Diabetes and Hypertension: What's the Target?

Many individuals who develop type 2 diabetes also have hypertension. Comorbid hypertension elevates risk of cardiovascular disease, and diabetes treatment guidelines ubiquitously recommend setting target blood pressures and treating until patients reach that goal if possible.

Actual target blood pressures differ between guidelines. Some recommend goals of 130/80 mmHg while others recommend 140/90 mmHg. This has precipitated controversy and discussion. Two points of contention are that for many patients, achieving lower blood pressure goals increases the risk of hypotension and the frequency of adverse events from medication may increase with more aggressive treatment.

A review article that appears in the journal Diabetologia reviews available evidence and discusses the feasibility of each target blood pressure.

The investigators first present evidence that favors more conservative (higher) blood pressure targets, reporting that the European Society of Hypertension advocated for lower blood pressures (lower than 140/90 mmHg) in 2007. This recommendation was based on a number of randomized outcomes trials that demonstrated the treatment to this level improved cardiovascular outcomes.

Several meta-analyses of randomized trials also support conservative treatment of hypertension in patients who have diabetes.

Review of post hoc analyses of trial data—data that is less reliable than randomized studies in meta-analyses—also supports the theory that conservative treatment reduces macrovascular complications if systolic blood pressure is less than 140 mmHg. In this population, lowering blood pressure to less than 130 mmHg seems to have no additional benefit.

Ample evidence also shows that lower blood pressure targets offer further protection against stroke, especially if systolic blood pressure is in the 132 to 139 mmHg range. The primary study supporting this outcome was the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Researchers have re-analyzed this study and found that aggressive blood pressure reduction reduces stroke risk, improves CVD outcomes, and reduces risk of myocardial infarction.

A critical point is that achieving blood pressure control in patients with diabetes is often much more difficult than achieving blood pressure control in others.

The investigators noted that all patients with diabetes are not alike, and recommendations cannot be applied across all subpopulations. They also indicated that recommendations are often inconsistent, and clinicians will need to determine each individual patient's needs and preferences. In addition, clinicians need to adjust patient's blood pressure medication as they age and if they develop organ dysfunction.

In general, the researchers concluded that the studies provide solid evidence supporting systolic blood pressure goals of less than 140 mmHg and closer to 130 mmHg, if possible, in patients with diabetes.

Reference

Mancia G, Grassi G. Blood pressure targets in type 2 diabetes. Evidence against or in favour of an aggressive approach. Diabetologia. 2018 Jan 25. doi: 10.1007/s00125-017-4537-3. [Epub ahead of print]