Knowledge Lacking About Global Prevalence, Life Quality, Cost of FA
Physical impairment found to be main source of poor quality of life for patients
A substantial knowledge gap still exists about the prevalence of Friedreich’s ataxia (FA) around the world, as well as its impact on the quality of life of patients and caregivers, and care costs, a review study has found.
Nevertheless, the limited available data point to physical impairment as the main source of poor quality of life among patients and highlight the pronounced economic burden of non-medical and indirect costs.
Future studies on FA-associated quality of life and costs are needed to enable reliable and accurate assessment of the benefits of potential disease-modifying therapies, the researchers noted.
The study, “A systematic review of disease prevalence, health-related quality of life, and economic outcomes associated with Friedreich’s Ataxia,” was published in the journal Current Medical Research and Opinion.
What is known about the prevalence of FA globally?
FA is a rare, inherited, progressive neuromuscular disease estimated to affect 1 in 20,000–50,000 people. Research suggests it occurs in those of European, North African, Middle Eastern, or Indian origin, while being very rare, or absent, in sub-Saharan Africa, China, Japan, and Southeast Asia populations.
The disease, with symptom onset during childhood or adolescence, affects a person’s coordination, muscle strength, walking abilities, vision, hearing, speech, and swallowing skills.
As such, patients can use walking aids, wheelchairs, and supporting feeding methods, as well as physical therapy, occupational therapy, and surgery to manage some symptoms.
No approved treatments for FA are available to date, but several candidates are under development, with one — Reata Pharmaceuticals’ omaveloxolone — currently under review for approval in the U.S., with a decision expected no later than Nov. 30.
A comprehensive understanding of the disease’s features, impact on quality of life, and economic burden is essential not only for assessing benefits of treatment candidates in trials, but also for cost-effectiveness analyses that are part of the therapy approval process.
With this in mind, a team of researchers systematically reviewed published studies up to February describing either the frequency, health-related quality of life (HRQoL), or economic outcomes associated with FA.
From a total of 536 hits, 78 were assessed for eligibility, and 36 were included in the analysis: 22 studies on disease frequency, 12 on HRQoL, and two on care costs.
The publication year of studies on FA frequency ranged from 1968 to 2019, with most of these studies being conducted in European countries (eight in Italy alone). Only one study was conducted in the U.S., more specifically in Guam.
FA prevalence based on clinical diagnosis only varied by region/country, with the lowest being reported in Guam (no cases per 100,000 people) and the highest in Spain (3.83–4.71 per 100,000 people). Estimates based on clinical diagnosis alone were generally higher than those based on a combination of clinical and molecular methods.
“However, this is likely due to study region versus diagnostic method; a greater number of studies that relied on clinical diagnoses were conducted in regions where the prevalence of FA is known to be higher,” the researchers wrote.
What effect does FA have on quality of life?
HRQoL measures varied across the 12 studies, with the most commonly used being the 36-Item Short Form Health Survey (58.3%). The U.S. had the greatest representation across studies (33.3% of studies), and the number of patients included ranged from five to 651, and their mean age from 13.2 years to 40.98 years.
Results showed that FA patients generally have poorer quality of life and that the “physical components of HRQoL measures were the most consistently impacted,” the researchers wrote.
FA’s impact on non-physical domains and overall quality of life was less explored, and therefore, less clear. Still, available data suggested a role for social and emotional difficulties, mental health problems, lack of energy, and pain.
“The studies included in this review are limited in terms of the scope of their assessment of HRQoL, given that the impact of important disease outcomes, such as loss of mobility or the need for long-term care, are not directly assessed,” the team wrote.
Also, “it has been reported that current generic measures of HRQoL may be inadequate in terms of capturing the impact of FA,” further highlighting “the need for new disease-specific measures to better capture the impact of FA,” the researchers wrote.
In addition, none of the studies assessed caregivers’ quality of life, which is expected to be affected by this disabling disease.
The two eligible cost studies comprised four countries: the U.S. and Canada, and the U.K. and Germany. Both were published in 2013 and data on healthcare resource utilization and costs were obtained through self-report from patients, caregivers, and/or physicians, as an FA-specific international diagnostic code was only created in late 2020.
This “has precluded the use of administrative claims data to assess direct medical expenditures associated with the disease,” the researchers wrote.
Results showed a high frequency of cardiology and neurology visits among FA patients across all four regions.
The direct medical burden “was large” for FA but most costs consisted of non-medical direct costs — such as provision of care (either at home or in care facilities) — and indirect costs, including “productivity losses to both patients and their caregivers,” the team wrote.
These findings highlight that “there is still a lack of current studies among many regions where FA is present,” and that “patient and caregiver HRQoL are not completely understood, particularly with respect to important disease outcomes,” the researchers wrote.
Moreover, the “full extent of the economic burden has not been comprehensively assessed,” meaning that the disease’s true economic burden may be underestimated.
“Future efforts should address the gaps identified in this review, which will be required to assess the full impact of emerging therapies,” the researchers concluded.
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