Screening for familial hyper-beta-lipoproteinaemia in children in hospital

Statins for children with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia is one of the most common inherited metabolic diseases and is an autosomal dominant disorder meaning heterozygotes, or carriers, are affected. Those who are homozygous have severe disease. The average worldwide prevalence of heterozygous familial hypercholesterolemia is at least 1 in 500, although recent genetic epidemiological data from Denmark and next generation sequencing data suggest the frequency may be closer to 1 in 250. Diagnosis of familial hypercholesterolemia in children is based on elevated total cholesterol and low-density lipoprotein cholesterol levels or DNA-based analysis, or both. Coronary atherosclerosis has been detected in men with heterozygous familial hypercholesterolemia as young as 17 years old and in women with heterozygous familial hypercholesterolemia at 25 years old. Since the clinical complications of atherosclerosis occur prematurely, especially in men, lifelong treatment, started in childhood, is needed to reduce the risk of cardiovascular disease. In children with the disease, diet was the cornerstone of treatment but the addition of lipid-lowering medications has resulted in a significant improvement in treatment. Anion exchange resins, such as cholestyramine and colestipol, were found to be effective, but they are poorly tolerated. Since the 1990s studies carried out on children aged 6 to 17 years with heterozygous familial hypercholesterolemia have demonstrated significant reductions in their serum total and low-density lipoprotein cholesterol levels. While statins seem to be safe and well-tolerated in children, their long-term safety in this age group is not firmly established. This is an update of a previously published version of this Cochane Review.

OBJECTIVES

To assess the effectiveness and safety of statins in children with heterozygous familial hypercholesterolemia.

SEARCH METHODS

Relevant studies were identified from the Group's Inborn Errors and Metabolism Trials Register and Medline. Date of most recent search: 04 November 2019.

SELECTION CRITERIA

Randomized and controlled clinical studies including participants up to 18 years old, comparing a statin to placebo or to diet alone.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for inclusion and extracted data.

MAIN RESULTS

We found 26 potentially eligible studies, of which we included nine randomized placebo-controlled studies (1177 participants). In general, the intervention and follow-up time was short (median 24 weeks; range from six weeks to two years). Statins reduced the mean low-density lipoprotein cholesterol concentration at all time points (high-quality evidence). There may be little or no difference in liver function (serum aspartate and alanine aminotransferase, as well as creatinine kinase concentrations) between treated and placebo groups at any time point (low-quality evidence). There may be little or no difference in myopathy (as measured in change in creatinine levels) (low-quality evidence) or clinical adverse events (moderate-quality evidence) with statins compared to placebo. One study on simvastatin showed that this may slightly improve flow-mediated dilatation of the brachial artery (low-quality evidence), and on pravastatin for two years may have induced a regression in carotid intima media thickness (low-quality evidence). No studies reported rhabdomyolysis (degeneration of skeletal muscle tissue) or death due to rhabdomyolysis, quality of life or compliance to study medication.

AUTHORS' CONCLUSIONS

Statin treatment is an effective lipid-lowering therapy in children with familial hypercholesterolemia. Few or no safety issues were identified. Statin treatment seems to be safe in the short term, but long-term safety remains unknown. Children treated with statins should be carefully monitored and followed up by their pediatricians and their care transferred to an adult lipidologist once they reach 18 years of age. Large long-term randomized controlled trials are needed to establish the long-term safety issues of statins.

Statins for children with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia is one of the most common inherited metabolic diseases and is an autosomal dominant disorder meaning heterozygotes, or carriers, are affected. Those who are homozygous have severe disease. The average worldwide prevalence of heterozygous familial hypercholesterolemia is at least 1 in 500, although recent genetic epidemiological data from Denmark and next generation sequencing data suggest the frequency may be closer to 1 in 250. Diagnosis of familial hypercholesterolemia in children is based on elevated total cholesterol and low-density lipoprotein cholesterol levels or DNA-based analysis, or both. Coronary atherosclerosis has been detected in men with heterozygous familial hypercholesterolemia as young as 17 years old and in women with heterozygous familial hypercholesterolemia at 25 years old. Since the clinical complications of atherosclerosis occur prematurely, especially in men, lifelong treatment, started in childhood, is needed to reduce the risk of cardiovascular disease. In children with the disease, diet was the cornerstone of treatment but the addition of lipid-lowering medications has resulted in a significant improvement in treatment. Anion exchange resins, such as cholestyramine and colestipol, were found to be effective, but they are poorly tolerated. Since the 1990s studies carried out on children aged 6 to 17 years with heterozygous familial hypercholesterolemia have demonstrated significant reductions in their serum total and low-density lipoprotein cholesterol levels. While statins seem to be safe and well-tolerated in children, their long-term safety in this age group is not firmly established. This is an update of a previously published version of this Cochane Review.

