Screening for Fabry disease among 619 hemodialysis patients in Saudi Arabia.

OBJECTIVES: To determine the prevalence of Fabry disease (FD) among Saudi patients on hemodialysis. METHODS: This prospective study was conducted in 3 major hospitals in the Kingdom of Saudi Arabia (KSA). All adult patients (greater than 18 years old) attending the dialysis unit who have end-stage renal disease (ESRD) and on hemodialysis were included. Known patients with FD and those who refused to participate in the study were excluded. All eligible patients were screened for FD using dry blood spot (DBS) for alpha-galactosidase A (α-Gal A). A positive DBS (enzyme activity less than 40%) was followed by another con rmatory enzyme assay. When the second DBS sample was also positive (enzyme activity less than 40%), a Sanger sequencing of the GLA gene was performed. RESULTS: A total of 619 patients with ESRD and on hemodialysis were screened for FD using DBS for α-Gal A enzyme level. Enzymatic activity was below 40% in 11 samples. On retesting, 3 females had less than 20% enzymatic activity suggesting FD. Sanger sequencing of these 3 females showed the variant c.1055C greater than G (p.Ala352Gly) confirming the diagnosis of FD. Family screening of one of these 3 patients revealed one asymptomatic female carrying the same variant. CONCLUSION: The prevalence of FD in this cohort was 4.8 per 1000 patients. Screening of Fabry patients with ESRD seems to be a cost-effective strategy. Furthermore, relatives of the patients identified by screening enhances this screening strategy.

Global research on Fabry's disease: Demands for a rare disease.

BACKGROUND: Fabry disease (FD), the second most prevalent lysosomal storage disorder, is classified as a rare disease. It often leads to significant quality of life impairments and premature death. Many cases remain undiagnosed due to the rarity and heterogeneity. Further, costs related to treatment often constitute a substantial financial burden for patients and health systems. While its epidemiology is still unclear, newborn screenings suggest that its actual prevalence rate is significantly higher than previously suspected. METHODS: Based on well-established methodologies, this study gives an overview about the background of the development of FD-related research and provides a critical view of future needs. RESULTS: On the grounds of benchmarking findings, an increasing research activity on FD can be observed. Most publishing countries are the USA, some European countries, Japan, Taiwan, and South Korea. In general, high-income countries publish comparably more on FD than low- or middle-income economies. The countries' financial and infrastructural background are unveiled as crucial factors for the FD research activity. CONCLUSIONS: Overall, there is a need to foster FD research infrastructure in developing and emerging countries with focus on cost-intensive genetic research that is independent from economic interests of big pharmaceutical companies.

Cost Efficacy of α-Galactosidase A Enzyme Screening for Fabry Disease.

The prevalence of Fabry disease (FD) in adult patients with suspected hypertrophic cardiomyopathy (HCM) has been reported between 0.3% and 4%. Fabry disease-specific therapy necessitates early diagnosis; however, the optimal screening strategy and cost efficacy of routine α-galactosidase A (α-gal A) vs comprehensive galactosidase alpha gene (GLA) testing remain poorly understood. We identified 1192 patients who underwent routine α-gal A screening between January 1, 2011, and December 31, 2017, for suspected HCM. Cost efficacy was explored using prevalence and cost estimates. Ten patients had reduced α-gal A enzyme activity, and 5 (3 women) were ultimately diagnosed with FD (prevalence estimate, 0.42%). An alternative cardiac diagnosis was made in 3 patients with mildly reduced enzyme activity. Two women with reduced borderline enzyme levels did not undergo confirmatory testing, but FD was not suspected. The number needed to screen to diagnose 1 patient with FD in a similar cohort is estimated at 238 (5 new cases per 1192 at-risk individuals) at a cost of approximately US $24,000 per diagnosis. We identified a 0.42% prevalence of FD using routine α-gal A screening in adult patients referred to a dedicated HCM center in the United States. Compared with more comprehensive genetic testing strategies, we identified a similar prevalence of FD at a lower cost per diagnosis.

PrEFiNe Plan: Strategic plan for Fabry diseases in Nephrology. / Plan PrEFiNE: Plan estratégico para la enfermedad de Fabry en Nefrología.

