Adherence to statin treatment in patients with familial hypercholesterolemia: A dynamic prediction model.

BACKGROUND: Statins are the primary therapy in patient with heterozygous familial hypercholesterolemia (HeFH). Non-adherence to statin therapy is associated with increased cardiovascular risk. OBJECTIVE: We constructed a dynamic prediction model to predict statin adherence for an individual HeFH patient for each upcoming statin prescription. METHODS: All patients with HeFH, identified by the Dutch Familial Hypercholesterolemia screening program between 1994 and 2014, were eligible. National pharmacy records dated between 1995 and 2015 were linked. We developed a dynamic prediction model that estimates the probability of statin adherence (defined as proportion of days covered >80%) for an upcoming prescription using a mixed effect logistic regression model. Static and dynamic patient-specific predictors, as well as data on a patient's adherence to past prescriptions were included. The model with the lowest AIC (Akaike Information Criterion) value was selected. RESULTS: We included 1094 patients for whom 21,171 times a statin was prescribed. Based on the model with the lowest AIC, age at HeFH diagnosis, history of cardiovascular event, time since HeFH diagnosis and duration of the next statin prescription contributed to an increased adherence, while adherence decreased with higher untreated LDL-C levels and higher intensity of statin therapy. The dynamic prediction model showed an area under the curve of 0.63 at HeFH diagnosis, which increased to 0.85 after six years of treatment. CONCLUSION: This dynamic prediction model enables clinicians to identify HeFH patients at risk for non-adherence during statin treatment. These patients can be offered timely interventions to improve adherence and further reduce cardiovascular risk.

Novel PCSK9 (Proprotein Convertase Subtilisin Kexin Type 9) Variants in Patients With Familial Hypercholesterolemia From Cape Town.

OBJECTIVE: Familial hypercholesterolemia (FH) is characterized by elevated low-density lipoprotein-cholesterol and markedly increased cardiovascular risk. In patients with a genetic diagnosis, low-density lipoprotein receptor (LDLR) mutations account for >90% of cases, apolipoprotein B (APOB) mutations for ≈5% of cases, while proprotein convertase subtilisin kexin type 9 (PCSK9) gain of function mutations are rare (<1% of cases). We aimed to evaluate the functional impact of several novel PCSK9 variants in a cohort of patients with FH by genetic cascade screening and in vitro functionality assays. Approach and Results: Patients with clinically diagnosed FH underwent genetic analysis of LDLR, and if negative, sequential testing of APOB and PCSK9. We analyzed cosegregation of hypercholesterolemia with novel PCSK9 variants. Gain of function status was determined by in silico analyses and validated by in vitro functionality assays. Among 1055 persons with clinical FH, we identified nonsynonymous PCSK9 variants in 27 (2.6%) patients and 7 of these carried one of the 4 previously reported gain of function variants. In the remaining 20 patients with FH, we identified 7 novel PCSK9 variants. The G516V variant (c.1547G>T) was found in 5 index patients and cascade screening identified 15 additional carriers. Low-density lipoprotein-cholesterol levels were higher in these 15 carriers compared with the 27 noncarriers (236±73 versus 124±35 mg/dL; P<0.001). In vitro studies demonstrated the pathogenicity of the G516V variant. CONCLUSIONS: In our study, 1.14% of cases with clinical FH were clearly attributable to pathogenic variants in PCSK9. Pathogenicity is established beyond doubt for the G516V variant.

Interpretation of laboratory results after gastric bypass surgery: the effects of weight loss and time on 30 blood tests in a 5-year follow-up program.

BACKGROUND: Long-term follow-up with blood tests is essential for bariatric surgery to be a successful treatment for obesity and related co-morbidities. Adverse effects, deficiencies, and metabolic improvements need to be controlled. OBJECTIVE: We investigated the effects of time and weight loss on laboratory results in each postoperative phase after laparoscopic Roux-en-Y gastric bypass (LRYGB). SETTING: Bariatric center of excellence, general hospital, Netherlands. METHODS: We retrospectively evaluated results of 30 blood tests, preoperatively and at 6 months, 1 year, 2 years, and 5 years after LRYGB. The 2019 Dutch bariatric chart was used to define weight loss responses as outstanding (>p[percentile curve]+1 SD), average (p+1 SD to p-1 SD), and poor (

Statin therapy reduces plasma angiopoietin-like 3 (ANGPTL3) concentrations in hypercholesterolemic patients via reduced liver X receptor (LXR) activation.

