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. Keywords: Ankle-brachial blood pressure index, All-cause mortality, Cardio-cerebrovascular mortality, Peripheral arterial disease, Arterial calcification