Addition of orlistat to conventional treatment in adolescents with severe obesity

Evaluation of a child for secondary causes of obesity and comorbidities

BACKGROUND

A 15-year-old boy who had been overweight since the age of 6 months was referred to an adolescent obesity clinic for further assessment of his comorbidities and management of his obesity. The patient had no history of developmental delay or abnormal growth velocity. He had previously tested negative for Prader-Willi syndrome and the melanocortin-4 receptor gene mutation. The patient had made numerous attempts at weight loss in the past, but any weight loss he achieved had been temporary. At presentation, the patient had a BMI of 52.3 kg/m(2), a waist circumference of 156 cm, blood pressure of 130/85 mmHg and severe acanthosis nigricans in the cervical and axillary skin folds.

INVESTIGATIONS

Measurement of height, weight, waist circumference and blood pressure; screening tests, including a fasting glucose test, 2 h glucose-tolerance test, measurements of blood lipids and liver function tests.

DIAGNOSIS

Morbid obesity, metabolic syndrome, nonalcoholic fatty liver disease, impaired glucose tolerance and dyslipidemia.

MANAGEMENT

The patient was assigned to an extensive lifestyle-modification and behavior-modification program, with clinic-based follow-up every 4 weeks.

Interventions for treating obesity in children

BACKGROUND

Child and adolescent obesity is increasingly prevalent, and can be associated with significant short- and long-term health consequences.

OBJECTIVES

To assess the efficacy of lifestyle, drug and surgical interventions for treating obesity in childhood.

SEARCH STRATEGY

We searched CENTRAL on The Cochrane Library Issue 2 2008, MEDLINE, EMBASE, CINAHL, PsycINFO, ISI Web of Science, DARE and NHS EED. Searches were undertaken from 1985 to May 2008. References were checked. No language restrictions were applied.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) of lifestyle (i.e. dietary, physical activity and/or behavioural therapy), drug and surgical interventions for treating obesity in children (mean age under 18 years) with or without the support of family members, with a minimum of six months follow up (three months for actual drug therapy). Interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data following the Cochrane Handbook. Where necessary authors were contacted for additional information.

MAIN RESULTS

We included 64 RCTs (5230 participants). Lifestyle interventions focused on physical activity and sedentary behaviour in 12 studies, diet in 6 studies, and 36 concentrated on behaviorally orientated treatment programs. Three types of drug interventions (metformin, orlistat and sibutramine) were found in 10 studies. No surgical intervention was eligible for inclusion. The studies included varied greatly in intervention design, outcome measurements and methodological quality.Meta-analyses indicated a reduction in overweight at 6 and 12 months follow up in: i) lifestyle interventions involving children; and ii) lifestyle interventions in adolescents with or without the addition of orlistat or sibutramine. A range of adverse effects was noted in drug RCTs.

AUTHORS' CONCLUSIONS

While there is limited quality data to recommend one treatment program to be favoured over another, this review shows that combined behavioural lifestyle interventions compared to standard care or self-help can produce a significant and clinically meaningful reduction in overweight in children and adolescents. In obese adolescents, consideration should be given to the use of either orlistat or sibutramine, as an adjunct to lifestyle interventions, although this approach needs to be carefully weighed up against the potential for adverse effects. Furthermore, high quality research that considers psychosocial determinants for behaviour change, strategies to improve clinician-family interaction, and cost-effective programs for primary and community care is required.

Management approaches for pediatric obesity

Childhood obesity is a worldwide problem that has reached epidemic proportions, resulting in an increased prevalence of premature obesity-related morbidities, and, thus, probable increased health-care costs to treat children. The development of viable approaches to manage this epidemic is crucial. Most experts in the field of childhood obesity agree that the prevention of obesity in children should be the first line of management. Pediatricians must be adept at recognizing children at risk of obesity, calculating and plotting the BMI at all visits, using a change in the BMI to identify excessive weight gain, and monitoring for comorbidities associated with obesity. If obesity is present, the cornerstone of treatment is modification of dietary and exercise habits. Practice-based counseling and community-based programs that support and encourage lifestyle modifications have yielded promising short-term results. Children with severe comorbidities who are unable to achieve lifestyle modifications can be considered for either pharmacologic therapy or surgery, but these options should be considered as a last resort. Early intervention and prevention strategies are the most cost-effective methods of dealing with this issue.