BACKGROUND AND AIMS: Statins suppress hepatic mRNA expression of ANGPTL3 encoding angiopoietin-like 3 in healthy subjects, but it is unknown if plasma ANGPTL3 concentrations are affected by statins prescribed to hypercholesterolemic patients in clinical practice. We therefore investigated the effect of statin treatment on plasma ANGPTL3 concentrations in hypercholesterolemic patients. In addition, we explored the underlying mechanism by which statins regulate ANGPTL3 in vitro. METHODS: Plasma ANGPTL3 concentrations were measured in 93 genetically confirmed familial hypercholesterolemia (FH) patients who were using statin therapy and 61 statin naïve FH patients. Moreover, concentrations were measured in 14 hypercholesterolemic patients who discontinued their statin treatment for 4 weeks. In vitro studies were performed with Huh7 human hepatoma cells. RESULTS: Plasma ANGPTL3 concentrations were 15% lower in statin treated FH patients compared to statin naïve FH patients (145 (120-193) vs. 167 (135-220) ng/ml, p = 0.012). Statin discontinuation resulted in a 21% (p<0.001) increase of plasma ANGPTL3 concentrations. Simvastatin reduced ANGPTL3 mRNA expression and ANGPTL3 secretion of Huh7 cells. Liver X receptor (LXR) activation with T0901317 increased ANGPTL3 mRNA expression and ANGPTL3 secretion by 6- and 3-fold, respectively. Adding simvastatin did not mitigate this effect but adding the LXR antagonist GSK2230 to simvastatin-incubated Huh7 cells diminished simvastatin-induced reductions in ANGPTL3 mRNA expression and ANGPTL3 secretion. Simvastatin reduced intracellular oxysterol concentrations. Oxysterols are endogenous LXR ligands, implying that simvastatin suppresses ANGPTL3 secretion via reduced oxysterol-mediated LXR activation. CONCLUSIONS: Statins lower plasma ANGPTL3 concentrations in hypercholesterolemic patients, likely due to decreased oxysterol-mediated LXR activation.

Risk Factors for Cholecystectomy After Laparoscopic Roux-En-Y Gastric Bypass.

BACKGROUND: Patients who have undergone bariatric surgery are at risk for subsequent cholecystectomy. We aimed to identify risk factors for cholecystectomy after laparoscopic Roux-en-Y gastric bypass (LRYGB). METHODS: We conducted a retrospective case-control study of patients who underwent LRYGB between 2013 and 2015. Cases underwent cholecystectomy because of biliary symptoms after LRYGB. For each case, two controls were selected without subsequent cholecystectomy. Logistic regression analyses were used to identify risk factors. RESULTS: Between 2013 and 2015, 1780 primary LRYGBs were performed. We identified 233 (13.1%) cases who had undergone cholecystectomy after a median (IQR) of 12 (8-17) months, and 466 controls. Female gender (OR (95% CI) 1.83 (1.06-3.17)), Caucasian ethnicity (OR (95% CI) 1.82 (1.10-3.02)), higher percent total weight loss (%TWL) at 12 months (OR (95% CI) 1.06 (1.04-1.09)), and preoperative pain syndrome (OR (95% CI) 2.72 (1.43-5.18)) were significantly associated with an increased risk for cholecystectomy. Older age (OR (95% CI) 0.98 (0.96-0.99)) and preoperative statin use were associated with a reduced risk (OR (95% CI) 0.56 (0.31-1.00)). A dose-effect relationship was found between the intensity of preoperative statin and risk for cholecystectomy. CONCLUSIONS: In our study, higher %TWL and preoperative pain syndrome were associated with an increased risk for cholecystectomy besides the traditional risk factors female gender and Caucasian ethnicity. These factors can be used to identify high-risk patients, who might benefit from preventive measures. Whether statins can protect bariatric patients from developing gallstones should be investigated prospectively.

