Venular oxygen saturation is increased in young patients with type 1 diabetes and mild nonproliferative diabetic retinopathy

Abstract

Purpose: To clarify how early in the development of diabetic retinopathy (DR) can oxygen (O₂ ) saturation changes be detected.

Methods: Retinal oximetry was performed in a cross-sectional study, involving 14- to 30-year-old individuals: 185 with type 1 diabetes (T1D) and 94 controls. The subjects were divided into four groups according to the grade of DR. One-way ANOVA and post hoc tests were used to test for differences in the mean O₂ saturations between the groups.

Results: Fifty-eight (31 %) of the T1D patients had nonproliferative DR. There was no significant difference in O₂ saturations between controls and T1D patients with no DR. Arteriolar and venular O₂ saturations in T1D patients were significantly higher in moderate/severe DR than in no DR (p = 0.009 and p > 0.001), while venular O₂ saturation was significantly higher in mild DR than in no DR (p = 0.013).

Conclusion: Increase in venular O₂ saturation could not be detected before mild retinopathy had developed, and the retinal O₂ saturation increase was measurable on the venular side first. Our results suggest that the increase in O₂ saturation is likely a consequence of DR.

Keywords: diabetes type 1; diabetic complications; diabetic retinopathy; retinal microvasculature; retinal oximeter; retinal oximetry; retinal vessel oxygen saturation; retinal vessels.