Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

BACKGROUND

Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies.

METHODS

For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia.

FINDINGS

Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified.

INTERPRETATION

Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life.

FUNDING

Pfizer, Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Daiichi Sankyo, and Regeneron.

Global perspective of familial hypercholesterolaemia: a cross-sectional study from the EAS Familial Hypercholesterolaemia Studies Collaboration (FHSC)

BACKGROUND

The European Atherosclerosis Society Familial Hypercholesterolaemia Studies Collaboration (FHSC) global registry provides a platform for the global surveillance of familial hypercholesterolaemia through harmonisation and pooling of multinational data. In this study, we aimed to characterise the adult population with heterozygous familial hypercholesterolaemia and described how it is detected and managed globally.

METHODS

Using FHSC global registry data, we did a cross-sectional assessment of adults (aged 18 years or older) with a clinical or genetic diagnosis of probable or definite heterozygous familial hypercholesterolaemia at the time they were entered into the registries. Data were assessed overall and by WHO regions, sex, and index versus non-index cases.

FINDINGS

Of the 61 612 individuals in the registry, 42 167 adults (21 999 [53·6%] women) from 56 countries were included in the study. Of these, 31 798 (75·4%) were diagnosed with the Dutch Lipid Clinic Network criteria, and 35 490 (84·2%) were from the WHO region of Europe. Median age of participants at entry in the registry was 46·2 years (IQR 34·3-58·0); median age at diagnosis of familial hypercholesterolaemia was 44·4 years (32·5-56·5), with 40·2% of participants younger than 40 years when diagnosed. Prevalence of cardiovascular risk factors increased progressively with age and varied by WHO region. Prevalence of coronary disease was 17·4% (2·1% for stroke and 5·2% for peripheral artery disease), increasing with concentrations of untreated LDL cholesterol, and was about two times lower in women than in men. Among patients receiving lipid-lowering medications, 16 803 (81·1%) were receiving statins and 3691 (21·2%) were on combination therapy, with greater use of more potent lipid-lowering medication in men than in women. Median LDL cholesterol was 5·43 mmol/L (IQR 4·32-6·72) among patients not taking lipid-lowering medications and 4·23 mmol/L (3·20-5·66) among those taking them. Among patients taking lipid-lowering medications, 2·7% had LDL cholesterol lower than 1·8 mmol/L; the use of combination therapy, particularly with three drugs and with proprotein convertase subtilisin-kexin type 9 inhibitors, was associated with a higher proportion and greater odds of having LDL cholesterol lower than 1·8 mmol/L. Compared with index cases, patients who were non-index cases were younger, with lower LDL cholesterol and lower prevalence of cardiovascular risk factors and cardiovascular diseases (all p<0·001).

INTERPRETATION

Familial hypercholesterolaemia is diagnosed late. Guideline-recommended LDL cholesterol concentrations are infrequently achieved with single-drug therapy. Cardiovascular risk factors and presence of coronary disease were lower among non-index cases, who were diagnosed earlier. Earlier detection and greater use of combination therapies are required to reduce the global burden of familial hypercholesterolaemia.

FUNDING

Pfizer, Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Daiichi Sankyo, and Regeneron.

Decreased Insulin Sensitivity and Impaired Fibrinolytic Activity in Type 2 Diabetes Patients and Nondiabetics with Ischemic Stroke

We analyzed (a) insulin sensitivity (IS), (b) plasma insulin (PI), and (c) plasminogen activator inhibitor-1 (PAI-1) in type 2 diabetes (T2D) patients with (group A) and without (group B) atherothrombotic ischemic stroke (ATIS), nondiabetics with ATIS (group C), and healthy controls (group D). IS was determined by minimal model (Si). Si was lower in A versus B (1.18 ± 0.67 versus 2.82 ± 0.61 min-1/mU/L × 104; P < 0.001) and in C versus D (3.18 ± 0.93 versus 6.13 ± 1.69 min-1/mU/L × 104; P < 0.001). PI and PAI-1 were higher in A versus B (PI: 19.61 ± 4.08 versus 14.91 ± 1.66 mU/L; P < 0.001, PAI-1: 7.75 ± 1.04 versus 4.57 ± 0.72 mU/L; P < 0.001) and in C versus D (PI: 15.14 ± 2.20 versus 7.58 ± 2.05 mU/L; P < 0.001, PAI-1: 4.78 ± 0.98 versus 3.49 ± 1.04 mU/L; P < 0.001). Si correlated with PAI-1 in T2D patients and nondiabetics, albeit stronger in T2D. Binary logistic regression identified insulin, PAI-1, and Si as independent predictors for ATIS in T2D patients and nondiabetics. The results imply that insulin resistance and fasting hyperinsulinemia might exert their atherogenic impact through the impaired fibrinolysis.

