Is aspirin use associated with age-related macular degeneration? A meta-analysis

Aspirin is one of the most widely used medications in the world. The evidence on its effect on the risk of age-related macular degeneration (AMD) appears inconsistent across different types of studies. The aim of this meta-analysis was to evaluate the association between aspirin use and the risk of AMD.

Relevant studies were searched using databases including PubMed, EMBASE, Cochrane Library and MEDLINE up to March 2014. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated by random-effects or fixed-effect models. The heterogeneity was assessed by the inconsistency index (I(2) ). The publication bias was evaluated by Begg's funnel plot and Egger's weighted regression. Sensitivity analysis was also performed in different ways.

Ten eligible studies including 180 834 individuals based on the inclusion criteria were analysed in this meta-analysis. The pooled RR for the aspirin use on the risk of AMD was 1·137 (95% CI, 1·003-1·289; I(2) , 68·4%). The pooled RR for the aspirin use on the risk of early and late AMD was 1·19 (95% CI, 0·92-1·53; I(2) , 82·6%) and 1·22 (95% CI, 0·87-1·72; I(2) , 55·7%), respectively. In different types of late AMD, the pooled RR was 1·95 (95% CI, 1·40-2·72; I(2) , 27%) for neovascularization and 0·84 (95% CI, 0·62-1·15; I(2) , 0%) for geographic atrophy. The pooled RR in studies with standardized AMD classification was 1·307 (95% CI, 1·006-1·698; I(2) , 79·2%).

This meta-analysis updates similar reviews that included studies with various types of biases. A rigorous analysis shows a weak but statistically significant association between aspirin use and the risk of AMD; a result which is different to that previously reported.