Hypertensive Retinopathy and Risk of Serious Cardiovascular Events: Five Years Prospective Cohort Study in Primary Care

Abstract

Introduction: Poorly controlled hypertension causes damage to the retinal microcirculation, which is predictive and associated to risk of stroke. Studies have shown that retinal microvascular changes can be reliably documented by retinal photographs. This study aims at examine the associative risk and incident of hypertensive retinopathy related serious cardiovascular events in primary care. Methodology: This is a prospective cohort study involving hypertensive patients in one regional primary care clinic of Hong Kong. Eligible digital retinal photographs of hypertensive patients done in the period Jan 1, 2011 to Dec 31, 2012 were graded based on Wong & Mitchell criteria. Consecutive subjects with hypertensive retinopathy (HTR) and without HTR (Non-HTR) were allocated to cohort and control group respectively until ceiling of 138. All patients will be followed prospectively for five years to exam the incidence of serious cardiovascular events. The relative risk of hypertensive retinopathy related serious cardiovascular events were investigated. Results: The cohort group patients are younger (mean age 57.3 versus 61.0, P<0.01), and have higher proportion of comorbid hyperlipidaemia (P=0.02). There are no statistical difference in sex, smoking status, duration of hypertension (HT), number of anti-hypertensive medication taking and mean blood pressure. At five year, both groups have no cardiovascular related mortality. Cohort group has 13 events of cardiovascular disease (incidence rate 9.42%), while control group has 5 events (incidence rate 3.62%). The five year realative risk (RR) of HTR for serious cardiovascular events is 2.77 (95% CI: 0.96-7.98, P=0.051), while five year RR of HTR for stroke is 9.56 (95% CI 1.19-76.5, P=0.010). With logistic regression analyasis, HTR is independent risk factor for stroke, with RR 8.55 (p=0.047). Conclusion: Hypertensive retinopathy is the independent predictive risk factor for stroke. The sensitivity and specificity of HT patients with HTR in predicting stroke in 5 years is 90.0% and 51.5% respectively.