Ankle-brachial index measured by oscillometry is predictive for cardiovascular disease and premature death in the Japanese population: An individual participant data meta-analysis

Background and aims: The ankle–brachial index (ABI) is a predictor of cardiovascular disease (CVD) and premature death. However, few studies on this marker are available in the general Asian populations. This study aimed to investigate the association between ABI measured with oscillometry and the risk of these outcomes. Methods: We conducted an individual participant data meta-analysis in 10,679 community-dwelling Japanese individuals without a history of CVD. The primary outcome was a composite of CVD events and all-cause mortality. Results: During an average of 7.8 years of follow-up, 720 participants experienced the primary outcome. The multivariable-adjusted hazard ratios (HRs) of the primary outcome significantly increased with a lower ABI. The HRs were 1.07 (95% confidence interval [CI] 0.91–1.27) for ABI of 1.00–1.09, HR 1.37 (95% CI 1.04–1.81) for ABI of 0.91–0.99, and HR 1.60 (95% CI 1.06–2.41) for ABI of ≤0.90, compared with ABI of 1.10–1.19. Furthermore, a high ABI (≥1.30) was associated with a greater risk of outcome (HR 2.42 [95% CI 1.14–5.13]). Similar tendencies were observed for CVD events alone and all-cause mortality alone. Addition of ABI to a model with the Framingham risk score marginally improved the c-statistics (p = 0.08) and integrated discrimination improvement (p < 0.05) for the primary outcome. Conclusions: The present study suggests that lower and higher ABI are significantly associated with an increased risk of CVD and all-cause mortality in the Japanese population. The ABI, which is easily measured by oscillometry, may be incorporated into daily clinical practice to identify high-risk populations.