LDL-cholesterol target achievement in patients with heterozygous familial hypercholesterolemia at Groote Schuur Hospital: Minority at target despite large reductions in LDL-C.

BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) is characterized by markedly increased LDL-cholesterol (LDL-C) and premature cardiovascular disease (CVD). LDL-C lowering is the cornerstone of therapy. The aim of our study was to evaluate LDL-C target achievement and explore reasons for not reaching target in FH patients attending a public-sector lipid clinic at Groote Schuur Hospital in Cape Town, South Africa. METHODS: We reviewed clinical records of patients with genetically confirmed heterozygous FH (heFH) retrospectively. For patients seen after 2013, when new guidelines were published, we determined reasons for use of submaximal therapy. RESULTS: Our study population consisted of 776 adult heFH patients. A substantial proportion (41%) of those younger than 50 years of age had already experienced a cardiovascular event. The mean (±SD) untreated and best achieved LDL-C values during follow up were 8.1 ±â€¯2.1 and 4.0 ±â€¯1.5 mmol/l, respectively. Despite a mean LDL-C reduction of 50%, only 140 (25%) achieved an LDL-C ≤ 3.0 mmol/l. Of the 164 participants with follow up after 2013, 42 did not reach LDL-C < 3.0 mmol/l and did not use maximal therapy (26%). The commonest reasons for not using maximum therapy were statin side-effects (n = 15, 36%) and acceptance by the patient (n = 9, 22%) or the physician (n = 8, 19%) of the control achieved. CONCLUSIONS: The heFH population in Cape Town is characterized by high baseline LDL-C, a high prevalence of CVD at presentation and low rates of achieving an LDL-C target of 3.0 mmol/l.

Achieved LDL cholesterol levels in patients with heterozygous familial hypercholesterolemia: A model that explores the efficacy of conventional and novel lipid-lowering therapy.

BACKGROUND: A large proportion of patients with heterozygous familial hypercholesterolemia (heFH) do not reach low-density lipoprotein cholesterol (LDL-c) levels advocated by international guidelines (<70 mg/dL or <100 mg/dL). OBJECTIVE: We set out to model which proportion of patients reach targets using conventional and novel therapies. METHODS: We performed a cross-sectional analysis in a large cohort of genetically identified heFH patients and calculated the proportion reaching treatment targets in four scenarios: (1) after 50% LDL-c reduction (representing maximal dose statin); (2) after 70% LDL-c reduction (maximal dose statin + ezetimibe); (3) additional 40% LDL-c reduction representing cholesteryl ester transfer protein inhibitor (CETPi); and (4) 60% LDL-c reduction (proprotein convertase subtilisin/kexin type 9 inhibitors [PCSK9i]), on top of scenario 2. We applied 100% adherence rates and literature-based adherence rates from 62% to 80%. RESULTS: We included 1,059 heFH patients with and 9,420 heFH patients without coronary heart disease (CHD). With maximal dose statin, 8.3% and 48.1% of patients with and without CHD would reach their recommended LDL-c targets, respectively. This increases to 54.3% and 93.2% when ezetimibe is added. Addition of CETPi increases these numbers to 95.7% and 99.7%, whereas adding PCSK9i would result in 99.8% and 100% goal attainment. Using literature-based adherence rates, these numbers decrease to 3.8% and 27.3% for maximal dose statin, 5.8% and 38.9% combined with ezetimibe, 31.4% and 81.2% when adding CETPi, and 40.3% and 87.1% for addition of PCSK9i. CONCLUSIONS: Less than 10% with and 50% of heFH patients without CHD would reach treatment targets with maximal dose statin, but this substantially increases on addition of ezetimibe, CETPi, or PCSK9i. However, considering recently published adherence data, this might be lower in real life, especially in heFH patients with CHD.

Determining When to Add Nonstatin Therapy: A Quantitative Approach.

