What is the clinical utility of DNA testing in patients with familial hypercholesterolaemia?

PURPOSE OF REVIEW: Familial hypercholesterolaemia is a common genetic disorder of lipid metabolism in which patients have a significantly elevated risk of early coronary heart disease, which can be substantially lowered by treatment with the statin class of drugs. In many countries in Europe, tracing of relatives using DNA information, once the family mutation has been identified, is being actively carried out. The present review examines the specificity and clinical utility of DNA testing in patients with familial hypercholesterolaemia. RECENT FINDINGS: Technological progress has improved the detection rate in patients with the strongest clinical suspicion of familial hypercholesterolaemia to more than 70-80%. Patients carrying a mutation have, on average, higher low-density lipoprotein cholesterol levels and greater risk of early coronary heart disease, and studies have reported the utility of DNA information in the identification of affected relatives. More than 1000 different molecular causes of familial hypercholesterolaemia are documented in the University College London database, and although more than 90% of these clearly cause familial hypercholesterolaemia, the remainder require careful interpretation. SUMMARY: DNA testing, as an adjunct to the measurement of plasma low-density lipoprotein cholesterol levels, has clinical utility in providing an unequivocal diagnosis in patients and in identifying affected relatives at an early age so that they can be offered lifestyle advice and appropriate lipid-lowering therapies. Researchers and DNA diagnostic laboratories need to interpret novel sequence changes with caution in order to avoid a false positive diagnosis.     

Current management of severe homozygous hypercholesterolaemias

PURPOSE OF REVIEW: This review focuses on recent advances in the management of patients with homozygous familial hypercholesterolaemia, autosomal recessive hypercholesterolaemia and familial defective apolipoprotein B. RECENT FINDINGS: Autosomal recessive hypercholesterolaemia has been described as a 'phenocopy' of homozygous familial hypercholesterolaemia. Although the clinical phenotypes are similar, autosomal recessive hypercholesterolaemia seems to be less severe, more variable within a single family, and more responsive to lipid-lowering drug therapy. The cardiovascular complications of premature atherosclerosis are delayed in some individuals and involvement of the aortic root and valve is less common than in homozygous familial hypercholesterolaemia. Apheresis is still the treatment of choice in homozygous familial hypercholesterolaemia and in autosomal recessive hypercholesterolaemia patients in whom maximal drug therapy does not achieve adequate control. In addition to the profound cholesterol-lowering effects of apheresis, other potentially beneficial phenomena have been documented: improved vascular endothelial function and haemorheology, reduction in lipoprotein (a) and procoagulatory status, and a decrease in adhesion molecules and C-reactive protein. SUMMARY: Patients with severe homozygous hypercholesterolaemia illustrate the natural history of atherosclerosis within a condensed timeframe. Effective cholesterol-lowering treatment started in early childhood is essential to prevent onset of life-threatening atherosclerotic involvement of the aortic root and valve, and the coronary arteries. Noninvasive methods for regular monitoring of the major sites involved in the atherosclerotic process are necessary in patients with no symptoms or signs of ischaemia. Management of patients with severe homozygous hypercholesterolaemia continues to be a major challenge.     

Why it's time for a national health program in the United States.

The United States lacks a coherent national health program. Current programs leave major gaps in coverage and recently have become more restrictive. Influential policies that have failed to correct crucial problems of the health-care system include competitive strategies, corporate intervention, and public-sector cutbacks with bureaucratic expansion. A national health program that combines elements of national health insurance and a national health service is a policy that would help solve current health-care problems. Previous proposals for national health insurance contained weaknesses that would need correction under a national program. Based on the experiences of other economically advanced countries, a national health program could provide universal entitlement to health care while controlling costs and improving the health-care system through structural reorganization. Current proposals for a national health program contain several basic principles dealing with the scope of services, copayments, financing, cost controls, physician and professional associations, personnel and distribution, prevention, and participation in policy making. Support for a national health program is growing rapidly. Such a program would help protect all people who live in this country from unnecessary illness, suffering, and early death.     

