Use of cholestyramine in the treatment of children with familial combined hyperlipidemia

Successful pharmacological management of a child with compound heterozygous familial hypercholesterolemia and review of the recent literature

Severe familial hypercholesterolemia (SFH) is characterized by markedly elevated low-density lipoprotein cholesterol (LDL-C) and severe early-onset cardiovascular disease if left untreated. We report on the decade-long therapeutic journey of a 15-year-old boy with SFH due to a severe compound heterozygous genotype. He presented at the age of 5 years with widespread xanthomas and LDL-C of 17.4 mmol/L. He was diagnosed with SFH, initially treated with colestyramine that was subsequently combined with simvastatin. At the age of 12 years, he was diagnosed to have supravalvular aortic stenosis and ezetimibe/atorvastatin was introduced in place of colestyramine/simvastatin. At the age of 14 years, he received triple therapy with evolocumab, initially at the recommended dose of 420 mg monthly and then reduced to 140 mg biweekly. Currently at the age of 15 years, he is on atorvastatin 40 mg ON, ezetimibe 10 mg OM, and evolocumab 140 mg biweekly, achieving LDL-C levels of 2.4 mmol/L. Genetic testing identified compound heterozygous mutations in the LDL receptor genes [c.(940 + 1_941-1) (1845 + 1_1846-1)dup] and exon 12, nucleotide c.1747 C > T, amino acid p.(His583Tyr). Medical management without lipoprotein apheresis can achieve target LDL-C in children with SFH. Our patient, who developed supravalvular aortic stenosis at the age of 12 years, needed early aggressive treatment when SFH guidelines and newer drugs for young children were unavailable. Our patient demonstrated that 140 mg biweekly of evolocumab has the same cholesterol-lowering effect as the recommended 420 mg monthly dose.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF DYSLIPIDEMIA AND PREVENTION OF CARDIOVASCULAR DISEASE

OBJECTIVE

The development of these guidelines is mandated by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPGs).

METHODS

Recommendations are based on diligent reviews of the clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols.

RESULTS

The Executive Summary of this document contains 87 recommendations of which 45 are Grade A (51.7%), 18 are Grade B (20.7%), 15 are Grade C (17.2%), and 9 (10.3%) are Grade D. These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world medical care. The evidence base presented in the subsequent Appendix provides relevant supporting information for Executive Summary Recommendations. This update contains 695 citations of which 203 (29.2 %) are EL 1 (strong), 137 (19.7%) are EL 2 (intermediate), 119 (17.1%) are EL 3 (weak), and 236 (34.0%) are EL 4 (no clinical evidence).

CONCLUSION

This CPG is a practical tool that endocrinologists, other health care professionals, health-related organizations, and regulatory bodies can use to reduce the risks and consequences of dyslipidemia. It provides guidance on screening, risk assessment, and treatment recommendations for a range of individuals with various lipid disorders. The recommendations emphasize the importance of treating low-density lipoprotein cholesterol (LDL-C) in some individuals to lower goals than previously endorsed and support the measurement of coronary artery calcium scores and inflammatory markers to help stratify risk. Special consideration is given to individuals with diabetes, familial hypercholesterolemia, women, and youth with dyslipidemia. Both clinical and cost-effectiveness data are provided to support treatment decisions.

