The behavior of systolic blood pressure variability indices in the SPRINT trial. A randomized clinical trial
Authors: Rueda-Ochoa O L , Reyes-Prada M A , Celis Amaya R S ,   Electrocardiography Research Group, Industrial University of Santander
Published: October 2021

Abstract

Background
We previously report that intensive hypertension treatment increases visit-to-visit variability in the total SPRINT population and in all subgroups under study, based on coefficient of variation (CV) calculated during all follow-up time, previous to SPRINT primary outcome. It becomes important describes the behavior of other long-term SBP variability indices.

Purpose
To evaluate the interaction between intensive treatment and systolic blood pressure variability, measured during the first year of follow-up, by coefficient of variation (CV), standard deviation (SD), variability independent of the mean (VIM), and average true variability (ARV), and its contribution to SPRINT primary outcome.

Methods
We include 9068 SPRINT participants with 128139 repeated SBP measurements. Participants were randomly assigned to intensive (SBP &lt;120 mmHg) vs standard treatment (SBP between 135–139 mmHg). The primary outcome was a composite outcome of myocardial infarction, other acute coronary syndromes, acute decompensated heart failure, stroke, and cardiovascular mortality. The coefficient of variation (CV), standard deviation (SD), variability independent of the mean (VIM), and average true variability (ARV) was calculated taking into account all SBP measurements during the first year of follow-up. Effect of the interaction between intensive treatment and SBP variability indices over the SPRINT primary outcome was calculated in both total population and each SPRINT subgroups.

Results
All SBP variability indices showed association with increase the risk of the SPRINT primary outcome. However, all interaction terms between treatment and SBP variability were not statistically significant. The ARV of intensive treatment group, showed a tendency to increase the risk in all its quartiles and deciles, being significantly associated with the development of the primary outcome for the fourth, eighth and tenth deciles (see table). Regarding the intensive treatment subgroups, the male subpopulation showed a significant risk of primary outcome in the upper decile of all indices and in the upper quartile of them, except CV. As well as in the subpopulation that was not of black race, the risk was evidenced in the decile and upper quartile of all the indices (see table)

Conclusions
ARV is the visit-to-visit blood pressure variability index that presented the most significant increase for the development of the primary outcome after the first year of follow-up in the SPRINT study intensive treatment population. Aiming to corroborate the association between intensive treatment and the adverse cardiovascular events risk, is required the evaluation of the visit-to-visit variability indices in other randomized clinical trials with larger populations which compares standard and intensive treatment.

Funding Acknowledgement
Type of funding sources: None. Hd: higher decile; Hq: higher quartile