Retinal Vascular Tortuosity in Persons with Diabetes and Diabetic Retinopathy

1. Muhammad Bayu Sasongko^1,2
2. Tien Y Wong^1,3
3. Thanh T Nguyen¹
4. Carol Yim-lui Cheung³
5. Jonathan Shaw⁴
6. Jie Jin Wang^1,5

¹Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Australia
²Department of Ophthalmology, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Indonesia
³Singapore Eye Research Institute, National University of Singapore, Singapore
⁴Baker IDI Heart and Diabetes Institute, Caulfield, Victoria, Australia
⁵Centre for Vision Research, University of Sydney, Sydney, Australia

Purpose: To examine the association of retinal vessel tortuosity with diabetes and diabetic retinopathy (DR).

Methods: A clinic-based study of 327 participants (224 diabetes [85 type 1, 139 type 2] and 103 non diabetic controls) aged ≥ 18 years old. DR was graded from fundus photographs according to modified Airlie House Classification system and categorized into mild, moderate and vision-threatening DR (VTDR). Retinal vessel tortuosity (tortuosity index) was measured from digital retinal photographs using a semi-automated computer program following standardized protocol.

Results: There were 114 (44%) participants with DR. After controlling for age, gender, duration of diabetes, HbA1c, blood pressure, BMI, cholesterol, triglyceride, use of insulin and lipid-lowering drugs, compared to non-diabetic subjects, retinal arteriolar and venular tortuosity were increased in persons with diabetes without DR (mean differences 12.4 x 10-3 and 13.3 x 10-3, respectively; both P<0.001) and in those with DR (mean differences 15.4 x 10-3 and 15.0 x 10-3, respectively; both P<0.001) compared to non-diabetic controls. Among subjects with diabetes, increase arteriolar tortuosity was significantly associated with mild NPDR (OR 1.53, 95% CI 1.03 – 2.05, per standard deviation increase in arteriolar tortuosity), moderate NPDR (OR 1.67, 95% CI 1.10 – 2.55) but not VTDR (OR 0.91, 95% CI 0.54 – 1.54). No association with DR was found for venular tortuosity.

Conclusions: Persons with diabetes were more likely to have more tortuous retinal arterioles and venules than persons without diabetes. In persons with diabetes, increased arteriolar tortuosity was associated with mild and moderate levels of DR.