For some patients with type 2 diabetes, antihypertensive medication may raise the risk of cardiovascular death.
The researchers - including Mattias Brunström of the Department of Public Health and Clinical Medicine at Umeå University in Sweden - found that antihypertensive drugs may increase the risk of cardiovascular death for diabetes patients with a systolic blood pressure under 140 mm/Hg.
While almost 1 in 2 people in the US have high blood pressure, or hypertension, the condition affects around 2 in 3 Americans with diabetes, putting them at higher risk of stroke, heart disease and other cardiovascular problems.
As such, people with diabetes are often prescribed medication to help lower blood pressure.
The American Diabetes Association recommend a systolic blood pressure target of less than 140 mm/Hg for patients with type 2 diabetes - the most common form of diabetes - though a target of less than 130 mm/Hg is recommended for some patients, if it can be achieved safely.
For their study, Brunström and his colleague Bo Carlberg, also of the Department of Public Health and Clinical Medicine at Umeå, set out to investigate whether the effects of antihypertensive medication vary dependent on a patient's blood pressure prior to treatment.
Increased cardiovascular death risk for some diabetes patients
The team conducted a meta-analysis of 49 randomized controlled trials - involving a total of 73,738 participants - that looked at the cardiovascular outcomes of people with diabetes who were receiving blood pressure-lowering medication.
The vast majority of participants had type 2 diabetes, and subjects were followed-up for at least 12 months.
The team looked at the blood pressure of participants before treatment and assessed the cardiovascular effects of antihypertensive medication.
Among subjects whose blood pressure was less than 140 mm/Hg prior to antihypertensive treatment, however, no cardiovascular benefits were identified. In fact, these participants were found to be at greater risk of cardiovascular death.
Commenting on the findings, Brunström says:
"Our study shows that intensive blood pressure-lowering treatment using antihypertensive drugs may be harmful for people with diabetes and a systolic blood pressure less than 140 mm/Hg."
The researchers stress that because most study participants had type 2 diabetes, their results may not apply to people with type 1 diabetes or those with diabetes who have normal blood pressure.
Additionally, they point out that anti-hypertensive medication is crucial to most people with diabetes who have systolic blood pressure above 140 mm/Hg. "In practice, it is important to remember that undertreatment of high blood pressure is a bigger problem than overtreatment," adds Brunström.
Still, the team says the findings could have important implications for clinical guidelines for diabetes patients with high blood pressure, noting that many countries are due to review such guidelines in the next few years.
"It has been discussed to recommend even lower blood pressure levels for people with diabetes - maybe as low as 130," says Brunström. "We are hoping that our study, which shows potential risks of such aggressive blood pressure-lowering treatment, will come to influence these guidelines."
Earlier this month, Medical News Today reported on a study detailing the creation of insulin-producing mini-stomachs, which researchers say could offer a new cellular therapy for diabetes.