ABBREVIATIONS

4S = Scandinavian Simvastatin Survival Study A1C = glycated hemoglobin AACE = American Association of Clinical Endocrinologists AAP = American Academy of Pediatrics ACC = American College of Cardiology ACE = American College of Endocrinology ACS = acute coronary syndrome ADMIT = Arterial Disease Multiple Intervention Trial ADVENT = Assessment of Diabetes Control and Evaluation of the Efficacy of Niaspan Trial AFCAPS/TexCAPS = Air Force/Texas Coronary Atherosclerosis Prevention Study AHA = American Heart Association AHRQ = Agency for Healthcare Research and Quality AIM-HIGH = Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides trial ASCVD = atherosclerotic cardiovascular disease ATP = Adult Treatment Panel apo = apolipoprotein BEL = best evidence level BIP = Bezafibrate Infarction Prevention trial BMI = body mass index CABG = coronary artery bypass graft CAC = coronary artery calcification CARDS = Collaborative Atorvastatin Diabetes Study CDP = Coronary Drug Project trial CI = confidence interval CIMT = carotid intimal media thickness CKD = chronic kidney disease CPG(s) = clinical practice guideline(s) CRP = C-reactive protein CTT = Cholesterol Treatment Trialists CV = cerebrovascular CVA = cerebrovascular accident EL = evidence level FH = familial hypercholesterolemia FIELD = Secondary Endpoints from the Fenofibrate Intervention and Event Lowering in Diabetes trial FOURIER = Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects With Elevated Risk trial HATS = HDL-Atherosclerosis Treatment Study HDL-C = high-density lipoprotein cholesterol HeFH = heterozygous familial hypercholesterolemia HHS = Helsinki Heart Study HIV = human immunodeficiency virus HoFH = homozygous familial hypercholesterolemia HPS = Heart Protection Study HPS2-THRIVE = Treatment of HDL to Reduce the Incidence of Vascular Events trial HR = hazard ratio HRT = hormone replacement therapy hsCRP = high-sensitivity CRP IMPROVE-IT = Improved Reduction of Outcomes: Vytorin Efficacy International Trial IRAS = Insulin Resistance Atherosclerosis Study JUPITER = Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin LDL-C = low-density lipoprotein cholesterol Lp-PLA2 = lipoprotein-associated phospholipase A2 MACE = major cardiovascular events MESA = Multi-Ethnic Study of Atherosclerosis MetS = metabolic syndrome MI = myocardial infarction MRFIT = Multiple Risk Factor Intervention Trial NCEP = National Cholesterol Education Program NHLBI = National Heart, Lung, and Blood Institute PCOS = polycystic ovary syndrome PCSK9 = proprotein convertase subtilisin/kexin type 9 Post CABG = Post Coronary Artery Bypass Graft trial PROSPER = Prospective Study of Pravastatin in the Elderly at Risk trial QALY = quality-adjusted life-year ROC = receiver-operator characteristic SOC = standard of care SHARP = Study of Heart and Renal Protection T1DM = type 1 diabetes mellitus T2DM = type 2 diabetes mellitus TG = triglycerides TNT = Treating to New Targets trial VA-HIT = Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial VLDL-C = very low-density lipoprotein cholesterol WHI = Women's Health Initiative.

Optimal management of familial hypercholesterolemia: treatment and management strategies

Familial hypercholesterolemia is an autosomally dominant disorder caused by various mutations in low-density lipoprotein receptor genes. This will lead to elevated levels of total and low-density lipoprotein cholesterol, which may in turn lead to premature coronary atherosclerosis and cardiac-related death. The symptoms are more severe in the homozygous type of the disease. Different options for the treatment of affected patients are now available. Diet therapy, pharmacologic therapy, lipid apheresis, and liver transplantation are among the various treatments. We clinically review the treatment and management strategies for the disease in order to shed light on the optimal management of familial hypercholesterolemia.

Approaches to dyslipidemia treatment in children and adolescents

Atherosclerosis represents a disease that begins in childhood, and alterations in lipid concentration play a fundamental role in the development of this condition. Children and adolescents with high cholesterol levels are more likely than their peers in the general population to present with dyslipidemia in adulthood. Precocious identification of dyslipidemias associated with premature cardiovascular disease is crucial during childhood to delay or prevent the atherosclerotic process. The National Cholesterol Education Program has established guidelines for the diagnosis and treatment of dyslipidemia during pediatric age. It has been suggested that a heart-healthy diet should begin at 2 years of age, and no adverse effects on psychological aspects, growth, pubertal development and nutritional status in children and adolescents limiting total and saturated fat intake have been demonstrated. Pharmacotherapy should be considered in children aged 10 years or older when low-density lipoprotein cholesterol concentrations remain very high despite dietary therapy, especially when multiple risk factors are present. The lipid-lowering drugs recommended for childhood and adolescence are resins and statins. The increasing use of statins is dependent on their effectiveness and safety. Ezetimibe, a selective cholesterol absorption inhibitor, may provide a similar cholesterol-lowering effect as that reached with statin treatment. This review provides an update on recent advances in the therapy of dyslipidemia, especially hypercholesterolemia, during pediatric age and adolescence.

