MONTREAL — Major depression is associated with a twofold increase in the risk of incident diabetic foot ulcers, according to the results of a large, prospective, population-based cohort study.
The findings suggest strong benefits in screening for and treating depression to prevent this complication, said Dr. Lisa Williams, of the department of dermatology at the University of Washington, Seattle.
“Depression is twice as common in patients with diabetes,” she said at the annual meeting of the Society for Investigative Dermatology. “At any one time, 11%-12% of patients with diabetes have major depression, and 31% have significant depressive symptoms.”
Until now, it has not been known whether depression increases the incidence of diabetic foot ulcers. However, it is known that “depression is associated with more severe and larger diabetic foot ulcers, and poor healing and recurrence. Depression is also associated with a threefold increase in mortality rate among patients with their first foot ulcer,” she said.
Her study, funded by the National Institute of Mental Health, included 3,474 patients from the Pathways Epidemiologic Study, a prospective cohort of primary care diabetes patients from nine clinics in western Washington State.
Major and minor depression were assessed using the Patient Health Questionnaire (PHQ-9), and there was a mean follow-up of about 4 years. New-onset foot ulcers were assessed during the course of the study, using ICD-9 codes.
There were 401 diagnoses of major and 290 diagnoses of minor depression in the cohort, and 121 incident foot ulcers, said Dr. Williams, who reported no conflicts of interest.
Compared with patients with no depression, Dr. Williams and her coinvestigators found a significant increase in the risk of foot ulcers in patients with major, but not minor, depression (hazard ratios, 2.0 and 1.3, respectively).
There was no difference between depressed and nondepressed patients in foot self-care. However, previous research has shown that depression in patients with diabetes is associated with poor self-care, as well as hyperglycemia, smoking, and obesity, she said. “In our study, we found that compared with nondepressed patients, depressed patients were older, unmarried, had [a higher BMI], were more likely to smoke, and had more diabetes complications.