BACKGROUND: Costs and uncertainty about the benefits of nonstatin therapies limit their use. OBJECTIVES: The authors sought to identify patients who might benefit from the addition of a nonstatin to background statin therapy. METHODS: We performed systematic reviews of subgroup analyses from randomized trials and observational studies with statin-treated participants to determine estimated 10-year absolute risk of atherosclerotic cardiovascular disease (ASCVD) and to define high-risk and very high-risk patients. We used the relative risk reductions for the addition of a nonstatin to lower low-density lipoprotein (LDL-C) used to determine the number needed to treat (NNT) to prevent 1 ASCVD event over 5 years for each patient group and to allow comparisons with 5-year cost analyses. RESULTS: The 10-year ASCVD risk is at least 30% (very high risk) for statin-treated participants with clinical ASCVD and comorbidities, and 20% to 29% (high risk) for those with ASCVD without comorbidities or who have heterozygous familial hypercholesterolemia. Adding ezetimibe to reduce low-density LDL-C by 20% would provide a 5-year NNT ≤50 for very high-risk patients with LDL-C ≥130 mg/dl or for high-risk patients with LDL-C ≥190 mg/dl, and an NNT ≤30 for very high-risk patients with LDL-C ≥160 mg/dl. Adding a PCSK9 monoclonal antibody to lower LDL-C by at least 50% would provide an NNT ≤50 for very high-risk and high-risk patients with LDL-C ≥70 mg/dl, and an NNT ≤30 for very high-risk and high-risk patients with an LDL-C ≥130 mg/dl. CONCLUSIONS: Adding ezetimibe or PCSK9 monoclonal antibodies to maximally tolerated statin therapy may be cost effective in very high-risk and high-risk patients, depending on baseline LDL-C levels.

Statins in Familial Hypercholesterolemia: Consequences for Coronary Artery Disease and All-Cause Mortality.

BACKGROUND: A statin-induced reduction of coronary artery disease (CAD) events and mortality has not been adequately quantified in patients with heterozygous familial hypercholesterolemia (FH). OBJECTIVES: This study estimated the relative risk reduction for CAD and mortality by statins in heterozygous FH patients. METHODS: The authors included all adult heterozygous FH patients, identified by the Dutch screening program for FH between 1994 and 2013, who were free of CAD at baseline. Hospital, pharmacy, and mortality records between 1995 and 2015 were linked to these patients. The primary outcome was the composite of myocardial infarction, coronary revascularization, and death from any cause. The effect of statins (time-varying) was determined using a Cox proportional hazard model, while correcting for the use of other lipid-lowering therapy, thrombocyte aggregation inhibitors, and antihypertensive and antidiabetic medication. The authors applied inverse-probability-for-treatment weighting (IPTW) to account for differences at baseline between statin users and never-users. RESULTS: The authors obtained medical records of 2,447 patients, of whom 888 were excluded on the basis of age <18 years or previous CAD. Simvastatin 40 mg and atorvastatin 40 mg accounted for 23.1% and 22.8% of all prescriptions, respectively. Statin users (n = 1,041) experienced 89 CAD events and 17 deaths during 11,674 person-years of follow-up versus statin never-users (n = 518), who had 22 CAD events and 9 deaths during 4,892 person-years (combined rates 8.8 vs. 5.3 per 1,000 person-years, respectively; p < 0.001). After applying IPTW and adjusting for other medications, the hazard ratio of statin use for CAD and all-cause mortality was 0.56 (95% confidence interval: 0.33 to 0.96). CONCLUSIONS: In patients with heterozygous FH, moderate- to high-intensity statin therapy lowered the risk for CAD and mortality by 44%. This is essential information in all cost-effectiveness studies of this disorder, such as when evaluating reimbursement of new lipid-lowering therapies.

Clinical phenotype in relation to the distance-to-index-patient in familial hypercholesterolemia.