Clinical and laboratory assessment of cardiovascular risk in children: Guidelines for screening, evaluation, and treatment

The early lesions of atherosclerosis begin in childhood and are related to antecedent cardiovascular disease (CVD) risk factors. Environmental and genetic factors (eg, diet, obesity, exercise, and certain inherited dyslipidemias) influence progression of such lesions. Identification of youth at risk for atherosclerosis includes an integrated assessment of these predisposing factors. Treatment starts with a diet low in total and saturated fat and cholesterol, use of water-soluble fiber, plant stanols and plant sterols, weight control, and exercise. Drug therapy, for example, with inhibitors of hydroxymethylglutaryl-CoA reductase, bile acid sequestrants, and cholesterol absorption inhibitors, can be considered in those with a positive family history of premature CVD and low-density lipoprotein cholesterol >160 mg/dL after dietary and hygienic measures. Candidates for drug therapy often include those with familial hypercholesterolemia, familial combined hyperlipidemia, the metabolic syndrome, polycystic ovarian syndrome, type 1 diabetes, and the nephrotic syndrome. Such dietary and drug therapy appears safe and efficacious. Early identification and treatment of youth with CVD risk factors and dyslipidemia are likely to retard the atherosclerotic process. Optimal detection and treatment of high-risk children either from the general population or from families with premature CVD will require a comprehensive universal screening and evaluation program.

Rational approach to the treatment for heterozygous familial hypercholesterolemia in childhood and adolescence: a review

Atherosclerosis represents a disease that begins in childhood and in which LDL cholesterol plays a pivotal role for the development of the pathology. Children and adolescents with high cholesterol levels are more likely than their peers to present cholesterol elevation as adults. The identification of genetic dyslipidemias associated with premature cardiovascular disease is crucial during childhood to delay or prevent the atherosclerotic process. Guidelines for the diagnosis and treatment of hypercholesterolemia during pediatric age are available from the National Cholesterol Education Program. A heart-healthy diet should begin at the age of 2 yr and a large number of studies have demonstrated no adverse effects on nutritional status, growth, pubertal development, and psychological aspects in children and adolescents limiting total and saturated fat intake. Pharmacotherapy should be considered in children over 10 yr of age when LDL cholesterol concentrations remain very high despite severe dietary therapy, especially when multiple risk factors are present. The only lipid-lowering drugs recommended up to now for childhood and adolescence are resins reported to be effective and well tolerated, although compliance is very poor because of unpalatability. The use of statins is increasing and seems to be effective and safe in children, even if studies enrolled a small number of patients and evaluated efficacy and safety for short-term periods. Recently, an interesting drug represented by ezetimibe has been found that may provide cholesterol-lowering additive to that reached with statin treatment. This review provides an update on recent advances in the diagnosis, therapy, and follow-up of familial hypercholesterolemia during pediatric age and adolescence.

Screening and treatment for lipid disorders in children and adolescents: systematic evidence review for the US Preventive Services Task Force

OBJECTIVE

This was a systematic evidence review for the US Preventive Services Task Force, intended to synthesize the published evidence regarding the effectiveness of selecting, testing, and managing children and adolescents with dyslipidemia in the course of routine primary care.

METHODS

Literature searches were performed to identify published articles that addressed 10 key questions. The review focused on screening relevant to primary care of children without previously identified dyslipidemias, but included treatment trials of children with dyslipidemia because some drugs have only been tested in that population.

RESULTS

Normal values for lipids for children and adolescents are defined according to population levels (percentiles). Age, gender, and racial differences and temporal trends may alter these statistical cut points. Approximately 40% to 55% of children with elevated total cholesterol and low-density lipoprotein levels will continue to have elevated lipid levels on follow-up. Current screening recommendations based on family history will fail to detect substantial numbers (30%-60%) of children with elevated lipid levels. Drug treatment for dyslipidemia in children has been studied and shown to be effective only for suspected or proven familial monogenic dyslipidemias. Intensive dietary counseling and follow-up can result in improvements in lipid levels, but these results have not been sustained after the cessation of the intervention. The few trials of exercise are of fair-to-poor quality and show little or no improvements in lipid levels for children without monogenic dyslipidemias. Although reported adverse effects were not serious, studies were generally small and not of sufficient duration to determine long-term effects of either short or extended use.

CONCLUSIONS

Several key issues about screening and treatment of dyslipidemia in children and adolescents could not be addressed because of lack of studies, including effectiveness of screening on adult coronary heart disease or lipid outcomes, optimal ages and intervals for screening children, or effects of treatment of childhood lipid levels on adult coronary heart disease outcomes.

