By Randy Dotinga
TUESDAY, Feb. 10, 2015 (HealthDay News) -- A new analysis shows that people with type 2 diabetes are less likely to suffer heart attacks, strokes or die early when they take blood pressure medications -- even if they don't actually have high blood pressure.
"Stroke, heart attack and other circulatory diseases are the biggest cause of premature death and disability in people with diabetes," said review author Dr. Kazem Rahimi, deputy director with the George Institute for Global Health at the University of Oxford in England. "Any intervention that safely reduces the risk, even if modestly, will have an important effect."
According to the American Diabetes Association, an estimated two-thirds of people with diabetes have high blood pressure or take blood pressure medication. Diabetics tend to have higher blood pressure than other people, Rahimi said, and this can lead to health problems.
It's clear that lowering high blood pressure is good for diabetics, Rahimi said, but it's less certain whether patients "whose blood pressure is not very high should be treated with blood pressure-lowering drugs and how far their blood pressure should be reduced. It is also less well-known how blood pressure-lowering affects a range of other potential health complications such as diabetic eye disease."
Blood pressure-lowering drugs are not harmless. While they're often inexpensive, sometimes costing just pennies per pill, they can cause side effects such as dizziness and fatigue.
In the new review, researchers analyzed 40 studies with a total of just over 100,000 participants. The studies were randomized and controlled, meaning some diabetics got the blood-pressure medications and some didn't; researchers then watched to see what happened next.
Each decrease of 10 mm Hg in the systolic blood pressure reading -- the top number in a reading -- lowered the risk of early death by 13 percent, heart attacks and similar problems by 11 percent, coronary heart disease by 12 percent and stroke by 27 percent. The study found that the risk of albuminuria (too much protein in the urine) and retinopathy (an eye condition) also fell, by 17 percent and 13 percent, respectively.
What did diabetes have to do with the lowering of risk in the patients who took blood pressure medications? It's not clear. Rahimi said it's possible that the results could be similar in people without diabetes. Research continues into this question, he noted.
Dr. Bryan Williams, a professor of medicine with University College London who studies high blood pressure and diabetes, said the review findings suggest "we should consider lowering blood pressure further than recommended in current guidelines" to reduce the risk of stroke.
Williams, who wrote a commentary accompanying the review, added: "If I was a younger diabetic, I would certainly want my blood pressure well controlled, always below 140/90 mm Hg and below 130/80 mm Hg if possible. As patients get older, they sometimes tolerate such aggressive treatment less well, but it is worth trying to reach a level of blood pressure that is as low as tolerated without symptoms."
What's next? Rahimi said he expects the study will change how doctors treat patients with diabetes, especially because the review didn't show signs of harm from the blood pressure medications.
Still, the research showed that the positive effect of the drugs was smaller in diabetics with lower blood pressure levels. "For a small group of diabetic people," he said, "this could mean that the expected benefit of blood pressure-lowering may not be large enough for them to take blood pressure-lowering tablets."
The study was published in the Feb. 10 issue of the Journal of the American Medical Association.