HbA1c variability predicts depression in elderly people with type 2 diabetes
medwireNews: High variability in glycemic control may be associated with depression in elderly people with type 2 diabetes, according to a large observational study.
The researchers, led by Ramit Ravona-Springer (Sheba Medical Center, Israel), note that while mean glycated hemoglobin (HbA1c) is recognized as predictor of some diabetes-related complications, HbA1c variability – independent of mean HbA1c levels – has previously shown positive associations with several complications of diabetes.
The current results, they say, “stress the potential value of HbA1c variability, which may better reﬂect the course of type 2 diabetes over time, in predicting depression.”
The 837 study patients, aged an average of 73 years, were participants of the Israel Diabetes and Cognitive Decline study and had been randomly selected from a diabetes registry. Each patient had an average of 18 HbA1c measurements over a mean of 8.7 years, and 10% overall had clinically significant depression (≥6 points on the 15-item version of the Geriatric Depression Scale).
A higher HbA1c standard deviation (SD) score, indicating increased variability in glycemic control, was significantly associated with a larger number of depressive symptoms, increasing 1.31-fold with each 1% increase in HbA1c-SD. This was after adjusting for factors including age, years in the diabetes registry, gender, blood pressure, lipoprotein levels, cognitive performance, and diabetes medication.
The results also remained unchanged after excluding HbA1c values from the first year after the type 2 diabetes diagnosis, when high variability in HbA1c levels might be expected.
By contrast, average HbA1c levels were not significantly associated with depressive symptoms.
The researchers report in Diabetes Care that the findings are “particularly relevant for subjects with poor glycemic control.”
While high variability in HbA1c-SD was associated with depressive symptoms in patients irrespective of whether they had HbA1c levels above or below the treatment target cutoff of 7%, the relationship was stronger in those with levels above 7%.
The direction of the association remains to be elucidated, but the team points out that “[d]epression diagnosis at entry into the diabetes registry was not associated with subsequent variability in HbA1c.”
They conclude that “long-term stability of glycemic control may help prevent depressive symptoms in elderly individuals with type 2 diabetes.”
By Catherine Booth
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