Antidepressants May Help Improve Glycemic Control in Patients With ‘Diapression’

According to recent estimates, 20 to 30 percent of people with type 2 diabetes also have comorbid depression—or “diapression” as some experts call it. Some studies suggest that these two conditions have a bidirectional relationship, in which having one of these disorders increases the risk of developing the other.

Considering the prevalence and risks of this comorbidity—patients with both disorders have increased risks of heart problems, dementia, and death—there has not been extensive research into how antidepressant treatment affects patients with diabetes.

Frontline selective serotonin reuptake inhibitor (SSRI) antidepressants typically do not have strong associations with metabolic problems, but less is known of whether the medications affect glycemic control. A few, small clinical studies have found that SSRIs may improve glucose metabolism, while others suggest tricyclic antidepressants may make it worse.

Saint Louis University

“At the moment, however, the sparse data have not led to any specific recommendations on treating comorbid patients, and I believe that most practitioners do not alter their standard approaches for treating either depression or diabetes in patients who have both,” said Jay Brieler, M.D., an assistant professor of family and community medicine at Saint Louis University School of Medicine.

To determine whether diabetes might alter a patient’s response to depression therapy, Brieler and colleagues carried out a large, retrospective analysis of primary care patients in the St. Louis area. An analysis of electronic health records obtained from a large health center in St. Louis from 2008 to 2013 revealed 1,399 patients who had been diagnosed with diabetes (based on the ICD codes in the patients’ records) and received at least one A1c measurement taken between 2009 to 2012. (A1c measures the amount of glycated hemoglobin in the blood, which reflects blood glucose levels.)

This population set included patients who had been diagnosed with depression and were taking antidepressants, patients who had been diagnosed with depression but were not taking medication, and patients with no diagnosis of depression. (Depression was also determined based on ICD codes, and treatment was determined using prescription information.)

Good glycemic control (defined as A1c of less than 7.0 percent) was achieved by over 50 percent of patients with depression who were taking antidepressants compared with 34 percent of untreated patients with depression. A total of 42 percent of patients with no depression achieved glycemic control over the course of the study.

On average, the A1c scores in the antidepressant group were 7.41, compared with 8.13 for patients with untreated depression and 7.76 for patients with no depression.

There were some differences in the groups, as the patients with comorbid depression and diabetes had a higher proportion of white and female patients. Participants in this group also had a longer history of smoking and higher clinic utilization. Nevertheless, even when considering these potential confounding traits, Brieler’s analysis suggested that patients who took antidepressants were twice as likely as those not taking medication to achieve good glycemic control.

These results appeared in the February issue of Family Practice.

“This was a good study in that they had a nice size, and the population came from primary care clinics, which lends some validity to the results,” said Erik Vanderlip, M.D., an assistant professor of psychiatry at the University of Oklahoma School of Community Medicine and a member of APA’s Council on Psychosomatic Medicine.

“Given the fact that they just looked at diagnostic codes, there is a lot of important information that wasn’t discerned, such as how severe each patient’s depression was or how well they improved with medication,” he continued.

“However, I still think these findings add a bean to the bucket of using antidepressants to manage patients with diabetes and depression.”

Brieler noted that some of the clinics where the participants in the study were seen have started to administer the PHQ-9 (Patient Health Questionnaire) instrument (which can quickly screen for depression and assess severity) on a regular basis. He said that he hopes additional studies will be able to answer whether reduced depressive symptoms may be driving the improvements in glucose control or whether glucose control leads to a reduction in symptoms of depression.

“I also think that a randomized, controlled trial that compares SNRIs and SSRIs with both depression outcomes and glycemic measurements would be valuable to tease out whether these improvements are due to metabolic or behavioral mechanisms,” he told Psychiatric News.

While Vanderlip agreed it could be interesting to see how each class of antidepressant might influence glycemic control, he noted that the best option for managing patients with co-occurring diabetes and depression would likely be the collaborative care model.

“Wayne Katon led a great study that was published in 2010 in the New England Journal of Medicine that showed how a team-based approach that focused on both disorders at the same time produced better improvements, and I think that was an elegant model that still holds true today.”

The study authors declared no funding for this analysis of medical information. ■