title: Depression and incident diabetic retinopathy: a prospective cohort study.
abstract: OBJECTIVE
  This study examined whether depression is associated with a higher incidence of diabetic retinopathy among adults with type 2 diabetes after controlling for sociodemographic factors, health risk behaviors and clinical characteristics.
  
  
  METHODS
  This study included 2359 patients enrolled in Pathways Epidemiologic Follow-Up Study, a prospective cohort study investigating the impact of depression in primary care patients with type 2 diabetes. The predictor of interest was baseline severity of depressive symptoms assessed with the Patient Health Questionnaire-9 (PHQ-9). The outcome was incident diabetic retinopathy. Risk of diabetic retinopathy was assessed using logistic regression, and time to incident diabetic retinopathy was examined using Cox proportional hazard models.
  
  
  RESULTS
  Over a 5-year follow-up period, severity of depression was associated with an increased risk of incident retinopathy [odds ratio =1.026; 95% confidence interval (CI) 1.002-1.051] as well as time to incident retinopathy (hazard ratio=1.025; 95% CI 1.009-1.041). The risk of incident diabetic retinopathy was estimated to increase by up to 15% for every significant increase in depressive symptoms severity (5-point increase on the PHQ-9 score).
  
  
  CONCLUSIONS
  Diabetic patients with comorbid depression have a significantly higher risk of developing diabetic retinopathy. Improving depression treatment in patients with diabetes could contribute to diabetic retinopathy prevention.
authors.affiliation: Department of Psychiatry & Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA. nidas@uw.edu
authors.forename: Nida
authors.initials: N
authors.lastname: Sieu
authors.forename: Wayne
authors.initials: W
authors.lastname: Katon
authors.forename: Elizabeth H B
authors.initials: EH
authors.lastname: Lin
authors.forename: Joan
authors.initials: J
authors.lastname: Russo
authors.forename: Evette
authors.initials: E
authors.lastname: Ludman
authors.forename: Paul
authors.initials: P
authors.lastname: Ciechanowski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology* / Q000523:psychology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000453:epidemiology* / Q000523:psychology*; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D012647:Self-Assessment; D011795:Surveys and Questionnaires; D014861:Washington / Q000453:epidemiology