medwireNews: Baseline diastolic blood pressure (DBP) does not influence the cardiovascular gains from reducing systolic blood pressure (SBP) in people with type 2 diabetes using a standard glucose-lowering regimen, indicates a secondary analysis of ACCORD data.
The researchers found no evidence for a J- or U-shaped relationship between DBP and cardiovascular disease (CVD) outcomes in ACCORD participants who were randomly assigned to receive standard glycemic control.
“Hence, low baseline DBP should not be an impediment to intensive SBP lowering in the setting of standard glycemia,” write Srinivasan Beddhu (University of Utah School of Medicine, Salt Lake City, USA) and study co-authors in Diabetes Care.
However, the team also found evidence for an adverse impact of baseline low DBP in people given both intensive BP control and intensive glycemic control.
All ACCORD participants were randomly assigned to receive standard versus intensive glucose lowering and 4731 participants were also assigned to receive a standard or intensive antihypertensive regimen.
In the latter subgroup, intensive versus standard BP treatment reduced the risk for the combined CVD outcome by a significant 24% among participants assigned to receive standard glycemic control. This reduction remained consistent across all baseline levels of DBP, and when comparing DBPs above or below 70 mmHg.
The researchers say that a trial design such as ACCORD’s, with active BP reduction, is ideal for testing whether DBP genuinely influences the effect of SBP lowering on outcomes.
They point out that previous “strong causal inferences” about an adverse effect of low DBP have come from observational data, and suggest that “the underlying processes (such as increased arterial stiffness) that lead to a decline in DBP rather than the level of DBP per se might be the reason for the observed associations of worse outcomes with lower DBP.”
In ACCORD, the intensity of the BP intervention did not influence CVD outcomes in the intensive glycemic control group, or the risk for all-cause mortality in either group. And baseline DBP did not alter the relationships between treatment and CVD outcomes in the intensive glycemic control group, or all-cause mortality in the standard control group.
However, people assigned to receive both intensive glycemic control and intensive BP control appeared to have an increased all-cause mortality risk at lower baseline DBPs. Those with DBP at or below 70 mmHg had a 1.93-fold increased mortality risk with intensive versus standard BP control, whereas there was no such effect for those with higher baseline DBP.
For this reason, “caution might be warranted regarding intensive SBP lowering in the setting of intensive glycemic control when baseline DBP is low,” say the researchers.
medwireNews is an independent medical news service provided by Springer Healthcare. © 2020 Springer Healthcare part of the Springer Nature Group