BACKGROUND AND AIM: We evaluated whether the severity of the familial hypercholesterolemia (FH) phenotype, i.e. increased levels of low-density lipoprotein cholesterol (LDL-C) and cardiovascular disease (CVD) risk, decreases in more distantly related patients within one family. METHODS: We included heterozygous FH patients identified by genetic cascade screening in the Netherlands from 1994 to 2014. A cascade starts with identification of a genetically proven FH patient ("index patient") followed by testing in first degree relatives. If a mutation carrier is identified, their first degree relatives are tested as well, and so on. The associations between distance-to-index (expressed as family relationship) and both LDL-C levels and CVD risk, were evaluated using multivariable linear and Cox regression models. RESULTS: Distance-to-index could be determined in 13,374 patients. Mean (± standard error) levels of LDL-C did not differ significantly in 1st, 2nd, 3rd, and 4th or more family members: 5.46 (1.42), 5.17 (1.42), 4.89 (1.37), and 4.58 (1.27) mmol/L, respectively (adjusted p-for-trend: 0.104). The adjusted hazard ratio of increasing distance-to-index for CVD was 0.92 (95% CI: 0.82-1.03). CONCLUSION: This study was the first to investigate the association between distance-to-index and the phenotype of a monogenetic disorder. The absence of a decrease of phenotype severity lends support for genetic cascade testing in FH.

PCSK9 inhibition: the way forward in the treatment of dyslipidemia.

Barely a decade after the discovery of the gene encoding proprotein convertase subtilisin/kexin type 9 (PCSK9) and its recognition as a key player in cholesterol metabolism, PCSK9 inhibition is now considered an exciting approach in the reduction of residual risk of cardiovascular disease. The progress from PCSK9 discovery to the development of targeted treatment has been unprecedented in terms of scale and speed. The first suggestion of a link between PCSK9 and hypercholesterolemia was published in 2003; a decade later, two meta-analyses of clinical trials comparing anti-PCSK9 treatment to placebo or ezetimibe, including >10,000 hypercholesterolemic individuals, were published. Currently, three PCSK9 inhibitors are being evaluated in clinical outcome trials and the results will determine the future of these lipid-lowering therapies by establishing their clinical efficacy in terms of cardiovascular event reduction, safety, and the consequences of prolonged exposure to very low levels of LDL-cholesterol. Irrespective of their outcomes, the exceptionally rapid development of these drugs exemplifies how novel technologies, genetic validation, and rapid clinical progression provide the tools to expedite the development of new drugs.

The impact of LDLR function on fibroblast growth factor 21 levels.

CONTEXT: Fibroblast growth factor 21 (FGF21) has been described to have beneficial effects on glucose and lipid metabolism, and FGF21 analogs are currently evaluated in phase 1 trials. However, the complete spectrum of effects and regulators of FGF21 is yet partly elucidated. Recent studies have shown that FGF21 plays a role in transmembrane cholesterol transport. OBJECTIVE: We set out to examine the association between FGF21 and LDLR mediated transmembrane cholesterol transport, by comparing FGF21 levels in patients with genetically impaired LDLR function and unaffected relatives. Secondly, we explored whether the severity of the LDLR mutation was associated with FGF21 levels. METHODS: We performed a cross-sectional study in carriers of an LDLR mutation and their unaffected relatives. Subjects were eligible if they participated in the Dutch national screening program for familial hypercholesterolemia (FH), were 18-55 years old, and were carrier of a pathogenic LDLR mutation with an untreated LDL-C level below the 75(th) or above the 90(th) percentile of the general population, or did not carry an FH mutation. The outcome measure was the level of FGF21, which was assessed using ELISA. RESULTS: We included 224 carriers of an LDLR mutation and 148 unaffected relatives. FGF21 levels were lower in LDLR mutation carriers compared to unaffected relatives (median [interquartile range]: 96.92 [60.80-174.05] versus 136.98 [77.34-219.47] pg/mL, respectively; p = 0.08), but after adjusting for potential confounders, there was no association between LDLR mutations and FGF21 levels (p = 0.70). Neither, did we find a relationship between the severity of LDLR mutations and FGF21 levels (p = 0.51, after adjustment for potential confounders). CONCLUSIONS: We showed that levels of FGF21 are not different in patients with and without LDLR mutations, which suggests that decreased LDLR expression does not have a negative effect on FGF21 levels. Given the potential beneficial effects of FGF21 analogs on lipids and lipoproteins in a phase 1 study, we deem this of great interest for future treatment options for FH patients.

