Does aspirin increase the risk of age-related macular degeneration?

Effect of Low-Dose Aspirin on the Course of Age-Related Macular Degeneration: A Secondary Analysis of the ASPREE Randomized Clinical Trial

Importance

Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in old age. There is no proven intervention to prevent AMD and, apart from lifestyle, nutritional, and supplement advice, there is no intervention to delay its progression.

Objective

To determine the impact of long-term low-dose aspirin on the incidence and progression of AMD.

Design, Setting and Participants

The Aspirin in Reducing Events in the Elderly-AMD (ASPREE-AMD) study was an Australian-based substudy of the ASPREE trial, a multicenter, international, randomized, double-masked, placebo-clinical trial investigating the efficacy of low-dose aspirin in prolonging disability-free survival among older individuals. Retinal photography was conducted at baseline from March 2010 to January 2015, then 3 and 5 years after randomization. AMD status was determined using color retinal images and treatment records. Australian participants in ASPREE aged 70 years and older without dementia, independence-limiting physical disability, cardiovascular disease, or chronic illness limiting 5-year survival and with gradable retinal images at baseline were included. Data were analyzed from December 2022 to December 2023.

Interventions

Aspirin (100 mg daily, enteric coated) or placebo.

Main Outcomes and Measures

Incidence of AMD and progression from early/intermediate to late AMD. Outcomes were analyzed by modified intention-to-treat analysis.

Results

A total of 4993 participants were enrolled in this substudy. Baseline characteristics were similar between groups. At the time of sponsor-determined trial termination, retinal follow-up data were available for 3208 participants, 3171 of whom were analyzed for AMD incidence and progression, with a median (IQR) age of 73.5 (71.5-76.4) years and even sex distribution (1619 [51%] female). Median (IQR) follow-up time was 3.1 (3.0-3.5) years. Cumulative AMD incidence was 195 of 1004 (19.4%) in the aspirin group and 187 of 979 (19.1%) in the placebo group (relative risk [RR], 1.02; 95% CI, 0.85-1.22; P = .86). Cumulative progression from early/intermediate AMD to late AMD was observed in 14 of 615 (2.3%) participants in the aspirin group and 18 of 573 (3.1%) in the placebo group (RR, 0.72; 95% CI, 0.36-1.44; P = .36).

Conclusions and Relevance

In this trial, low-dose aspirin administered for 3 years did not affect the incidence of AMD. The evidence was weaker for progression of AMD due to low number of progressed cases. Overall, these results do not support suggestion that low-dose daily aspirin prevents the development or progression of AMD.

Trial Registration

anzctr.org Identifier: ACTRN12613000755730.

Age-Related Macular Degeneration: Epidemiology and Clinical Aspects

Age-related macular degeneration (AMD) is a degenerative disease of the human retina affecting individuals over the age of 55 years. This heterogeneous condition arises from a complex interplay between age, genetics, and environmental factors including smoking and diet. It is the leading cause of blindness in industrialized countries. Worldwide, the number of people with AMD is predicted to increase from 196 million in 2020 to 288 million by 2040. By this time, Asia is predicted to have the largest number of people with the disease. Distinct patterns of AMD prevalence and phenotype are seen between geographical areas that are not explained fully by disparities in population structures. AMD is classified into early, intermediate, and late stages. The early and intermediate stages, when visual symptoms are typically absent or mild, are characterized by macular deposits (drusen) and pigmentary abnormalities. Through risk prediction calculators, grading these features helps predict the risk of progression to late AMD. Late AMD is divided into neovascular and atrophic forms, though these can coexist. The defining lesions are macular neovascularization and geographic atrophy, respectively. At this stage, visual symptoms are often severe and irreversible, and can comprise profoundly decreased central vision in both eyes. For these reasons, the condition has major implications for individuals and society, as affected individuals may experience substantially decreased quality of life and independence. Recent advances in retinal imaging have led to the recognition of an expanded set of AMD phenotypes, including reticular pseudodrusen, nonexudative macular neovascularization, and subtypes of atrophy. These developments may lead to refinements in current classification systems.

Baseline characteristics and age-related macular degeneration in participants of the "ASPirin in Reducing Events in the Elderly" (ASPREE)-AMD trial

PURPOSE

To describe the baseline participant characteristics in the ASPREE-AMD study, investigating the effect of aspirin on AMD incidence and progression.

METHODS

Australian participants from the ASPirin in Reducing Events in the Elderly (ASPREE) trial, randomized to 100 mg aspirin daily or placebo, had non-mydriatic, digital color fundus images graded according to the Beckman AMD classification. Associations with AMD were determined for baseline characteristics and genetic risk variants.