OBJECTIVES

To assess the effectiveness and safety of statins in children with heterozygous familial hypercholesterolemia.

SEARCH METHODS

Relevant studies were identified from the Group's Inborn Errors and Metabolism Trials Register and Medline.Date of most recent search: 20 February 2017.

SELECTION CRITERIA

Randomized and controlled clinical studies including participants up to 18 years old, comparing a statin to placebo or to diet alone.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for inclusion and extracted data.

MAIN RESULTS

We found 26 potentially eligible studies, of which we included nine randomized placebo-controlled studies (1177 participants). In general, the intervention and follow-up time was short (median 24 weeks; range from six weeks to two years). Statins reduced the mean low-density lipoprotein cholesterol concentration at all time points (moderate quality evidence). Serum aspartate and alanine aminotransferase, as well as creatinine kinase concentrations, did not differ between treated and placebo groups at any time point (low quality evidence). The risks of myopathy (low quality evidence) and clinical adverse events (moderate quality evidence) were very low and also similar in both groups. In one study simvastatin was shown to improve flow-mediated dilatation of the brachial artery (low quality evidence), and in another study treatment with pravastatin for two years induced a significant regression in carotid intima media thickness (low quality evidence).

AUTHORS' CONCLUSIONS

Statin treatment is an effective lipid-lowering therapy in children with familial hypercholesterolemia. No significant safety issues were identified. Statin treatment seems to be safe in the short term, but long-term safety remains unknown. Children treated with statins should be carefully monitored and followed up by their pediatricians and their care transferred to an adult lipidologist once they reach 18 years of age. Large long-term randomized controlled trials are needed to establish the long-term safety issues of statins.

Statins for children with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia is one of the most common inherited metabolic diseases; the average worldwide prevalence of heterozygous familial hypercholesterolemia is at least 1 in 500. Diagnosis of familial hypercholesterolemia in children is based on highly elevated low-density lipoprotein (LDL) cholesterol level or DNA-based analysis, or both. Coronary atherosclerosis has been detected in men with heterozygous familial hypercholesterolemia as young as 17 years old and in women with heterozygous familial hypercholesterolemia at 25 years old. Since the clinical complications of atherosclerosis occur prematurely, especially in men, lifelong hypolipidemic measures, started in childhood, are needed to reduce the risk of cardiovascular disease. In children with familial hypercholesterolemia, diet is as yet the cornerstone of treatment. Anion exchange resins, such as cholestyramine and colestipol, have also been found to be effective, but are poorly tolerated. Since the 1990s statin studies have been carried out among children with familial hypercholesterolemia (aged 7 to 17 years). Statins greatly reduced their serum LDL cholesterol levels. Even though statins seem to be safe and well-tolerated in children, their long-term safety in this age group is not firmly established.

OBJECTIVES

To assess the effectiveness and safety of statins in children with familial hypercholesterolemia.

SEARCH METHODS

Relevant studies were identified from the Group's Inborn Errors and Metabolism Trials Register and Medline.Date of most recent search: 14 October 2013.

SELECTION CRITERIA

Randomized and controlled clinical studies including participants up to 18 years old, comparing a statin to placebo or to diet alone.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for inclusion and extracted data.

MAIN RESULTS

We found 21 potentially eligible studies, of which we included eight randomized placebo-controlled studies (1074 participants). In general, the intervention and follow-up time was short (median 24 weeks; range from six weeks to two years). Statins reduced the mean LDL cholesterol concentration at all time points. Serum aspartate and alanine aminotransferase, as well as creatinine kinase concentrations, did not differ between treated and placebo groups at any time point. The risks of myopathy and clinical adverse events were very low and also similar in both groups. In one study simvastatin was shown to improve flow-mediated dilatation of the brachial artery, and in another study treatment with pravastatin for two years induced a significant regression in carotid intima media thickness.

