Patients with age-related macular degeneration (AMD) shouldn’t avoid aspirin if it’s medically necessary, a spin-off investigation from the Age-Related Eye Disease Studies (AREDS and AREDS2) reports.

The investigation, published in Ophthalmology, found aspirin wasn’t significantly associated with AMD progression, geographic atrophy or the neovascular form of the disease in patients who were involved in both study arms.

The large investigation enrolled 3,734 AREDS participants, 28.1% of whom took aspirin and 71.9% did not. In the AREDS2 group, 49.9% were on an aspirin regimen, while 50.1% were in the control group. Researchers used color fundus photography to track disease progression and matched aspirin users 1:1 with non-users.

The 1,950 matched patients in the AREDS group were followed up at approximately 10 years. At that time, researchers found 23.3% had progressed to late AMD, 17.7% developed geographic atrophy and 14.3% progressed to neovascular AMD.

At the approximate five-year follow up for the 1,694 matched patients in the AREDS2 group, investigators reported 38% developed late AMD, 24.6% progressed to geographic atrophy and 20.1% developed neovascular AMD.

Researchers found no significant association with progression to late AMD for the three outcomes in both studies.

“Aspirin use was not significantly associated with progression to late AMD or its subtypes, in either the AREDS or the AREDS2,” the researchers wrote in their paper. “Patients with AMD need not avoid aspirin for this reason, when its use is medically indicated.”