Treatment of childhood obesity

PURPOSE OF REVIEW

To provide an overview of treatments for childhood obesity, highlighting recent advances and recommendations.

RECENT FINDINGS

The three main treatment modalities are lifestyle interventions, medications, and bariatric surgery. Recent data support the short-term effectiveness of lifestyle interventions, and show that continued behavioral intervention increases the likelihood of a sustained effect for up to 2 years. New studies and regulatory decisions on medications for obesity (including orlistat, sibutramine, and metformin) are discussed. Emerging data suggest substantial weight loss after bariatric surgery in morbidly obese adolescents but also indicate adverse effects. An expert panel recently provided guidelines that alter definitions of obesity and offer a framework for obesity management. These guidelines are compared with others, and integrated recommendations presented.

SUMMARY

While primary prevention of childhood obesity is important, broadly effective methods to do so are not yet available. Given the large population of obese children and the risks they face, an emphasis on treatment is also critical. We suggest a staged approach, emphasizing early intervention and lifestyle changes. We also suggest limiting bariatric surgery to selected adolescents in Institutional Review Board-approved research studies. Health-policy interventions can facilitate both prevention and treatment of childhood obesity.

Pediatric obesity: parallels with addiction and treatment recommendations

Rates of pediatric obesity have increased dramatically over the past decade. This trend is especially alarming because obesity is associated with significant medical and psychosocial consequences. It may contribute to cardiovascular, metabolic, and hepatic complications, as well as to psychiatric difficulties. The development of obesity appears to be influenced by a complex array of genetic, metabolic, and neural frameworks, along with behavior, eating habits, and physical activity. Numerous parallels exist between obesity and addictive behaviors, including genetic predisposition, personality, environmental risk factors, and common neurobiological pathways in the brain. Typical treatments for pediatric obesity include behavioral interventions targeting diet or exercise. These treatments have yielded mixed results and typically have been examined in specialty clinic populations, limiting their generalizability. There are limited medication options for overweight children and adolescents, and no approved medical intervention in children younger than 16 years old. Bariatric surgery may be an option for some adolescents, but due to the risks of surgery, it is often seen as a last resort. The parallels between addiction and obesity aid in developing novel interventions for pediatric obesity. Motivational enhancement and cognitive-behavioral strategies used in addiction treatment may prove to be beneficial.

Effects of lifestyle intervention and metformin on weight management and markers of metabolic syndrome in obese adolescents

PURPOSE

The purposes of this study are threefold: to determine what components of the metabolic syndrome are present in obese adolescents, to determine what differences exist in the effects of lifestyle intervention versus lifestyle intervention plus metformin on weight management and select markers of metabolic syndrome in obese adolescents, and to determine which factors predict weight loss in obese adolescents treated with lifestyle changes and metformin.

DATA SOURCES

The study was a secondary data analysis utilizing a retrospective chart review of 63 obese adolescents aged 11 through 18 who were treated for obesity at the LeBonheur Youth Lifestyle Clinic from January 1, 2000, through June 30, 2005. Lifestyle interventions included diet, exercise, and counseling. The medication utilized was metformin. Outcomes evaluated included body mass index, relative body mass index (RBMI), weight, waist and hip circumference, blood pressure, serum lipid levels, fasting plasma glucose, 2-h oral glucose tolerance tests, and insulin levels. Changes in mean values between groups were evaluated using the General Linear Models procedure. Logistic regression was utilized to determine which factors might predict weight loss.

CONCLUSIONS

The metformin group (N= 37) tended to be heavier, older, and had more components of the metabolic syndrome than the nonmetformin group (N= 26). All components of the metabolic syndrome were present in both groups (overall prevalence 55%). Both groups had a downward trend in RBMI, a surrogate marker for weight loss, but only the metformin group had a significant loss in RBMI points from baseline to end. There was a trend toward better diastolic blood pressure at 6 months in the metformin group (p= 0.06), which was not seen in the nonmetformin group. The only predictors of weight loss were higher RBMI (those who were heavier lost more) and the absence of type 2 diabetes mellitus (type 2 DM) (those with type 2 DM were less likely to lose 10 or more points in RBMI).