Outcome of case finding among relatives of patients with known heterozygous familial hypercholesterolaemia

ObjectivesTo assess the feasibility of detecting new cases of heterozygous familial hypercholesterolaemia by using a nurse led genetic register.DesignCase finding among relatives of patients with familial hypercholesterolaemia.SettingTwo lipid clinics in central and south Manchester.Subjects259 (137 men and 122 women) probands and 285 first degree relatives.ResultsOf the 200 first degree relatives tested, 121 (60%) had inherited familial hypercholesterolaemia. The newly diagnosed patients were younger than the probands and were generally detected before they had clinically overt atherosclerosis. Concentrations of serum cholesterol were, respectively, 8.4 (1.7 SD) mmol/l and 8.1 (1.9 SD) mmol/l in affected men and women and 5.6 (1.0 SD) mmol/l and 5.6 (1.1 SD) mmol/l in unaffected men and women. Screening for risk factors as recommended in recent guidelines for coronary heart disease prevention would have failed to identify most of the affected relatives in whom hypertension, diabetes mellitus, cigarette smoking, and obesity were uncommon.ConclusionsBy performing cholesterol tests on 200 relatives, 121 new patients with familial hypercholesterolaemia were discovered. Because 1 in 500 people in the UK are affected by this condition, to detect a similar number by population screening over 60 000 tests would be required, and only a few of these patients would have been detected had cholesterol testing been restricted to those with other risk factors for coronary heart disease. A case exists for organising a genetic register approach, linking lipid clinics nationally.     

Phenotypic variability in familial hypercholesterolaemia: an update

Heterozygous familial hypercholesterolaemia is among the most common inherited dominant disorders, and is characterized by severely elevated LDL-cholesterol levels and premature cardiovascular disease. Although the cause of familial hypercholesterolaemia is monogenic, there is a substantial variation in the onset and severity of atherosclerotic disease symptoms. Additional atherogenic risk factors of environmental, metabolic and genetic origin, in conjunction with the LDL receptor defect, are presumed to influence the clinical phenotype in familial hypercholesterolaemia. The present review discusses recent developments in this field.     

ApoB100/LDLR-/- hypercholesterolaemic mice as a model for mild cognitive impairment and neuronal damage

Recent clinical findings support the notion that the progressive deterioration of cholesterol homeostasis is a central player in Alzheimer's disease (AD). Epidemiological studies suggest that high midlife plasma total cholesterol levels are associated with an increased risk of AD. This paper reports the plasma cholesterol concentrations, cognitive performance, locomotor activity and neuropathological signs in a murine model (transgenic mice expressing apoB100 but knockout for the LDL receptor [LDLR]) of human familial hypercholesterolaemia (FH). From birth, these animals have markedly elevated LDL-cholesterol and apolipoprotein B100 (apoB100) levels. These transgenic mice were confirmed to have higher plasma cholesterol concentrations than wild-type mice, an effect potentiated by aging. Further, 3-month-old transgenic mice showed cholesterol (total and fractions) concentrations considerably higher than those of 18-month-old wild-type mice. The hypercholesterolaemia of the transgenic mice was associated with a clear locomotor deficit (as determined by rotarod, grip strength and open field testing) and impairment of the episodic-like memory (determined by the integrated memory test). This decline in locomotor activity and cognitive status was associated with neuritic dystrophy and/or the disorganization of the neuronal microtubule network, plus an increase in astrogliosis and lipid peroxidation in the brain regions associated with AD, such as the motor and lateral entorhinal cortex, the amygdaloid basal nucleus, and the hippocampus. Aortic atherosclerotic lesions were positively correlated with age, although potentiated by the transgenic genotype, while cerebral β-amyloidosis was positively correlated with genetic background rather than with age. These findings confirm hypercholesterolaemia as a key biomarker for monitoring mild cognitive impairment, and shows these transgenic mice can be used as a model for cognitive and psycho-motor decline.     

Contrasting patterns of coronary atherosclerosis in normocholesterolaemic smokers and patients with familial hypercholesterolaemia.

An angiographic comparison was made of the extent and severity of coronary artery disease in 25 patients with heterozygous familial hypercholesterolaemia and 25 normocholesterolaemic patients with coronary artery disease in whom heavy cigarette consumption was the chief risk factor. The patients with familial hypercholesterolaemia were younger and included a much higher proportion of women than the smokers. Significantly more patients with familial hypercholesterolaemia had disease of the main stem of the left coronary artery (eight v none, p less than 0.05) and triple-vessel disease (18 v four, p less than 0.05). Disease affecting only distal vessels occurred in five smokers, whereas all the patients with familial hypercholesterolaemia showed a combination of proximal and distal lesions. These findings suggest that cigarette smoking and familial hypercholesterolaemia predispose to different patterns of coronary atheroma. Early coronary angiography with a view to coronary artery bypass surgery seems desirable in symptomatic patients with familial hypercholesterolaemia because of the common association of this disorder with life-threatening left main-stem disease.     