Familial combined hyperlipidemia in a North Indian kindred

Familial combined hyperlipidemia is the most common genetic hyperlipidemia and is responsible for premature coronary artery disease. It is genetically heterogenous and no single diagnostic marker exists. The authors report an affected North Indian kindred spanning three successive generations with a possible autosomal dominant pattern of inheritance and all of them had combined dyslipidemia [elevated total cholesterol, predominantly the low density lipoprotein (LDL) fraction and elevated triglycerides]. The proband, a 4-month-old male baby, was incidentally discovered to have a lipaemic serum and so further evaluated. Both the index case and his maternal grandmother, a non-obese diabetic (type 2) with hypertension, had an atherogenic lipoprotein phenotype. Lipaemia retinalis was documented in this baby but xanthomas and coronary artery disease were not noted in the kindred. The present case report highlights the failure of dietary therapy in the proband and explores new options.

Treatment of dyslipidemia in children and adolescents

The early lesions of atherosclerosis begin in childhood, and are related to antecedent cardiovascular disease risk factors. Environmental and genetic factors such as diet, obesity, exercise, and certain inherited dyslipidemias influence the progression of such lesions. The identification of youth at risk for atherosclerosis includes an integrated assessment of these predisposing factors. Treatment starts with a diet low in total and saturated fat and cholesterol, the use of water-soluble fiber and plant sterols, weight control, and exercise. Drug therapy, for example, with inhibitors of hydroxymethylglutaryl CoA reductase, bile acid sequestrants, and cholesterol absorption inhibitors, can be considered in those with a positive family history of premature coronary artery disease and a low-density lipoprotein cholesterol above 160 mg/dL, after dietary and hygienic measures. Candidates for drug therapy often include those with familial hypercholesterolemia, familial combined hyperlipidemia, the metabolic syndrome, polycystic ovarian syndrome, type I diabetes, and the nephrotic syndrome. We review the safety and efficacy of dietary and drug therapy, and propose an updated diagnostic and therapeutic algorithm that includes the metabolic syndrome. The early identification and treatment of youth with dyslipidemias is likely to retard the atherosclerotic process.

Efficacy and safety of lovastatin therapy in adolescent girls with heterozygous familial hypercholesterolemia

OBJECTIVE

The present study was designed to evaluate the lipid-altering efficacy, safety, and tolerability of lovastatin treatment in adolescent girls with heterozygous familial hypercholesterolemia.

METHODS

A total of 54 postmenarchal girls, aged 10 to 17 years, were enrolled in a 24-week, double-blind, randomized, placebo-controlled study. After a 4-week diet/placebo run-in period, patients were randomized to 1 of 2 groups: (1) treatment with diet plus lovastatin 20 mg/day for 4 weeks, followed by diet plus lovastatin 40 mg/day for 20 weeks, or (2) diet plus placebo for 24 weeks.

RESULTS

Baseline values of lipids, lipoproteins, and apolipoproteins (apo) were comparable between treatment groups. Lovastatin treatment was efficacious at reducing low-density lipoprotein cholesterol by 23% to 27%, total cholesterol by 17% to 22%, and apo B by 20% to 23% at weeks 4 and 24, respectively. Between-treatment group differences were not statistically significant for triglycerides, very-low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or apo A-I. Lovastatin was generally safe and well tolerated. There were no clinically significant alterations in vital signs (blood pressure and pulse rate), anthropomorphic measurements (height, weight, and BMI), hormone levels (luteinizing hormone, follicle-stimulating hormone, dehydroepiandrosterone sulfate, estradiol, and cortisol), menstrual cycle length, or tests of liver and muscle function.

CONCLUSIONS

Lovastatin offers an efficacious and well-tolerated treatment option for improving lipid profiles in adolescent girls with familial hypercholesterolemia.

