Trajectories of choriocapillaris perfusion in healthy individuals and patients with diabetes mellitus: a prospective cohort study

PURPOSE: To evaluate the longitudinal rate of choriocapillaris flow deficits (CFD) in healthy participants and patients with diabetes mellitus. METHODS: This prospective cohort study included healthy individuals and diabetic patients without diabetic retinopathy (non-DR) or with mild-to-moderate non-proliferative DR (NPDR). The swept-source optical coherence tomography angiography (OCTA) was adopted for quantifying CFD annually, and linear mixed models were used to analyse the CFD change and its 95% CI overtime. RESULTS: A total of 1025 individuals were included, including 465 healthy controls, 454 in the non-DR group and 106 in the NPDR group. Significant increase in CFDs was observed in NPDR group (0.423%, 95% CI 0.230% to 0.616%) and non-DR group (0.319%, 95% CI 0.225% to 0.412%), which were higher than the CFD in healthy controls (0.173%, 95% CI 0.079% to 0.266%). After adjusting for other factors, the non-DR and NPDR group had a greater annual elevation of CFD by 0.171% (95% CI 0.060% to 0.283%; p=0.003) and 0.258% (95% CI 0.068% to 0.449%; p=0.008) in comparisons with controls. Furthermore, higher serum creatinine and glycated haemoglobin levels, poorer best-corrected visual acuity, lower OCTA image quality scores and smaller CFD at baseline were independently related to accelerated CFD worsening (all p<0.05). CONCLUSIONS: The CFD among healthy individuals and patients with diabetes increased consistently overtime, regardless of the presence or absence of DR, suggesting that CFD alterations could be an early indicator of microvascular complications, potentially aiding in the earlier DR detection.