Diabetes Patients With Depression, Anxiety Symptoms at Higher Risk of Mortality

When people with diabetes experience symptoms of depression and/or anxiety, their risk of mortality increases—particularly for men with only depressive symptoms.

Previous research has shown that depression is 5 times more prevalent in people with diabetes and is linked to a higher risk of death, but there have been few studies of how comorbid anxiety symptoms are potentially associated with mortality in diabetics. A group of researchers set out to assess the risk of death associated with type 2 diabetes and symptoms of depression or anxiety. Their findings were published in Diabetes Care.

The study analyzed health survey responses from more than 64,000 adults in Norway. The primary dependent variables were type 2 diabetes status and levels of 2 affective symptoms, anxiety and depression, as determined by self-reported assessment tools. Data on age, sex, education, lifestyle factors, comorbid conditions, and other covariates were also collected.

Over the 18-year study period, about 1 in 5 of the individuals without diabetes died, while two-thirds of the diabetes group died. Compared with the reference group without diabetes and without any symptoms of depression and anxiety, the risk of death increased, from smallest to largest in magnitude, for those with any affective symptoms, those with diabetes only at baseline, and those with affective symptoms comorbid with diabetes.

These patterns were observed for exposure to either affective symptom or a combination of both depression and anxiety symptoms. Of the types of affective symptoms, depression symptoms were associated with the largest increase in the hazard ratio of death among diabetics. The increase in mortality risk for diabetics with both depression and anxiety was slightly smaller, and having just anxiety symptoms was associated with the lowest increase in mortality risk.

Interestingly, the effects of mental health symptoms on mortality risk seemed to differ by gender. The diabetic men saw their mortality risk increase with exposure to any symptom or the combination of both, but mortality risk in women with diabetes only increased in the presence of depression symptoms, and was actually lowered for those with anxiety or comorbid depression-anxiety symptoms.

The study authors summarized the results into 4 main findings:

• Mortality risk was lowest for affective symptoms alone, higher for diabetes alone, and highest for both combined.
• Excess mortality among those with diabetes was observed to be lowest for anxiety alone, higher for combined depression and anxiety, and highest for depression alone.
• The effects of mental health symptoms appeared to be stronger in men with diabetes than in women.
• Overall, the highest risk of death was observed in men with diabetes and concurrent symptoms of depression alone.

The researchers noted that these associations were not necessarily causal relationships, but could arise from the complex interactions between type 2 diabetes and affective disorders. For instance, the presence of depression symptoms can discourage patients from seeking medical help, leading to poorer disease management, but the “cognitive burden of diabetes is also suggested to increase low mood and negative thoughts, leading to worse diabetes self-care,” the study authors wrote.

The researchers concluded that further research into these relationships is warranted, particularly as their findings in a Norwegian population may not be applicable to more diverse settings.