AUTHORS' CONCLUSIONS

Statin treatment is an efficient lipid-lowering therapy in children with familial hypercholesterolemia. No significant safety issues were identified. Statin treatment seems to be safe in the short term, but long-term safety is unknown. Children treated with statins should be carefully monitored and followed up by their pediatricians or physicians into adulthood. Large long-term randomized controlled trials are needed to establish the long-term safety issues of statins.

Serum total cholesterol and ferritin and blood haemoglobin concentrations in primary schoolchildren

Serum total cholesterol and ferritin and haemoglobin concentrations were measured in blood samples obtained by venepuncture in 378 of 593 children aged 5-6 or 8-9 years from seven primary schools in Canterbury. This study formed part of an investigation to assess the feasibility of including a venepuncture procedure for monitoring purposes in primary schoolchildren. Although only one child had a very low haemoglobin concentration of 61 g/l, a large percentage, 25% in the rising 6 years and 7% in the rising 9 years, had concentrations between 100 and 115 g/l--that is, less than the reference fifth centile. Eight per cent had a serum ferritin concentration less than 8 micrograms/l. Cholesterol concentrations higher than 5.2 mmol/l were found in 20% of the 5-6 year olds and 23% of the 8-9 year olds, and in 19% of boys and 25% of girls. About 5% of children had cholesterol concentrations above 6 mmol/l. The number of children with anaemia, iron deficiency, and high cholesterol raises serious concerns about the nutritional and coronary heart disease risk of British children.

Familial hypercholesterolaemia: pilot study to identify children at risk

AIMS

To evaluate a more effective method of identifying children with familial hypercholesterolaemia by screening a population at high risk.

METHODS

Domiciliary measurement of random cholesterol concentration was made in 200 children who were first or second degree relatives of subjects with premature onset coronary artery disease. Measurements were taken by a health visitor using a portable analyser.

RESULTS

Twelve new cases of familial hypercholesterolaemia were identified during the first nine months of the study. Random cholesterol concentrations were within the normal range (< 5.2 mmol/l) in 70.5% of samples tested. Forty two (21%) of patients tested had a borderline cholesterol (5.2-5.9 mmol/l) but 50% of these fell within the normal range when fasting capillary samples were analysed. Children with significant hypercholesterolaemia on random testing (concentrations of > 5.9 mmol/l) (8.5%) also had fasting venous blood assayed for high density lipoprotein (HDL) cholesterol and tri-glyceride in the laboratory. Results indicated that 6.5% of patients screened were at high risk of cardiovascular disease (ratio of total: HDL cholesterol of > 4.5), and 1% had a moderately increased risk (ratio 3.5-4.5).

CONCLUSIONS

Children with familial hypercholesterolaemia can be identified from a selected "high risk" population by measuring random capillary cholesterol concentration.

Longitudinal study of cholesterol values in 68 children from birth to 11 years of age

Sixty eight children born in 1977 who were taking part in an unrelated study of childhood asthma were selected to have their serum cholesterol concentrations measured at birth, and at 4 months and 1, 2, 3, 4, 5, and 11 years of age. Concentrations of high density lipoprotein were measured at 5 and 11 years. Cholesterol values increased rapidly from birth and plateaued at 1 year. There was a further small rise just before puberty. Tracking of values was seen after the age of 1 year, but did not become established until 4 years of age. The cholesterol concentrations in girls were marginally higher than those in boys. The mean (SD) values of cholesterol (mmol/l) for boys were: at birth, 1.7 (0.4); at 1 year, 3.9 (0.9); at 5 years, 5.2 (1.9); and at 11 years, 5.0 (0.7). For girls the corresponding figures were; at birth, 1.9 (0.6); at 1 year, 4.7 (1.0); at 5 years, 4.6 (0.7); and at 11 years, 5.1 (0.7). The mean (SD) high density lipoprotein concentrations (mmol/l) for boys were: at 5, 1.16 (0.35) and at 11, 1.51 (0.23). For girls they were 1.28 (0.30) and 1.56 (0.27), respectively. The serum cholesterol concentrations in these children were high compared with published figures from north America.

Treatment of hypercholesterolemia

After discussing the indications for treatment of familial hypercholesterolemia and the importance of a differential diagnosis, the authors describe drug therapy for the disorder with special attention to combined drug regimens. The surgical treatment of hypercholesterolemia and the treatment of homozygous and other forms of hypercholesterolemia are also detailed.

