Dutch Lipid Clinic Network Score Research Articles

Prevalence and management of familial hypercholesterolemia in patients with coronary artery disease: The heredity survey.

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high levels of low density lipoprotein cholesterol (LDL-C) predisposing to premature cardiovascular disease. Its prevalence varies and has been estimated around 1 in 200-500. The Heredity survey evaluated the prevalence of potential FH and the therapeutic approaches among patients with established coronary artery disease (CAD) or peripheral artery disease (PAD) in which it is less well documented. Data were collected in patients admitted to programs of rehabilitation and secondary prevention in Italy. Potential FH was estimated using Dutch Lipid Clinic Network (DLCN) criteria. Potential FH was defined as having a total score≥6. Among the 1438 consecutive patients evaluated, the prevalence of potential FH was 3.7%. The prevalence was inversely related to age, with a putative prevalence of 1:10 in those with <55yrs of age (male) and <60yrs (female). Definite FH (DLCN score>8) had the highest percentages of patients after an ACS (75% vs 52.5% in the whole study population). At discharge, most patients were on high intensity statin therapy, but despite this, potential FH group still had a higher percentage of patients with LDL-C levels not at target and having a distance from the target higher than 50%. Among patients with established coronary heart disease, the prevalence of potential FH is higher than in the general population; the results suggest that a correct identification of potential FH, especially in younger patients, may help to better manage their high cardiovascular risk.

Familial hypercholesterolemia: The Italian Atherosclerosis Society Network (LIPIGEN)

Background and aimsPrimary dyslipidemias are a heterogeneous group of disorders characterized by abnormal levels of circulating lipoproteins. Among them, familial hypercholesterolemia is the most common lipid disorder that predisposes for premature cardiovascular disease. We set up an Italian nationwide network aimed at facilitating the clinical and genetic diagnosis of genetic dyslipidemias named LIPIGEN (LIpid TransPort Disorders Italian GEnetic Network). MethodsObservational, multicenter, retrospective and prospective study involving about 40 Italian clinical centers. Genetic testing of the appropriate candidate genes at one of six molecular diagnostic laboratories serving as nationwide DNA diagnostic centers. Results and conclusionsFrom 2012 to October 2016, available biochemical and clinical information of 3480 subjects with familial hypercholesterolemia identified according to the Dutch Lipid Clinic Network (DLCN) score were included in the database and genetic analysis was performed in 97.8% of subjects, with a mutation detection rate of 92.0% in patients with DLCN score ≥6. The establishment of the LIPIGEN network will have important effects on clinical management and it will improve the overall identification and treatment of primary dyslipidemias in Italy.

Detection of familial hypercholesterolemia in patients from a general practice database

ObjectivesFamilial hypercholesterolemia (FH) is the most common monogenic lipid disorder associated with premature coronary heart disease. Early cholesterol-lowering therapy could effectively reduce cardiovascular disease morbidity and mortality in these patients. However, the majority of people with FH are undiagnosed, also due to low awareness and knowledge of FH in general practice, despite the high number of contacts GPs have with most of their patients which allows a systematic and effective approach to the detection of this condition. Here, we present a simple method to improve detection and to enhance awareness of FH in primary care using GP electronic health records. MethodsWe used electronic data from the Co.S. Consortium, involving more than 600 Italian affiliated GPs. Electronic data include demographic information, laboratory test results, recorded history of vascular disease and prescription of an HMG-CoA reductase inhibitor class medication. We performed a partial assessment of the Dutch Lipid Clinic Network (DLCN) score using those data that were recorded or available. We also sought to determine the prevalence of possible FH based on age-specific LDL-cholesterol thresholds employed by the diagnostic criteria of MEDPED and the non-age adjusted cut-off point (LDL-C ≥190 mg/dL). ResultsData on LDL-C were available for 162,864 subjects. Mean LDL-C levels (SD) were 124.3 (33.6) mg/dL for non-treated subjects and 106.4 (38.5) mg/dL for statin-treated subjects. The cut-off of LDL-C ≥190 mg/dL yielded a prevalence of 2.9% among non-treated subjects and of 3.5% among statin-treated patients. Using the cut-off of ≥250 mg/dL, the prevalence was 0.1% among non-treated subjects and 0.3% among statin-treated patients. Using the cut-off ≥330 mg/dL (suggesting a probable diagnosis of FH according to the DLCN score) the prevalence was 0.01% and 0.02%. According to the stratification proposed by MEDPED criteria for the general population, the age-specific LDL-cholesterol thresholds identified 0.7% among non-treated subjects and 18.5% among statin-treated patients. ConclusionThe diagnosis of FH is possible in general medicine and should be an integral part of the GP's activity.

