The national and subnational prevalence and burden of age–related macular degeneration in China

BACKGROUND: Age–related macular degeneration (AMD) is the third most common cause of blindness, and the fourth leading cause of visual impairment worldwide, but little is known about the burden of this disease in the most populous country–China. This study provides the first comprehensive estimates of the prevalence and burden of AMD in China from 1990 to 2015, with projections till 2050. METHODS: In this study, a systematic review and meta–analysis was conducted to estimate the prevalence of AMD in China. China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Biomedicine Literature Database (CBM–SinoMed), PubMed, Embase and Medline were searched before September 2016. Multilevel mixed–effect meta–regression was performed to define the prevalence rates of AMD and its subtypes. UN population data were used to estimate and project the number of people affected from 1990 to 2050. Based on different demographic and geographic features, the national burden of AMD in 2000 and 2010 was distributed to different regions in China. RESULTS: Our search returned 2016 citations, of which 25 met the inclusion criteria. The prevalence of any AMD ranged from 2.44% (95% CI = 1.85–3.22) in people aged 45–49 years to 18.98% (95% CI = 15.05–23.66) in people aged 85–89 years. Prevalence of early AMD ranged from 1.79% (95% CI = 1.05–3.02) to 10.05% (95% CI = 6.17–15.97), and, in the case of late AMD, from 0.38% (95% CI = 0.16–0.97) to 3.88% (95% CI = 1.68–9.13). In late AMD, the prevalence of geographic atrophy (GA) was 0.15% (95% CI = 0.05–0.47) in people aged 45–49 years and 1.09% (95% CI = 0.35–3.36) in those aged 85–89 years, and the prevalence of neovascular AMD (NVAMD) ranged between 0.24% (95% CI = 0.11–0.50) and 2.79% (95% CI = 1.33–5.77). The number of people with any AMD was 12.01 million (95% CI = 9.29–15.46) in 1990 and 26.65 million (95% CI = 20.62–34.27) in 2015. Within the same period, the number of people with early AMD increased from 9.44 million (95% CI = 7.74–11.15) to 20.91 million (95% CI = 17.16–24.68), and those with late AMD rose from 2.58 million (95% CI = 1.56–4.30) to 5.74 million (95% CI = 3.46–9.59). In late AMD, the number of people living with GA ranged from 0.87 million (95% CI = 0.40–1.83) in 1990 to 1.93 million (95% CI = 0.89–4.08) in 2015, and NVAMD from 1.71 million (95% CI = 1.16–2.47) to 3.81 million (95% CI = 2.57–5.51). The projected number of people with any AMD in 2020 is 31.23 million (95% CI = 24.18–40.14), increasing to 55.19 million (95% CI = 43.04–70.30) in 2050. Between different regions, the South Central owed the most AMD cases (5.50 million in 2000 and 7.52 million in 2010), whereas the North–West China the least (0.66 million in 2000 and 0.95 million in 2010). CONCLUSIONS: The estimates in this study suggest a substantial burden of AMD in China, with the ageing process in Chinese society, this burden will be increasing in the foreseen future. Primary and secondary prevention and treatment and effective government response are urgently needed. Improved epidemiological studies are also required to better develop eye–care strategies and health services.