BALTIMORE – Distinct patterns of blood pressure changes in midlife are associated with varying degrees of risk for cardiovascular disease and death, according to a multisite study.
These patterns of change contributed to risk for both CVD and mortality, separate from the known association of absolute elevation of systolic blood pressure with CVD and death. Natalia Petruski-Ivleva of the University of North Carolina, Chapel Hill, and colleagues identified SBP patterns emerging from the biracial, multisite Atherosclerosis Risk in Communities (ARIC) study and presented the results at the American Heart Association Epidemiology and Prevention, Lifestyle and Cardiometabolic Health 2015 Scientific Sessions.
The study included 9,882 patients from the ARIC population who had recorded BPs at four study visits between 1987 and 1998, and whose outcomes were tracked over the period from 1987 to 2011. Median follow-up after the last study visit was 13.2 years. Participants were grouped by patterns of change in SBP over time using a latent class growth model; this analytic model allowed for the discovery of similar groups of cases within the data.
Results were adjusted for age and demographic characteristics, as well as for self-reported hypertension medication use. In addition to all-cause mortality, outcomes included coronary heart disease, heart failure, and stroke.
In all, six distinct patterns emerged of change in SBP over the study visit period, with three groups having SBPs consistently below the threshold of 140 mm Hg, and three other groups showing varying patterns of elevation. About 84% of participants fell into one of the three groups that showed parallel patterns of SBP change, with pressures slowly rising over time, but never exceeding 140 mm Hg. The remainder of participants were grouped into three other patterns. One showed a steep increase over time from an initial SBP just under 140 mm Hg to a final reading just over 160 mm Hg; a second showed high and sustained SBPs of more than 160 mm Hg at all study visits. Finally, some participants had initially elevated SBPs that fell to the normal range by the end of the study.
Overall, analysis showed a gradient of risk, with lower SBP associated with lower risk of CVD and death. This was true even for those participants in the first three groups, whose SBPs stayed below 140 mm Hg throughout. Notably, the pattern of steep increase of already elevated SBP, as well as that of sustained elevated blood pressures, were both associated with the highest all-cause mortality. Reducing SBP to less than 140 mm Hg was not associated with reduced risk of CHD in the final group.
The three higher-risk groups were more likely to be obese, black, on hypertension medication, and have diabetes. They were also older on average than participants with the three nonelevated patterns.
These patterns of change, said Ms. Petruski-Ivleva, “contribute varying amounts of risk of CVD and mortality in addition to the risk imparted by the absolute SBP level.” Though the clinical significance of these patterns of blood pressure change needs more examination, she said that the results underscore the cumulative impact of elevated SBP through midlife.