Expanded field swept-source OCT angiography biomarkers associated with microvascular complications of diabetes mellitus.

PURPOSE: To assess the association among retinal imaging biomarkers on expanded field swept-source optical coherence tomography angiography (EF SS-OCTA) and non-ocular microvascular complications of diabetes mellitus (DM). METHODS: This retrospective, cross-sectional study included 146 eyes from 100 adults with diabetes mellitus (DM), across various stages of diabetic retinopathy. Patients were imaged with EF SS-OCTA (6 × 6 mm, Montage 15 × 15 mm). Mixed effect logistic models were used to identify SS-OCTA metrics associated with the occurrence of non-ocular microvascular complications, while controlling for age, DM duration, and types of treatment that patients received prior to their appointment. Patients’ eyes were treated as random effects, while metrics like ischemia index (Ratio ischemia index = pixels of the NPAs (nonperfusion areas) / pixels of the total image area) and neovascularization real area were rescaled for interpretability. NV (neovascular) VD (vessel density) and VSD (vessel skeletonized density) values are the VD and VSD only of the manually outlined areas of neovascularization. VD is the total area of perfused vasculature per unit area in a region of measurement, while VSD is the total length of perfused vasculature per unit area in a region of measurement. RESULTS: 54 patients had diabetic peripheral neuropathy (DPN), 25 had neither DPN nor diabetic kidney disease (DKD) and 17 had DKD. NV VSD and NV VD (OR = 2.45, p = 0.001) were significantly associated with both DPN and DKD combined (OR = 2.45, p = 0.003; OR = 2.45, p = 0.001, respectively) as well as in separate analyses of DPN (OR = 1.68, p = 0.033; OR = 1.73, p = 0.018, respectively) and DKD (OR = 2.19, p = 0.007; OR = 2.23, p = 0.002, respectively) alone. Ratio Ischemia index (OR: 1.75, p = 0.028) was significantly associated only with DPN. CONCLUSION: NV VSD and NV VD were significantly associated with both DPN and DKD while ratio ischemia index was only significantly associated with DPN, underscoring the potential utility of EF SS-OCTA metrics in predicting and monitoring non-ocular microvascular complications in clinical practice.