Association Between Systolic Blood Pressure Time in Target Range Indices and Adverse Cardiovascular Outcomes

There is no consensus on optimal time points or systolic blood pressure (SBP) ranges for calculating SBP time in target range (TTR).

The purpose of this study was to examine the association between various SBP TTR metrics and long-term major adverse cardiovascular events (MACEs).

This post hoc analysis of SPRINT (Systolic Blood Pressure Intervention Trial) included participants with complete SBP records and excluded those with events in the initial 2 years. SBP TTR indices were calculated using 3 distinct time points and 3 SBP ranges. The SBP TTR index was the percentage of BP segments within the target SBP ranges. MACE, a composite of heart attack, stroke, heart failure, and cardiovascular death, was the primary outcome.

The study included 7,134 participants, of which 280 had a MACE. The median follow-up was 3.91 years. The SBP TTR 110-140 mm Hg in the initial 3 months (3-month TTR 110-140) had the optimal association with incident MACEs (HR per SD increase: 0.898 [95% CI: 0.788-1.022], relative informativeness = 24,398%). Furthermore, a cutoff value of 0.65 for 3-month TTR 110 to 140 index was identified by threshold saturation analysis and used to evaluate early SBP control. No difference in MACE was seen between different mean SBP subgroups in those with good early control (3-month TTR >0.65) (P = 0.88), but in those with poor early control (3-month TTR ≤0.65), a higher mean SBP of 130 to 140 mm Hg was related to increased MACEs risk (P = 0.019).

In nondiabetic hypertensive patients, the 3-month TTR 110 to 140 mm Hg index was independently associated with 2-year MACEs. A cutoff of TTR index as 0.65 indicated that the patient was within BP target range 65% of the time, combined with mean SBP, could potentially be used as a metric for early control stability and late cardiovascular risks. (Systolic Blood Pressure Intervention Trial [SPRINT]; NCT01206062).