Lipoprotein measurements--a necessity for precise assessment of risk in children from high-risk families

Serum lipids and lipoproteins were measured in 67 high-risk children, aged between 2 and 17 years, who were the offspring of 33 fathers with hypercholesterolaemia. 18 of the 33 fathers had had a myocardial infarction (MI) before 44 years of age. In 15 of the fathers there was no history of accelerated coronary heart disease (CHD). No difference in the concentrations of the serum lipids and lipoproteins was found between the children whose fathers had a history of MI (n = 31) and the children with no family history of CHD (n = 36). Serum lipids and lipoproteins were also measured in a control group of 19 children, aged between 2 and 17, whose parents were normolipaemic and had no history of atherosclerosis. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDLc) concentrations were significantly higher—5·47 ± 1·36 mmol/l (211 ± 52 mg/100 ml) and 3·55 ± 1·16 mmol/l (137 ± 45 mg/100 ml) respectively—in the 67 `high-risk' children than in the control group—TC, 4·46 ± 0·64 mmol/l (172 ± 25 mg/100 ml); LDLc, 2·56 ± 0·64 mmol/l (99 ± 25 mg/100 ml). No statistically significant difference was found in serum triglyceride (TG) or high-density lipoprotein-cholesterol (HDLc) concentrations between these two groups. In 7 of the high-risk children, raised levels of serum TC >5·74 mmol/l (>221 mg/100 ml) were due to raised HDLc >1·95 mmol/l (>75 mg/100 ml) and normal LDLc <3·84 mmol/l (<148 mg/100 ml). In spite of their increased TC levels these children are probably at a lower risk for CHD as a result of the protective effect of HDL. In 3 children, raised concentrations of LDLc (>3·84 mmol/l) were accompanied by low levels of HDLc (<1·19 mmol/l) and normal concentrations of TC (<5·74 mmol/l). These children are probably at the highest risk for CHD. The correct diagnosis would have been missed in 10 (15%) of the children had only TC been measured. It is therefore imperative to measure lipoprotein levels in addition to TC in all children from `high-risk' families, regardless of their TC concentrations.

Hyperlipidaemia, smoking and hypertension. The place of the hyperlipidaemias

Of the primary hyperlipidaemias, familial hypercholesterolaemia (hyerbetalipoproteinaemia, type II) is always expressed in childhood and carries a high risk for the early development of coronary heart disease. The diagnosis can be established with a high degree of certainty by estimating the serum cholesterol concentration in selected children in whom the genetic risk is known to be great, e.g. if a parent or other first-degree relative is known to have the disease, or if a parent has had an attack of ischaemic heart disease at a young age. Screening of the general population in order to detect this disorder is not advocated. Treatment by either diet or drugs will lower serum cholesterol but long-term compliance is poor and the effect of treatment on the atherosclerotic process has not been evaluated. Follow-up studies must be maintained.

Familial hypertriglyceridaemic states are rarely fully expressed during childhood, and screening for them at this age is not practicable. Control of co-existent obesity and dietary treatment are usually successful in lowering serum lipids but long-term results have not yet been evaluated.

In a childhood population, single estimations of serum cholesterol or triglyceride should be interpreted with caution. Percentile rank correlations for serum cholesterol are of the order of 0·61 and for triglyceride of 0·31. Prediction of adult values cannot therefore be assured in childhood and the place of hyperlipidaemia in the childhood population as a risk factor for coronary heart disease in adult life is not established. Thus population screening of serum lipids in children cannot be justified. Evidence that a change in the diet of children which would be expected to lower serum lipids will also delay the development of atherosclerosis in general and coronary heart disease in particular is lacking. Nevertheless the dietary changes which have been recommended for adults can safely be followed by children, and changes in eating habits are perhaps more likely to succeed if promoted on a family basis rather than for individual sections of the population.

Diagnosing familial hypercholesterolaemia in childhood by measuring serum cholesterol

The serum cholesterol concentrations of 134 children aged 1-16 years who had at least one first-degree relative with presumed familial hypercholesterolaemia showed a bimodal distribution, and, using the maximum likelihood technique, two overlapping curves could be fitted. The mean value of the affected children (heterozygotes) was 8-9 mmol/l and that of the unaffected 4-9 mmol/l. The two curves intersected at 6-77 mmol/l, and at this point 5% of the unaffected children had values over 6-77 mmol/l and 3-5% of the heterozygotes had values under 6-77 mmol/l. If this cholesterol concentration is used as a cut-off point 4-25% of cases would be misdiagnosed.