Detecting familial hypercholesterolemia by serum lipid profile screening in a hospital setting: Clinical, genetic and atherosclerotic burden profile

Background and aimsFamilial hypercholesterolemia (FH) is underdiagnosed and public cholesterol screening may be useful to find new subjects. In this study, we aim to investigate the prevalence of FH patients in a hospital screening program and evaluate their atherosclerotic burden using intima-media thickness (IMT). Methods and resultsWe screened 1575 lipid profiles and included for genetic analysis adults with a low-density lipoprotein (LDL) cholesterol >190 mg/dL and triglycerides <200 mg/dL and first-degree child relatives with LDL cholesterol >160 mg/dL and triglycerides <200 mg/dL. The diagnosis of FH was presumed by Dutch Lipid Clinic Network (DLCN) criteria and confirmed by the presence of the genetic variant. Mean common carotid intima-media thickness (IMT) was assessed using consensus criteria. After confirming LDL cholesterol value and excluding secondary hypercholesterolemia, 56 subjects with a DLCN ≥4 performed genetic analysis. Of these, 26 had an FH genetic variant. The proportion of patients with a mutation having a DLCN score of 6–8 was 75%; in individuals with a DLCN score >8 it was 100%. Mean IMT was higher in FH patients compared to non FH (0.73 [0.61–0.83] vs 0.71 [0.60–0.75] mm, p < 0.01). Moreover, we detected two mutations not previously described. Finally, simple regression analysis showed a correlation of IMT with LDL cholesterol >190 mg/dL and corneal arcus (p < 0.01 and p < 0.001, respectively). ConclusionsA hospital screening was useful to detect FH subjects with increased atherosclerosis. Also, next-generation sequencing was able to detect new FH mutations.

Evaluation of clinical and laboratory parameters used in the identification of index cases for genetic screening of familial hypercholesterolemia in Brazil

Background and aimsThere is controversy on the accuracy of different diagnostic criteria for familial hypercholesterolemia (FH). The aim of this study is to assess the performance of different clinical criteria used to identify individuals for FH genetic cascade screening in Brazil. MethodsAll index cases (IC) registered in the Hipercol Brasil program between 2011 and 2016 were analyzed. Inclusion criteria were age ≥18 years and elevated LDL-cholesterol (LDL-C) levels, with a conclusive result in the genetic test, whether positive or negative. Initially, we tested the multivariable association between clinical and laboratory markers and the presence of an FH causing mutation. Then, we analyzed sensitivity, specificity, positive and negative predictive values for the LDL-C quartile distribution, LDL-C as a continuous variable, as well as the performance measures for the Dutch Lipid Clinic Network (DLCN) score to identify a mutation. ResultsOverall, 753 ICs were included and an FH causing mutation was found in 34% (n = 257) of the subjects. After multivariable analysis, LDL-C as a continuous variable, tendon xanthomas and corneal arcus were independently associated with the presence of FH mutations. LDL-C values ≥ 230 mg/dL (5.9 mmol/L) had the best tradeoff between sensitivity and specificity to diagnose a mutation. The DLCN score presented a better performance than LDL-C to identify a mutation, area under the ROC curve were 0.744 (95% CI: 0.704–0.784) and 0.730 (95% CI: 0.687–0.774), respectively, p=0.014. ConclusionsIn our population, LDL ≥230 mg/dL is a feasible criterion to indicate ICs to genetic testing.

Causative mutations and premature cardiovascular disease in patients with heterozygous familial hypercholesterolaemia.

Background Familial hypercholesterolemia is a common autosomal dominant disease, caused by mutations leading to elevated low-density lipoprotein (LDL) cholesterol and, if untreated, to premature cardiovascular disease. Methods Patients (young adults with a family history of hypercholesterolaemia or premature cardiovascular disease) with LDL cholesterol concentration ≥4.9 mmol/l, after excluding Familial Combined Hyperlipidaemia, were evaluated for causative mutations, Dutch Lipid Clinic Network score calculation and non-invasive ultrasound examination of carotid arteries. Results Of the 263 patients, 210 were heterozygotes for LDL receptor ( LDLR) mutations, four had APOB gene mutations, one PCSK9 gene mutation, while 48 had no evidence of mutations. Among 194 unrelated index cases 149 had mutations (77%). Among patients with LDLR mutations ( n = 145), there were five compound heterozygotes, 75 patients with null mutations and 65 with missense mutations. As many as 178 patients underwent a follow-up and treatment (statin ± ezetimibe), achieving a mean reduction of 49% in LDL cholesterol, with 21% of patients reaching the LDL goal of 2.6 mmol/l. In a multivariate analysis, carotid plaques, at ultrasound examination, were associated with the presence of genetic mutation ( p = 0.001), LDL cholesterol ( p < 0.001), Dutch Lipid Clinic Network score ( p < 0.001), independently of age, gender, smoking habits and systolic blood pressure. The presence of carotid plaque ( p = 0.017), LDL cholesterol ( p < 0.003), Dutch Lipid Clinic Network score ( p < 0.001) were independently associated with premature cardiovascular disease. Conclusions We identified patients with causative mutations in 82% of the cases under study. In addition to LDL cholesterol and Dutch Lipid Clinic Network score, carotid plaques in ultrasound evaluation provide direct evidence of premature vascular disease and are associated with high risk for cardiovascular events.

