The eyes – and kidneys – have it

Tracking microvascular abnormalities in the retina should be a pair of tests in order to successfully identify early whether a patient is at risk of serious cardiovascular disease in the future, according to a new study.

The eyes – and the cholesterol and other signs spotted by an optometrist – have already served as a warning sign for the disease for many patients.

However, in the search for a reliable early disease indicator, a Singapore-US research team looked at both microvascular abnormalities in the retina and the ratio of the molecules albumin and creatinine in a patient’s urine, in a new paper published in the journal Scientific Reports.

Of the nearly 3500 Asian patients tracked for just under six years, people with both retinal abnormalities and an increase of albumin in their urine were 6.71 times more likely to later experience a cardiovascular event than people who had neither symptom, the paper noted.

Trained graders using vessel analysis software on retinal fundus photographs assessed if a patient had microvascular abnormalities.

The consideration of both the changes in the retina and the kidneys were important, the researchers emphasised. A number of factors can cause a short-term jump in the urinary albumin and creatinine levels – however, measurements of retinal microvascular changes are far more stable and repeatable.

Patients with retinopathy alone had just over twice the risk and people with just the symptom urinary albumin had 1.6 times the risk of cardiovascular disease, highlighting the importance of both measurements.

The paper explained that: “Retinal vessels, measuring 100 to 300 μm in size, offer a unique and easily accessible ‘window’ to study the health and disease of the human microcirculation. There is increasing evidence showing that retinal microvascular changes, reflecting systemic microcirculation damage, may provide additional value in cardiovascular disease risk prediction.”

The new research backs up similar international studies that have looked at either the eyes or the kidneys to understand a patient’s risk of having a cardiovascular event, the scientists wrote.

“Our findings highlight the combined prognostic value of two readily accessible and quantifiable markers of microvascular disease,” the paper concluded.