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'Detrimental cycle' of hypoglycaemia and dementia in elderly with diabetes

Older patients with diabetes are more likely to develop dementia if they suffer severe hypoglycaemia, and in turn, more likely to have subsequent hypoglycaemic events if they develop dementia, shows a US study.

 

The study

Researchers followed up 783 older adults with diabetes, aged an average of 74 years and free of dementia at baseline, for 12 years, to examine the relationship between hypoglycaemia and dementia.

The findings

A total of 61 (7.8%) individuals had a reported hypoglycaemic event that required hospitalisation over the 12-year follow-up, of whom 21 (2.7%) had more than one such event, and 148 (18.9%) individuals developed dementia. Those with a severe hypoglycaemic event were significantly more likely to develop dementia, with a rate of 34.4% compared with 17.6% among those who did not have a reported hypoglycaemic event.

After multivariable adjustment for confounders including age, sex, education, insulin use, race/ethnicity, lipid levels, HbA1c levels and baseline cognitive function, the risk of dementia was doubled among those who had a severe hypoglycaemic event, compared with those who did not. Similarly, the rate of hypoglycaemic events causing hospitalisation was higher among individuals with dementia, compared with those without dementia, at 14.2% and 6.3%, respectively. After multivariable adjustment, the risk of a subsequent severe hypoglycaemic event was three-fold greater among those with a preceding dementia diagnosis than those without.

What this means for GPs

The researchers concluded: ‘Hypoglycaemia may impair cognitive health, and reduced cognitive function may increase the risk for a hypoglycaemic event that could further compromise cognition, resulting in a detrimental cycle.’ Authors of a related editorial commented: ‘Efforts to mitigate the risk of hypoglycaemia are clearly warranted to improve quality of life and potentially prevent the associated adverse events. After problem solving through fixable causes of hypoglycaemia, patients and clinicians should consider setting higher HbA1c targets that may yield a safer management programme.’

JAMA Intern Med 2013, online 10 June

Readers' comments (1)

  • Vinci Ho

    It certainly becomes essential to consider a different HBA1c target in these elderly diabetics on insulin or sulphonylurea .
    One test might be helpful in type 2 diabetics on insulin is C peptide level in blood . Although it is not totally reflecting the situation , it gives an idea how much natural insulin is still coming out from beta islet cells. As exogenous insulin does not contain C peptide and type2 DM is usually characterised by hyperinsulinaemia (hence high level of C peptide) , a very low C peptide level could point to too much injected insulin .
    Furthermore,I don't know how often people are referring to the insulin dosage reference of 0.5units/kg/day to assess the overall situation of the amount injected daily...

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