Abstract
In patients with hypertension and pre-frailty or frailty, the influence of systolic (SBP) and diastolic blood pressure (DBP) time in target range (TTR) on clinical outcomes is unclear. Thus, we conducted a post hoc analysis of the Systolic Blood Pressure Intervention Trial (SPRINT). Classifying 4208 participants into frail and non-frail groups using a frailty index, the study calculated blood pressure time in target range (BP-TTR) for the first three months using the Rosendaal method. The primary endpoint included a composite of nonfatal myocardial infarction (MI), acute coronary syndromes, stroke, acute decompensated heart failure (ADHF), and cardiovascular death. Relationships between BP-TTR and outcomes were analyzed using Kaplan-Meier curves, Cox models, and restricted cubic spline curves, with subgroup analysis for further insights. In a median follow-up of 3.17 years, primary outcomes occurred in 6.7% of participants. Kaplan-Meier analysis showed that a lower systolic blood pressure time in target range (SBP-TTR) (0%-25%) correlated with an increased cumulative incidence of the primary outcome (p < .001), nonfatal MI (P = .021), stroke (P = .004), and cardiovascular death (P = .002). A higher SBP-TTR (75%-<100%) was linked to a reduced risk of these outcomes. The restricted cubic spline (RCS) curve revealed a linear association between SBP-TTR and the primary outcome (non-linear P = .704). Similar patterns were observed for diastolic blood pressure time in target range (DBP-TTR). Subgroup analysis showed that the protective effect of higher SBP-TTR was less pronounced at low DBP-TTR levels (P for interaction = .023). In conclusion, this study highlights the importance of maintaining BP within the target range to mitigate cardiovascular risks in this population.