IMPLICATIONS FOR PRACTICE

All components of the metabolic syndrome are present in obese adolescents. The use of lifestyle changes and lifestyle changes plus metformin both produce some degree of weight loss, but subjects on metformin in this study lost significantly more RBMI points than those on lifestyle changes alone. Subjects with type 2 DM are less likely to lose weight than those without type 2 DM. Larger studies and studies with subjects more representative of the general population need to be carried out to assist in the development of evidence-based practice guidelines.

State of the Art Review: Long-term Pharmacotherapy for Overweight and Obesity: A Review of Sibutramine, Orlistat, and Rimonabant

The objective of this review is to evaluate the safety and efficacy of pharmacotherapy for long-term maintenance of weight loss in overweight and obese patients. Literature was obtained through a MEDLINE (1966 to July 2006) search and a bibliographic review of published articles. Key terms used included overweight, obesity, sibutramine, orlistat, and rimonabant. The search was further limited to clinical trials in humans and in the English language. Obesity is a chronic condition requiring long-term therapy. Two agents, sibutramine and orlistat, are currently approved by the Food and Drug Administration for the long-term treatment of obesity. Rimonabant, marketed in Europe as Accomplia, has demonstrated efficacy for long term weight loss, however an Food and Drug Administration advisory panel voted against its approval in June 2007 due to safety concerns (psychiatric effects). For clinically meaningful results, these agents must be used in conjunction with lifestyle therapy, including a hypocaloric diet, increased physical activity, and behavioral modification. This article reviews clinical trials evaluating the safety and efficacy of sibutramine, orlistat, and rimonabant in reducing weight and examines other health benefits and risks associated with these agents.

Pharmacotherapeutic options for overweight adolescents

OBJECTIVE

To evaluate the safety and efficacy of current pharmacotherapeutic options for weight loss in overweight adolescents.

DATA SOURCES

Literature was obtained through MEDLINE Ovid (1996-April 2007) and EMBASE Drugs and Pharmacology (1991-2nd quarter 2007) searches and a bibliographic review of published articles. Key words included adolescents, overweight, obesity, anti-obesity agents, drug therapy, orlistat, sibutramine, and metformin.

STUDY SELECTION AND DATA EXTRACTION

All studies published in the English language that evaluated the use of pharmacotherapy for the treatment of overweight adolescents were critically analyzed; pertinent articles were selected for this review.

DATA SYNTHESIS

Orlistat has been approved for use in adolescents between the ages of 12 and 16 years. The most frequently reported adverse effects of orlistat were gastrointestinal; reduced concentrations of fat-soluble vitamins were also observed. Of the 6 clinical trials published, 5 have shown statistically significant reductions in body mass index (BMI) from baseline, ranging from 0.55 to 4.09 kg/m2; one small trial failed to demonstrate significant weight reduction compared with placebo. Sibutramine has also been evaluated for use in overweight adolescents in 6 trials. Trials demonstrated a statistically significant reduction in BMI up to 5.6 kg/m2 (from baseline). Of concern is evidence indicating that sibutramine therapy may be associated with elevated blood pressure, increased pulse rate, depression, and suicidal ideations. Lastly, metformin has recently been evaluated for weight loss in overweight adolescents; small, short-term trials demonstrate modest reductions in weight and BMI.

CONCLUSIONS

Orlistat has been proven both safe and effective for weight reduction in overweight adolescents. Sibutramine has also been proven effective in reducing weight in this population; however, the potential for severe adverse effects requires further investigation. Metformin has demonstrated promising results in small trials; its role in the treatment of overweight adolescents will remain investigational until further research is conducted.

New drug policy in childhood obesity

OBJECTIVE

To update physicians, especially paediatricians, in the rapidly developing field of pharmacotherapy of childhood and adolescent obesity.

METHODS

The paper reviews current and investigational antiobesity drugs.

RESULTS

At present, there are only few drugs approved by the Food and Drug Administration (FDA) for the treatment of adult obesity. The most important ones are sibutramine and orlistat. The FDA in the USA approved the latter drug in 2003, and it has recently been approved by the European Union for the treatment of adolescents. There are several investigational antiobesity agents but only few new and promising substances like Rimonabant (a cannabinoid receptor antagonist) and axokine (ciliary neutrotrophic factor) are already at an advanced stage of development.

CONCLUSION

In adults, it seems to be justified using drugs for long-term treatment of 'medically important' obesity. Strict guidelines concerning the treatment of obese adolescents with orlistat are needed. It is only hoped that double-blind placebo-controlled studies investigating the new and promising drugs will also include adolescents and provide sufficient scientific data to get them licensed for the treatment of obese adolescents.

