Clinical utility of Spectral-Domain Optical Coherence Tomography (SD-OCT) marker Disorganization of Retinal Inner Layers (DRIL) in Diabetic Retinopathy (DR)

Abstract

Purpose : Diabetic retinopathy (DR) is a vision-threatening microvascular complication that affects one-third of all diabetics. Fundus examination and imaging, commonly spectral domain optical coherence tomography (SD-OCT), are used to screen for, diagnose and monitor complications of DR. Disorganization of retinal inner layers (DRIL) is an understudied SD-OCT parameter. To investigate the clinical utility of DRIL in DR, we evaluate its relationship with several DR risk and progression factors.

Methods : A retrospective cohort study was conducted at a large academic center following Institutional Review Board approval. The cohort comprised 1,175 randomly selected, non-consecutive patients with ICD-9/10 codes for type 2 diabetes with and without retinopathy between September 2009 and January 2019 (n=2,083 eyes). Demographics, anti-hyperglycemic history, hemoglobin A1c (HbA1c), and VA were obtained by electronic medical record review. SD-OCT scans were evaluated for DRIL by two trained, double-blinded graders. Disagreement was arbitrated by a third blinded grader. Interrater reliability was tested with a kappa statistic. Generalized estimating equation logistic regression models were used to evaluate relationships between variables.

Results : Of 2,083 eyes, 28.08% (n=585) demonstrate presence of DRIL with high interrater reliability (K=0.88, 95% confidence interval (CI) [0.86-0.90]). Insulin users have more severe DR (p<.0001). DRIL is associated with worse VA (p<.001) and DR severity (p<.0001). Unadjusted, insulin usage appears to be associated with DRIL (OR 1.91, 95% CI [1.49-2.45]), however after accounting for DR severity, we find that DRIL is not associated with insulin usage (p=0.25). The remaining DR-related factors (other anti-hyperglycemic usage, HbA1c, sex, race and age) are not associated with DRIL.

Conclusions : DRIL is a promising clinical parameter in patients with DR. SD-OCT marker DRIL is strongly associated with severity of DR and worse VA, supporting its utility as an unfavorable prognostic predictor. Initially, DRIL appeared strongly associated with insulin use, however after adjusting for DR severity, DRIL is not associated with insulin use. Thus, DR severity confounds the relationship between DRIL and insulin use.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Figure 1. Distribution of Visual Acuity by DRIL Status.

 

Table 1. Multivariable Model Evaluating Associations with DRIL.