Retinal Vascular Tortuosity in Hospitalized Patients with Type 2 Diabetes and Diabetic Retinopathy in China

Abstract

Context: Diabetic patients are at high risk for microvascular complications of disease such as diabetic retinopathy (DR) and diab etic neuropathy. Imaging the retinal micro-vasculature offers a chance to measure quantitatively the microvascular changes in diabetic patients’ onset and progression. However, the relation between retinal biomarkers and diabetic risk factors is unclear in Chinese hospitalized type 2 diabetic patients. Aims: To examine the associations of retinal vascular tortuosity with risk factors of type 2 diabetes and diabetic retinopathy in Chinese hospitalized patients. Patients and Methods: Our cross-sectional study includes 504 participants with type 2 diabetes hospitalized in the department of endocrinology in Shengjing hospital, Shenyang, China. Patients’ socio-demographic, clinical and biological information was retrieved from their ID card, the interview, and the local hospital information system. Retinal photographs were taken by laser-scanning ophthalmoscopy of both eyes and checked if gradable for analysis. The weighted mean and standard deviation of tortuosity were calculated from the retinal photographs using a novel robust and fully automatic quantitative method. DR was assessed from the retinal photographs by the ophthalmologist according to the modified Airlie House classification into No DR and Any DR in our current study. Data were analyzed by SPSS Version 22 with Student’s t test, Mann-Whitney U test, Chi-square test, and linear regression. Results: For the total participants (504) in this study, the weighted mean and standard deviation (SD) of tortuosity was 12.05 × 10?3 (SD: 1.66 × 10?3) and 24.31 × 10?3 (SD: 3.69 × 10?3), respectively. 386 (76.6%) patients were diagnosed with DR who had older age, long duration of diabetes, higher brachial ankle pulse wave velocity (baPWV), higher systolic blood pressure (SBP), higher diastolic blood pressure (DBP), and higher retinal vascular tortuosity values. In univariable linear regression analyses, older age, longer duration, higher baPWV, higher urine microalbuminuria, higher urine albumin/creatinine ratio, diagnosed with high blood pressure, thrombosis or Any DR, were significantly associated with both higher tortuosity measures (all P values < 0.05). In multivariable-adjusted linear regression analyses, age and diabetes duration (all P values < 0.05) were independently and positively associated with both tortuosity measures, after adjustment for low-density lipoprotein (LDL), high-density lipoprotein (HDL) and high blood pressure. Furthermore, after adding some kidney failure factors, the urine albumin/creatinine ratio was also an independent risk factor of vascular tortuosity. These associations remained even after including or excluding the factor of DR. Conclusions: Retinal vascular tortuosity is independently associated with older age, longer duration, and higher urine albumin/creatinine ratio in Chinese hospitalized type 2 diabetic patients, regardless of the presence of DR. This suggests that retinal vascular tortuosity might be a successful early indicator of diabetic microvascular complications, like diabetic retinopathy and diabetic neuropathy, and that the precise quantitative measurement of retinal vascular tortuosity is an effective biomarker in the screening and assessment of diabetic microvascular complications.