Identifying genetic risk variants for coronary heart disease in familial hypercholesterolemia: an extreme genetics approach.

Mutations in the low-density lipoprotein receptor (LDLR) gene cause familial hypercholesterolemia (FH), a disorder characterized by coronary heart disease (CHD) at young age. We aimed to apply an extreme sampling method to enhance the statistical power to identify novel genetic risk variants for CHD in individuals with FH. We selected cases and controls with an extreme contrast in CHD risk from 17,000 FH patients from the Netherlands, whose functional LDLR mutation was unequivocally established. The genome-wide association (GWA) study was performed on 249 very young FH cases with CHD and 217 old FH controls without CHD (above 65 years for males and 70 years of age for females) using the Illumina HumanHap550K chip. In the next stage, two independent samples (one from the Netherlands and one from Italy, Norway, Spain, and the United Kingdom) of FH patients were used as replication samples. In the initial GWA analysis, we identified 29 independent single nucleotide polymorphisms (SNPs) with suggestive associations with premature CHD (P<1 × 10(-4)). We examined the association of these SNPs with CHD risk in the replication samples. After Bonferroni correction, none of the SNPs either replicated or reached genome-wide significance after combining the discovery and replication samples. Therefore, we conclude that the genetics of CHD risk in FH is complex and even applying an 'extreme genetics' approach we did not identify new genetic risk variants. Most likely, this method is not as effective in leveraging effect size as anticipated, and may, therefore, not lead to significant gains in statistical power.

Increased carotid intima-media thickness predicts cardiovascular events in aortic coarctation.

BACKGROUND: Adult post-coarctectomy patients (CoA) demonstrate increased cardiovascular morbidity and mortality. The carotid intima-media thickness (CIMT), a marker for atherosclerosis, is increased in CoA. The aim was to evaluate the predictive value of CIMT for cardiovascular events. METHODS AND RESULTS: Consecutive CoA patients were prospectively studied during 10.1±0.7 years follow-up. At baseline and follow-up echocardiography, MRI imaging and CIMT imaging were performed, while cardiovascular events were registered. CIMT data were compared with controls. The composite endpoint included: myocardial infarction, cerebrovascular events (CVAs), and (sudden) cardiac death. 160 CoA patients were studied (median age 31.7 (18-74 years), 64% male). Events occurred in 11 patients (7%), five (3%) with myocardial infarction, four (2.5%) with an ischemic CVA and two (1%) died suddenly. An increased CIMT (≥0.8 mm) (HR=15.44, P=<0.001) was predictive for the occurrence of cardiovascular events. Baseline CIMT was increased in CoA compared to controls (0.64±0.12 mm vs 0.57±0.07 mm, P=0.005). CIMT progression rates were similar (0.0091±0.016 mm/year vs 0.0097±0.018 mm/year, P=0.84). Signs of atherosclerosis occurred significantly earlier in CoA patients. CONCLUSION: The contemporary cardiovascular event rate in CoA is 11% in 10 years. Atherosclerosis seems to appear earlier in CoA patients as compared to controls. CoA patients with a CIMT exceeding 0.8mm have a fifteen fold higher cardiovascular risk. CIMT seems to be a useful tool for cardiovascular risk assessment in CoA.

Quality assessment of the genetic test for familial hypercholesterolemia in the Netherlands.

Introduction. Familial hypercholesterolemia (FH) is an inherited disorder associated with a severely increased risk of cardiovascular disease. Although DNA test results in FH are associated with important medical and ethical consequences, data on accuracy of genetic tests is scarce. Methods. Therefore, we performed a prospective study to assess the overall accuracy of the DNA test used in the genetic cascade screening program for FH in The Netherlands. Individuals aged 18 years and older tested for one of the 5 most prevalent FH mutations, were included consecutively. DNA samples were analyzed by the reference and a counter-expertise laboratory following a standardized procedure. Results. 1003 cases were included. In the end, 317 (32%) carried an FH mutation, whereas in 686 (69%) samples no mutation was found. The overall accuracy of the reference laboratory was 99.8%, with two false positive results identified by the counter-expertise laboratory. Conclusion. The currently used mutation analysis is associated with a very low error rate. Therefore, we do not recommend routine use of duplicate testing.

