End Point–Based Threshold for the Ambulatory Arterial Stiffness Index

BACKGROUND: The ambulatory arterial stiffness index (AASI) is increasingly used in clinical research and practice. This individual-participant meta-analysis aims to consolidate the prognostic accuracy of AASI in the general population and to derive an end point-based AASI risk threshold. METHODS: In 12 558 individuals enrolled in 14 population studies (48.8% women; mean age, 59.3 years), AASI was derived by regressing 24-hour diastolic on systolic blood pressure (mm Hg/mm Hg). Using Cox regression, the risk-carrying AASI threshold was established by examining stepwise increasing AASI levels and by determining the AASI level, yielding a 10-year risk similar to an office systolic pressure of 140 mm Hg. RESULTS: Over 10.7 years (median), 3027 all-cause deaths and 2183 cardiovascular end points occurred. In all participants, multivariable-adjusted hazard ratios expressing the all-cause deaths and cardiovascular end point risk per 1-SD AASI increment were 1.08 (95% CI, 1.04-1.13) and 1.13 (95% CI, 1.07-1.18). In a randomly defined subset of 8189 individuals, the risk-carrying AASI thresholds converged to 0.50 with hazard ratios (≥0.50 versus