Association between ankle-brachial blood pressure index with all-cause and cardiovascular mortality in adults without arterial stiffness

PURPOSE: To explore the relationship between ankle-brachial blood pressure index (ABPI) and all-cause or cardiovascular mortality in adults without arterial stiffness. METHODS: A total of 6784 participants without arterial stiffness were enrolled from National Health and Nutrition Examination Survey 1999–2004. The hazard ratio (HR) and 95% confidence interval (CI) of ABPI associating with the risk of all-cause and cardiovascular mortality was calculated by Cox proportional regression models adjusted for demographic and traditional risk factors. Dose-response relationship was explored with restricted cubic spines. RESULTS: After an average follow-up of 12.1 years, 1844 all-cause deaths and 299 cardiovascular deaths occurred. Compared with the lowest ABPI quartile, the second quartile was associated with the lowest risk of all-cause mortality (HR 0.89, 95%CI 0.79–0.98; p = 0.036) and cardiovascular mortality (HR 0.75, 95%CI 0.56–0.98; p = 0.048). Besides, dose-response analysis revealed that ABPI was nonlinearly correlated to all-cause mortality (p for nonlinearity < 0.001) and linearly correlated to cardiovascular mortality (p for nonlinearity = 0.459). CONCLUSIONS: The relationship between ABPI and all-cause and cardiovascular mortality followed a L-shape curve. A lower ABPI was independently associated with an increased risk of all-cause and cardiovascular mortality in adults without arterial stiffness.