Researchers at the Royal Victorian Eye and Ear Hospital, Victoria, Australia, have published a study on several retinal biomarkers using retinal vascular measurements, focused on all all-cause mortality, including biomarkers associated with premature mortality. The researchers aim to assess biological mechanisms connecting them to increased mortality risk. The work published in the Translational Vision Science & Technology (TVST, 2024;13[1]:2,) used over 60,000 images to explore the association between retinal microvasculature measurements and all-cause and premature mortality. While the participants from mainly from a white population and from small geographical regions, different ethnic groups and geographical regions will be required to confirm the results for a broader population.
According to the researchers, in the UK, 22.8% of deaths in 2020 were considered “avoidable”, and screening for vulnerable individuals at risk of death from preventable causes may provide clear benefits for public healthcare. The microvascular health on the retina has previously shown associations between retinal vascular features and systemic health conditions, including retinal vessel measurements associated with hypertension, cardiovascular disease, metabolic syndrome, and mortality. In addition, retinal vascular tortuosity and complexity are associated with cardiovascular outcomes, Alzheimer’s disease progression, cognitive dysfunction, cognitive function, chronic obstructive pulmonary disease, and obstructive sleep apnoea syndrome. Regardless, such associations are limited to date. However, a recent particular deep learning algorithm – the Retina-based Microvascular Health Assessment System (RMHAS) – “completes the segmentation and quantification within 2 seconds and extracts hundreds of measurements simultaneously”.
Following their analysis on 66,415 participants. The researchers have reported 18 and 10 retinal vascular measurements that were significantly associated with all-cause mortality and premature mortality, respectively. In a fully adjusted model, vascular features with all-cause mortality and premature mortality showed: arterial bifurcation density (branching angle), number of arterial segments (complexity), interquartile range and median absolute deviation of arterial curve angle (tortuosity), mean and median values of mean pixel widths of all arterial segments in each image (caliber), skeleton density of arteries in macular area (density), and minimum venular arc length (length). The Australian researchers, including several collaborators from University of Cambridge, Capital Medical University, Beijing and the Hong Kong Polytechnic University, Kowloon concluded that the, “18 retinal vascular measurements were significantly linked to all-cause mortality, with 16 originating from arteries. Similarly, 10 retinal vascular measurements exhibited significant associations with premature mortality, with nine being arterial parameters. Lower arterial bifurcation density was significantly associated with both all-cause mortality and premature mortality risk (branching angle, bifurcation density (artery), HR(95% CI) 0.94, p 0.01 (all-cause mortality), and HR(95% CI) 0.93, p 0.005, (premature mortality). RMHAS has been validated thoroughly with proven performance and accuracy across different datasets and images of varied quality.