Influence of baseline arterial stiffness on effects of intensive compared with standard blood pressure control: a post hoc analysis of the STEP trial

BACKGROUND: The benefits and risks of intensive versus standard systolic blood pressure (SBP) treatment in older patients with arterial stiffness (AS) remains unclear. This study aims to investigate the interaction between the baseline AS and SBP treatments on cardiovascular outcomes. METHODS: In this post hoc analysis of the Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) trial, we involved 6865 participants with complete data regarding baseline brachial-ankle pulse wave velocity (baPWV). Patients were categorized by baseline AS status (AS, baPWV ≥ 1800 cm/s; non-AS, baPWV < 1800 cm/s). The primary outcome was a composite of cardiovascular events. The secondary outcomes were stroke, acute coronary syndrome (ACS), major cardiovascular events (MACE), and all-cause death. Cox regression was used to calculate hazard ratios for the outcomes. RESULTS: During a mean follow-up of 2.69 years, a total of 248 primary outcome events and 81 all-cause deaths occurred. The hazard ratios for the primary outcome were 0.76 (95% confidence interval (CI), 0.54-1.09) and 0.63 (95% CI, 0.43-0.92) in the AS and non-AS groups, respectively (P for interaction = 0.43), and that for stroke was 0.58 (95% CI, 0.33-1.02) and 0.48 (95% CI, 0.23-0.99) in the AS and non-AS groups, respectively (P for interaction = 0.68). Effects of intensive SBP treatment on safety outcomes and all-cause death were also similar in the two groups (P for interaction > 0.05 for all). CONCLUSIONS: In the STEP trial, the beneficial effects of intensive SBP treatment were similar among those in the AS group and the non-AS group at baseline. TRIAL REGISTRATION: STEP ClinicalTrials.gov number, NCT03015311. Registered 2 January 2017.