Alternative cascade-testing protocols for identifying and managing patients with familial hypercholesterolaemia: systematic reviews, qualitative study and cost-effectiveness analysis.

Background: Cascade testing the relatives of people with familial hypercholesterolaemia is an efficient approach to identifying familial hypercholesterolaemia. The cascade-testing protocol starts with identifying an index patient with familial hypercholesterolaemia, followed by one of three approaches to contact other relatives: indirect approach, whereby index patients contact their relatives; direct approach, whereby the specialist contacts the relatives; or a combination of both direct and indirect approaches. However, it is unclear which protocol may be most effective. Objectives: The objectives were to determine the yield of cases from different cascade-testing protocols, treatment patterns, and short- and long-term outcomes for people with familial hypercholesterolaemia; to evaluate the cost-effectiveness of alternative protocols for familial hypercholesterolaemia cascade testing; and to qualitatively assess the acceptability of different cascade-testing protocols to individuals and families with familial hypercholesterolaemia, and to health-care providers. Design and methods: This study comprised systematic reviews and analysis of three data sets: PASS (PASS Software, Rijswijk, the Netherlands) hospital familial hypercholesterolaemia databases, the Clinical Practice Research Datalink (CPRD)-Hospital Episode Statistics (HES) linked primary-secondary care data set, and a specialist familial hypercholesterolaemia register. Cost-effectiveness modelling, incorporating preceding analyses, was undertaken. Acceptability was examined in interviews with patients, relatives and health-care professionals. Result: Systematic review of protocols: based on data from 4 of the 24 studies, the combined approach led to a slightly higher yield of relatives tested [40%, 95% confidence interval (CI) 37% to 42%] than the direct (33%, 95% CI 28% to 39%) or indirect approaches alone (34%, 95% CI 30% to 37%). The PASS databases identified that those contacted directly were more likely to complete cascade testing (p < 0.01); the CPRD-HES data set indicated that 70% did not achieve target treatment levels, and demonstrated increased cardiovascular disease risk among these individuals, compared with controls (hazard ratio 9.14, 95% CI 8.55 to 9.76). The specialist familial hypercholesterolaemia register confirmed excessive cardiovascular morbidity (standardised morbidity ratio 7.17, 95% CI 6.79 to 7.56). Cost-effectiveness modelling found a net health gain from diagnosis of -0.27 to 2.51 quality-adjusted life-years at the willingness-to-pay threshold of £15,000 per quality-adjusted life-year gained. The cost-effective protocols cascaded from genetically confirmed index cases by contacting first- and second-degree relatives simultaneously and directly. Interviews found a service-led direct-contact approach was more reliable, but combining direct and indirect approaches, guided by index patients and family relationships, may be more acceptable. Limitations: Systematic reviews were not used in the economic analysis, as relevant studies were lacking or of poor quality. As only a proportion of those with primary care-coded familial hypercholesterolaemia are likely to actually have familial hypercholesterolaemia, CPRD analyses are likely to underestimate the true effect. The cost-effectiveness analysis required assumptions related to the long-term cardiovascular disease risk, the effect of treatment on cholesterol and the generalisability of estimates from the data sets. Interview recruitment was limited to white English-speaking participants. Conclusions: Based on limited evidence, most cost-effective cascade-testing protocols, diagnosing most relatives, select index cases by genetic testing, with services directly contacting relatives, and contacting second-degree relatives even if first-degree relatives have not been tested. Combined approaches to contact relatives may be more suitable for some families. Future work: Establish a long-term familial hypercholesterolaemia cohort, measuring cholesterol levels, treatment and cardiovascular outcomes. Conduct a randomised study comparing different approaches to contact relatives. Study registration: This study is registered as PROSPERO CRD42018117445 and CRD42019125775. Funding: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 27, No. 16. See the NIHR Journals Library website for further project information.

Familial hypercholesterolaemia is an inherited condition that causes raised cholesterol levels from birth and increases risk of heart disease if left untreated. After someone in a family is found to have familial hypercholesterolaemia (called an index case), their close relatives need to be contacted and checked to see if they have familial hypercholesterolaemia, using genetic or cholesterol testing. This is called 'cascade testing'. We planned to find the most cost-effective and acceptable way to do this. The relatives could be contacted for testing by the index case (indirect approach), by a health-care professional (direct approach) or by a combination of both approaches. We found, based on looking at hospital records, that more relatives were tested if health-care professionals directly contacted relatives. In previous studies, slightly more relatives were tested for familial hypercholesterolaemia with a combination approach. Interviews with patients also suggested that the direct approach was the most effective, but the most acceptable and successful approach depends on family relationships: using one approach for some families and using both for other families. Furthermore, by looking at the health-care records of large numbers of patients, we confirmed that people with a recorded diagnosis of familial hypercholesterolaemia in general practice records have a much higher risk of heart disease than the general population, and this was especially so for those with previous heart disease and/or raised cholesterols levels when diagnosed. However, one-quarter of new patients with familial hypercholesterolaemia recorded in their records were not treated within 2 years, with less than one-third reaching recommended cholesterol levels. We used what we had learned to help us estimate the most cost-effective way to do cascade testing. This showed that if the health service directly contact all relatives simultaneously for further assessment, rather than the current approach whereby close (first-degree) relatives are contacted first, this was cost-effective and good value for money.

Estimation of the prevalence of cholesteryl ester storage disorder in a cohort of patients with clinical features of familial hypercholesterolaemia.