Inheritance pattern of familial hypercholesterolemia and markers of cardiovascular risk.

Studies in children and adults have resulted in conflicting evidence in the quest for the answer to the hypothesis that offspring from hypercholesterolemic mothers might have an increased cardiovascular risk. Previous studies might have suffered from limitations such as cohort size and clinical sampling bias. We therefore explored this hypothesis in large cohorts of both subjects with familial hypercholesterolemia (FH) and unaffected siblings in a wide age range. In three cohorts (cohort 1: n = 1,988, aged 0-18 years; cohort 2: n = 300, 8-30 years; cohort 3: n = 369, 18-60 years), we measured lipid and lipoproteins as well as carotid intima-media thickness (c-IMT) in offspring from FH mothers versus FH fathers. For LDL cholesterol, triglycerides (TGs), and c-IMT, we performed a pooled analysis. No significant differences could be observed in c-IMT, lipid, or lipoprotein levels from offspring of FH mothers versus FH fathers. Pooled analyses showed no significant differences for either LDL cholesterol [mean difference 0.02 (-0.06,0.11) mmol/l, P = 0.60], TGs [mean difference 0.07 (0.00,0.14) mmol/l, P = 0.08], or c-IMT [mean difference -0.00 (-0.01,0.01) mm, P = 0.86]. Our data do not support the hypothesis that cardiovascular risk markers are different between offspring from FH mothers and FH fathers.

Discriminative ability of LDL-cholesterol to identify patients with familial hypercholesterolemia: a cross-sectional study in 26,406 individuals tested for genetic FH.

BACKGROUND: Screening for familial hypercholesterolemia (FH) within affected families is often based on cutoff values for low-density lipoprotein cholesterol (LDL-C). However, the diagnostic accuracy of LDL-C levels is influenced by the magnitude of the LDL-C overlap between FH patients and unaffected relatives. The purpose of the current study was to assess to what extent this overlap is influenced by the severity of specific FH mutations. METHODS AND RESULTS: Individuals were eligible if they underwent family screening for FH between 2003 and 2010. The entire cohort was then compared with those who were investigated for the presence of the most severe mutations (class 1). The area under the receiver operating characteristics curve and the sensitivity of the 90th percentile of LDL-C were calculated for both cohorts. We included 26 406 individuals, of whom 9169 (35%) carried an FH-causing mutation. In the entire cohort at baseline, mean LDL-C was 4.63 ± 1.44 mmol/L for FH carriers (n=5372) and 2.96 ± 0.96 mmol/L for unaffected relatives (n=15 148); P<0.001. The corresponding operating characteristics curve (95% CI) was 86.6% (85.9%-87.2%), and the cutoff level of LDL-C above the 90th percentile showed a sensitivity of 68.5%. The operating characteristics curve and sensitivity significantly improved when the 5933 individuals tested for class 1 mutations were assessed separately; 96.2% (95.3%-97.1%) and 91.3%, respectively. CONCLUSIONS: In summary, the overlap in terms of LDL-C levels between those with molecularly proven FH and unaffected relatives is to a large extent because of the high prevalence of modestly severe LDL-receptor mutations in the Netherlands.

Plasma PCSK9 levels and clinical outcomes in the TNT (Treating to New Targets) trial: a nested case-control study.

