Evaluation of Optimal Diastolic Blood Pressure Range Among Adults With Treated Systolic Blood Pressure Less Than 130 mm Hg

Abstract

Importance: Extremely low diastolic blood pressure has been reported to be associated with increased adverse cardiovascular events (ie, the diastolic J-shape phenomenon); however, current US guidelines recommend an intensive blood pressure target of less than 130/80 mm Hg without mentioning the lower limits of diastolic blood pressure.

Objectives: To evaluate whether there is a diastolic J-shape phenomenon for patients with an treated systolic blood pressure of less than 130 mm Hg and to explore the safe and optimal diastolic blood pressure ranges for this patient population.

Design, setting, and participants: This cohort study analyzed outcome data of patients at high cardiovascular risk who were randomized to intensive or standard blood pressure control and achieved treated systolic blood pressure of less than 130 mm Hg in the Systolic Blood Pressure Intervention Trial (SPRINT) and Action to Control Cardiovascular Risk in Diabetes-Blood Pressure (ACCORD-BP) trial. Data were collected from October 2010 to August 2015 (SPRINT) and from September 1999 to June 2009 (ACCORD-BP). Data were analyzed from January to May 2020.

Exposure: Treated diastolic blood pressure, divided in intervals of less than 60, 60 to less than 70, 70 to less than 80, and 80 mm Hg and greater.

Main outcomes and measures: The primary outcome was a composite of all-cause death, nonfatal myocardial infarction, and nonfatal stroke. A composite cardiovascular outcome, including cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke, was among the key secondary outcomes.

Results: A total of 7515 patients (mean [SD] age, 65.6 [8.7] years; 4553 [60.6%] men) were included in this analysis. The nominally lowest risk was observed at a diastolic blood pressure between 70 and 80 mm Hg for the primary outcome, the composite cardiovascular outcome, nonfatal myocardial infarction, and cardiovascular death. A mean diastolic blood pressure of less than 60 mm Hg was associated with significantly increased risk of the primary outcome (hazard ratio [HR], 1.46; 95% CI, 1.13-1.90; P = .004), the composite cardiovascular outcome (HR, 1.74; 95% CI, 1.26-2.41; P = .001), nonfatal myocardial infarction (HR, 1.73; 95% CI, 1.15-2.59; P = .008), and nonfatal stroke (HR, 2.67; 95% CI, 1.26-5.63; P = .01).

Conclusions and relevance: This cohort study found that lowering diastolic blood pressure to less than 60 mm Hg was associated with increased risk of cardiovascular events in patients with high cardiovascular risk and an treated systolic blood pressure less than 130 mm Hg. The finding that a diastolic blood pressure value between 70 and 80 mm Hg was an optimum target for this patient population merits further study.

Figure 1.. Patient Selection and Allocation Chart

ACCORD-BP indicates Action to Control Cardiovascular Risk in Diabetes–Blood Pressure; DBP, diastolic blood pressure; SBP, systolic blood pressure; and SPRINT, Systolic Blood Pressure Intervention Trial.

Figure 2.. Adjusted Hazard Ratios (HRs) for Achieved Diastolic Blood Pressure (DBP) and Outcomes at Achieved Systolic BP of Less Than 130 mm Hg

The primary outcome consisted of all-cause death, nonfatal myocardial infarction, and nonfatal stroke. The cardiovascular outcome was composed of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke.

Figure 3.. Cubic Splines of the Adjusted Hazard Ratios for Achieved Diastolic Blood Pressure

The primary outcome consisted of all-cause death, nonfatal myocardial infarction, and nonfatal stroke. The cardiovascular outcome was composed of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke. The reference is diastolic blood pressure of 80 mm Hg. Shaded areas indicate 95% CIs.

Figure 4.. Cubic Splines for the Adjusted Hazard Ratios for Mean Diastolic Blood Pressure Change From Baseline

The primary outcome consisted of all-cause death, nonfatal myocardial infarction, and nonfatal stroke. The cardiovascular outcome was composed of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke. The reference is no change in diastolic blood pressure from baseline. Shaded areas indicate 95% CIs.