Like macular degeneration, hypertension is a common problem among older adults. However, because the two so often coincide, it’s unclear exactly how they may be related. A new study investigating these conditions and treatment strategies for wet AMD patients affected by hypertension might have found a particular way that the two conditions are associated.

The study included 3,096 wet AMD patients (41.7% female, 58.3% male; aged 50 to 96) at a single center in China from 2002 to 2019. The researchers found a significant association between the two conditions and, after adjusting for sex and age, they reported a significant association between hypertension in wet AMD and the number of injections they received. Hypertension status wasn’t significantly associated with need for vitrectomy.

 “The reason why wet AMD patients with hypertension need more anti-VEGF treatment than those without hypertension may be that the renin-angiotensin-aldosterone system (RAAS) not only affects critical components of the heart and cardiovascular system, but also influences blood vessels in the retina,” the researchers wrote in their paper. “Angiotensin 2 (Ang 2) caused apoptosis in retinal endothelial cells, which can cross the blood-retina barrier and support the development of choroidal neovascularization. Additionally Ang 2 can reduce the blood flow to the choroid by decreasing the diameter of retinal arterioles and capillaries. Moreover, Ang 2 upregulates VEGFR-2, which contributes to the development of choroidal neovascularization (CNV) by destroying the balance of antiangiogenic and angiogenic factors.”

The team believes that RAAS hyperactivity, which promotes inflammation resulting in macrophage infiltration that induces CNV, may aggravate wet AMD progression, requiring greater need for those with hypertension to receive anti-VEGF treatments than those without hypertension.

The researchers concluded that hypertension was significantly correlated with wet AMD. After a regular series of three anti-VEGF injections, wet AMD patients with hypertension were more likely to receive anti-VEGF injections than those without hypertension. “These results may facilitate prospective research on the prevention of wet AMD and contribute to the management of wet AMD patients,” the researchers wrote.