TUESDAY, July 6, 2010 (HealthDay News) -- Lower may not be better when it concerns blood pressure levels in type 2 diabetics who also have heart disease.
New research finds that patients with diabetes and coronary artery disease did not have fewer strokes or heart attacks, and actually were more likely to die when their blood pressure was maintained under 130 mm Hg, compared to patients with "usual blood pressure control," putting them in the 130 to 140 range.
In healthy adults, blood pressure levels of 120/80 are recommended.
"We found that after a mean follow-up of just under three years in patients with diabetes and coronary artery disease, lowering systolic blood pressure [the top number] to less than 130 . . . did not have any benefit compared to lowering blood pressure to between 130 and 140," said Rhonda Cooper-DeHoff, lead author of the study published in the July 7 issue of the Journal of the American Medical Association.
These findings, along with similar data recently released from the large ACCORD study, would suggest that "lowering blood pressure intensively does not provide any benefit over and above usual blood pressure reduction," said Cooper-DeHoff, who is associate professor of pharmacotherapy and translational research and division of cardiovascular medicine at the Colleges of Pharmacy and Medicine, University of Florida, Gainesville.
Time would be better spent focusing on other modifiable heart disease risk factors, such as cholesterol, she advised.
Various organizations, including the American Diabetes Association, currently recommend that diabetics keep their blood pressure under 130/80 mm Hg, but it's been less clear what to recommend for patients with type 2 diabetes and coronary artery disease.
To this end, the researchers involved in the new study analyzed data on 6,400 type 2 diabetics aged 50 or over who also had coronary artery disease. The participants were part of a larger trial investigating whether specific medication regimens were better than others for preventing heart attacks and other long-term heart problems.
Volunteers first received either a calcium antagonist or beta blocker, then an ACE inhibitor or a diuretic or both. The goal was to reach blood pressure levels of 130/85.
Individuals in the study who had blood pressure between 130 mm Hg and 140 mm Hg (usual control) and those who maintained tight control (less than 130 mm Hg) had roughly the same rate of cardiovascular events.
And, for the first time, the results showed that individuals with systolic blood pressure under 120 had a 15 percent higher risk of dying than those with the higher blood pressure readings.
"We don't need to push below 130 so maybe we save a blood pressure medication and save some of those adverse effects associated with extra [blood pressure] medication and concentrate on some other goals that are still important in patients with diabetes," said Cooper-DeHoff.
Another expert agreed.
Dr. Fouad Kandeel, chair of the department of diabetes and endocrinology at City of Hope, in Duarte, Calif, said the results of both this and the ACCORD trial should guide clinicians to not attempt to push blood pressure levels too low in patients who already have cardiovascular disease.
It's not absolutely clear why tighter control didn't lead to better outcomes but Kandeel thinks it is probably related to the degree of disease.
"The damage was already done [in the patients in this study] and when you push the blood pressure down too much you may actually be inducing unreasonable effects that make the patient vulnerable to cardiac events," he said.
But that doesn't mean that tight control of blood pressure isn't a good thing in early-stage patients. "The early phase patient might deserve tight control so they don't develop the complications [of diabetes]," he said.
The trial was partially funded by drug maker Abbott Laboratories.
The American Diabetes Association has more on living with type 2 diabetes and high blood pressure.