Depression in patients with diabetes doubled their risk for developing dementia, data showed.
Study researcher Wayne Katon, MD, of the University of Washington School of Medicine, told Healio.com that health care providers are actively trying to address depression in this patient population.
“Health care systems are developing health services interventions to improve screening and quality of treatment for depression in patients with chronic medical illnesses such as diabetes,” Katon said.
Katon and colleagues analyzed data collected on 19,239 patients aged 30 to 75 years with type 2 diabetes. The patients were part of the Kaiser Permanente Northern California Diabetes Registry, a multiethnic cohort of insured patients with diabetes.
Clinically significant symptoms of depression were determined using DSM-IV criteria, and incident cases of clinically recognized dementia were identified based on the presence of one or more ICD-9-CM codes of uncomplicated senile dementia. Patients with evidence of one or more dementia diagnoses prior to baseline were excluded from the study. The researchers estimated the association between depression and incident dementia diagnosis in years 3 through 5 of follow up.
During the 3- to 5-year period, 2.1% of patients with comorbid depression and diabetes (incidence rate of 5.5 per 1,000 person-years), compared with 1% of patients with diabetes alone (incidence rate of 2.6 per 1,000 person-years), had one or more ICD-9-CM diagnoses of dementia. Patients with comorbid depression had a 100% increased risk of dementia during the 3 to 5 years after baseline (AHR=2.02; 95% CI, 1.73-2.35).
Patients who took insulin, with or without oral hypoglycemic treatment, had a substantially lower risk of dementia associated with depression (HR=1.59; 95% CI, 1.17-2.18), compared with patients not treated with insulin (HR=2.82; 95% CI, 2.33-3.42).
Results also showed that patients aged younger than 65 years had a substantially higher risk for dementia associated with depression (HR=4.42; 95% CI, 3.11-6.29), compared with patients aged more than 65 years (HR=2.01; 95% CI, 1.65-2.45). The researchers said this finding is troubling from a public health and cost perspective. “The temporal patterning underscores the importance of developing early interventions to potentially reduce the incidence of dementia,” they wrote.
There are a number of biologic mechanisms that could link depression with dementia, according to the researchers.
“Depression severity has been associated with a higher risk of biologic abnormalities such as hypothalamic-pituitary axis dysfunction,” they wrote. “Dysregulation of the hypothalamic-pituitary axis associated with depression has been linked to higher glucocorticoid production and impaired negative feedback. Dysregulation of cortisol may damage brain areas involved in cognition such as the hypothalamus as well as decrease neurogenesis in key brain areas.”
For more information on programs targeting depression in patients with chronic illnesses like diabetes, visit www.teamcarehealth.org.
Disclosure: Dr. Katon’s relevant financial activities outside of the study include board membership for Eli Lilly and Wyeth and honoraria for lectures for Eli Lilly, Wyeth, Pfizer and Forest.