Role of lipid-lowering pharmacotherapy in children

For patients with coronary artery disease and healthy middle-aged or older individuals with elevated cholesterol levels, treatment with cholesterol-lowering drugs reduces morbidity and sometimes mortality. Treatment reverses established atherosclerotic lesions within a relatively short period of time, suggesting that starting cholesterol-lowering drugs in adulthood is adequate for most people at risk. Children with genetic lipid disorders, including familial hypercholesterolaemia and familial combined hyperlipidaemia, may be candidates for earlier therapy. A complete assessment of risk factors should be undertaken to determine which children are at highest risk. Treatment should start with diet, because diet is an important independent protective factor for disease. The bile acid sequestrants (resins) are the only drugs approved for children and may reduce low density lipoprotein (LDL)-cholesterol levels by 15 to 20% at best. Long term tolerability is good, but many children will not take the resins because they find them unpalatable. Tablet formulations have higher acceptability. Some children require supplementation with fat soluble vitamins or folate. Although hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have not been tested in long term studies in children, safety records are excellent in adults. Short term studies show that HMG-CoA reductase inhibitors reduce LDL-cholesterol levels similarly in children and in adults. Thus, the drugs may be used in low dosages to treat some adolescents with exceptional risk of disease.

Effect of medications on taste: example of amitriptyline HCl

Use of medications is a major factor that contributes to taste losses in the elderly. Epidemiological studies suggest that community-dwelling elderly over the age of 65 use an average of 2.9 to 3.7 medications, and this number increases significantly for elderly living in retirement and nursing homes. The tricyclic antidepressant amitriptyline HCl is used by at least half a million people aged 65 years or more. In human studies performed here, amitriptyline HCl was found to have a bitter, unpleasant taste of its own. In addition, it blocked responses to other taste stimuli in both humans and gerbils. This blockage in humans was greater when amitriptyline HCl was applied continuously to the tongue than when it was applied intermittently. Continuous application of the drug affected all of the taste qualities to varying degrees, while intermittent application led to taste decrements only for salts. Electrophysiological studies in gerbils also revealed taste decrements after a short adaptation to amitriptyline HCl.

Compliance with cardiovascular disease prevention strategies: a review of the research

The efficacy of cardiovascular risk-reduction programs has been established. However, the extent to which risk-reduction interventions are effective may depend on adherence. Non-compliance, or non-adherence, may occur with any of the recommended or prescribed regimens and may vary across the treatment course. Compliance problems, whether occurring early or late in the treatment course, are clinically significant, as adherence is one mediator of the clinical outcome. This article, which is based on a review of the empirical literature of the past 20 years, addresses compliance across four regimens of cardiovascular risk reduction: pharmacological therapy, exercise, nutrition, and smoking cessation. The criteria for inclusion of a study in this review were: (a) focus on cardiovascular disease risk reduction; (b) report of a quantitative measure of compliance behavior; and (c) use of a randomized controlled design. Forty-six studies meeting these criteria were identified. A variety of self-report, objective, and electronic measurement methods were used across these studies. The interventions employed diverse combinations of cognitive, educational, and behavioral strategies to improve compliance in an array of settings. The strategies demonstrated to be successful in improving compliance included behavioral skill training, self-monitoring, telephone/mail contact, self-efficacy enhancement, and external cognitive aids. A series of tables summarize the intervention strategies, compliance measures, and findings, as well as the interventions demonstrated to be successful. This review reflects the progress made over two decades in compliance measurement and research and, further, advances made in the application of behavioral strategies to the promotion of cardiovascular risk reduction.

A rational approach to treating hypercholesterolaemia in children. Weighing the risks and benefits

Because atherosclerosis is a continuous process throughout life, expert panels have suggested guidelines to reduce the risk of cardiovascular disease, starting from childhood. The guidelines focus on population-based measures and on treating hypercholesterolaemia in individual children. Low-fat diets in children have been widely debated. There is little evidence that growth is stunted or that nutritional deficiencies arise if the energy that is lost by limiting fat intake is substituted with other nutrients. Dietary fibre, plant sterols and fish oils have been used to modify lipid levels in children; however, the efficacy of these dietary adjuncts is limited. Bile acid-binding resins are the only approved drugs to lower cholesterol levels in children and appear to be well tolerated. However, compliance with resins is low because of unpalatability, so low dosages are preferred and vitamin supplementation is prudent. Data on HMG CoA reductase inhibitors and fibrates are insufficient to recommend these drugs at present. Drug treatment should be restricted to children who are at exceptionally high risk of disease, usually those with genetic dyslipidaemias.

