Patients with diabetes who also suffer from depression are more likely to develop a serious complication known as diabetic retinopathy, a disease that damages the eye’s retina, and causes blindness, a five-year study finds….
Co-author Wayne Katon, M.D., director of health services and psychiatric epidemiology at the University of Washington Medical School, in Seattle, noted that, “Our study controlled for obesity, smoking, sedentary lifestyle and HbA1c levels, and still found that depression was associated with an increased risk of retinopathy.”
They studied 2,359 patients with diabetes enrolled in the Pathways Epidemiologic Study and assessed their levels of depression using the Patient Health Questionnaire-9 (PHQ-9), a self-reported survey of depression symptoms.
Over the five-year follow-up period, 22.9 percent of the patients who had PHQ-9 scores that ranked as “major depression” developed diabetic retinopathy, compared with 19.7 percent of the patients without depression. With a five-point increase on the PHQ-9 score, patients’ risk of having diabetic retinopathy increased by up to 15 percent.
“Our findings suggested that psychobiologic changes associated with depression such as increased cortisol levels and activity of blood-clotting factors may be linked to the development of retinopathy,” Katon said.
Todd Brown, M.D., an assistant professor of medicine at the division of endocrinology and metabolism at Johns Hopkins University stated that, “There is no question that the burden of depression among patients with diabetes is very high and that depression is a risk factor for worse outcomes in patients with diabetes, as was seen in this study.” He added that multiple explanations might account for these findings — some related to biological changes and some due to behavioral social issues, such as decreased physical activity and poorer utilization of health care.
Brown said that, “The big question with all of this is whether identifying and treating depression in patients with diabetes will change clinical outcomes.” “And currently, there are no universal recommendations for depression screening among patients with diabetes.”
Sieu N, et al. Depression and incident diabetic retinopathy: a prospective cohort study. Gen Hosp Psych online, 2011