Higher BP trajectories in early adulthood linked to increased CAC in middle age

Long-term patterns of BP change in early adulthood may provide additional information about risk for development of coronary artery calcium later in life.

According to researchers for a new study, “single measures of BP levels are associated with the development of atherosclerosis; however, long-term patterns in BP and their effect on cardiovascular disease risk are poorly characterized.”

Using prospective cohort data from the CARDIA study, researchers evaluated 4,681 participants who were aged 18 to 30 years at baseline in 1985-1986 and followed for 25 years until 2010-2011. They examined systolic, diastolic and mid-BP at baseline and at various time points out to 25 years.

The primary outcome was coronary artery calcification (CAC) ≥Agatston score of 100 Hounsfield units (HU) at 25 years, which previous research has identified as a marker of high risk for coronary events. CAC score at 25 years was available for 3,442 of the participants.

Identification of common BP trajectories

Participants were stratified into five mid-BP trajectories:

Low-stable, defined as low mid-BP throughout follow-up;
Moderate-stable, defined as moderate mid-BP throughout follow-up;
Moderate-increasing, defined as moderate mid-BP at baseline with a rapid increase beginning at approximately age 35 years;
Elevated-stable, defined as relatively elevated BP levels throughout follow-up; or
Elevated-increasing, defined as those with high BP levels.

At 25 years, 21.8% of participants were considered low-stable, 42.3% moderate-stable, 12.2% moderate-increasing, 19% elevated-stable and 4.8% were elevated-increasing, Norrina B. Allen, PhD, MPH, of Northwestern University Feinberg School of Medicine, and colleagues found. African Americans were significantly more likely to be in the elevated-stable and elevated-increasing groups compared with whites (P<.001).

After adjustment for demographic characteristics, other CV risk factors and antihypertensive medication use, elevated BP trajectories were associated with CAC score ≥100 HU at 25 years.

Compared with the low-stable group, adjusted ORs for CAC score ≥100 HU at 25 years were 1.44 (95% CI, 0.83-2.49) for the moderate-stable group; 1.86 (95% CI, 0.91-3.82) for the moderate-increasing group; 2.28 (95% CI, 1.24-4.18) for the elevated-stable group; and 3.7 (95% CI, 1.66-8.2) for the elevated-increasing group.

The adjusted prevalence of a CAC score ≥100 HU at 25 years in the low-stable group was 5.8%.

Compared with the low-stable group, the ORs represent absolute increases of 2.7% for the moderate-stable group, 5% for the moderate-increasing group, 6.3% for the elevated-stable group and 12.9% for the elevated-increasing group for the prevalence of a CAC score ≥100 HU at 25 years, Allen and colleagues wrote.

Additional adjustment for baseline systolic BP and diastolic BP and 25-year systolic BP and diastolic BP did not change the results.

Similar results were observed when stratifying participants by long-term trajectories in systolic BP, but the results were attenuated when stratifying participants by long-term trajectories in diastolic BP, according to the researchers.

“Long-term trajectories in BP may assist in more accurate identification of individuals with subclinical atherosclerosis,” Allen and colleagues wrote. “Additional research is needed to examine the utility of specific BP trajectories in risk prediction for clinical CVD events and to explore the effect of lifestyle modification, treatment, and timing of intervention on lifetime trajectories in BP and outcomes.”

A novel approach

George L. Bakris

In a related editorial, Pantelis A. Sarafidis, MD, MSc, PhD, from Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece, and George L. Bakris, MD, from University of Chicago School of Medicine, noted that one limitation of the study is that CAC score is a surrogate endpoint, not a hard morbidity or mortality endpoint, but it would take another 25 years of follow-up to have adequate power for those events. Bakris is a member of Cardiology Today’s Editorial Board.

“The study by Allen and colleagues presents a novel approach for assessing coronary heart disease and CVD risk, and the data offer an important perspective to support a preventive approach to reduce coronary heart disease risk by demonstrating (1) the existence of widely different BP trajectories ranging from young adulthood through middle age and (2) the relationship of increasing BP trajectories within groups that are African American, are obese, or have diabetes,” they wrote.

For more information:

Allen NB. JAMA. 2014;311:490-497.

Sarafidis PA. JAMA. 2014;311:471-472.

Disclosure: One researcher reports financial ties with Merck and Takeda. Sarafidis reports financial ties with AstraZeneca, Daiichi Sankyo and Novartis. Bakris reports financial ties with AbbVie, Bayer, Daiichi Sankyo, Janssen, Medtronic, Novartis, Relypsa and Takeda.