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In the setting of standard glycemic treatment, intensively lowering systolic blood pressure (SBP) in individuals with type 2 diabetes (T2D) significantly decreases the risk for cardiovascular events irrespective of baseline diastolic blood pressure (DBP), according to the results of a study published in Diabetes Care.
T2D has been associated with arterial stiffness and wide pulse pressure and there are concerns that intensive lowering of SBP in individuals with T2D could result in low DBP with potentially damaging effects.
To examine whether low baseline DBP modifies the effects of intensively lowered SBP on cardiovascular disease (CVD) outcomes in individuals with T2D, data from 4731 participants in the Action to Control Cardiovascular Risk in Diabetes Blood Pressure (ACCORD BP) study were analyzed. Individuals with a hemoglobin A1c (HbA1c) of ≤7.5%, SBP of 130 to 180 mm Hg on ≤3 antihypertensive therapies, and <1 g proteinuria/d were eligible for inclusion in ACCORD BP. Individuals with no evidence of CVD were required to be ≥55 years of age and have ≥2 CVD risk factors, left ventricular hypertrophy, significant atherosclerosis, or albuminuria to be included. Individuals with known CVD who were aged ≥40 years were included.
Participants in ACCORD BP were randomly assigned to either intensive SBP therapy targeting <120 mm Hg or standard SBP therapy targeting <140 mm Hg. Participants were also randomly assigned to either intensive glycemic therapy targeting an HbA1c of <6.0% or standard glycemic therapy targeting an HbA1c of 7.0% to 7.9%.
The primary CVD composite outcome was defined as the time to occurrence of nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. Baseline DBP was divided into tertiles (≤70 mm Hg, 71-79 mm Hg, and ≥80 mm Hg).
The mean achieved SBP was similar across tertiles of baseline DBP in both SBP intervention groups, and the mean DBP observed in follow-up was higher in the standard SBP treatment group compared with the intensive SBP treatment group within each baseline DBP tertile.
A total of 694 CVD composite events occurred over 21,466 patient-years of follow-up and 292 all-cause deaths occurred over 23,413 patient-years of follow-up. Intensive SBP therapy with standard glycemic treatment decreased the risk for the CVD composite outcome (hazard ratio [HR], 0.76; 95% CI, 0.59-0.98) but not for all-cause mortality (HR 0.84, 95% CI, 0.60-1.17). Intensive SBP therapy plus intensive glycemic treatment did not significantly decrease the risk for the primary CVD composite (HR, 1.06; 95% CI, 0.81-1.40) or the risk for all-cause mortality (HR 1.34; 95% CI, 0.98-1.85).
For individuals in the standard glycemic treatment groups, baseline DBP was not associated with the effect of intensive SBP lowering on the risk for the CVD composite outcome or all-cause mortality. Baseline DBP also did not have any association with the effect of intensive SBP lowering on the CVD composite outcome in patients receiving intensive glucose-lowering therapy. However, individuals receiving both intensive glycemic and intensive SBP treatment who were in the lowest baseline DBP tertile were at significantly greater risk for all-cause mortality (HR, 1.93; 95% CI, 1.18-3.14) than individuals with higher baseline DBP levels.
Taken together, these findings demonstrated that regardless of baseline DBP, an intensive SBP-lowering intervention in conjunction with a standard glycemic treatment significantly reduced the risk for CVD events in individuals with T2D. Based on their findings, the study authors concluded that “baseline DBP should not be an impediment to intensive SBP lowering in the setting of standard glycemia.”
The study authors encouraged further investigation into the causality of low DBP on myocardial damage, as existing studies supporting this hypothesis have been observational. “If lowering DBP is deleterious below a certain DBP, one would expect that the effects of lowering SBP on CVD outcomes and death would be modified by baseline level of DBP,” they noted, which was not observed in this study.
Reference
Ilkun OL, Green T, Cheung AK, et al. Influence of baseline diastolic blood pressure on effects of intensive blood pressure lowering on cardiovascular outcomes and all-cause mortality in type 2 diabetes [published online May 15, 2020]. Diabetes Care. doi:10.2337/dc19-2047