BACKGROUND AND AIM: Familial hypercholesterolaemia is caused by variants in the low-density lipoprotein cholesterol metabolic pathway involving LDLR, APOB and PCSK9 genes. A national genetic testing service in Wales, UK has observed that no familial hypercholesterolaemia variant is found in almost 80% patients with the familial hypercholesterolaemia phenotype. It has recently been suggested that some adult patients with a familial hypercholesterolaemia phenotype may have cholesteryl ester storage disease which can also present as a mixed hyperlipidaemia. The commonest genetic cause of cholesteryl ester storage disease is an exon 8 splice junction variant in the LIPA gene (rs116928232, c.894G>A; E8SJM) previously found to have an allele frequency of 0.0011 (1 in 450 individuals) in a large European population. This study investigated the prevalence of the E8SJM in patients with a familial hypercholesterolaemia phenotype in Wales, UK. METHOD: A total of 1203 patients with a clinical suspicion of familial hypercholesterolaemia but no familial hypercholesterolaemia variant were invited to participate. Of these, 668 patients provided informed written consent. Stored DNA samples from 663 patients were genotyped for the E8SJM variant. RESULTS: Three heterozygotes were identified (allele frequency 0.0023). Whole gene sequencing of the LIPA gene was undertaken in these three individuals, but no other variants were found. Therefore, there were no cholesteryl ester storage disease patients (homozygote or compound heterozygote) identified in this cohort. CONCLUSION: The allele frequency 0.0023 (1 in 221 individuals) for the E8SJM variant was more prevalent in this cohort than in a European population study; however, no cholesteryl ester storage disease homozygotes were identified. We found no evidence to support routine testing for cholesteryl ester storage disease in adult patients with a familial hypercholesterolaemia phenotype.

Cost effectiveness of cascade testing for familial hypercholesterolaemia, based on data from familial hypercholesterolaemia services in the UK.

AIMS: Familial hypercholesterolaemia (FH) is a vastly under-diagnosed genetic disorder, associated with early development of coronary heart disease and premature mortality which can be substantially reduced by effective treatment. Patents have recently expired on high-intensity statins, reducing FH treatment costs. We build a model using UK data to estimate the cost effectiveness of DNA testing of relatives of those with monogenic FH. METHODS AND RESULTS: A Markov model was used to estimate the cost effectiveness of cascade testing, using data from UK cascade services. The estimated incremental cost effectiveness ratio (ICER) was £5806 and the net marginal lifetime cost per relative tested was £2781. More than 80% of lifetime costs were diagnosis-related and incurred in the 1st year. In UK services, 23% of 6396 index cases were mutation-positive. For each mutation-positive index case, 1.33 relatives were tested, resulting overall in a rate of 0.31 tested relatives per tested index case. If the number of relatives tested per tested index case rose to 3.2 (projected by National Institute for Health and Care Excellence in 2008) the ICER would reduce to £2280 and lifetime costs to £1092. CONCLUSION: Cascade testing of relatives of those with suspected FH is highly cost effective. The current Europe-wide high levels of undiagnosed FH, and associated morbidity and mortality, mean adoption of cascade services should yield substantial quality of life and survival gains.

Diagnostic scoring for familial hypercholesterolaemia in practice.

PURPOSE OF REVIEW: Diagnostic scoring for familial hypercholesterolaemia (FH) can be used either to screen for possible FH or guide the selection of patients for genetic (DNA) testing. We review the published diagnostic criteria and discuss the options for future development. RECENT FINDINGS: Scoring systems have been developed internationally based on lipid values and various combinations of clinical signs and cardiovascular history. The predictive value varies according to the test population, be it lipid clinic referrals, general population, or relatives of patients with FH. Also, there is increasing recognition of genetic heterogeneity in FH so that criteria are of differing predictive value depending on the genetic variant of FH. SUMMARY: These clinical scoring systems are increasingly used to guide selection of patients for FH genetic testing but no single approach has yet emerged as the system of choice. Further refinement of these scoring tools using more sophisticated calculators are superseding the more manual approaches. These are well suited to web-based tools or smartphone applications.

Validation of a new method for non-invasive assessment of vasomotor function.

BACKGROUND: Reactive hyperaemia induces a slowing of pulse wave velocity (PWV) in conduit arteries of healthy subjects (flow-mediated slowing (FMS)). This could be an alternative method for assessing peripheral vasomotor function to the gold standard method of flow-mediated dilatation (FMD) a more expensive and technically demanding technique. We aimed to assess the reproducibility of FMS in healthy participants and to test its ability to detect differences in vasomotor function in patients with familial hypercholesterolaemia (FH) and post-lipoprotein apheresis (LA) treatment. METHODS: Altogether 25 healthy participants were studied on two occasions to assess reproducibility of FMS. In a case control study of 22 patients with FH and matched healthy controls, FMD and FMS were compared. An intervention study in 12 patients with FH looked at the impact of a single LA treatment on FMS assessed pre and post treatment. RESULTS: FMS demonstrated good reproducibility (coefficient of variation (CoV) 7.3%). Patients with FH had reduced FMS in comparison to matched healthy controls (FMS% FH -15.13 ± 5.04% vs controls -18.41 ± 5.15%, p = 0.023), with no difference in FMD% between the two groups. A single LA treatment significantly improved FMS (pre -18.81 ± 9.84 vs post -24.09 ± 7.61%, p = 0.016). CONCLUSIONS: FMS is a reproducible technique, which is able to detect differences in vasomotor function both in a condition associated with endothelial dysfunction and following an acute intervention known to improve endothelial function. This simple technique has potential for accessible assessment of vasomotor function in clinical studies.