The optimal blood pressure target in diabetes mellitus: a quest coming to an end?

Abstract

The presence of hypertension in patients with diabetes mellitus (DM) substantially increases cardiovascular risk. Blood pressure (BP) decrease in these individuals is associated with large reductions in cardiovascular morbidity and mortality, but the optimal BP levels in DM still remain a matter of important controversy. For almost 20 years, guidelines recommended an office BP target of <130/80 mmHg in diabetic individuals, following evidence from trials randomizing patients to diastolic BP levels. When the action-to-control-cardiovascular-risk-in-diabetes-blood-pressure (ACCORD-BP) study showed that systolic BP (SBP) <120 mmHg was associated with similar risk to SBP < 140 mmHg in type 2 DM, all guidelines stepped back to recommend a SBP < 140 mmHg, despite the obvious limitations of ACCORD-BP, including the surprisingly low event rate and the actual average BP of 133.5/70.5 mmHg in the "standard-target" arm. In contrast, the systolic-blood-pressure-intervention-trial (SPRINT) showed cardiovascular benefits in hypertensive patients without DM randomized to SBP<120 versus <140 mmHg and many believed that absence of between-group differences in ACCORD-BP was rather a matter of power and not of dissimilar cardiovascular profile of diabetic patients. In this regard, the American-College-of-Cardiology/American-Heart-Association 2017 BP guidelines advocated a BP target of <130/80 in all hypertensives, including those with DM. However, the 2018 American-Diabetes-Association recommendations were not in the same direction, suggesting BP goal <140/90 for most patients, with the exception of those with "high cardiovascular risk", where a <130/80 mmHg target may apply. This review presents the evidence from old and recent trials relevant to optimal BP levels in DM, aiming to shed light in this major clinical question.