BACKGROUND: Renal failure is one of the main causes of death in patients with Fabry disease (FD). Due to the low prevalence of FD, delayed diagnosis and misdiagnosis, often the correct diagnosis is made when organ damage is already present. Early recognition of the disease would allow the prevention of severe complications and the premature death of patients with FD. OBJECTIVE: We present here the PrEFiNE project, which includes a wide spectrum of activities with the aim of improve knowledge and diagnosis of FD. The project is sponsored by Shire Iberia (http://shireiberica.com/) METHODS: From January 2016 to the end of 2017 several activities will be carried out, starting with a survey to evaluate current FD knowledge among nephrologists; in addition some studies to assess prevalence of this disease will be performed. One study will include patients receiving dialysis, another study will cover kidney transplant patients, and a pilot study in chronic kidney disease in stage 3-5 predialysis. Also planned is a pharmacoeconomic study to focus on burden of FD. At the same time medical education activities will be conducted both on line and on site. Plan for dissemination will include medical publications and diffusion to media. PrEFiNE Project will finish with the publication of a compilation book on FD in Nephrology including all planned activities and proposing recommendations based on results and detected unmet needs. PrEfiNE Plan will be coordinated by severa scientific committees, one at national level and 10 other regionals comittees, tha will be responsible to ensure the maximum scientific quality of proposed activities. An advisory board will supervise the project. DISCUSSION: PrEfiNE project will evaluate an action plan focused on improving FD knowledge to make necessary recommendations for an early recognition of the disease. In addition will generate a plan to improve previously undetected needs.

Descriptive epidemiology of Fabry disease among beneficiaries of the Specified Disease Treatment Research Program in Japan.

BACKGROUND: Fabry disease (FD) is a rare X-linked lysosomal storage disorder and is included in the Specified Disease Treatment Research Program in Japan, which subsidizes medical care for beneficiaries with rare and other, designated diseases. However, no report on the epidemiologic features of Fabry disease has been published in Japan. METHODS: We used clinical research data reports submitted to the program between 2003 and 2008 to assess the epidemiologic features of 315 beneficiaries with FD. RESULTS: Of the 315 program beneficiaries, 198 were men (mean age, 37.4 years) and 117 were women (mean age, 51.2 years). The overall incidence in Japan was 0.25 cases per 100,000 individuals, and prevalence among men was 1.78 times that among women. More than 80% of beneficiaries were capable of working, going to school, or doing housework; however, 46 beneficiaries (14.6%) required home care, and 9 (2.9%) were living in hospitals or other medical facilities. As compared with the previous year, the clinical course of FD at beneficiary registration was unchanged for 178 of 290 beneficiaries (61.4%), worse for 81 (27.9%), and improved or cured for 31 (10.7%). The distribution of beneficiary-related characteristics was similar between men and women, and no significant difference was observed. CONCLUSIONS: The high percentage (>80%) of individuals with FD who were able to work, attend school, and perform tasks such as housework could reflect an improvement in the clinical course of FD after enzyme replacement therapy. We must continue data collection and conduct further studies to improve our understanding of the descriptive epidemiology of FD.

A systematic review of the clinical effectiveness and cost-effectiveness of enzyme replacement therapies for Fabry's disease and mucopolysaccharidosis type 1.