RESULTS

ASPREE-AMD sub-study enrolled 4993 participants with gradable macular images. Median age was 73.4 years (IQR, 71.5, 76.6), 52% were female, 10% had diabetes mellitus, 73% had hypertension, and 44% were former/current smokers. Early, intermediate and late AMD (detected in 20.6%, 16.1%, 1.1%, respectively), significantly associated with age, were also associated with increasing HDL levels: OR = 1.52 (95%CI, 1.26, 1.84), OR = 1.43 (1.17, 1.77) and OR = 1.96 (1.02, 3.76), respectively. Female sex was associated with early [OR = 1.37 (1.16, 1.62)], and intermediate [OR = 1.35 (1.12, 1.63)] AMD, as was previous regular use of aspirin, with OR = 1.46 (1.11, 1.92) and OR = 1.37 (1.01, 1.85), respectively. Current smoking had increased odds for late AMD, OR = 4.02 (1.42, 11.36). Genetic risk variant rs3750846 (ARMS2/HTRA1) was associated with each AMD stage (p < 0.001), risk variants rs570618 and rs10922109 (CFH) with intermediate and late AMD (p < 0.001), and rare variant rs147859257 (C3) with late AMD (p < 0.001). The randomized groups were well balanced for all analyzed AMD risk factors.

CONCLUSIONS

Observed associations are typical of AMD. The ASPREE-AMD clinical trial provides a unique opportunity to determine the risks and benefits of low-dose aspirin for AMD incidence and progression in elderly population.

TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry: ACTRN 12613000755730.

The Association of Aspirin Use with Age-Related Macular Degeneration Progression in the Age-Related Eye Disease Studies: Age-Related Eye Disease Study 2 Report No. 20

PURPOSE

To analyze the potential association between aspirin use and progression of age-related macular degeneration (AMD).

DESIGN

Two prospective cohort studies within 2 controlled clinical trials of oral supplementation for age-related eye disease.

PARTICIPANTS

Age-Related Eye Disease Study (AREDS) participants 55 to 80 years of age and AREDS2 participants 50 to 85 years of age.

METHODS

Propensity scores for aspirin use were calculated for AREDS and AREDS2 participants separately by logistic regression. Of the participants without late AMD (geographic atrophy [GA] or neovascular AMD) in either eye at study baseline, aspirin users were matched 1:1 with nonusers by propensity score (separately 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).

MAIN OUTCOME MEASURES

Progression to late AMD on color fundus photographs, graded centrally.

RESULTS

Of the 3734 eligible AREDS participants, 1049 (28.1%) were taking aspirin, and of the 2403 eligible AREDS2 participants, 1198 (49.9%) were taking aspirin. After matching by propensity score, the characteristics of the users and nonusers were similar in both studies. Of the 1950 matched AREDS participants and 1694 matched AREDS2 participants, over a median follow-up of 10.1 years and 5.0 years, respectively, the numbers who progressed to late AMD, GA, or neovascular AMD were 454 (23.3%), 345 (17.7%), and 278 (14.3%), respectively, in AREDS and 643 (38.0%), 402 (24.6%), and 341 (20.1%) in AREDS2. The hazard ratios of progression in quintile 5 (highest propensity for aspirin use) versus 1 (reference) were 1.17 (P = 0.35), 1.24 (0.25), and 0.95 (0.81), respectively, in AREDS and 1.26 (0.09), 1.46 (0.03), and 1.12 (0.58) in AREDS2. No significant association with progression to late AMD was observed for quintiles 2 through 5 for any of the 3 outcomes in either study.

CONCLUSIONS

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

Age-related macular degeneration in a randomized controlled trial of low-dose aspirin: Rationale and study design of the ASPREE-AMD study

Purpose

Although aspirin therapy is used widely in older adults for prevention of cardiovascular disease, its impact on the incidence, progression and severity of age-related macular degeneration (AMD) is uncertain. The effect of low-dose aspirin on the course of AMD will be evaluated in this clinical trial.

Design

A sub-study of the ‘ASPirin in Reducing Events in the Elderly’ (ASPREE) trial, ASPREE-AMD is a 5-year follow-up double-blind, placebo-controlled, randomized trial of the effect of 100 mg daily aspirin on the course of AMD in 5000 subjects aged 70 years or older, with normal cognitive function and without cardiovascular disease at baseline. Non-mydriatic fundus photography will be performed at baseline, 3-year and 5-year follow-up to determine AMD status.

Primary outcome measures

The incidence and progression of AMD. Exploratory analyses will determine whether aspirin affects the risk of retinal hemorrhage in late AMD, and whether other factors, such as genotype, systemic disease, inflammatory biomarkers, influence the effect of aspirin on AMD.

Conclusion

The study findings will be of significant clinical and public interest due to a potential to identify a possible low cost therapy for preventing AMD worldwide and to determine risk/benefit balance of the aspirin usage by the AMD-affected elderly. The ASPREE-AMD study provides a unique opportunity to determine the effect of aspirin on AMD incidence and progression, by adding retinal imaging to an ongoing, large-scale primary prevention randomized clinical trial.