Eye vessels predict CV risk in African–American diabetes patients
MedWire News: The likelihood of African‑Americans with Type 1 diabetes experiencing incident hypertension and lower extremity arterial disease (LEAD) over a 6-year period can be predicted by their retinal vessel caliber at baseline, say researchers.
Specifically, a narrow central retinal arteriolar equivalent (CRAE) significantly predicted any cardiovascular disease (CVD) or LEAD occurring during that time, they write, in the Archives of Ophthalmology.
The team also found that large central retinal venular equivalent (CRVE) diameter at baseline significantly predicted 6-year incidence of hypertension.
"The clinical implication of our finding is that, in addition to retinal arteries, changes in the diameter of retinal veins may be used as an indicator of response to medical treatment of hypertension," suggest Monique Roy (New Jersey Medical School, Newark, USA) and co-workers.
They examined data for 468 African‑American patients with Type 1 diabetes who had undergone eye examinations for diabetic retinopathy and follow up for CVD between 1993 and 1997.
Mean baseline CRAE measurements among patients who developed any CVD, heart disease or stroke, LEAD, hypertension, or who had died at 6 years were 161, 163, 158, 170, and 160 µm, respectively, compared with 170, 170, 169, 172, and 168 µm in patients who did not experience these outcomes.
The equivalent CRVE measurements at baseline were 255, 256, 253, 262, and 257 µm for study participants who experienced the above outcomes, versus 254, 254, 254, 253, and 254 µm for those who did not.
After multivariate analysis adjusted for factors including baseline age, body mass index, and socioeconomic status, a narrower baseline CRAE was significantly associated with 6-year incidence of any CVD and LEAD, at odds ratios (ORs) of 1.54 and 1.92 per quartile decrease, but not heart disease or stroke.
A larger baseline CRVE was significantly predictive of 6-year hypertension (OR=1.54 per quartile increase), report Roy et al.
Both narrower CRAE and larger CRVE significantly predicted mortality (ORs=1.33, 1.37) during the follow-up period after further adjusting results for baseline mean arterial blood pressure, they add.
Prompted by the low number of patients with incident heart disease, stroke, or LEAD, a separate analysis including only age, CRAE, and either proteinuria or mean arterial blood pressure as variables showed that only proteinuria ‑ not narrower CRAE ‑ was significantly predictive of incident heart disease or stroke.
Roy and colleagues explain that wider CRVE as a predictor of hypertension is consistent with venular changes seen in microcirculation in the prehypertensive stage, and may represent the retinal vasculature responding to chronic hypoxia. Wider diameter measurements have also been previously associated with various traditional CVD factors including endothelial dysfunction, they add.
"The mechanisms that may be involved are unclear and may include genetic as well as environmental factors," the team concludes.
By Sarah Guy