Retinal Vessel Measurements as Clinically Useful Predictors in Veterans
Condition: Diabetes
Study type: Observational

Summary: 
      Diabetic complications are an important source of blindness and mortality among Veterans.
      Their occurrence is unpredictable because of the highly variable effect of factors such as
      weight, diet and exercise. Improved prediction of diabetes complications has the potential to
      improve the care for Veterans with diabetes, especially if this can be done without any extra
      effort for the Veterans or their caretakers. All Veterans with diabetes in VHA are required
      to undergo annual retinal photography to screen for current diabetic retinopathy. The
      investigators have recently developed an automated, precise, fast, novel tool for measuring
      retinal vessels in these images. Manual measurement of retinal vessels has shown that these
      can predict future -not current- development of hypertension and also diabetic retinopathy.
      If the investigators can confirm that their tool can flag those Veterans at increased risk
      for developing these diabetes complications, this will allow earlier intervention and
      prevention. Because the tool only uses the images that are being taken anyway, there is no
      extra effort for either the Veteran or VA staff.
    

Detailed description: 
      Background: the investigators hypothesize that retinal vessel derived biomarkers, obtained
      using their automated, precise, fast, novel tool for measuring retinal vessels in retinal
      images can identify Veterans at increased risk for diabetic retinopathy and hypertension,
      before any overt signs of retinopathy or increased blood pressure have become apparent.
      Population studies have shown that changes in arterial and venous diameter are associated
      with future development of these complications.

      Purpose: Determine the potential utility of retinal vessel derived biomarkers, from color
      fundus photographs, as a non-invasive independent risk factor for diabetic retinopathy (DR)
      and hypertension in Veterans with diabetes.

      Methods: Aim 1. The investigators will evaluate automatically derived retinal vessel
      parameters (arterial and retinal vessel width and branch relationships) as an early biomarker
      for future development of hypertension no less than 2 years later, with normal current normal
      blood pressure. The investigators will compare this biomarker in retinal images from 500
      Veterans with diabetes, all of whom did not have hypertension at the time of imaging, for
      those who were and were not diagnosed with hypertension no more than 3 years later. Aim 2. To
      evaluate automatically derived retinal vessel parameters as an early biomarker for the risk
      for development of diabetic retinopathy (defined as transition from less than moderate
      retinopathy AND no apparent macular edema according to the International Clinical Diabetic
      Retinopathy and Diabetic Macular Edema Severity Scale) in at risk Veterans with diabetes. The
      investigators will compare this biomarker in retinal images from a population of 4000
      Veterans with diabetes, currently without DR, ~10% of who developed retinopathy no less than
      two years later while the remainder did not.
    

Intervention name(s): Vessel measurements
Intervention type(s): Other
Intervention description(s): Measurement of retinal vessels
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        The investigators will identify a random sample of 4500 Veterans with diabetes from the
        Greater LA and Iowa City screening programs, who were imaged at least 3 years ago for DR
        screening, and did not have hypertension (AHA definition) at that time
      
Biospecimen description: 
      Retinal images - vessel parameters
    
Keywords: diabetes; computer; retina; vessel; analysis