Morning blood pressure tied to target-organ damage

By Eleanor McDermid, Senior medwireNews Reporter

Physicians should ask patients to take home blood pressure (BP) readings in the morning as well as the evening before making therapeutic decisions, say researchers.

Their findings, from 4310 patients enrolled in the Japan Morning Surge Home Blood Pressure (J-HOP) Study, show that although both readings were associated with subclinical organ damage, the associations were stronger for the morning than evening measurements.

Furthermore, morning BP tended to be associated with different measures of target-organ damage than did evening BP.

“Although morning BP and evening BP have equal association with organ damage, only measurement of evening BP is likely to underestimate the risk of organ damage in individuals from Japan,” says the team, led by Satoshi Hoshide (Jichi Medical University School of Medicine, Tochigi, Japan).

The J-HOP participants, who all had at least one cardiovascular risk factor, were asked to measure their BP at home in the morning before eating or taking any antihypertensives and in the evening, again before taking antihypertensive medication.

Their morning systolic BP (SBP) readings were significantly associated with all six measures of target-organ damage used in the study, and their evening readings were associated with all except for carotid intima-media thickness (IMT).

In a multiple linear regression model, evening SBP improved the ability of morning SBP to predict the urinary albumin–creatinine ratio and brachial–ankle pulse wave velocity, after accounting for other variables including age, vascular risk factors, antihypertensive use and clinic SBP.

But evening SBP did not improve the ability of morning SBP to predict left ventricular mass index, brain natriuretic peptide, IMT or high-sensitivity cardiac troponin T.

Morning SBP also tended to be a more accurate predictor of target-organ damage in area under the receiver operating characteristic curve analysis, although not significantly so.

“The fact that morning BP had a greater clinical impact on organ damage compared with evening BP might have been related to the effects of antihypertensive treatment,” suggest the researchers in the American Journal of Hypertension.

About 80% of the study participants were taking antihypertensive medication, and Hoshide et al suggest that those with elevated morning BP “might be affected by an insufficient duration of action of antihypertensive treatment”.

They therefore say: “In treated patients, control of morning BP is important for regression of organ damage.”

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