in risk factors (ie, high cortisol, high sympathetic tone, hypercoagulability, hypofibrinolysis, and drug concentration nadirs).4 Other patient behaviour, like squatting or eating, may respectively raise or lower BP, predisposing to BP instability and stroke.5 The study by Asayama et al builds on previous data6 confirming the enhanced value of home BP as a predictor of target organ damage compared with office BP readings.
Footnotes
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For correspondence: Dr Y Imai, Tohoku University Graduate School of Pharmaceutical Science and Medicine, Sendai, Japan. rinsyobureau.tohoku.ac.jp
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Source of funding: not stated