Global Burden of Dry Age-Related Macular Degeneration: A Targeted Literature Review

Age-related macular degeneration (AMD) is a leading cause of blindness, particularly in higher-income countries. Although dry AMD accounts for 85% to 90% of AMD cases, a comprehensive understanding of the global dry AMD burden is needed.

A targeted literature review was conducted in PubMed, MEDLINE, Embase, and the Cochrane Database of Systematic Reviews (1995-2019) to identify data on the epidemiology, management, and humanistic and economic burden of dry AMD in adults. A landscape analysis of patient-reported outcome (PRO) instruments in AMD was also conducted via searches in PubMed (1995-2019), ClinicalTrials.gov, PROQOLID, PROLABELS, and health technology assessment reports (2008-2018).

Thirty-seven of 4205 identified publications were included in the review. Dry AMD prevalence was 0.44% globally, varied across ethnic groups, and increased with age. Patients with dry AMD had higher risks of all-cause mortality (hazard ratio [HR] = 1.46; 95% CI, 0.99-2.16) and tobacco-related (HR = 2.86; 95% CI, 1.15-7.09) or cancer deaths (HR = 3.37; 95% CI, 1.56-7.29; P = 0.002) than those without dry AMD. Smoking, increasing age or cholesterol levels, and obesity are key risk factors for developing dry AMD. No treatment guidelines were identified for dry AMD specifically; management focuses on risk factor reduction and use of dietary supplements. In the United States and Italy, direct medical costs and health care resource utilization were lower in patients with dry versus wet AMD. Patients with dry AMD, particularly advanced disease, experienced significant visual function impairment. Dry AMD symptoms included reduced central vision, decreased ability to see at night, increased visual blurriness, distortion of straight lines and text, and faded color vision. Most PRO instruments used in AMD evaluations covered few, if any, of the identified symptoms reported by patients with dry AMD. Although the Quality of Life and Vision Function Questionnaire, 25-item National Eye Institute Vision Function Questionnaire, Low Vision Quality of Life, Impact of Vision Impairment-Very Low Vision, and Functional Reading Independence Index had strong content validity and psychometric properties in patients with dry AMD, they retained limited coverage of salient concepts.

Despite dry AMD accounting for most AMD cases, there are substantial gaps in the published literature, particularly the humanistic and economic burden of disease and the lack of differentiation among dry, wet, or unspecified dry AMD. The significant burden of illness alludes to a high unmet need for tolerable and effective treatment options, as well as PRO instruments with more coverage of dry AMD symptoms and salient concepts.