The socioeconomic epidemiology of inherited retinal diseases in Portugal

Inherited retinal diseases (IRDs) are a group of rare degenerative disorders of the retina that can lead to blindness from birth to late middle age. Knowing the target population and its resources is essential to better plan support measures. The aim of this study was to evaluate the socioeconomic characteristics of regions in Portugal where IRD patients reside to inform the planning of vision aid and rehabilitation intervention measures. This study included 1082 patients from 973 families, aged 3 to 92 years, with a mean age of 44.8 ± 18.1 years. Patients living with an IRD were identified in 190 of the 308 municipalities. According to this study, the estimated IRD prevalence in Portugal was 10.4 per 100,000 inhabitants, and by municipalities, it ranged from 0 to 131.2 per 100,000 inhabitants. Overall, regions with a higher prevalence of IRD have a lower population density (r=-0.371, p < 0.001), a higher illiteracy rate (r = 0.404, p < 0.001) and an overall older population (r = 0.475, p < 0.001). Additionally, there is a lower proportion of doctor per capita (r = 0.350, p < 0.001), higher social security pensions beneficiaries (r = 0.439, p < 0.001), worse water quality for human consumption (r=-0.194, p = 0.008), fewer audiences at the cinema (r=-0.315, p < 0.001) and lower proportion of foreign guests in tourist accommodations (r=-0.287, p < 0.001). The number of identified patients with IRD varied between regions. Using data from national statistics (PORDATA), we observed differences in socioeconomic characteristics between regions. Multiple targeted aid strategies can be developed to ensure that all IRD patients are granted full clinical and socioeconomic support.