Comparison of BP variability, cumulative BP, and BP trajectory for predicting cardiovascular events in the general population

OBJECTIVE: Systolic blood pressure variability (SBPV), cumulative systolic BP (cumSBP), and systolic blood pressure trajectory (trajSBP) are major indices describing characteristics of BP changes. The aim of this study was to compare their discrimination abilities for cardiovascular (CV) events. METHODS: In 51698 subjects, associations were assessed using Cox regression in the overall cohort and Framingham risk score (FRS) stratified groups. Individuals with <10%, 10%-20%, and >20% 10-year CV risk were categorized into the low-, intermediate-, and high-risk group, respectively. Discrimination capabilities were evaluated using the area under curve (AUC), Harrell's C index, net reclassification index (NRI), and integrated discrimination index (IDI). RESULTS: Within a mean follow-up of 6.83 ± 0.89 years, 2330 participants had CV events, and all three markers were significantly associated with CV events. TrajSBP provided the best additional discriminative value for CV events, with improvements of 1.54% in AUC%, 0.01 in Harrell's C, 37.52% in NRI%, and 0.59% in IDI%. CumSBP had good additional discriminative capability in the intermediate to high FRS groups, but the effect sizes were smaller than those of trajSBP. Although, SBPV improved the predictive capabilities in the low-to intermediate-risk groups, the effect sizes were much smaller than those of the other indices. Sensitivity analyses excluding patients who underwent antihypertensive therapy revealed similar patterns but higher effect sizes than in the overall population. CONCLUSION: TrajSBP provides the best additional discrimination capabilities based on traditional risk profiles and may assist the risk stratification and individual prediction for future CV events.