Blood Pressure Control in Diabetics: How Much is Too Much?

Hypertension is a term used to describe the presence of increased blood pressure. Hypertension most often has an unknown cause and is not linked to an underlying disease state. High blood pressure can increase the risk for adverse cardiovascular events, stroke, and various damage to other organs. Hypertension is a common comorbidity in patients with established diabetes mellitus, also known as type 2 diabetes. Diabetes, like hypertension, is also linked to the development of cardiovascular disease. Although current hypertension guidelines suggest that patients with diabetes maintain a systolic blood pressure below 130 mmHg, there is controversy to whether such control is beneficial.

The investigators behind the Action to Control Cardiovascular Risk in Diabetes (ACCORD) blood pressure trial assessed whether intensive (systolic blood pressure > 120) was more beneficial than standard (systolic blood pressure > 140) therapy in diabetic patients. Specifically, the trial targeted diabetic patients with an increased risk for cardiovascular disease. That is, 40 years of age or older with established cardiovascular disease, or 55 years of age or older with atherosclerotic plaque, left ventricular hypertrophy, albuminuria, or two of the following risk factors: dyslipidemia, smoking, obesity, or hypertension.

4,733 recruited patients were randomized without blinding into either the standard or intensive blood pressure control groups, as described above. Investigators used standard and accepted therapeutic approaches to regulate blood pressure levels. The primary outcome the trial was a combination of the time to a nonfatal heart attack or stroke, or death due to a cardiovascular event.

Interestingly, the primary outcome did not differ significantly between the intensive and standard therapy groups. That is, the rates of the composite of time to nonfatal heart attack, stroke, or death due to a cardiovascular event did not differ between treatment groups. The rate in the standard group was 2.09% and 1.87% in the intensive group. Death from any cause, or from a cardiovascular event, was also not different between the two groups. However, the number and rate of strokes was significantly reduced in the intensive group.

The authors pointed out that due to concentrated blood pressure control, the rate of adverse drug events was higher in the intensive group. The investigators also calculated that to prevent one stroke, 89 patients would need to be treated intensively for 5 years. With such data, clinicians need to weigh the risks and benefits of intensive blood pressure control in diabetics.

References:

Effects of intensive blood-pressure control in type 2 diabetes mellitus. ACCORD Study Group. N Engl J Med. 2010 Apr 29;362(17):1575-85.