Lay testing cadres and point-of-care diagnostic tests for HIV and other diseases: An essential combination in health service delivery

Zibusiso Ndlovu and Tom Ellman discuss the potential value of task sharing in provision of testing for HIV and other infectious diseases.

Summary points

• Lack of access to testing plays a major role in the underdiagnosis of infectious and noncommunicable diseases, leading to higher morbidity and mortality.
• Point-of-care (POC) tests can offer rapid results, allowing for timely initiation of therapy. However, mere availability of POC tests in health facilities does not ensure utilization. Conducting POC tests has been shown to be a burden on highly trained frontline healthcare workers (HCWs; clinicians and nurses), who often have a broader scope of responsibilities and are critically scarce in many settings.
• The continual emergence of easy-to-use POC tests has not been accompanied by investment in a cadre of health workers to support their delivery, especially at decentralized health facilities where patients initially seek healthcare support.
• Historically, implementation of task shifting for POC tests has proven difficult due to lack of integration into national human resource structures and fiscal plans and lack of explicit national policies promoting task shifting, together with resistance from laboratory professionals.
• We propose that the scope of work for existing lay health worker (LHW) cadres could be broadened/remodeled to include POC tests for HIV services including for advanced HIV disease and other priority diseases, especially in primary healthcare or lower level facilities without laboratories. Policy makers and national program managers could ensure that this is part of broader national health workforce policies.
• Concerns of professional and/or regulatory bodies must be addressed, and these bodies (medical and laboratory councils) can guide national policy on which POC tests can be task shifted to less laboratory-trained cadres, and they could also lead in the development of a framework of education and supervision to ensure sustainability and maintenance of professional standards.
• Lay testing initiatives can scale up access to the multitude of available essential POC tests, for maximal impact of disease testing, closer to where people live. This can improve global health and accelerate progress toward universal health coverage.

     

Implementation of a Cloud-Based Electronic Medical Record to Reduce Gaps in the HIV Treatment Continuum in Rural Kenya

Background

Electronic medical record (EMR) systems are increasingly being adopted to support the delivery of health care in developing countries and their implementation can help to strengthen pathways of care and close gaps in the HIV treatment cascade by improving access to and use of data to inform clinical and public health decision-making.

Methods

This study implemented a novel cloud-based electronic medical record system in an HIV outpatient setting in Western Kenya and evaluated its impact on reducing gaps in the HIV treatment continuum including missing data and patient eligibility for ART. The impact of the system was assessed using a two-sample test of proportions pre- and post-implementation of EMR-based data verification and clinical decision support.

Results

Significant improvements in data quality and provision of clinical care were recorded through implementation of the EMR system, helping to ensure patients who are eligible for HIV treatment receive it early. A total of 2,169 and 764 patient records had missing data pre-implementation and post-implementation of EMR-based data verification and clinical decision support respectively. A total of 1,346 patients were eligible for ART, but not yet started on ART, pre-implementation compared to 270 patients pre-implementation.

Conclusion

EMR-based data verification and clinical decision support can reduce gaps in HIV care, including missing data and eligibility for ART. A cloud-based model of EMR implementation removes the need for local clinic infrastructure and has the potential to enhance data sharing at different levels of health care to inform clinical and public health decision-making. A number of issues, including data management and patient confidentiality, must be considered but significant improvements in data quality and provision of clinical care are recorded through implementation of this EMR model.     

