We quantitatively evaluated the dose-response association of low and normal ankle brachial index (ABI) with the risk of morbidity and mortality from cardiovascular diseases (CVDs). PubMed, Embase, and Web of Science were systematically searched for cohort studies. Random effects or fixed effects models were used to estimate the pooled relative risks (RRs) and 95% confidence intervals (95% CIs). Generalized least squares regression was used to assess study-specific dose-response associations per 0.1 ABI decrease. Restricted cubic splines were used to evaluate linear or nonlinear trends. Twelve cohort studies (57 031 participants) were included in this meta-analysis. For low vs normal ABI levels, the pooled RRs were 2.03 (95% CI, 1.72-2.41; I2 = 52.9%; pheterogeneity=0.030) and 2.29 (95% CI, 1.98-2.64; I2 = 39.5%; pheterogeneity =0.158) for CVD morbidity and CVD mortality, respectively. For per 0.1 ABI decrease from 1.40 the risk for CVD morbidity and CVD mortality increased by 8% (1.08, 95% CI 1.04-1.11) and 11% (1.11, 95% CI 1.07-1.15), respectively. Restricted cubic splines showed inverse linear associations for CVD morbidity and CVD mortality. As a non-invasive index, lower ABI was significantly associated with the increased risk of morbidity and mortality from CVDs in an inverse linear manner.
Keywords: ankle brachial index; cardiovascular morbidity and mortality; cohort study; dose-response; meta-analysis.