Relationship between obesity, adipocytokines and inflammatory markers in type 2 diabetes: relevance for cardiovascular risk prevention

This study aimed to analyse the impact of obesity in type 2 diabetes (T2D) on adipocytokines (adiponectin, leptin and resistin) and inflammatory markers (TNF-α, IL-6 and hsCRP) as cardiovascular risk factors. A cross-sectional study comparing the basal levels of adipocytokines and inflammatory markers was done in 18 obese (BMI ≥ 30 kg/m²) (group A), 21 overweight (25 kg/m² ≤ BMI < 30 kg/m²) (group B), 25 non-obese T2D patients (group C) and 15 non-obese controls (group D). The lowest levels of adiponectin and the highest levels of leptin, resistin, TNF-α, IL-6 and hsCRP were found in group A. Adiponectin levels were significantly lower, and resistin, TNF-α, and hsCRP levels were elevated in group C vs. D. However, leptin and IL-6 levels differed significantly between groups A and B, but not between groups C and D. Moreover, we found a significant negative correlation between adiponectin and TNF-α, but not with other markers, which was independent of the presence of obesity. In contrast, leptin and resistin correlated with the inflammatory markers, and this correlation was obesity-dependent. Our results suggest that obesity influences cardiovascular risk primarily through changes in leptin and resistin and less efficiently at the level of adiponectin.

High Risk First Degree Relatives of Type 1 Diabetics: An Association with Increases in CXCR3(+) T Memory Cells Reflecting an Enhanced Activity of Th1 Autoimmune Response

We analyzed the level of (a) CXCR3(+) (Th1) and CCR4(+) (Th2) T memory cells (b) interferon- γ inducible chemokine (IP-10)(Th1) and thymus and activation-regulated chemokine (TARC)(Th2), in 51 first degree relatives (FDRs) of type 1 diabetics (T1D) (17 high risk FDRs (GADA(+), IA-2(+)) and 34 low risk FDRs (GADA(-), IA-2(-))), 24 recent-onset T1D (R-T1D), and 18 healthy subjects. T memory subsets were analyzed by using four-color immunofluorescence staining and flowcytometry. IP-10 and TARC were determined by ELISA. High risk FDRs showed higher levels of CXCR3(+) and lower level of CCR4(+) T memory cells compared to low risk FDRs (64.98 ± 5.19 versus 42.13 ± 11.11; 29.46 ± 2.83 versus 41.90 ± 8.58%, resp., P < 0.001). Simultaneously, both IP-10 and TARC levels were increased in high risk versus low risk FDRs (160.12 ± 73.40 versus 105.39 ± 71.30; 438.83 ± 120.62 versus 312.04 ± 151.14 pg/mL, P < 0.05). Binary logistic regression analysis identified the level of CXCR3(+) T memory cells as predictors for high risk FDRs, together with high levels of IP-10. The results imply that, in FDRs, the risk for T1D might be strongly influenced by enhanced activity of Th1 and diminished activity of Th2 autoimmune response.

Human fetal islet transplantation in type 1 diabetics: comparison of immunological effects between multiple implantation regimens