Cost effectiveness analysis of different approaches of screening for familial hypercholesterolaemia

ObjectivesTo assess the cost effectiveness of strategies to screen for and treat familial hypercholesterolaemia.DesignCost effectiveness analysis. A care pathway for each patient was delineated and the associated probabilities, benefits, and costs were calculated.ParticipantsSimulated population aged 16-54 years in England and Wales.InterventionsIdentification and treatment of patients with familial hypercholesterolaemia by universal screening, opportunistic screening in primary care, screening of people admitted to hospital with premature myocardial infarction, or tracing family members of affected patients.ResultsTracing of family members was the most cost effective strategy (£3097 (€5066, $4479) per life year gained) as 2.6 individuals need to be screened to identify one case at a cost of £133 per case detected. If the genetic mutation was known within the family then the cost per life year gained (£4914) was only slightly increased by genetic confirmation of the diagnosis. Universal population screening was least cost effective (£13 029 per life year gained) as 1365 individuals need to be screened at a cost of £9754 per case detected. For each strategy it was more cost effective to screen younger people and women. Targeted strategies were more expensive per person screened, but the cost per case detected was lower. Population screening of 16 year olds only was as cost effective as family tracing (£2777 with a clinical confirmation).ConclusionsScreening family members of people with familial hypercholesterolaemia is the most cost effective option for detecting cases across the whole population.

What is already known on this topic

In the United Kingdom there are an estimated 110 000 men and women with familial hypercholesterolaemia, only a small percentage of whom have been identified to dateWithout identification and treatment, over half of these people will have a fatal or non-fatal coronary heart disease event by the age of 50 (men) or 60 (women)Effective treatment of high cholesterol concentrations reduces total and coronary heart disease mortalityNo recommended screening strategy currently exists in the United Kingdom for familial hypercholesterolaemia

What this study adds

Computer modelling has shown that the earlier familial hypercholesterolaemia is diagnosed the more cost effective the screening strategy becomesIdentifying relatives of people with familial hypercholesterolaemia is the most cost effective screening option for all age groupsAs technology improves and the cost of statins falls all strategies will become more cost effective     

Priorities for conserving global species richness and endemism

The Convention on Biological Diversity aims to encourage and enable countries to conserve biological diversity, to use its components sustainably and to share benefits equitably. Species richness and endemism are two key attributes of biodiversity that reflect the complexity and uniqueness of natural ecosystems. National data on vertebrates and higher plants indicate global concentrations of biodiversity and can assist in defining priorities for action. Projections indicate that species and ecosystems will be at maximum risk from human activities during the next few decades. Prompt action by the world community can minimise the eventual loss of species. Highest priorities should be to: (i) strengthen the management of ecosystems containing a large proportion of global biodiversity; (ii) help developing countries complete their biodiversity strategies and action plans, monitor their own biodiversity, and establish and maintain adequate national systems of conservation areas; (iii) support actions at the global level, providing benefit to all countries in managing their own biodiversity. Generally, resources will best be spent in safeguarding ecosystems and habitats that are viable and important for global biodiversity, and which are threatened by factors that can be controlled cost-effectively. Other important criteria are representativeness, complementarity and insurance.     

Implementing voluntary medical male circumcision for HIV prevention in Nyanza Province, Kenya: lessons learned during the first year

Background

In 2007, the World Health Organization endorsed male circumcision as an effective HIV prevention strategy. In 2008, the Government of Kenya (GoK) launched the national voluntary medical male circumcision (VMMC) program in Nyanza Province, the geographic home to the Luo, the largest non-circumcising ethnic group in Kenya. Currently, several other African countries are in the early stages of implementing this intervention.

Methods and Results

This paper uses data from a health facility needs assessment (n = 81 facilities) and a study to evaluate the implementation of VMMC services in 16 GoK facilities (n = 2,675 VMMC clients) to describe Kenya''s experience in implementing the national program. The needs assessment revealed that no health facility was prepared to offer the minimum package of services as outlined by the national guidelines, and partner organizations were called upon to fill this gap. The findings concerning human resource shortages facilitated the GoK''s decision to endorse trained nurses to provide VMMCs, enabling more facilities to offer the service. Findings from the evaluation study resulted in replacing voluntary counseling and testing (VCT) with provider-initiated testing and counseling (PITC) and subsequently doubling the proportion of VMMC clients tested for HIV.

Conclusions

This paper outlines how certain challenges, like human resource shortages and low HIV test rates, were addressed through national policy changes, while other challenges, like large fluctuations in demand, were addressed locally. Currently, the program requires significant support from partner organizations, but a strategic plan is under development to continue to build capacity in GoK staff and facilities. Coordination between all parties was essential and was facilitated through the formation of national, provincial, and district VMMC task forces. The lessons learned from Kenya''s VMMC implementation experience are likely generalizable to other African countries.     

