To test the hypothesis that digoxin, an inhibitor of Na+ -K+ -ATPase activity, accelerates the progression of diabetic retinopathy.
We compared the incidence and risk of retinopathy in 120 digoxin-taking vs. 867 non-digoxin-taking diabetic participants in the Wisconsin Epidemiologie Study of Diabetic Retinopathy (WESDR) and in 117 digoxin-taking vs. 1,883 non-digoxin-taking diabetic subjects in the Early Treatment Diabetic Retinopathy Study (ETDRS). In both studies, retinopathy was detected by grading stereoscopic color photographs using the modified Airlie House classification scheme, and a two-step difference in baseline retinopathy grade was considered significant.
After controlling for other risk factors, we found no statistically significant association with either 4-year incidence of retinopathy (WESDR) or progression of retinopathy (WESDR and ETDRS) in patients taking digoxin at baseline compared with those not taking digoxin.
These data suggest that digoxin therapy does not adversely affect the course of diabetic retinopathy.