Presence of chronic diabetic foot ulcers is associated with more frequent and more advanced retinopathy.

AIMS: To clarify the frequency and severity of diabetic retinopathy in a group of people with Type 2 diabetes and chronic diabetic foot ulcers, and to compare visual acuity, levels of retinopathy and clinical significant macular oedema with a matched control group of people with Type 2 diabetes without a history of chronic diabetic foot ulcers.

METHODS: Visual acuity and fundus imaging were evaluated in 90 white people with at least 3 months' duration of full-thickness diabetic foot ulcers below the ankle and the results compared with those in 180 white people with Type 2 diabetes without a history of chronic diabetic foot ulcers (control group). Controls were matched for age, sex and duration of diabetes.

RESULTS: Despite similar age and diabetes duration, severe non-proliferative or proliferative diabetic retinopathy was present in 41% of the people in the diabetic foot ulcer group as compared to 15% in the control group (P<0.001). Only 6% in the diabetic foot ulcer group was without any diabetic retinopathy as compared to 34% among controls. Proliferative diabetic retinopathy was more common in the diabetic foot ulcer group (31% vs 8%; P<0.001), but time-to-proliferative diabetic retinopathy did not differ between groups. Clinically significant macular oedema was more frequently present, and the diabetic foot ulcer group exhibited significantly worse results in best and worst eye visual acuity testing.

CONCLUSIONS: In this northern European setting almost all people with Type 2 diabetes and chronic diabetic foot ulcers had diabetic retinopathy. Almost one-third had proliferative diabetic retinopathy as compared to <10% in our matched control group. More advanced diabetic retinopathy was linked to worse visual acuity.