Direct and indirect costs associated with declining distance visual acuity: A nationwide longitudinal cost‐of‐illness study with 11‐year follow‐up

PURPOSE: To examine the direct and indirect costs associated with declining distance visual acuity (VA). METHODS: A longitudinal approach was applied to a large, nationally representative sample with extensive data, including VA measured at two time points. The data of 3867 eligible participants aged 30 years or older at baseline were linked with national registers to estimate health care utilization from 1999 to 2013. A prevalence-based bottom-up approach was utilized to calculate the direct and indirect costs at the 2019 level. Data were adjusted for age, sex and incident comorbidities using generalized linear modelling (GLM). To estimate the cost-of-illness (COI), observed expenses among individuals whose VA declined during the follow-up were compared to the counterfactual situation where VA had not declined, based on the regression analyses. Both individual and population-level costs were reported. RESULTS: The annual total direct health care costs per person were €976 for those with non-declining VA and €1838 for those with declining VA (adjusted to match persons without decline in VA). The adjusted indirect costs were €14 579 and €22 631 for the working age subgroups, respectively. In counterfactual analysis, the annual COI associated with declining VA was estimated at €1166 from direct and €6411 from indirect cost sources. At the population level, the direct costs were €0.3 billion and the indirect costs, calculated for the working-age population, were €0.4 billion annually. CONCLUSION: In total, 7.6% of the national direct health care costs were attributed to declining VA, highlighting the savings potential if the prevalence of declining VA could be reduced.