AGE-DEPENDENT INCREMENTAL PREDICTIVE VALUE OF CENTRAL BLOOD PRESSURE TO PREDICT CARDIOVASCULAR OUTCOMES: A COHORT STUDY INVOLVING 34,289 PARTICIPANTS USING THE UK BIOBANK

Abstract

Objective: It remained unclear whether central blood pressures (BP) provided incremental prognostic information on cardiovascular disease (CVD) over brachial BP in different age groups. This study aimed to investigate the age-stratified association of CVD with brachial and central BPs, and to evaluate the corresponding improvement in risk prediction. Design and method: This longitudinal cohort study included 34,289 adults without baseline CVD from the UK Biobank dataset. Baseline characteristics were collected from May 2014 to March 2020 (last follow-ups, September 2021). Participants were categorized into middle-aged and older aged groups using the cut-off of age 65. Brachial systolic blood pressure (SBP) and pulse pressure (PP) were measured by digital oscillometric technique using the Vicorder system, and central SBP and PP were obtained from pulse wave analysis. The primary endpoint was a composite cardiovascular outcome consisting of cardiovascular mortality combined with non-fatal coronary events, heart failure and stroke. Multivariable-adjusted hazard ratios (HRs) expressed the risk of CVD events associated with BP increments of 10 mmHg. Akaike Information Criteria (AIC) was used for model comparisons. Results: In middle-aged (N = 17,383, median age = 57.5) and older adult (N = 16,906, median age = 70.4) group, 243 and 566 experienced a CVD event over the median follow-up of 42.4 and 36.9 months respectively. In both groups, CVD events were associated with brachial or central SBP (p< = 0.002). Model fitness was better for central SBP in middle-aged adults (AIC 4427.2 vs 4429.5), but model fitness was better for brachial SBP in older adults (AIC 10246.7 vs 10247.1). Central SBP remained significantly associated to CVD events (HR = 1.05; 95% CI: 1.0-1.1) and improved model fitness (AIC = 4426.6) after adjustment of brachial SBP only in the middle-age adults. These results were consistent for PP. Conclusions: In middle-aged adults, higher central BP were associated with greater risks of CVD events, even after adjusting for brachial BP indexes. For older adults, the superiority of central BP was not observed. Therefore, central BP may be considered as important measurement for estimating primary CVD risks for middle-aged individuals.