OBJECTIVES: To determine the clinical effectiveness and cost-effectiveness of the administration of intravenous enzyme replacement therapy (ERT) to symptomatic patients for the prevention of long-term damage and symptoms in Fabry's disease and in mucopolysaccharidosis type 1 (MPS1). DATA SOURCES: Electronic databases from inception up to mid-2004. Contact with clinical experts. REVIEW METHODS: Relevant studies were identified and assessed using recommended quality criteria. RESULTS: The results suggested beneficial effects of ERT for Fabry's disease on measures of pain, cardiovascular function and some end-points reflecting neurosensory function. Renal function appeared to be stabilised by ERT. At present there are no utility-related health-related quality of life data on which to assess the relative health gain of ERT in MPS1. In order to be able to demonstrate the full extent of health gain from treatment, it was necessary to review the natural history of untreated patients in each disease in order to try to estimate the health loss prevented. The published information for Fabry's disease tallied with descriptions of a multi-system, life-threatening disorder particularly involving kidney, heart and brain with individual patients exhibiting many manifestations. The fragmentary information reviewed in 16 studies relevant to the natural history of MPS1 did not generate a coherent picture of disease progression and could provide little added value to published narrative reviews. For Fabry's disease, the mean cost per patient (50 kg) treated is around pounds sterling 85,000 per annum in England and Wales. The cost per patient varies considerably by dose. No published evidence reporting an economic evaluation of ERT for Fabry's disease was identified by this review. A dynamic decision model was constructed based on a birth cohort of male patients who are followed up until death. Owing to lack of information reported in the literature, many assumptions had to be applied. The key assumptions were that ERT returns patients to full health and a normal life expectancy. As far as possible, all assumptions favoured rather than detracted from the value of ERT. ERT was assumed to restore patients to full health in the base case. The estimated incremental cost-effectiveness ratio (ICER) in the base case was pounds sterling 252,000 per QALY (agalsidase beta). Univariate sensitivity analysis around the key assumptions produced ICERs ranging from pounds sterling 602,000 to pounds sterling 241,000. The base case unit cost of ERT was taken as pounds sterling 65.1/mg based on the cost of agalsidase beta. The unit cost would have had to be reduced to pounds sterling 9 to obtain an ICER of pounds sterling 30,000 per QALY. For MPS1, the mean cost per child patient (20 kg) treated is approximately pounds sterling 95,000 and an adult (70 kg) around pounds sterling 335,000 per annum in England and Wales. The cost per patient varies considerably by dose. There is no published evidence reporting an economic evaluation of ERT for MPS1 and no study was identified that reported the quality of life of MPS1 patients within a utility format. Furthermore, no or minimal information of the severity and rate of change of clinical manifestations of disease or the impact of ERT on these factors was identified. Information on the effect of ERT on mortality is also lacking owing to the relatively short time that the treatment has been available. Given this lack of data, it was not possible to develop a cost-effectiveness model of ERT treatment for MPS1 as the model would consist almost completely of assumptions based on no published evidence, leading to an incremental cost per QALY result that would be meaningless. CONCLUSIONS: Although ERT for treating the 'average' patient with Fabry's disease exceeds the normal upper threshold for cost-effectiveness seen in NHS policy decisions by over sixfold, and the value for MPS1 is likely to be of a similar order of magnitude, clinicians and the manufacturers argue that, as the disease is classified as an orphan disease under European Union legislation, it has special status, and the NHS has no option but to provide ERT. More information is required before the generalisability of the findings can be determined. Although data from the UK have been used wherever possible, this was very thin indeed. Nonetheless, even large errors in assumptions made will not reduce the ICER to anywhere near the upper level of treatments usually considered cost-effective. In order to overcome limited evidence on the natural history of the disease and the clinical effectiveness of the intervention, the establishment of disease-specific data registries is suggested to facilitate the process of technology assessment and improving patient care. These registries should attempt to include all affected patients in the UK, and collect longitudinal patient level data on clinically relevant problems, interventions received and quality of life in a utility format.

[Fabry disease--a diagnostic and therapeutic challenge]. / Fabrys sykdom--en diagnostisk og terapeutisk utfordring.

BACKGROUND: Fabry disease, unlike most other metabolic diseases, is prone to familiar and regional clustering because of X-linked inheritance and normal fertility in affected men. Affected individuals can be offered intravenous enzyme replacement therapy. MATERIALS AND METHODS: In two counties in western Norway there are 41 affected individuals, giving a minimum prevalence of the disease of 1 in 17,000. The patient material is briefly presented. We discuss some of the administrative and financial challenges that this type of diseases present in our public health system. RESULTS AND INTERPRETATION: The great variability in disease expression and severity within and between families delays the diagnosis and necessitates a broad clinical follow up of affected persons. A false diagnosis is often made (e.g. MS, irritable colon, a psychiatric disorder, idiopathic hypertrophic cardiomyopathy, or kidney failure). The follow up regime is briefly described, with special emphasis on the practical and financial implications of enzyme replacement therapy in Norway.