OBJECTIVES: The purpose of this study was to investigate whether high levels of circulating proprotein convertase subtilisin kexin type 9 (PCSK9) would increase cardiovascular risk in statin-treated patients. BACKGROUND: Statins activate low-density lipoprotein (LDL) receptor gene expression, thus lowering plasma LDL levels. But statins also activate the expression of PCSK9, a secreted inhibitor of the LDL receptor, thereby limiting their beneficial effects. METHODS: We have measured the plasma PCSK9 levels of 1,613 patients with stable coronary heart disease enrolled in the Treating to New Targets study, a randomized trial that compared the efficacy of high- versus low-dose atorvastatin. After a run-in period with atorvastatin 10 mg daily, patients were randomized to either continue with 10 mg or be up-titrated to 80 mg of atorvastatin, and followed during 5 years for major cardiovascular events (MCVEs). RESULTS: Circulating PCSK9 levels measured at randomization were predictive of clinical outcomes in the group randomized to remain on atorvastatin 10 mg (p = 0.039), but not in the group that intensified atorvastatin treatment to 80 mg (p = 0.24). Further, PCSK9 levels measured 1 year post-randomization did not change upon increase of the statin dose. CONCLUSIONS: PCSK9 levels predict cardiovascular events in patients treated with low-dose atorvastatin. (A Study to Determine the Degree of Additional Reduction in CV Risk in Lowering LDL Below Minimum Target Levels [TNT]; NCT00327691).

Advances in genetics show the need for extending screening strategies for autosomal dominant hypercholesterolaemia.

Aims Autosomal dominant hypercholesterolaemia (ADH) is a major risk factor for coronary artery disease. This disorder is caused by mutations in the genes coding for the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin 9 (PCSK9). However, in 41% of the cases, we cannot find mutations in these genes. In this study, new genetic approaches were used for the identification and validation of new variants that cause ADH. Methods and results Using exome sequencing, we unexpectedly identified a novel APOB mutation, p.R3059C, in a small-sized ADH family. Since this mutation was located outside the regularly screened APOB region, we extended our routine sequencing strategy and identified another novel APOB mutation (p.K3394N) in a second family. In vitro analyses show that both mutations attenuate binding to the LDLR significantly. Despite this, both mutations were not always associated with ADH in both families, which prompted us to validate causality through using a novel genetic approach. Conclusion This study shows that advances in genetics help increasing our understanding of the causes of ADH. We identified two novel functional APOB mutations located outside the routinely analysed APOB region, suggesting that screening for mutations causing ADH should encompass the entire APOB coding sequence involved in LDL binding to help identifying and treating patients at increased cardiovascular risk.

Cardiovascular risk in relation to functionality of sequence variants in the gene coding for the low-density lipoprotein receptor: a study among 29,365 individuals tested for 64 specific low-density lipoprotein-receptor sequence variants.

AIMS: A plethora of mutations in the LDL-receptor gene (LDLR) underlie the clinical phenotype of familial hypercholesterolaemia (FH). For the diagnosis of FH, it is important, however, to discriminate between pathogenic and non-pathogenic mutations. The aim of the current study was to assess whether true pathogenic mutations were indeed associated with the occurrence of coronary artery disease (CAD) when compared with non-functional variants. The latter variants should not exhibit such an association with CAD. METHODS AND RESULTS: We assessed 29 365 individuals tested the 64 most prevalent LDLR variants. First, we determined pathogenicity for each of these sequence variants. Subsequently, a Cox-proportional hazard model was used to compare event-free survival, defined as the period from birth until the first CAD event, between carriers and non-carriers of LDLR mutations. Fifty-four sequence variants in the LDLR gene were labelled as pathogenic and 10 as non-pathogenic. The 9 912 carriers of a pathogenic LDLR mutation had a shorter event-free survival than the 18 393 relatives who did not carry that mutation; hazard ratio 3.64 [95% confidence interval (CI): 3.24-4.08; P< 0.001]. In contrast, the 355 carriers of a non-pathogenic LDLR variant had similar event-free survival as the 705 non-carrying relatives; hazard ratio 1.00 (95% CI: 0.52-1.94; P= 0.999). CONCLUSION: These findings with respect to clinical outcomes substantiate our criteria for functionality of LDLR sequence variants. They also confirm the CAD risk associated with FH and underline that these criteria can be used to decide whether a specific sequence variant should be used in cascade screening.