Office x Ambulatory BP

August 6, 2019

Association of Office and Ambulatory Blood Pressure With Mortality and Cardiovascular Outcomes

Wen-Yi Yang, MD, PhD^1,2; Jesus D. Melgarejo, MD³; Lutgarde Thijs, MSc¹; et alZhen-Yu Zhang, MD, PhD^1,2; José Boggia, MD, PhD⁴; Fang-Fei Wei, MD, PhD¹; Tine W. Hansen, MD, PhD⁵; Kei Asayama, MD, PhD^6,7; Takayoshi Ohkubo, MD, PhD^6,7; Jørgen Jeppesen, MD, PhD⁸; Eamon Dolan, MD, PhD⁹; Katarzyna Stolarz-Skrzypek, MD, PhD¹⁰; Sofia Malyutina, MD, PhD¹¹; Edoardo Casiglia, MD, PhD¹²; Lars Lind, MD, PhD¹³; Jan Filipovský, MD, PhD¹⁴; Gladys E. Maestre, MD, PhD^3,15; Yan Li, MD, PhD¹⁶; Ji-Guang Wang, MD, PhD¹⁶; Yutaka Imai, MD, PhD⁶; Kalina Kawecka-Jaszcz, MD, PhD¹⁰; Edgardo Sandoya, MD, PhD¹⁷; Krzysztof Narkiewicz, MD, PhD¹⁸; Eoin O’Brien, MD, PhD¹⁹; Peter Verhamme, MD, PhD²⁰; Jan A. Staessen, MD, PhD^1,21; for The International Database on Ambulatory Blood Pressure in Relation to Cardiovascular Outcomes (IDACO) Investigators

Author Affiliations Article Information

JAMA. 2019;322(5):409-420. doi:10.1001/jama.2019.9811

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Key Points

Question  What is the association of office and ambulatory blood pressure with subsequent risk of mortality and cardiovascular outcomes?

Findings  In a population-based cohort of 11 135 adults, higher 24-hour and nighttime blood pressure readings were significantly associated with greater risks of death and cardiovascular events that included cardiovascular mortality combined with nonfatal coronary events, heart failure, or stroke. This association persisted after adjusting for other blood pressure measurements taken during an office visit or during ambulatory monitoring.

Meaning  Higher 24-hour and nighttime blood pressure readings were significantly associated with greater risks of death and a composite of cardiovascular outcomes, although statistically the incremental model improvement was small.

Abstract

Importance  Blood pressure (BP) is a known risk factor for overall mortality and cardiovascular (CV)-specific fatal and nonfatal outcomes. It is uncertain which BP index is most strongly associated with these outcomes.

Objective  To evaluate the association of BP indexes with death and a composite CV event.

Design, Setting, and Participants  Longitudinal population-based cohort study of 11 135 adults from Europe, Asia, and South America with baseline observations collected from May 1988 to May 2010 (last follow-ups, August 2006-October 2016).

Exposures  Blood pressure measured by an observer or an automated office machine; measured for 24 hours, during the day or the night; and the dipping ratio (nighttime divided by daytime readings).

Main Outcomes and Measures  Multivariable-adjusted hazard ratios (HRs) expressed the risk of death or a CV event associated with BP increments of 20/10 mm Hg. Cardiovascular events included CV mortality combined with nonfatal coronary events, heart failure, and stroke. Improvement in model performance was assessed by the change in the area under the curve (AUC).

Results  Among 11 135 participants (median age, 54.7 years, 49.3% women), 2836 participants died (18.5 per 1000 person-years) and 2049 (13.4 per 1000 person-years) experienced a CV event over a median of 13.8 years of follow-up. Both end points were significantly associated with all single systolic BP indexes (P < .001). For nighttime systolic BP level, the HR for total mortality was 1.23 (95% CI, 1.17-1.28) and for CV events, 1.36 (95% CI, 1.30-1.43). For the 24-hour systolic BP level, the HR for total mortality was 1.22 (95% CI, 1.16-1.28) and for CV events, 1.45 (95% CI, 1.37-1.54). With adjustment for any of the other systolic BP indexes, the associations of nighttime and 24-hour systolic BP with the primary outcomes remained statistically significant (HRs ranging from 1.17 [95% CI, 1.10-1.25] to 1.87 [95% CI, 1.62-2.16]). Base models that included single systolic BP indexes yielded an AUC of 0.83 for mortality and 0.84 for the CV outcomes. Adding 24-hour or nighttime systolic BP to base models that included other BP indexes resulted in incremental improvements in the AUC of 0.0013 to 0.0027 for mortality and 0.0031 to 0.0075 for the composite CV outcome. Adding any systolic BP index to models already including nighttime or 24-hour systolic BP did not significantly improve model performance. These findings were consistent for diastolic BP.

Conclusions and Relevance  In this population-based cohort study, higher 24-hour and nighttime blood pressure measurements were significantly associated with greater risks of death and a composite CV outcome, even after adjusting for other office-based or ambulatory blood pressure measurements. Thus, 24-hour and nighttime blood pressure may be considered optimal measurements for estimating CV risk, although statistically, model improvement compared with other blood pressure indexes was small.