Influence of Baseline Diastolic Blood Pressure on the Effects of Intensive Blood Pressure Lowering: Results From the STEP Randomized Trial

Abstract

Background: The STEP (Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients) trial demonstrated that intensive systolic blood pressure (SBP) lowering has cardiovascular benefits. However, the influence of baseline diastolic blood pressure (DBP) on the effects of intensive blood pressure lowering on cardiovascular outcomes has not been fully elucidated.

Methods: We performed a post hoc analysis of the STEP trial. Participants were randomly allocated to intensive (110 to <130 mm Hg) or standard (130 to <150 mm Hg) treatment groups. The effects of intensive SBP lowering on the primary composite outcome (stroke, acute coronary syndrome, acute decompensated heart failure, coronary revascularization, atrial fibrillation, and cardiovascular death), major adverse cardiac event (a composite of the individual components of the primary outcome except for stroke), and all-cause mortality were analyzed according to baseline DBP as both a categorical and a continuous variable.

Results: The 8259 participants had a mean age of 66.2±4.8 years, and 46.5% were men. Participants with lower DBP were slightly older and had greater histories of cardiovascular disease, diabetes, and hyperlipidemia. Within each baseline DBP quartile, the mean achieved DBP was lower in the intensive versus standard group. The effects of intensive SBP lowering were not modified by baseline DBP as a continuous variable or as a categorical variable (quartiles, or <70, 70 to <80, and ≥80 mm Hg; all P value for interaction >0.05).

Conclusions: The beneficial effects of intensive SBP lowering on cardiovascular outcomes were unaffected by baseline DBP. Lower DBP should not be an obstacle to intensive SBP control.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03015311.

Keywords: aged; cardiovascular outcomes; diastolic blood pressure; hypertension; intensive blood pressure lowering.