News Release

Intensively reducing blood sugar does not necessarily help slow cognitive decline in diabetes

Peer-Reviewed Publication

The Lancet_DELETED

Intensively lowering blood glucose offers no additional benefit in preventing cognitive decline in people with type 2 diabetes, according to the ACCORD MIND study published Online First in The Lancet Neurology. People older than 70 years of age with type 2 diabetes are twice as likely as those without the disease to develop cognitive impairment linked to their diabetes. In theory, intensive lowering of glucose levels could slow cognitive deterioration.

To test this hypothesis, a team led by Lenore J Launer at the National Institute on Aging, National Institutes of Health, Bethesda, USA, studied a subset of patients in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. They recruited nearly 3000 participants aged 55󈞼 years who had type 2 diabetes, were at high risk for cardiovascular disease, and had high blood glucose levels (glycated haemoglobin A1c >7•5%, >58 mmol/mol).

Patients were randomly assigned to receive an intensive glycaemic treatment strategy to ensure that measurements of haemoglobin A1c remained lower than 6•0% (42 mmol/mol) or current standard treatment strategies to ensure that haemoglobin A1c stayed between 7•0 and 7•9% (53󈞫 mmol/mol).

The goal was to measure cognitive ability (through cognitive tests) and brain volume (through MRI) after 40 months, but an increased risk of dying in the intensive strategy group led the researchers to switch all the participants to the standard glucose-lowering strategy at a median treatment time of 39 months.

Overall, the findings showed no difference in cognitive ability between the groups. Although the patients in the intensive group had a significantly larger brain volume at 40 months than patients in the standard treatment group, the increased risk of dying and other factors, such as no overall benefit on cardiovascular disease events, an increase in hypoglycaemic events, and weight gain, meant that intensive treatment cannot be recommended.

The authors say: "We feel it is reasonable to suggest that a larger decline in brain capacity will lead to earlier loss of function and possibly dementia—the MIND participants at an average age of 62 years are already experiencing an annual decline of TBV [total brain volume] in the range reported for people 15 years older".

They conclude: "Cognitive function affects the ability of patients to follow complex disease management protocols, and impaired cognition predicts cardiovascular disease and severe hypoglycaemic events. Early prevention strategies to reduce the risk of cognitive impairment are needed because, as the longevity of patients with diabetes increases, so too does the number reaching an age at which cognitive disorders become clinically apparent. Optimum treatment strategies for brain health in older people with type 2 diabetes are needed and should be assessed in the context of a comprehensive assessment of therapeutic strategies to manage type 2 diabetes and its consequences."

In a linked Comment, Geert Jan Biessels at the Rudolf Magnus Institute of Neuroscience, Utrecht, Netherlands, says: "At present it is still unclear whether dysglycaemia is a key factor in accelerated cognitive decline and dementia in type 2 diabetes. Although cross-sectional studies report associations between raised HbA1c concentrations and cognition, longitudinal studies show no consistent relation with cognitive decline. Therefore, preventive treatment might also need to target factors other than dysglycaemia."

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Dr Lenore J Launer, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA. Via the NIA Office of Communications and Public Liaison.
E) nianews3@mail.nih.gov T) + 1 301 496 1752.

Dr Geert Jan Biessels, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, Netherlands.
E) g.j.biessels@umcutrecht.nl T) +31 88 755 6564


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