Global prevalence of age-related macular degeneration and disease burden projection for 2020 and 2040: a systematic review and meta-analysis

Background Numerous population-based studies of age-related macular degeneration have been reported around the world, with the results of some studies suggesting racial or ethnic diff erences in disease prevalence. Integrating these resources to provide summarised data to establish worldwide prevalence and to project the number of people with age-related macular degeneration from 2020 to 2040 would be a useful guide for global strategies. Methods We did a systematic literature review to identify all population-based studies of age-related macular degeneration published before May, 2013. Only studies using retinal photographs and standardised grading classifi cations (the Wisconsin age-related maculopathy grading system, the international classifi cation for age-related macular degeneration, or the Rotterdam staging system) were included. Hierarchical Bayesian approaches were used to estimate the pooled prevalence, the 95% credible intervals (CrI), and to examine the diff erence in prevalence by ethnicity (European, African, Hispanic, Asian) and region (Africa, Asia, Europe, Latin America and the Caribbean, North America, and Oceania). UN World Population Prospects were used to project the number of people aff ected in 2014 and 2040. Bayes factor was calculated as a measure of statistical evidence, with a score above three indicating substantial evidence. Findings Analysis of 129 664 individuals (aged 30–97 years), with 12 727 cases from 39 studies, showed the pooled prevalence (mapped to an age range of 45–85 years) of early, late, and any age-related macular degeneration to be 8·01% (95% CrI 3·98–15·49), 0·37% (0·18–0·77), and 8·69% (4·26–17·40), respectively. We found a higher prevalence of early and any age-related macular degeneration in Europeans than in Asians (early: 11·2% vs 6·8%, Bayes factor 3·9; any: 12·3% vs 7·4%, Bayes factor 4·3), and early, late, and any age-related macular degeneration to be more prevalent in Europeans than in Africans (early: 11·2% vs 7·1%, Bayes factor 12·2; late: 0·5% vs 0·3%, 3·7; any: 12·3% vs 7·5%, 31·3). There was no diff erence in prevalence between Asians and Africans (all Bayes factors <1). Europeans had a higher prevalence of geographic atrophy subtype (1·11%, 95% CrI 0·53–2·08) than Africans (0·14%, 0·04–0·45), Asians (0·21%, 0·04–0·87), and Hispanics (0·16%, 0·05–0·46). Between geographical regions, cases of early and any age-related macular degeneration were less prevalent in Asia than in Europe and North America (early: 6·3% vs 14.3% and 12·8% [Bayes factor 2·3 and 7·6]; any: 6·9% vs 18·3% and 14·3% [3·0 and 3·8]). No signifi cant gender eff ect was noted in prevalence (Bayes factor