The burden of illness in thyroid eye disease: current state of the evidence

Introduction Thyroid eye disease (TED) is a disabling autoimmune condition characterized by proptosis and progressive orbital inflammation involving the extraocular muscles, orbital fat, and connective tissues. Clinical features include facial disfigurement, diplopia, dry eyes, and in severe cases, vision loss. Consequently, individuals with TED suffer significant physical and psychological burdens that impact their quality of life. Currently, there is no standardized definition or International Classification of Diseases code for TED, and the disease landscape remains incompletely understood; moreover, TED diagnostic criteria and treatment recommendations have not been thoroughly assessed across diverse populations. It is necessary to better understand the clinical, humanistic, and economic burden of TED and identify gaps in our knowledge to improve TED management and outcomes. Methods To describe the current understanding of TED epidemiology, diagnosis, disease burden, and recent TED treatment guidelines, a targeted literature review was conducted, searching multiple databases using key words of specific search topics (i.e., TED; epidemiology, humanistic, economic, and clinical burden; treatment; and practice guidelines) for articles published between October 2013 and October 2023 in the United States, United Kingdom, and Europe (France, Germany, Italy, and Spain). Articles published between May 2014 and May 2024 describing diverse racial and sociodemographic presentations of TED were included. Results TED is a complex disease with an array of risk factors, including thyroid dysfunction, thyroid-stimulating immunoglobin, smoking, and comorbid conditions. The natural history of TED is not clearly defined, and diagnosis is complicated due to the array of phenotypes and orbital symptoms observed. Although novel first-line treatments are available in select countries, there is an unmet need for improved treatments for moderate-to-severe and sight-threatening TED. Individuals with TED continue to experience poor health-related quality of life due to the clinical burden that TED imposes along with large healthcare resource utilization costs and treatment costs, and economic evaluation studies are limited. Importantly, there is still a need for studies that explore diverse populations and the impact of race and ethnicity on the disease landscape. Conclusion TED remains an incompletely characterized disease with major knowledge gaps, particularly among historically underserved populations.