Abstract 15010: Relationship Between Low Diastolic Blood Pressure, All-Cause Mortality and Cardiovascular Outcomes: A Meta-Analysis

Abstract

Background: Reduction of diastolic blood pressure (DBP) below 70mmHg may decrease perfusion to the heart and worsen cardiovascular (CV) outcomes. However, studies assessing the association between low DBP and clinical outcomes have yielded inconsistent results. Aim: To meta-analyze the association between low DBP and CV outcomes. Methods: We searched the MEDLINE, Scopus, and Cochrane CENTRAL databases up until December 2022 for studies reporting the risk of all-cause mortality (ACM) or CV outcomes in patients with low versus normal DBP. Patients with a DBP of 70-80mmHg were considered the control and were compared to those with a DBP of 60-69mmHg and <60mmHg. Outcomes of interest were all-cause mortality (ACM), major adverse cardiac events (MACE), myocardial infarction (MI), and ischemic stroke. Subgroup analysis was performed to assess whether pre-existing CV disease was an effect modifier. Findings from studies were pooled using a random-effects model to derive hazard ratios (HRs) and 95% confidence intervals. Results: Ten studies (n = 1,998,223 participants) met the eligibility criteria. A mean achieved DBP<60mmHg was associated with a significantly increased risk of ACM (HR: 1.48 [1.26, 1.74]; P < 0.001) compared with a mean achieved DBP of 70-80mmHg ( Fig. 1a ). This association was significantly stronger in patients with pre-existing CV disease (P-interaction < 0.001). A DBP<60mmHg was also associated with a higher risk of MACE (HR: 1.84 [1.28, 2.65]; P < 0.001) and MI (HR: 1.49 [1.13, 1.97]; P < 0.001). However, a DBP<60mmHg had no significant association with ischemic stroke. A mean achieved DBP 60-69mmHg was associated with a significantly increased risk of ACM (HR: 1.11 [1.03, 1.20]; P < 0.001; Fig. 1b ), but not MACE, MI, or ischemic stroke. Conclusion: Reduction of DBP below 70mmHg, particularly below 60mmHg, is associated with an increased risk of mortality. This association is stronger in patients with pre-existing CV disease.