Antidepressant adherence linked to lower risk of advanced complications of diabetes

For patients with diabetes and depression, regular use of an antidepressant was associated with a lower risk of death and advanced complications compared to poor adherence, a retrospective cohort study found.

Researchers used Taiwan's universal health insurance database to look at 36,276 patients with depression and newly treated diabetes between 2001 and 2014. Patients with pre-existing complications, a diagnosis of schizophrenia or bipolar disorder, or information errors in gender, age, or mortality date were excluded. The researchers classified antidepressant treatment patterns within a six-month window into the following categories: none, poor, partial, and regular use. They compared different classes of antidepressants and used benzodiazepines as a negative control exposure. The main outcomes were macrovascular complications, microvascular complications, and all-cause mortality. Results were published online July 14 by the Journal of Clinical Endocrinology & Metabolism.

Compared with poor use of antidepressants, regular use was associated with a reduced risk of macrovascular complications (adjusted hazard ratio [HR], 0.92; 95% CI, 0.84 to 1.00) and all-cause mortality (adjusted HR, 0.86; 95% CI, 0.75 to 0.98) (P<0.05 for both comparisons), but not microvascular complications (adjusted HR, 0.98; 95% CI, 0.88 to 1.09). Compared with poor antidepressant use, regular use of selective serotonin reuptake inhibitors was associated with a reduced risk of macrovascular complications (adjusted HR, 0.83; 95% CI, 0.74 to 0.94) and all-cause mortality (adjusted HR, 0.75; 95% CI, 0.62 to 0.91) (P<0.005 for both comparisons). Regular use of tricyclic or tetracyclic antidepressants was also associated with a lower risk of all-cause mortality (adjusted HR, 0.78 [95% CI, 0.62 to 0.96]; P<0.05) compared with poor use of antidepressants. On the other hand, antidepressant polypharmacy (two or more antidepressants prescribed concurrently) was associated with an increased risk of macrovascular complications (adjusted HR, 1.27 [95% CI, 1.03 to 1.57]; P<0.05) compared with poor antidepressant use. Regular use of a benzodiazepine showed no association with outcomes related to diabetes.

Among other limitations, the accuracy of depressive disorder diagnoses in the database was not perfect, the study authors noted. They added that data on blood glucose levels were not available in the database. “[C]linicians should emphasize antidepressant treatment adherence among patients with depression and diabetes mellitus,” the authors concluded. “However, several important unmeasured factors, such as body mass index, level of glycated hemoglobin, and lifestyle factors may have created a bias in our results. Such findings need to be replicated and confirmed in further investigations.”