Retinal microvascular abnormalities and blood pressure in older people: the Cardiovascular Health Study

Aim: To examine the relation between blood pressure and retinal microvascular abnormalities in older people. Methods: The Cardiovascular Health Study is a prospective cohort study conducted in four US communities initiated in 1989 to 1990. Blood pressure was measured according to standardised protocols at each examination. During the 1997-8 examination, retinal photographs were taken of 2405 people aged 69-97 years (2056 without diabetes and 349 with diabetes). Signs of focal microvascular abnormalities (focal arteriolar narrowing, arteriovenous nicking, and retinopothy) were evaluated from photographs according to standardised methods. To quantify generalised arteriolar narrowing, the photographs were digitised and diameters of individual arterioles were measured and summarised. Results: In non-diabetic people, elevated concurrent blood pressure taken at the time of retinal photography was strongly associated with presence of all retinal microvascular lesions. The multivariable adjusted odds ratios, comparing the highest to lowest quintile of concurrent systolic blood pressure, were 4.0 (95% confidence intervals (CI): 2.4 to 6.9, p test of trend<0.001) for focal arteriolar narrowing, 2.9 (95% CI: 1.6 to 5.3, p<0.001) for arteriovenous nicking, 2.8 (95% CI: 1.5 to 5.2, p<0.001) for retinopathy, and 2.1 (95% CI: 1.4 to 3.1, p<0.001) for generalised arteriolar narrowing. Generalised arteriolar narrowing and possibly arteriovenous nicking were also significantly associated with past blood pressure measured up to 8 years before retinal photography, even after adjustment for concurrent blood pressure. These associations were somewhat weaker in people with diabetes. Conclusions: Retinal microvascular abnormalities are related to elevated concurrent blood pressure in older people. Additionally, generalised retinal arteriolar narrowing and possibly orteriovenous nicking are related to previously elevated blood pressure, independent of concurrent blood pressure. These data suggest that retinal microvascular changes reflect severity and duration of hypertension.