China: Study on Diastolic Blood Pressure and Cardiovascular Risk

Lowering diastolic blood pressure (DBP) to less than 60 mm Hg is associated with an increased risk for cardiovascular (CV) events, finds a recent study. The study, published in the journal JAMA Network Open, suggests that DBP between 70 and 80 mm Hg should be an optimum target for patients with high cardiovascular risk and a treated systolic blood pressure less than 130 mm Hg.

Extremely low DBP is known to be associated with increased adverse CV events (i.e., the diastolic J-shape phenomenon). The current US guidelines recommend an intensive blood pressure target of under 130/80 mm Hg but don't mention the lower DBP limit. Considering this, Jingen Li, Beijing University of Chinese Medicine, Beijing, China, and colleagues aimed to evaluate whether there is a diastolic J-shape phenomenon for patients with a 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.

For this purpose, the researchers conducted a cohort study that analyzed outcome data of patients at high CV risk. They 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).

The primary outcome was a composite of all-cause death, nonfatal myocardial infarction, and nonfatal stroke.

The analysis included a total of 7515 patients (mean age, 65.6 years; 4553 [60.6%] men).

Key Findings of the Study

• 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), the composite cardiovascular outcome (HR, 1.74), nonfatal myocardial infarction (HR, 1.73), and nonfatal stroke (HR, 2.67).

"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," concluded the authors.

The study titled, "Evaluation of Optimal Diastolic Blood Pressure Range Among Adults With Treated Systolic Blood Pressure Less Than 130 mm Hg," is published in the journal JAMA Network Open.

DOI: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2776530