SAN FRANCISCO — Ambulatory blood pressure monitoring in the general population was a better predictor of cardiovascular mortality and morbidity than in-office blood pressure measurements in a 10-year study, Tine Willum Hansen, M.D., reported.
The investigators recorded baseline ambulatory and in-office blood pressure readings and other risk factors in 1,700 people aged 41–72 years who had no major cardiovascular diseases. The subjects were followed up 9.5 years later; 156 subjects had died of cardiovascular disease, had a stroke, or developed ischemic heart disease during that decade, she said at the annual meeting of the American Society of Hypertension.
For ambulatory measurements, every 10-mm Hg increase in systolic blood pressure at baseline, the relative risk for these three end points combined (cardiovascular death, ischemic heart disease, and stroke) increased by 35%. For every 10-mm Hg increase in diastolic blood pressure at baseline, the relative risk increased 27%, said Dr. Hansen of the Research Center for Prevention and Health, Copenhagen.
In contrast, for in-office measurements at baseline, every 10-mm Hg increase in systolic blood pressure raised the risk of the combined end points by 18%, and each 10-mm Hg increase in diastolic pressure raised the risk by 11%.
Only ambulatory blood pressure was a significant predictor of risk for the combined end points, Dr. Hansen said.
Compared with normotensive subjects at baseline, those with sustained hypertension based on either ambulatory or in-office measurements were more than twice as likely to die of cardiovascular disease or develop ischemic heart disease or stroke. Of normotensive subjects, 6% developed one of these end points, compared with 17% of those with sustained hypertension—a significant difference.
Compared with normotensives, subjects with isolated ambulatory hypertension showed a trend toward increased risk for the combined end points; this trend did not reach statistical significance. A similar trend was not seen in subjects with isolated in-office hypertension.
Among 474 “nondippers” (people whose blood pressures fell less than 10% at night) based on ambulatory measurements, those with hypertension had a 68% higher risk for the combined end points than did normotensive subjects, Dr. Hansen said.