Characterization of risk phenotypes of type 2 diabetes nonproliferative retinopathy

Abstract

Purpose : Phenotypes of diabetic retinopathy, particularly B and C, have been shown previously to be associated with risk of progression and development of sight-threatening complications (macular edema and proliferative retinopathy). In this work, we have further characterized these type 2 diabetes (T2D) retinopathy phenotypes, in terms of systemic and ocular features.

Methods : Patients with T2D and nonproliferative retinopathy (NPDR) were examined using 7-fields color fundus photography (CFP) and optical coherence tomography (OCT and OCTA). Phenotype classification was performed based on microaneurysm turnover (MAT, on CFP) and central retinal thickness (CRT, on OCT). Phenotype B was identified by low MAT (< 6) and increased CRT and Phenotype C by higher MAT (≥ 6) with or without increased CRT. ETDRS grading of seven fields CFP was performed. The following systemic factors were also evaluated: age, sex, diabetes duration, lipidic profile, inflammatory cytokines and hemoglobin A1c
(HbA1c).

Results : 141 eyes with NPDR, one eye per patient, 81 with phenotype B and 60 with phenotype C were included in the analysis. The patients presenting phenotype C had higher HbA_1c levels (p=0.048) and patients with phenotype B had higher values of HDL cholesterol (p=0.036) and interleukin-8 (p=0.027). Phenotype C was characterized by lower macular vessel density (p≤ 0.012) and thinning of the ganglion cell layer (GCL; p=0.006). As expected by the initial phenotype characterization, phenotype C showed higher MAT (p<0.001) and phenotype B higher values of retinal thickness (CRT, p<0.001). Phenotype C was also identified in eyes with more severe ETDRS level (50%, ETDRS 43-47) than phenotype B (17% ETDRS 43-37).

Conclusions : Of the two phenotypes of NPDR in T2D associated with risk of developing sight-threatening complications, phenotype C is characterized by microvascular alterations represented by higher MAT and increased capillary closure on OCTA and by neurodegenerative changes, represented by GCL thinning, whereas phenotype B is characterized locally by increased CRT and systemically by increased levels of inflammatory markers.

This is a 2021 ARVO Annual Meeting abstract.