Blood sugar swings tied to depression in elderly with type 2 diabetes

By Will Boggs MD

(Reuters Health) - Greater ups and downs of hemoglobin A1c (HbA1c), a marker of long-term blood sugar levels, are associated with a higher number of symptoms of depression in elderly individuals with type 2 diabetes, a recent Israeli study finds.

“The results suggest that maintaining stability in glycemic (‘blood sugar’) control may be important for prevention of depressive symptoms in elderly diabetic patients,” Dr. Ramit Ravona-Springer from Sheba Medical Center, Ramat Gan, and Tel-Aviv University told Reuters Health.

People with type 2 diabetes are twice as likely as people without diabetes to develop depression, which affects as many as a third of individuals 65 years and older. Variability in HbA1c has been associated with complications of diabetes, but there is little information about its relationship with depression, the study team writes in Diabetes Care.

Ravona-Springer’s team analyzed about nine years’ worth of data on 837 people with type 2 diabetes whose average age was nearly 73 years. The information included around 18 HbA1c measurements over the years for each participant, and results from a depression assessment at the start of the study period.

Average HbA1c was not associated with depressive symptoms, but the variability of HbA1c measurements was, such that each 1 percent increase in variability was associated with a 29 percent increase in the number of depressive symptoms, researchers found.

The relationship between HbA1c variability was true regardless of HbA1c level, but it was strongest among people whose HbA1c was above 7 percent, a common target for blood sugar control.

The researchers admit that the results just show an association and don't necessarily mean that blood sugar variability causes symptoms of depression.

Nevertheless, they conclude that better long-term stability of HbA1c - in other words, more consistent blood sugar control - might help to prevent depression in elderly people with type 2 diabetes.

“This study is ongoing,” Ravona-Springer said. “We thus expect to have even better understanding of the directional relationships of glycemic control and other diabetes-related characteristics with depression as we start analyzing longitudinal data,” she said in an email.

"The study hints at the importance of achieving stable A1c values at a certain age/point in a patient‘s diabetes history in contrast to trying to reduce A1c,” said Dr. Dominic Ehrmann from the Research Institute of the Diabetes Academy Mergentheim (FIDAM) in Bad Mergentheim, Germany, who has also studied the link between depression and diabetes.

“But (and this is a big but) this must be weighed against other clinical and medical objectives (e.g., complications, comorbidities, cognitive functioning),” he said by email.

“Depression/depressive symptoms should be an important factor in clinical decision making in elderly patients,” concluded Ehrmann, who wasn’t involved in the current study. “That is, the impact of therapy adjustments or changing treatment goals on depressive symptoms should be considered in clinical practice.”

SOURCE: Diabetes Care, online June 20, 2017.