Jennifer K Sun, MD, MPH

Retinal thickness measured by optical coherence tomography (OCT) may be a quantitative, noninvasive method for staging diabetic nephropathy and could serve as a biomarker for worsening disease, said investigators who followed a cohort of patients with long-duration type 1 diabetes.
In a study of 606 “Joslin medalists,” people who have lived with type 1 diabetes for at least half a century, those with increased central retinal thickness as measured by OCT were significantly more likely to have diabetic nephropathy independent of glycemic control, said Jennifer K Sun, MD, MPH, an ophthalmologist in the Beetham Eye Institute at the Joslin Diabetes Center in Boston, Massachusetts.
“Given the high correlation between retinal anatomy and measures of renal dysfunction, these results suggest similar underlying mechanisms between ophthalmic and non-ophthalmic microvascular complications,” Sun said.
Reasoning that there is a common underlying pathophysiology of diabetic complications, the investigators used OCT to determine whether one complication—central retinal thickness—could predict non-ocular complications. They also asked whether retinal thickness changes substantially over long duration of diabetes.
In their cohort of 606 medalists, they looked at retinopathy measured by ETDRS (Early Treatment Diabetic Retinopathy Study) protocol 7 standard field fundus photography and OCT, and at nephropathy (measured by microalbuminuria, estimated glomerular filtration rate, cystatin C, and chronic kidney disease stage), neuropathy (measured by the Michigan neuropathy screening instrument), and patient-reported history of cardiovascular disease (angina, coronary artery disease, coronary artery bypass graft, or leg claudication or bypass).
The patients had a median age of 69 years, with a median duration of diabetes of 57 years (range 54–61).
Comparing retinal zone thickness in the medalists with those of patients with diabetes of shorter duration, the authors found no significant differences in any portion of the retina.
Risk factors for diabetic macular edema in the medalists included age (P<.0001) and male sex (P<.001). There were no significant associations with either hemoglobin A1c, weight, height, body mass index, blood pressure, heart rate, or lipid parameters.

Publish date: Jun 27, 2011
Source: Medical Economics eConsult