Future CAD best predicted by morning home BP measurement

Kario K, Saito I, Kushiro T, et al.,
J Am Coll Cardiol. 2016;67(13):1519-1527. doi:10.1016/j.jacc.2016.01.037

Background

Clinic blood pressure (CBP) is strongly predictive of stroke events, but its association with coronary artery disease (CAD) is less clear [1,2]. Data from a large-scale database study revealed that 24-h diastolic BP (DBP) and isolated diastolic hypertension predict CAD in untreated people younger than 50 years of age [3]. Other studies showed a correlation between home BP (HBP) and CV events [4-6], but the relationship between HBP and CAD events was not reported.
HBP has the advantage of being easy to measure, and allowing repeated measures and long-term monitoring. The best time of day for HBP measurement remains to be determined, in order to predict CAD events. It has been shown that morning hypertension predicts CV events, since both incidence of CV events and BP peak in the early morning [7].
This analysis compared the relationships of morning HBP or CBP with the incidence of CAD (myocardial infarction and revascularization for angina) and stroke events, using data from the large real-world prospective HONEST study [8,9]. HONEST included olmesartan-naive outpatients with essential hypertension, who already owned a validated and approved electronic device for measuring HBP using the cuff-oscillometric principle.

Main results

• 127 stroke (2.92 per 1000 patient-years, PY) and 121 CAD events (2.78 per 1000 PY) occurred in 21591 patients (mean follow-up: 2.02+0.50 years).
• Incidence and HR of stroke and CAD events numerically increased in ascending categories of HSBP and CSBP, with statistically significantly higher incidences if HSBP>145 and CSBP>150 mmHg.
• HR for stroke events was significantly higher if morning HSBP>155, as compared with morning HSBP<125 mmHg (HR: 6.01, 95%CI: 2.85-12.68). At morning HSBP from 145 to 155 mmHg, a tendency towards higher stroke event risk as compared with those with <125 mmHg was seen (HR: 1.90, 95%CI: 0.90-3.99, P=0.091).
  Evening HSBP >145 mmHg was also associated with higher incidence and HR of stroke.
  Morning and evening HSBP predicted stroke events to a similar extent as does CSBP.
• Patients with morning HSBP>155 mmHg had significantly higher CAD event risk than those with <125 mmHg (HR: 6.24, 95%CI: 2.82-13.84), and a tendency of a higher risk was seen in those with morning HSBP between 145 and 155 mmHg (HR: 2.15, 95%CI: 0.98-4.71, P=0.056).
  Evening HSBP >155 mmHg showed a significantly higher incidence and HR of CAD events, but not evening HSBP between 145 and 155 mmHg.
  HR for CAD was significantly higher only when CSBP>160 mmHg (HR: 3.51, 95%CI: 1.71-7.20).
• No evidence was seen for a J-curve phenomenon in the relationship between morning HBP and stroke or CAD events.
• Addition of morning HSBP significantly improved goodness-of-fit of a model for stroke or CAD events including CSBP. Adding CSBP to a model including morning HSBP significantly but more weakly improved the goodness-of-fit for a stroke model, but did not improve the CAD events model.
• Both higher stroke and CAD event risk were seen in morning HDSP>90 vs. <75 mmHg.

Conclusion

These data show that morning HBP is a strong predictor of future CAD events, as well as stroke events. CSBP and evening SBP may underestimate CAD risk, as compared with morning HSBP. Morning HDBP and CDBP appear to underestimate the risk of CAD events as compared with morning HSBP or CSBP. Thus, morning HSBP may be a superior predictor of future CAD. No evidence of a J-curve in the relationship between morning HBP and stroke or CAD event risk was seen.
It should be noted that this analysis used data of 4 HBP measurements, which was compared with a single CBP measurement. The observed superiority of morning HBP may be the consequence of multiple measurements, but that might not pose problems in light of the more easily repeated HBP measurements.

Editorial comment [10]

In parallel to the debate on the ideal BP target, the notion that home BP measurements have greater prognostic significance than clinic BP deserves attention. Physicians appear more likely to increase antihypertensive drugs in response to home BP measurements, thus home BP measurements may reduce therapeutic inertia and improve hypertension control.
“The study in fact reported evening home BP and overall home BP (the average of morning and evening BPs), and the data show that using all home BP recordings instead of just the morning ones may be easier and at least as strongly associated if not more strongly associated with stroke and coronary artery disease. Thus, this study does not specifically demonstrate the value of morning home BP over the overall home BP.”
 “… the large pragmatic HONEST study suggests that it is time to design a randomized trial similar to SPRINT with treatment targets dictated by—not clinic BP—but home BP assessments. If home BP can predict cardiovascular outcomes at least as well as clinic BP, it is time to test this strategy for cost-effectiveness, convenience, and, ultimately, its capability to relieve cardiovascular morbidity and mortality with the simple expedient of home BP monitoring.”

Find this article online at JACC

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