Hypertension in Diabetes

Questions

1 Is hypertension common in patients with diabetes?

Diabetes and hypertension share pathophysiologic mechanisms of vascular dysfunction, so they commonly coexist, and hypertension is an important contributor to diabetes-associated vascular complications including kidney disease. According to the Centers for Disease Control and Prevention, about 74% of those with type 2 diabetes mellitus (T2DM) have hypertension, and in the San Antonio Heart Study, 85% of participants with T2DM had hypertension by the fifth decade of life. Interestingly, compared to hypertension, hyperglycemia itself in T2DM is a weak modifiable risk factor for cardiovascular disease (CVD), underscoring the importance of blood pressure (BP) control. The prevalence of hypertension in type 1 diabetes mellitus (T1DM) is significantly less, at 30% to 40% by the third decade of life after around 20 years diabetes duration. The following questions will focus on systolic blood pressure (SBP in mm Hg) as the SBP represents a stronger cardiovascular risk factor, especially with increasing age, than diastolic BP.

2 What are the current guideline-oriented BP goals in patients with hypertension and diabetes?

In 2014 the Eighth Joint National Committee (JNC) on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommended a target SBP of less than 140 mm Hg for patients with T2DM because many trials had demonstrated a benefit. The 2017 American College of Cardiology/American Heart Association (ACC/AHA) guidelines broadly recommend a target of SBP less than 130 mm Hg. It is important to note that many other guidelines did not follow this recommendation and continue to recommend a target SBP of less than 140 mm Hg in patients with diabetes, including the American Diabetes Association (ADA), the American Academy of Family Physicians, the Australian National Heart Foundation, and the National Institute for Health and Clinical Excellence.

3 What is the main evidence for current BP goals in patients with T2DM?

Numerous studies randomizing subjects, including patients with T2DM, to different BP regimens but not specific BP targets demonstrated a strong association between lower achieved BP and reduced cardiovascular risk, particularly stroke. This led to the recommendation of lowering SBP to less than 140 mm Hg. The UK Prospective Diabetes Study Substudy 38 (UKPDS 38) randomly assigned hypertensive diabetic patients to tight or less tight BP control and assessed the impact on micro- and macrovascular complications of diabetes. The tight group achieved a mean SBP of 144 mm Hg versus 154 mm Hg in the less tight group. In the group with tight control, all diabetes-related complications and the microvascular composite were significantly reduced, laying the foundation for the importance of BP control in T2DM. The Action to Control Cardiovascular Risk in Diabetes (ACCORD-BP) trial randomized 4733 participants with T2DM and a high CVD risk to either intensive control (SBP <120 mm Hg) or standard therapy (SBP <140 mm Hg). The mean achieved SBPs in the intensive group and standard group were 119.3 and 133.5, respectively. There was no difference in the primary composite endpoint of nonfatal myocardial infarction (MI), nonfatal stroke or cardiovascular mortality. The intensive group required on average 3.4 antihypertensives compared to 2.1 medications in the standard group. There were more adverse events with more creatinine elevations and electrolyte abnormalities in the intensive group. The Systolic Blood Pressure Intervention Trial (SPRINT), which randomized 9361 participants at high CVD risk to either intensive (SBP <120 mm Hg) or standard (SBP <140 mm Hg) goals, achieved a good separation between the intensive (121.4 with 2.8 drugs) and standard (136.2 with 1.8 drugs) arm with a significant reduction in the primary composite of MI, other acute coronary syndrome, stroke, heart failure, or cardiovascular mortality in the intensive group. Most importantly, the trial excluded patients with diabetes. The differing results between these trial results are unexplained but may reflect differences in the trials such as sample size or true differences in response to BP lowering of patients with T2DM. Thus the main evidence for BP targets in patients with diabetes supporting much lower targets (than the current SBP <140 mm Hg) is derived from trials reporting achieved BP and trials with randomized BP goals that excluded patients with diabetes. The current recommendations all include an individualized approach to BP control for the patient with diabetes and an SBP goal of at least 140 mm Hg or less. Table 18.1 summarizes current guidelines, and Table 18.2 summarizes major BP goal trials.

Table 18.1

Summarizing Current Guidelines

GUIDELINE GROUP	TARGET BP	COMMENTS
American College of Cardiology/American Heart Association (2017)	<130/80	Mainly driven by SPRINT results.
European Society of Cardiology and the European Society of Hypertension (2018)	<140/90	If tolerated, consider lower target of SBP 130 or less. In patients <65 years of age SBP should be lowered to 120–129 in most patients.
American Diabetes Association Standards of Medical Care (2019)	<140/90	Consider SBP <130 if high cardiovascular risk and further lowering is safe.
American Academy of Family Physicians (2014)	<140/90	In a 2017 update with the ACP for patients older than 60 years, the individualization of BP goals was emphasized.
Australian National Heart Foundation (2016)	<140/90	Consider lower targets in select high cardiovascular risk populations.
National Institute for Health and Clinical Excellence Draft (2019)	<140/90	For patients ≥80 years old, target SBP <150.

ACP, American College of Physicians; BP, blood pressure; SBP, systolic blood pressure; SPRINT , Systolic Blood Pressure Intervention Trial.

Table 18.2

Summarizing UKPDS, ACCORD-BP, and SPRINT

TRIAL	POPULATION	N	INTERVENTION	CONCLUSION	COMMENTS
UKPDS 38	Hypertensive patients with newly diagnosed T2DM	1148	Tight (SBP <150) or less tight (SBP <180) BP control	Significant reduction in all diabetes-related and microvascular endpoints in the tight compared to the less tight group.	The tight group achieved a SBP of 144 vs. 154 in the less tight group. Tight group required ≥3 BP medications.
ACCORD-BP	T2DM patients with CVD or CVD risk factors	4733	Intensive therapy (goal SBP <120) or standard therapy (goal SBP <140)	No difference in primary cardiovascular composite outcome.	Achieved SBP in intensive group of 119 and in standard group 134. More adverse events in intensive group.
SPRINT	Nondiabetic patients with SBP >130 and at increased cardiovascular risk	9631	Intensive therapy (goal SBP <120) or standard therapy (goal SBP <140)	Significant reduction of primary cardiovascular composite in the intensive compared to standard group.	Achieved SBP in intensive group of 121 and in standard group 136. More adverse events in intensive group. The intensive group required, on average, 3 BP medications.

ACCORD-BP, Action to Control Cardiovascular Risk in Diabetes-Blood Pressure; BP, blood pressure; N, number; SBP, systolic blood pressure; SPRINT, Systolic Blood Pressure Intervention Trial; T2DM, type 2 diabetes mellitus; UKPDS 38, UK Prospective Diabetes Study Substudy 38.

4 What is the evidence for BP goals in patients with T1DM?

No large randomized trials have specifically studied BP targets for CVD risk reduction in T1DM. The strong association between achieved BP and micro- and macrovascular events observed in T2DM is also true for T1DM. Guidelines mostly extrapolate from ACCORD-BP and SPRINT, and the ADA 2017 guidelines recommend a target SBP less than 140 mm Hg in T1DM. Similar to tight glycemic control, which is better tolerated in young patients, the ADA recommends considering lower individualized BP targets for young patients with T1DM as they may derive the most benefit.

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