Concurrent sickle cell hemoglobin C disease and diabetes mellitus: no added risk of proliferative retinopathy?

Of 148 adults with sickle cell hemoglobin C (SC) disease seen at Cook County Hospital and Clinics, Chicago, Illinois, eight patients had coexistent noninsulin-dependent diabetes mellitus. The clinical findings were notable for the paucity of retinal vascular changes. No patient showed proliferative diabetic retinopathy; one patient showed background diabetic retinopathy consisting of a few microaneurysms. Six of the eight patients showed no lesions of proliferative sickle retinopathy. Coexistence of noninsulin-dependent diabetes mellitus and SC disease does not appear to have an additive adverse effect on the presence or severity of proliferative retinopathy in the affected patient.