Implementation of national schistosomiasis control programmes in West Africa

Burkina Faso, Mali and Niger are countries endemic for schistosomiasis, with a high predominance of Schistosoma haematobium. With the support of the Bill and Melinda Gates Foundation through the Schistosomiasis Control Initiative, national control programmes were launched in these countries in 2004. Here, we describe the progress of implementation for each programme and the challenges for maintaining sustainability for schistosomiasis control in these countries.     

野生动物肇事公众责任保险发展困境与优化路径

野生动物肇事公众责任保险自开展以来, 存在着保险实施效果较差、承保机构参与不积极、保险范围难以扩大等问题, 在有效缓解人兽矛盾方面表现欠佳, 阻碍了生物多样性保护的落实与执行。本文以现阶段实施该保险的云南、西藏、浙江、四川为例梳理其应用模式, 并对具体地区的保险模式进行比较分析。研究表明, 野生动物肇事公众责任保险陷入发展困境的主要原因是产品设计不科学、财政经费不充足、政策制度不健全和保险体系不完善。建议优化保险要素设计、扩展经费来源渠道、健全配套政策法规, 建立政府主导、多方参与的中央财政补贴野生动物肇事公众责任保险体系, 该保险体系对于解决人兽冲突、支持生物多样性的保护、建立地球生命共同体具有重要的价值与意义。     

Bringing 3D tumor models to the clinic – predictive value for personalized medicine

Current decision‐guiding algorithms in cancer drug treatment are based on decades of research and numerous clinical trials. For the majority of patients, this data is successfully applied for a systemic disease management. For a number of patients however, treatment stratification according to clinically based risk criteria will not be sufficient. The most effective treatment options are ideally identified prior to the start of clinical drug therapy. This review will discuss the implementation of three‐dimensional (3D) cell culture models as a preclinical testing paradigm for the efficacy of clinical cancer treatment. Patient tumor‐derived cells in 3D cultures duplicate the individual tumor microenvironment with a minimum of confounding factors. Clinical implementation of such personalized tumor models requires a high quality of methodological and clinical validation comparable to other biomarkers. A non‐systematic literature search demonstrated the small number of prospective studies that have been conducted in this area of research. This may explain the current reluctance of many physicians and insurance providers in implementing this type of assay into the clinical diagnostic routine despite potential benefit for patients. Achieving valid and reproducible results with a high level of evidence is central in improving the acceptance of preclinical 3D tumor models.     

Differential dropout among SNP genotypes and impacts on association tests

BACKGROUND: Current biotechnologies are able to achieve high accuracy and call rates. Concerns are raised on how differential performance on various genotypes may bias association tests. Quantitatively, we define differential dropout rate as the ratio of no-call rate among heterozygotes and homozygotes. METHODS: The hazard ofdifferential dropout is examined for population- and family-based association tests through a simulation study. Also, we investigate detection approaches such as Hardy-Weinberg Equilibrium (HWE) and testing for correlation between sample call rate and sample heterozygosity. Finally, we analyze two public datasets and evaluate the magnitudes of differential dropout. RESULTS: In case-control settings, differential dropout has negligible effect on power and odds ratio (OR) estimation. However, the impact on family-based tests range from minor to severe depending on the disease parameters. Such impact is more prominent when disease allele frequency is relatively low (e.g., 5%), where a differential dropout rate of 2.5 can dramatically bias OR estimation and reduce power even at a decent 98% overall call rate and moderate effect size (e.g., OR(true) = 2.11). Both of the two public datasets follow HWE; however, HapMap data carries detectable differential dropout that may endanger family-based studies. CONCLUSIONS: Case-control approach appears to be robust to differential dropout; however, family-based association tests can be heavily biased. Both of the public genotype data show high call rate, but differential dropout is detected in HapMap data. We suggest researchers carefully control this potential confounder even using data of high accuracy and high overall call rate.     

Solution structure of the LDL receptor EGF-AB pair: a paradigm for the assembly of tandem calcium binding EGF domains.