Acceptability and compliance with two forms of cholestyramine in the treatment of hypercholesterolemia in children: a randomized, crossover trial

OBJECTIVE

To compare the acceptability, compliance, and effectiveness of two forms of cholestyramine resin in the treatment of hypercholesterolemia in children.

STUDY DESIGN

Patients aged 10 to 18 years with familial hypercholesterolemia were enrolled in a randomized, crossover trial of two 8-week periods of either a pill or powder form of cholestyramine at a dose of 8 gm/day.

RESULTS

Of 40 children enrolled, 38 completed both medication periods, with a median age of 13 years (range, 10 to 18). At the end of the study, 82% preferred the pill form, 16% the powder form and 2% neither form. Mean (+/-SD) compliance as assessed by the amount of medication taken was significantly greater for pills (61% +/- 31%) than powder (50% +/- 30%, p = 0.01). The form of the medication increased compliance by at least 25% for 16 patients (42%), 13 in favor of pills and 3 in favor of powder. Compliance was not associated with patient attitudes and perceptions of hypercholesterolemia, demographics, family history, previous experience with lipid-lowering medication, or lipid profile parameters. Significant mean reductions in low-density lipoprotein cholesterol concentrations were noted for both pills (-10% +/- 20%, p = 0.006) and powder (-15% +/- 17%, p = 0.0001), with no significant difference between forms (p = 0.16).

CONCLUSIONS

A change in bile acid-binding resin formulation from powder to pills significantly increases acceptability and compliance in some children with hypercholesterolemia.

Colestipol tablets in adolescents with familial hypercholesterolaemia

The objective of this study was to examine palatability and side effects of the new tablet formulation of colestipol. A clinical series of 23 boys and 4 girls aged 10-16 years with heterozygous familial hypercholesterolaemia were given 2-12 g colestipol daily for 6 months in an open study. There were no serious side effects. The median reduction in low density lipoprotein cholesterol level was 20%. All preferred the tablets to resin granules they had tried previously. We conclude that low-dose colestipol tablets appear to be safe and effective, and are preferred by adolescents.

Efficacy and safety of cholestyramine therapy in peripubertal and prepubertal children with familial hypercholesterolemia

OBJECTIVE

To determine the efficacy and safety of cholestyramine therapy in young children with familial hypercholesterolemia.

SUBJECTS

Boys aged 6 to 11 years (n = 57) and girls aged 6 to 10 years (n = 39) with familial hypercholesterolemia.

DESIGN

After 1 year of a low-fat, low-cholesterol diet, children with low-density lipoprotein (LDL) cholesterol levels > or = 4.9 mmol/L (190 mg/di) or < or = 4.1 mmol/L (160 mg/dl) in the presence of familial premature cardiovascular disease were randomly assigned to a double-blind comparison of 8 gm cholestyramine (n = 36) and placebo (n = 36) for 1 year.

OUTCOME MEASURES

The primary efficacy and safety outcomes were serum LDL cholesterol levels and height velocity, respectively. Secondary safety outcomes were erythrocyte folate, total plasma homocysteine, serum fat-soluble vitamins, and side effects.

RESULTS

Twenty-two subjects in the cholestyramine group and 26 in the placebo group completed the 1-year study. Most withdrawals from the study were related to unpalatability of the study drug or placebo. The LDL cholesterol levels changed by -16.9% (95% confidence interval, -10.8% to -22.9%) in the cholestyramine group compared with 1.4% (95% confidence interval, -4.4% to 7.2%) in the placebo group. Mean height velocity standard deviation scores during 1 year for the children in the cholestyramine and the placebo groups who had not started puberty were 0.24 +/- 1.14 and 0.11 +/- 0.68, respectively (not significant). In the cholestyramine group, mean levels of 25-hydroxyvitamin D decreased. One girl had low folate and elevated homocysteine levels, and there was one case of intestinal obstruction caused by adhesions.

CONCLUSIONS

Significant reductions in LDL cholesterol are achievable during treatment with cholestyramine in about half of eligible children. Growth is not adversely affected. Folate deficiency may occur, even with a low dose of cholestyramine, and vitamin D supplements should be considered. Caution should possibly be exercised in starting cholestyramine therapy within 3 months of abdominal surgery in children.

