An international study has shown that short-term blood sugar control
in patients with diabetes has a limited effect on their risk of
cardiovascular problems, such as heart disease and stroke.
Conventional
belief has been that high blood sugar is a major factor in
cardiovascular disease. However, this latest research adds to a growing
body of evidence that risk of cardiovascular disease in patients with
diabetes cannot be managed meaningfully by controlling blood sugar
alone.
The study, led by researchers at Harvard Medical School,
USA, and Hadassah Medical Centre, Israel, supported by other global
institutions, including St George’s, University of London, examined the
effect of the drug saxagliptin, a new class of medicine used to reduce
blood sugar levels, in patients with Type 2 diabetes.
There are
280 million people worldwide suffering with Type 2 diabetes, a disease
defined by high levels of blood sugar. Diabetes doubles the risk of
heart attack and stroke and can reduce life expectancy by up to six
years. Recognised long-term effects of the condition include blindness,
kidney failure, stroke and heart attack.
More than 16,000 patients
were studied for over two years to test saxagliptin’s cardiovascular
safety and also measure whether it could reduce the risk of
cardiovascular and kidney damage.
Researchers found that the drug
was as safe as existing glucose-controlling medicines. By lowering blood
sugar it also successfully reduced the damage diabetes causes to kidney
function.
Importantly, however, despite control of blood sugar
levels researchers found no significant reduction in the risk of major
cardiovascular events such as heart attack or stroke.
Professor
Kausik Ray, the study’s UK national lead from St George’s, University of
London, said: “Through this trial we studied the effects of a glucose
reducing drug on patients over a two-year period and observed that there
was no significant benefit from lowering blood sugar levels with
respect to the large blood vessels, which contribute to heart attacks
and strokes. We did, though, observe a benefit on smaller vessels that
contribute to kidney disease. This trial tells us that cardiovascular
risk among diabetes patients must be managed through other mechanisms.
“Controlling
blood sugar in the short term certainly doesn’t present a very
meaningful benefit to a patient at risk of cardiovascular problems,
although there could be gains over a much longer period. The most
effective way to manage cardiovascular disease is through established
interventions such as reducing blood pressure, managing cholesterol and
encouraging healthier lifestyles.
“It is clear to us now that, in
patients with diabetes, there are effective therapies that will reduce
their risk of kidney failure and there are separate therapies that will
help reduce their risk of cardiovascular problems. More research is
needed if we are to find new ways to manage cardiovascular risk in
future.”
The study, published by the New England Journal of
Medicine on Monday 2 September 2013, is the largest diabetes trial ever
carried out, conducted at 788 sites across 26 countries. It is also the
first since the Federal Drug Administration in the US and European
Medicines Agency revised regulations to give more robust assurance of
cardiovascular safety in glucose reducing therapies, following concern
that these may cause negative side effects on patient health.
Professor
Ray added: “This study also provides reassurance about the safety of a
new class of drug in a large number of patients, disproving data from
smaller studies about potential safety concerns.”
The full study can be read on the New England Journal of Medicine website.
