Using data from AREDS and AREDS2, investigators examined the relationship between aspirin use and AMD progression.

Study design

Researchers assessed progression to late AMD, geographic atrophy or neovascular AMD in more than 5,000 AREDS and AREDS participants. Overall, approximately 28% of AREDS and 50% of AREDS2 participants reported taking aspirin. Aspirin users were matched 1:1 with nonusers by propensity score (separate for AREDS and AREDS2). Proportional hazards regression was performed, adjusting for age, on the matched participants to evaluate associations between aspirin propensity score and progression to late AMD (and its subtypes). The main outcome measure was the progression to late AMD on color fundus photographs, graded centrally.

Outcomes

There was no indication from propensity score matching or proportional hazard analysis to suggest aspirin use elevates risk of progression to late AMD. These results were consistent across both cohorts and for atrophic and neovascular forms of late disease.

Limitations

This study was limited by its retrospective design and its assumption that aspirin use remained unchanged during follow-up. In addition, clinical trial participants may not be fully representative of the wider population. There was no data available on the number of participants taking aspirin less frequently (<5 times weekly); there is a possibility that the control groups contained some participants who were taking aspirin weekly or monthly

Clinical significance

This study adds more evidence indicating aspirin intake is unrelated with progression to late AMD or its subtypes. Patients with AMD need not avoid aspirin for this reason when its use is medically indicated.