Longitudinal analysis of health care costs in patients with childhood onset inherited retinal dystrophies compared to healthy controls

Background
We evaluated health care costs in patients with childhood onset visual impairment caused by inherited retinal dystrophies (IRD).

Methods
The IRD cohort, identified from the Danish Registry of Blind and Partially Sighted Children, was compared to age- and sex-matched controls from the national, Danish population registry. Information on health care expenditures for somatic and psychiatric in- and outpatient services, purchase of prescription medications and paid assistance at home were obtained from national registries for the years 2002–2017.

Results
We included 412 in the IRD cohort (6,290 person years) and 1656 (25,088 person years) in the control cohort. Average, annual health care expenditures from age 0–48 years of age were €1,488 (SD 4,711) in the IRD cohort and €1,030 (4,639) in the control cohort. The largest difference was for out-patient eye care (13.26 times greater, 95% confidence interval 12.90–13.64). Psychiatric in-patient expenditures were 1.71 times greater (95% CI 1.66–1.76) in the IRD cohort but psychiatric out-patient health care costs were comparable between groups.

Conclusions
Health care costs were approximately 40% greater in the IRD cohort compared to an age- and sex-matched sample from the general Danish population. This is relevant in the current situation with a number of trials aimed at treating IRDs using genetically based therapies. Although eye care expenditures were many times greater, they made up 
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Background
Childhood blindness is thought to affect 14 million children world-wide and whereas preventable causes dominate in developing nations, e.g. retinopathy of prematurity and cataract, inherited retinal dystrophies are a common cause of blindness and visual impairment in developed nations. [1] With the advent of expensive genetically based therapies such as voretigene neparvovec [2] there has been an increased focus on the health and economic benefits associated with treating inherited retinal diseases. However, no large scale direct evaluations are available. Previous reports have been based on indirect assumptions of expenditures [3, 4] or direct evaluation of a few affected patients, e.g. via questionnaires, which have been extrapolated to larger cohorts. [5, 6].

A substantial proportion of those affected by childhood onset retinal dystrophies have extra-ocular disease, e.g. Usher disease, Bardet-Biedl, or neuronal ceramide lipofuscinosis. [7, 8] Even those with non-syndromic childhood onset retinal dystrophy may require extra medical attention to evaluate or monitor general growth and development. Missing an important sensory function, such as vision, may influence early development, e.g. autistic features have been described among congenitally blind children [9] and mental and behavioral disorders are common in children with Usher syndrome. [10] Physical disease may also be more prevalent among those with visual impairment, e.g. visual impairment in adults is known be associated with an increased risk of falls [11] which may increase health care costs related to the management of injuries. Severe disease with onset in childhood may have repercussions extending well into adult life, e.g. survivors of childhood cancer report reduced quality of life especially for physical well-being compared to their siblings. [12].

The aim of the study was to assess health care costs in a cohort of patients with childhood onset retinal dystrophies without severe systemic comorbidities and to compare to an age- and sex-matched cohort drawn from the background population. We used comprehensive, national Danish registries to obtain a complete picture of somatic and psychiatric health care costs in both primary and secondary health care settings.