Abstract
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. 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. 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. 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. 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. 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). 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.
Highlights
High blood pressure (BP) is among the most important modifiable risk factors for cardiovascular disease and death.[1,2] Prevailing concepts regarding BP have changed dramatically over time
A mean diastolic blood pressure of less than 60 mm Hg was associated with significantly increased risk of the primary outcome, 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)
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
Summary
High blood pressure (BP) is among the most important modifiable risk factors for cardiovascular disease and death.[1,2] Prevailing concepts regarding BP have changed dramatically over time. Results of the Framingham Heart Study have shifted the emphasis on diastolic BP (DBP) to systolic BP (SBP) by showing that SBP was a more important risk factor for cardiovascular outcomes.[2] This has generated debate and relative neglect of the role of DBP in cardiovascular risk estimation.[3] Whether there is a diastolic J-shape phenomenon, meaning that both high and low DBP could increase cardiovascular risk, is among the most controversial issues. Mainly driven by the Systolic Blood Pressure Intervention Trial (SPRINT) trial,[16] which showed improved prognosis with intensive SBP lowering, the 2017 American Heart Association (AHA) Hypertension Guidelines[17] recommend an intensive BP target of less than 130/80 mm Hg, with no recommendation on lower limits of DBP. Given the great influence of the 2017 AHA guideline and the argument that the diastolic J-shape phenomenon only exists in the presence of high SBP (ie, >140 mm Hg),[19] it is critical to know whether the diastolic J-shape phenomenon exists in patients with SBP of less than 130 mm Hg and, if it does exist, what the safe and optimal DBP ranges are for this population
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