BACKGROUND: From the observed structure and sequence of a pair of calcium binding (cb) epidermal growth factor-like (EGF) domains from human fibrillin-1, we proposed that many tandem cbEGF domains adopt a conserved relative conformation. The low-density lipoprotein receptor (LDLR), which is functionally unrelated to fibrillin-1, contains a single pair of EGF domains that was chosen for study in the validation of this hypothesis. The LDLR is the protein that is defective in familial hypercholesterolaemia, a common genetic disorder that predisposes individuals to cardiovascular complications and premature death. RESULTS: Here, we present the solution structure of the first two EGF domains from the LDL receptor, determined using conventional NMR restraints and residual dipolar couplings. The cbEGF domains have an elongated, rod-like arrangement, as predicted. The new structure allows a detailed assessment of the consequences of mutations associated with familial hypercholesterolaemia to be made. CONCLUSIONS: The validation of the conserved arrangement of EGF domains in functionally distinct proteins has important implications for structural genomics, since multiple tandem cbEGF pairs have been identified in many essential proteins that are implicated in human disease. Our results provide the means to use homology modeling to probe structure-function relationships in this diverse family of proteins and may hold the potential for the design of novel diagnostics and therapies in the future.     

Health care costs and financing in world perspective.

Expenditures for health services, as a percentage of national wealth (gross national product, or GNP), have been rising throughout the world. Data to quantify this trend are available for many industrialized countries. The share of health spending derived from governmental sources has also been increasing. Mandatory or social insurance has developed to support health services in 70 nations. While widely used for paying doctors on a fee basis or by capitation, in Latin America doctors are organized in polyclinics and paid by salaries. General revenues are used to support Ministry of Health programs. Among health expenditures, the largest share goes to hospitalization. Cost sharing by patients is widely used to control rising costs. World trends have promoted equity in health care delivery.     

The genetics of coronary heart disease: the contribution of twin studies.

Despite the decline in coronary heart disease in many European countries, the disease remains an enormous public health problem. Although we know a great deal about environmental risk factors for coronary heart disease, a heritable component was recognized a long time ago. The earliest and best known examples of how our genetic constitution may determine cardiovascular risk relate to lipoprotein(a), familial hypercholesterolaemia and apolipoprotein E. In the past 20 years a fair number of polymorphisms assessed singly have shown strong associations with the disease but most are subject to poor repeatability. Twins constitute a compelling natural experiment to establish the genetic contribution to coronary heart disease and its risk factors. GenomEUtwin, a recently funded Framework 5 Programme of the European Community, affords the opportunity of comparing the heritability of risk factors in different European Twin Registries. As an illustration we present the heritabilities of systolic and diastolic blood pressure, based on data from over 4000 twin pairs from six different European countries and Australia. Heritabilities for systolic blood pressure are between 52 and 66% and for diastolic blood pressure between 44 and 66%. There is no evidence of sex differences in heritability estimates and very little to no evidence for a significant contribution of shared family environment. A non-twin based prospective case/cohort study of coronary heart disease and stroke (MORGAM) will allow hypotheses relating to cardiovascular disease, generated in the twin cohorts, to be tested prospectively in adult populations. Twin studies have also contributed to our understanding of the life course hypothesis, and GenomEUtwin has the potential to add to this.     

Cancer incidence estimation at a district level without a national registry: A validation study for 24 cancer sites using French health insurance and registry data

Background: District-level cancer incidence estimation is an important issue in countries without a national cancer registry. This study aims to both evaluate the validity of district-level estimations in France for 24 cancer sites, using health insurance data (ALD demands – Affection de Longue Durée) and to provide estimations when considered valid. Incidence is estimated at a district-level by applying the ratio between the number of first ALD demands and incident cases (ALD/I ratio), observed in those districts with cancer registries, to the number of first ALD demands available in all districts. These district-level estimations are valid if the ratio does not vary greatly across the districts or if variations remain moderate compared with variations in incidence rates. Methods: Validation was performed in the districts covered by cancer registries over the period 2000–2005. The district variability of the ALD/I ratio was studied, adjusted for age (mixed-effects Poisson model), and compared with the district variability in incidence rate. The epidemiological context is also considered in addition to statistical analyses. Results: District-level estimation using the ALD/I ratio was considered valid for eight cancer sites out of the 24 studied (lip–oral cavity–pharynx, oesophagus, stomach, colon–rectum, lung, breast, ovary and testis) and incidence maps were provided for these cancer sites. Conclusion: Estimating cancer incidence at a sub-national level remains a difficult task without a national registry and there are few studies on this topic. Our validation approach may be applied in other countries, using health insurance or hospital discharge data as correlate of incidence.