Retinal vessel diameters in multiple sclerosis: associations with disability, cardiovascular risk factors and retinal atrophy

Objective: To investigate if retinal vessel diameters on fundus imaging may be related to disability in people with multiple sclerosis and explore underlying mechanisms. Methods: People with multiple sclerosis received standardized static retinal vessel analysis to assess central retinal arteriolar and venular equivalents, neurological examination for the Expanded Disability Status Scale and optical coherence tomography for the macular ganglion cell-inner plexiform layer. Linear mixed-effect models and logistic regression were employed. Results: One hundred and seventy-nine people with multiple sclerosis (median age: 44 years, Expanded Disability Status Scale: 2.0, central retinal arteriolar equivalent: 184 µm, central retinal venular equivalent: 221 µm) were included. Retinal vessel diameters were related to age (central retinal arteriolar equivalent: p < 0.001, central retinal venular equivalent: p = 0.009), arterial hypertension (central retinal arteriolar equivalent: p = 0.008), higher body mass index (central retinal arteriolar equivalent: p = 0.042), and smoking (central retinal arteriolar equivalent: p = 0.028, central retinal venular equivalent: p < 0.001). A 5 μm decrease in vessel diameter increased the odds of being in the high (⩾4) Expanded Disability Status Scale group by 23.5% for central retinal arteriolar equivalent ( p = 0.026) and 23.9% for central retinal venular equivalent ( p = 0.018), after adjustment for age, treatment and cardiovascular risk factors. When additionally adjusting for macular ganglion cell-inner plexiform layer, the associations did not remain (central retinal arteriolar equivalent–Expanded Disability Status Scale: p = 0.355; central retinal venular equivalent–Expanded Disability Status Scale: p = 0.107). However, the area under the curve of these models was higher (0.883–0.896) compared to the models using only retinal vessels (0.836–0.837) or only macular ganglion cell-inner plexiform layer (0.858). Interpretation: Retinal vessel diameters show cross-sectional associations with cardiovascular risk factors, retinal atrophy and disability in people with multiple sclerosis, while longitudinal studies are warranted.