Previous studies have suggested that the multiple transplants might be equally metabolically efficient to a single regimen for human adult islets. The aim of this study was to compare immunological and metabolic parameters after each of the two regimens of human fetal islets (HFI). Group A single transplants (n = 9) had 180 +/- 20 x 1000 HFI equivalents (IEQs) implanted via a single intramuscular injection. In group B multiple transplants (n = 8) islets were implanted by three consecutive injections of 60 +/- 10 x 1000 IEQs at 7-day intervals. We analyzed the immunological parameters of CD4/CD8 T lymphocyte ratios; islet cell antibodies (ICAs) and insulin antibodies (IAs). We estimated insulin secreting capacity (ISC) as the metabolic parameter. We observed that the CD4+/CD8+ T-cell ratio increased, peaking on day 90, in similar fashion in both groups: day -1: A = 1.18 +/- 0.03 versus B = 1.19 +/- 0.04; on day 90: A = 1.79 +/- 0.09, versus B = 1.75 +/- 0.08 (P = NS) immediately before the decrease in C-peptide levels. Thereafter the ratios rapidly decreased without statistical differences. The levels of ICAs did not change. The levels of IAs, which were increased before transplant, then decreased without statistical differences between the groups. The values of ISC increased after transplant and then decreased similar to the T-cell ratio. Our results demonstrated that regimens of multiple and single HFIs did not show differences in the kinetics of the immunological response presumably mediating graft destruction. The CD4/CD8 ratio increased as the C-peptide level decreased, peaking on day 90 at the time of a decrease in C-peptide. These results may be useful for clinical studies of HFIs for type 1 diabetic patients.

Human fetal islet transplantation in type 1 diabetic patients: Comparison of metabolic effects between single and multiple implantation regimens

Previous studies suggest that multiple transplantations might be equally efficient to a single regimen for human adult islets. The aim of this study was to compare metabolic parameters after each of the two regimens of human fetal islet (HFI) transplantation in type 1 diabetics. In group A (single transplant, n = 9), 180 +/- 20 x 1000 HFI equivalents (IEQs) were implanted by a single IM injection; in group B (multiple transplants, n = 8) islets were implanted as three consecutive injections (60 +/- 10 x 1000 IEQs) at 7-day intervals. We analyzed the metabolic parameters on days -1, 30, 60, 90, 120, 150, and 180 after the procedure. Among the metabolic parameters, we evaluated insulin secretion capacity-ISC (C peptide, RIA), metabolic control (HbA1c, chromatography), and insulin daily dose IDD. We found that C peptide levels increased, peaking on day 90 (A: 0.38 +/- 0.15; B: 0.34 +/- 0.19 nmol/L, P = NS) and then rapidly decreasing without differences, the HbA1c levels and IDD decreased in the same manner without differences between the groups. Our results demonstrate that multiple and single islet transplant regimens are equally efficient to temporarily restore a significant ISC with improvement of metabolic and clinical parameters. The results imply that the two regimens have an equal clinical value.

Relation between course of disease in type 1 diabetes and islet cell antibodies

The aim of this study was to estimate the possibility of predicting the course of type 1 diabetes. We analyzed the importance of islet cell antibody levels and residual beta cell function in 46 newly diagnosed patients with diabetes. Islet cell antibodies (ICAs; Juvenile Diabetes Foundation [JDF] units) were determined at the time of diagnosis by the indirect immunofluorescent method. beta cell function was estimated by C peptide levels (nmol/L) before and after glucagon stimulation at the time of clinical remission. Of the 46 patients, 13 were ICA negative (group A). Among ICA-positive patients, ICAs were < 20 JDF units (group B) in 15, between 20 and 80 JDF in 9 (group C), and > 80 JDF in 9 (group D). In group A, 9 patients had clinical remission for 7.5 +/- 1.7 months. Their basal C peptide level was 0.26 +/- 0.05 nmol/L and it increased after stimulation to 44.5 +/- 2.5%. Ten patients in group B had remission for 6.2 +/- 1.5 months. Their basal C peptide levels (0.28 +/- 0.07 nmol/L) were similarly increased after stimulation (47.5 +/- 2.5%). In group C, all patients had remission and it was of the longest duration (14.7 +/- 1.5 months). They had the highest basal C peptide levels (0.45 +/- 0.12 nmol/L) with increases to 57.5 +/- 3.5%. Seven patients in group D with ICA levels > 80 JDF had a short remission (3.2 +/- 1.2 months) despite good basal C peptide levels (0.42 +/- 0.05 nmol/L) and excellent increases after stimulation (92.5%). Our results suggest that moderate levels of ICA are associated with good residual beta cell function and longer remission. Very high ICA levels (> 80 JDF) at the time of diagnosis despite better beta cell function are associated with short clinical remission. Therefore, high ICA levels could be a marker of strong autoimmune reaction and accelerated depletion of beta cell function.