HbA1c study identifies associations with mortality risk among older people with diabetes

Variable HbA1c levels among older adults with diabetes have been associated with increased mortality risk in a new study.
Scientists also observed that high and low HbA1c levels were also associated with mortality, highlighting that stable blood glucose control is important for improving mortality.
While the King’s College London study suggests that healthcare professionals should re-examine the relationship between HbA1c and mortality in older patients, the aspect of hypoglycemic medication is important. Achieving low HbA1c without medication should not be a concern whereas low HbA1c brought on by excess medication can be problematic.
The researchers examined data from 54,803 adults with either type 1 diabetes or type 2 diabetes across the UK, all of whom were aged at least 70 years.
Over a five-year period they assessed HbA1c values and observed an association for both sexes in which mortality risk increased when HbA1c values were higher than 63.9 mmol/mol (8%) or lower than 42.1 mmol/mol (6%).
It should be noted, most people with the low HbA1c levels will have been taking significant amounts of diabetes medication and so this should not put off people who are achieving a low HbA1c through a healthy lifestyle and minimal medication (such as those taking metformin only).
Additionally, mortality risk increased significantly when varying HbA1c was heightened in men and women individually and among the overall cohort.
“In the older populations, it is important to consider HbA1c values and trends as a health marker and not as a target. This may lead to a lack of vigilance in relation to high-risk patients with lower HbA1c variability,” said lead author Angus Forbes, PhD, professor of midwifery and palliative care at King’s College London.
Forbes added that hypoglycemic drugs “only marginally explained” this link and acknowledged that age-related factors, rather than excess blood sugar intensification treatment, could explain some of the results.
Benedict Jephcote, Editor of Diabetes.co.uk, said: “There are a number of factors which affect HbA1c in older people. People who are older or more frail may eat less, begin to lose weight and HbA1c will tend to come down in these cases. So, there may be a bi-directional effect that needs considering.
“There is a case to be made that people at a higher risk of dying soon may have lower HbA1c as a result of decreasing health, rather than HbA1c being necessarily the causal factor.”
The findings appear online in The Lancet Diabetes and Endocrinology.