Revised Dutch lipid clinic network score criteria adapted for pediatric age: Evaluation of this tool in pediatric patients with hypercholesterolemia

Revised Dutch lipid clinic network score criteria adapted for pediatric age: Evaluation of this tool in pediatric patients with hypercholesterolemia

The Place of a Tertiary Laboratory in an Opportunistic Screening for Familial Hypercholesterolaemia

Background: Familial hypercholesterolaemia (FH) is a common hereditary lipid disorder associated with high risk of cardiovascular disease. Emerging evidence suggests, FH is often both underdiagnosed and undertreated by health care providers. The prevalence of identified FH in a tertiary laboratory was assessed in this study. Method: We reviewed serum LDL-C level measured by a tertiary laboratory in Melbourne Australia over a six months period (July to December 2016). The prevalence of possible FH based on recommended LDL-C thresholds of 5 mmol/L as employed by the Dutch Lipid Clinic Network (DLCN) score was evaluated. Results: 4943 individuals had serum LDL-C assessment within this period, 106 patients; male/female ratio of 46/60 and mean age of 56, had LDL cholesterol of ≥ 5 mmol/L after exclusion of five patients (0.1%) with secondary causes. Despite a poor documentation of family history and physical examination, 1.8% had DLCNS of 3-5, 0.3% a score of 6-8 and 0.1% a score of >8 indicating a possible, probable and definite diagnosis of FH respectively. The cumulative prevalence of likely phenotypical FH based on an LDL-C ≥5.0 mmol/L was 2.1% (1: 50). General practitioners referred 37.1% of the total patients followed by cardiologists and endocrinologists equally 12.2% and remaining 38.5% by other specialists. Conclusion: This study highlights the potential role of a tertiary laboratory in an opportunistic screening for index cases of FH. These data support the benefit of establishing an efficient “alert system” along with a trigger “reflex testing” to facilitate screening and ensuring further referral to a lipid disorder specialist.

Efficacy of clinical diagnostic criteria for familial hypercholesterolemia genetic testing in Poland

Background and AimsFamilial hypercholesterolemia (FH), which leads to premature cardiovascular events, still remains underrecognized and undertreated in most countries. Untreated FH individuals aged 20–39 years are at 100-fold higher risk of mortality from coronary heart disease compared to those of a general population. Therefore, special efforts should be implemented to diagnose FH patients at early stages of life.The aim of this study was to evaluate the efficacy of the revised Dutch Lipid Clinic Network (DLCN) criteria proposed by the Polish Lipid Experts Forum to select index FH patients for DNA mutational analysis in Poland. MethodsThe study included 193 unrelated adult patients (mean age 48 ± 13 years) with clinical diagnosis of FH based on the revised DLCN score, tested sequentially for mutations in LDLR and APOB genes using bidirectional Sanger sequencing and MLPA techniques. The cut-off points of the clinical FH criteria score were assessed by ROC statistics to identify patients with the highest probability of carrying an FH-causing mutation. ResultsThe causal heterozygous LDLR or APOB mutation was identified in 41% (80/193) of probands. Adults aged <40 years were more likely to carry an FH-causing mutation compared to subjects aged ≥40 years (65% vs. 33%; p < 0.001). LDL-C thresholds for the molecular diagnosis of FH were 5.79 mmol/l for individuals aged<40 and 6.7 mmol/l for subjects ≥40 years old. The threshold values of the clinical diagnostic score for efficient selection of patients for genetic testing were 5 and 7 points for individuals aged <40 and ≥40 years, respectively. ConclusionsThe study validated the efficacy of proposed clinical FH criteria for the disease diagnosis in Poland. The clinical criteria score thresholds for positive FH molecular diagnosis differ depending on age (<40 and ≥40 years). We propose that in the healthcare systems with limited genetic testing resources individuals younger than 40 years, who fulfill the clinical criteria for possible, probable or definite FH should qualify for the FH mutation testing. The index patients aged ≥40 years with clinical diagnosis of probable or definite FH should also qualify for the genetic testing.

