In patients with type 2 diabetes mellitus, choriocapillaris flow deficit percentage (CC FD%) is independently associated with diabetic retinopathy progression and diabetic macular edema (DME) development, according to research published in the American Journal of Ophthalmology.
The study included participants with type 2 diabetes mellitus without diabetic retinopathy or with mild nonproliferative diabetic retinopathy free of diabetic macular edema at baseline. All participants underwent standard 7-field fundus photography, spectral-domain optical coherence tomography (OCT), and swept-source OCT angiography and were followed up annually for 3 years. The investigators quantified macular CC FD% and used logistic models to evaluate the association between CC FD% and diabetic retinopathy progression and DME development. They also evaluated the additional predictive value of CC FD% for outcome events.
A total of 1805 eyes of 903 patients were included in the analysis. In 3 years of follow up, 16.34% of eyes had diabetic retinopathy progression, and 6.54% of eyes developed DME.
After adjusting for confounding factors, the researchers found higher average CC FD% was correlated with diabetic retinopathy progression (odds ratio [OR], 3.41 per standard deviation [SD] increase; 95% confidence interval [CI], 2.65-4.39; P <.001) and DME development (OR, 1.37 per SD increase; 95% CI, 1.06-1.77; P =.016).
Using the Early Treatment of Diabetic Retinopathy Study (ETDRS) macular map, the team also found increased CC FD% in all regions was associated with diabetic retinopathy progression but increased CC FD% in the inferior field only was associated with DME development.
The researchers found the addition of average CC FD% to a conventional model based on established risk factors significantly improved the C-statistics for diabetic retinopathy progression (0.712 to 0.777; P <.001) and DME development (0.743 to 0.773; P =.044). Their estimated net reclassification and integrated discrimination improvement indices indicated that the addition of CC FD% led to a significant improvement in the discriminative performance for diabetic retinopathy progression and DME development.
“CC FD% exerts an incremental predictive value for 3-year DR progression and DME development, which is an encouraging finding,” according to researchers. “Our findings support the use of CC as a new biomarker for assessing the risk of DR progression and DME development and provide new insights into personalized management of [diabetic retinopathy] and DME.”
Limitations of the study included evaluation of CC perfusion in only a macular 3×3 mm2 area, an attrition rate of 18.9% due to mortality and loss to follow up/potential attrition bias, inclusion of only Chinese participants, no treatment for diabetic retinopathy or DME among the patients at baseline, and lack of evaluation of changes in CC FD%.
Chen Y, Zhu Z, Cheng W, et al. Choriocapillaris flow deficit as a biomarker for diabetic retinopathy and diabetic macular edema: 3-year longitudinal cohort: Choriocapillaris flow predicts DR progression and DME development. Am J Ophthalmol. November 24, 2022. doi:10.1016/j.ajo.2022.11.018