Low dose colestipol in adolescents with familial hypercholesterolaemia

The effects of orange flavoured colestipol granules, 10 g/day, in 37 boys and 29 girls aged 10-16 years with familial hypercholesterolaemia were examined first in an eight week double blind, placebo controlled protocol, then in open treatment for 44-52 weeks. All patients were on a low fat diet. Low density lipoprotein cholesterol levels were reduced by 19.5% by colestipol v 1.0% by placebo. Levels of serum folate, vitamin E, and carotenoids were reduced in the colestipol group, but not the vitamin E/cholesterol and carotenoid/cholesterol ratios or serum concentrations of vitamins A and D. After one year of colestipol, two thirds of the participants remained in the study, of whom half took > or = 80% of the prescribed dose. Those who took > or = 80% of the dose had a greater decrease in serum 25-hydroxyvitamin D levels than those who took < 80%. No adverse effects on weight gain or linear growth velocity were observed. Although low dose colestipol effectively reduces low density lipoprotein cholesterol levels, only a minority of adolescents adhered to the new formulation for one year. Folate and possibly vitamin D supplementation is recommended.

Recent advances in pediatrics

The challenging issues in pediatric pharmacotherapy are both profound and exciting. Microtechnologies for evaluating the impact of genetics in disease (e.g., using polymerase chain reactions) and the possibilities of therapeutic interventions create major clinical and ethical dilemmas that remain to be resolved. Inclusion of pediatric patients in drug development and marketing trials also remains a point of contention. Finally, well-established therapies should not be overlooked in favor of new but unestablished treatment approaches. Future columns will continue to use the current format, in which a few selected topics of high therapeutic importance are discussed. The research technologies, discussion of new drug therapy interventions, and preventive strategies most likely to benefit the health care of infants, children, and adolescents will remain the scope of this column.

Familial combined hyperlipidemia in children: clinical expression, metabolic defects, and management

The first evidence that elevation of plasma levels of cholesterol is a risk factor for the development of atherosclerosis in children came from the Bogalusa Heart Study in 1986, which reported an association between aortic fatty streaks in 3- to 26-year-old subjects and increased plasma levels of low-density lipoprotein cholesterol (LDL-C). The most compelling evidence of a cause-and-effect relationship has come from the multicenter cooperative study called the Pathobiological Determinants of Atherosclerosis in Youth. When the investigators examined the abdominal aorta and the right coronary artery of adolescents and young adults who had died of trauma, they found a significant relationship between the sum of the very low density lipoprotein (VLDL) plus LDL-C level and both fatty streaks and raised atherosclerotic lesions. They also found an inverse relationship between those lesions and increased high-density lipoprotein cholesterol (HDL-C) levels. In addition, their studies showed that smoking (as assessed by the serum thiocyanate level) promotes atherogenesis in children as young as age 15 years. Thus many pediatricians have now accepted the importance of identifying children with significant hypercholesterolemia so that appropriate dietary and life-style modifications can be recommended. This is especially important because there is often a major genetic component to the hyperlipidemia seen in children.

Familial combined hyperlipidemia in children: clinical expression, metabolic defects, and management

Familial combined hyperlipidemia (FCHL) is a dominantly inherited hyperlipidemia that occurs in at least 1% of the adult population and is responsible for 10% of premature coronary artery disease. In families referred for evaluation because of primary hyperlipidemia in a child, FCHL is expressed three times more commonly than familial hypercholesterolemia and half of the siblings are affected. Several metabolic defects apparently are associated with the FCHL phenotype. Most commonly, excess production of very low density lipoprotein apolipoprotein B can be demonstrated. In other families, reduced lipoprotein lipase activity is associated. One allele at a locus influencing apolipoprotein B levels predicts FCHL in a large proportion of families ascertained through affected children. Whether this allele is responsible for the excess of very low density lipoprotein apolipoprotein B detected in metabolic studies has not been elucidated. Management of FCHL in children begins with dietary modification. A bile acid sequestrant may be considered as well if diet cannot reduce the plasma low-density lipoprotein cholesterol level to less than 4.13 mmol/L (160 mg/dl) after the age of 10 years. Although the hydroxymethylglutaryl-coenzyme A reductase inhibitors are not currently recommended for children younger than 19 years of age, we speculate that they will be increasingly utilized for the management of FCHL in teenage boys who continue to have low density lipoprotein cholesterol levels greater than 4.13 mmol/L (160 mg/dl) after dietary modification.