Abstract 16554: Rapid Identification of Familial Hypercholesterolemia From Electronic Health Records

Background: Familial hypercholesterolemia (FH) is an important public health burden as it is a relatively common Mendelian genetic disorder which is associated with dramatically increased lifetime risk for premature atherosclerotic cardiovascular disease (ASCVD) due to elevated plasma low-density lipoprotein cholesterol (LDL-C) levels. Little is known about prevalence and control of FH in the US. Objective: To develop an electronic phenotyping algorithm for rapid identification of FH in electronic health records (EHRs) and thereby address knowledge gaps in prevalence and control of FH. Methods: We identified patients in the Mayo Employee and Community Health (ECH) system who met the following inclusion criteria: 1) gave research authorization, 2) any LDL-C in EHR ≥190 mg/dL; 2) triglycerides &lt;400 mg/dL; 3) absence of secondary causes of hyperlipidemia (hypothyroidism, cholestatic liver diseases, nephrotic syndrome, renal failure, and pregnancy). Next we applied the Dutch Lipid Clinic Network (DLCN) criteria to ascertain FH cases. ASCVD-related diagnosis codes, laboratory data, and medications were obtained from structured EHR datasets. We used the Mayo natural language processing (NLP) system to ascertain presence of family and personal history of premature ASCVD, xanthomas and corneal arcus from clinical text notes. Results: Of a total of 131,000 patients seen in ECH clinics between July 1993 and December 2014, 6018 met the inclusion criteria. Implementing the electronic phenotyping algorithm for FH in these patients identified 178 definite and 369 probable cases (DLCN score &gt;8 and 6-8 points, respectively) with an overall FH prevalence of 0.4% (1:240). Blinded expert review of 160 randomly chosen patients showed positive and negative predictive values for electronic phenotyping algorithm at 85% and 90%, respectively. Only 40% of these patients achieved LDL-C ≤100 mg/dL on treatment. Conclusions: 1) An EHR-based phenotyping algorithm that included NLP had reasonable accuracy in ascertaining FH cases. 2) Implementing this algorithm revealed the prevalence of FH in the study cohort to be nearly twice the current estimate of 1:500 in the general population. 3) Less than half of the FH patients had optimal LDL-C levels on treatment.

Genetic diagnosis of familial hypercholesterolaemia by targeted next-generation sequencing.

Maglio C., Mancina R. M., Motta B. M., Stef M., Pirazzi C., Palacios L., Askaryar N., Borén J., Wiklund O., Romeo S. (University of Gothenburg, Gothenburg, Sweden; University Magna Graecia of Catanzaro, Italy; University of Milan, Italy; Progenika Biopharma SA, Derio, Spain). Genetic diagnosis of familial hypercholesterolaemia by targeted next-generation sequencing.ObjectivesThe aim of this study was to combine clinical criteria and next-generation sequencing (pyrosequencing) to establish a diagnosis of familial hypercholesterolaemia (FH).Design, setting and subjectsA total of 77 subjects with a Dutch Lipid Clinic Network score of ≥3 (possible, probable or definite FH clinical diagnosis) were recruited from the Lipid Clinic at Sahlgrenska Hospital, Gothenburg, Sweden. Next-generation sequencing was performed in all subjects using SEQPRO LIPO RS, a kit that detects mutations in the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9) and LDLR adapter protein 1 (LDLRAP1) genes; copy-number variations in the LDLR gene were also examined.ResultsA total of 26 mutations were detected in 50 subjects (65% success rate). Amongst these, 23 mutations were in the LDLR gene, two in the APOB gene and one in the PCSK9 gene. Four mutations with unknown pathogenicity were detected in LDLR. Of these, three mutations (Gly505Asp, Ile585Thr and Gln660Arg) have been previously reported in subjects with FH, but their pathogenicity has not been proved. The fourth, a mutation in LDLR affecting a splicing site (exon 6–intron 6) has not previously been reported; it was found to segregate with high cholesterol levels in the family of the proband.ConclusionsUsing a combination of clinical criteria and targeted next-generation sequencing, we have achieved FH diagnosis with a high success rate. Furthermore, we identified a new splicing-site mutation in the LDLR gene.

