Ambulatory BP readings may provide best stroke prediction in older adults
Among older adults, all measures of ambulatory BP were associated with risk for stroke while office diastolic BP was only weakly associated, and central BP measures were not associated with stroke at all, researchers reported.
“Based on our results, the widespread use of ambulatory BP monitoring in older adults may be recommended to replace office BP for improving risk stratification for future stroke,” the researchers wrote in a study published in Hypertension.
The CABL study investigated CV predictors of subclinical cerebrovascular disease in a community-based cohort of participants older than 55 years. Participants in the CABL study (mean age, 71 years; 40% men; 70% Hispanic) underwent applanation tonometry of the radial artery for central BP and 24-hour ambulatory BP monitoring.
For this subanalysis of the CABL cohort, researchers compared the predictive utility of office, central and ambulatory BP measurements for stroke.
During nearly 10 years of follow-up, stroke occurred in 9.3% of the population. In addition, 27.5% of participants died without experiencing a stroke. All-cause death (excluding from stroke) was treated as a competing risk in all subsequent survival analyses.
Researchers reported that among in-office measurements, only diastolic BP was associated with stroke (HR = 1.32; 95% CI, 1.05-1.66; P = .016).
According to the study, none of the central BP variables were association with stroke (P for systolic BP = .94; P for diastolic BP = .13; P for central pulse pressure = .34).
After adjustment for confounders, all measures of ambulatory systolic and diastolic BP variables (24-hour, daytime and nighttime) were associated with stroke (P for all < .005).
After a multivariable competing risk analysis that included both ambulatory systolic and diastolic BP values obtained at the same time of the day, researchers reported that diastolic BP was more strongly associated with stroke compared with systolic BP in 24-hour, daytime and nighttime periods (P for all < .05).
“Controversies still exist regarding the use of a diastolic BP threshold for defining hypertension and initiating treatment, due to the possible existence of a J-shaped relationship between diastolic BP and adverse cardiovascular outcomes,” the researchers wrote. “Although high-risk patients have a treatment threshold set at 130/80 mm Hg in the current hypertension guidelines, no diastolic BP treatment threshold or target was recommended for older adults. Given the results of the present study, future research evaluating the additional impact of ambulatory diastolic BP reduction on the occurrence of stroke might be helpful in planning preventive strategies.”