Analysis of the frequency and spectrum of mutations recognised to cause familial hypercholesterolaemia in routine clinical practice in a UK specialist hospital lipid clinic

AimTo determine the frequency and spectrum of mutations causing Familial Hypercholesterolaemia (FH) in patients attending a single UK specialist hospital lipid clinic in Oxford and to identify characteristics contributing to a high mutation detection rate. Methods289 patients (272 probands) were screened sequentially over a 2-year period for mutations in LDLR, APOB and PCSK9 using standard molecular genetic techniques. The Simon Broome (SB) clinical diagnostic criteria were used to classify patients and a separate cohort of 409 FH patients was used for replication. ResultsAn FH-causing mutation was found in 101 unrelated patients (LDLR = 54 different mutations, APOB p.(Arg3527Gln) = 10, PCSK9 p.(Asp374Tyr) = 0). In the 60 SB Definite FH patients the mutation detection rate was 73% while in the 142 with Possible FH the rate was significantly lower (27%, p < 0.0001), but similar (14%, p = 0.06) to the 70 in whom there was insufficient data to make a clinical diagnosis. The mutation detection rate varied significantly (p = 9.83 × 10−5) by untreated total cholesterol (TC) levels (25% in those <8.1 mmol/l and 74% in those >10.0 mmol/l), and by triglyceride levels (20% in those >2.16 mmol/l and 60% in those <1.0 mmol/l (p = 0.0005)), with both effects confirmed in the replication sample (p for trend = 0.0001 and p = 1.8 × 10−6 respectively). There was no difference in the specificity or sensitivity of the SB criteria versus the Dutch Lipid Clinic Network score in identifying mutation carriers (AROC respectively 0.73 and 0.72, p = 0.68). ConclusionsIn this genetically heterogeneous cohort of FH patients the mutation detection rate was significantly dependent on pre-treatment TC and triglyceride levels.

Familial Hypercholesterolemia in the Danish General Population: Prevalence, Coronary Artery Disease, and Cholesterol-Lowering Medication

The diagnosis of familial hypercholesterolemia (FH) can be made using the Dutch Lipid Clinic Network criteria. This employs the personal and family history of premature coronary artery disease and hypercholesterolemia and the presence of a pathogenic mutation in the low-density lipoprotein receptor (LDLR) and apolipoprotein B (APOB) genes. We employed this tool to investigate the prevalence of FH and the associations between FH and coronary artery disease and cholesterol-lowering medication in the Copenhagen General Population Study. The study was of an unselected, community-based population comprising 69,016 participants. FH (definite/probable) was defined as a Dutch Lipid Clinic Network score higher than 5. Coronary artery disease was myocardial infarction or angina pectoris. The prevalence of FH was 0.73% (one in 137). Of participants with FH, 20% had an LDLR or APOB mutation. The prevalence of coronary artery disease among FH participants was 33%. Only 48% of subjects with FH admitted to taking cholesterol-lowering medication. The odds ratio for coronary artery disease off cholesterol-lowering medication was 13.2 (10.0-17.4) in definite/probable FH compared with non-FH subjects, after adjusting for age, gender, body mass index, hypertension, metabolic syndrome and diabetes, and smoking. The corresponding adjusted odds ratio for coronary artery disease in FH subjects on cholesterol-lowering medication was 10.3 (7.8-13.8). The prevalence of FH appears to be higher than commonly perceived in a general population of white Danish individuals, with at least half of affected subjects not receiving cholesterol-lowering medication. The very high risk of coronary artery disease irrespective of use of medication reflects the extent of underdiagnosis and undertreatment of FH in the community and primary care.

Molecular characterization of familial hypercholesterolemia in Spain

Familial hypercholesterolemia (FH), characterized by isolated elevation of plasmatic low-density lipoprotein (LDL) cholesterol and premature coronary heart disease (CHD), is associated with mutations in three major genes: LDL receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin 9 (PCSK9). We have analyzed 5430 Spanish index cases and 2223 relatives since 2004 with LIPOchip® genetic diagnostic platform, a microarray for the detection of Spanish common mutations in these three genes, including copy number variation (CNV) in LDLR, followed by sequencing analysis of the coding regions of LDLR and exon 26 of APOB, when the result is negative. Samples were received from hospitals of all around Spain. The preferred clinical criterion to diagnose FH was Dutch Lipid Clinic Network (DLCN) score. Our results show that there is a broad spectrum of mutations in the LDLR gene in Spain since about 400 different mutations were detected, distributed along almost the whole LDLR gene. Mutations in APOB (mainly p.Arg3527Gln) covered 6.5% of positive cases and only one PCSK9 mutation was detected. We found correlation between more severe mutations and the clinical diagnosis but also that 28% of FH patients harboring mutations do not have a definite clinical diagnosis. This study analyzes the mutation spectrum in Spain, remarks the importance of genetic diagnosis of FH patients, as well as the cascade screening, and shows how it is being carried out in Spain.