Pharmacotherapy for obesity

Pharmacotherapy for the management of obesity is primarily aimed at weight loss, weight loss maintenance and risk reduction, and has included thyroid hormone, amphetamines, phentermine, amfepramone (diethylpropion), phenylpropanolamine, mazindol, fenfluramines and, more recently, sibutramine and orlistat. These agents decrease appetite, reduce absorption of fat or increase energy expenditure. Primary endpoints used to evaluate anti-obesity drugs most frequently include mean weight loss, percentage weight loss and proportion of patients losing >or=5% and >or=10% of initial bodyweight. Secondary endpoints may include reduction in body fat, risk factors for cardiovascular disease and the incidences of diseases such as diabetes mellitus. Most pharmacotherapies have demonstrated significantly greater weight loss in patients on active treatment than those receiving placebo in short-term (<or=1 year) randomised controlled trials of pharmacological treatment in conjunction with a calorie-controlled diet or lifestyle intervention. The evidence of long-term efficacy is limited to sibutramine (2 years) and orlistat (4 years). These are the only drugs currently approved for the long-term management of obesity in adults. Sibutramine recipients randomised following 6 months' treatment to either sibutramine or placebo demonstrated significantly better weight maintenance at 2 years than those taking placebo (p<0.001), with >or=10% loss of initial bodyweight in 46% of patients. For patients taking orlistat, weight loss was 2.2 kg greater than those on placebo at 4 years (p<0.001), with significantly more patients achieving >or=10% loss of initial bodyweight (26.2% and 15.6%, respectively; p<0.001). Other drugs that have been evaluated for weight loss include ephedrine, the antidepressants fluoxetine and bupropion, and the antiepileptics topiramate and zonisamide. Two clinical trials with fluoxetine both reported no significant difference in weight loss compared with placebo at 52 weeks. Clinical trials evaluating ephedrine, bupropion, topiramate and zonisamide have demonstrated significantly greater weight loss than placebo but have been limited to 16-26 weeks' treatment. A major obstacle to the evaluation of the clinical trials is the potential bias resulting from low study completion rates. Completion rates varied from 52.8% of phentermine recipients in a 9-month study, to 40% of fenfluramine recipients in a 24-week comparative study with phentermine and 18% of amfepramone recipients in a 24-week study. One-year completion rates range from 51% to 73% for sibutramine and from 66% to 85% for orlistat. Other potential sources of bias include run-in periods and subsequent patient selection based on compliance or initial weight loss. Several potential new therapies targeting weight loss and obesity through the CNS pathways or peripheral adiposity signals are in early phase clinical trials. Over the next decade the drug treatment of obesity is likely to change significantly because of the availability of new pharmacotherapies to regulate eating behaviours, nutrient partitioning and/or energy expenditure.

Characterisation of morbidity in a UK, hospital based, obesity clinic

AIM

To identify clinical features which predict those most at risk of co-morbidities within an obesity clinic.

METHODS

Children attending an obesity clinic had fasting glucose, insulin, and lipids measured prior to a standard oral glucose tolerance test (OGTT). History and examination established birth weight, family history of type 2 diabetes/obesity, pubertal status, and presence of acanthosis nigricans. Central and total fat mass was estimated by bio-impedance.

RESULTS

Of the 126 children evaluated, 10.3% (n = 13) had impaired glucose tolerance (IGT); the majority (n = 11) of these would not have been identified on fasting glucose alone. Those with IGT were more likely to have a parental history of type 2 diabetes (relative risk 3.5). IGT was not associated with acanthosis nigricans. Twenty five per cent (n = 19) of those evaluated (n = 75) had evidence of the "metabolic syndrome" (MS). HDL cholesterol and triglyceride levels were related to insulin sensitivity (HOMA-R); HDL cholesterol was also related to birth weight SDS. We observed a trend for those with MS to have a lower birth weight SDS. The severity of obesity did not influence the likelihood of IGT or MS.

CONCLUSIONS

Significant numbers of obese children have associated co-morbidities. Analysis of fasting blood glucose samples alone is not satisfactory to adequately evaluate glucose homoeostasis. The overall level of obesity does not predict co-morbidities. Special attention should be given to those with parental diabetes and a history of low birth weight who are more likely to have IGT and abnormal lipid profiles respectively.

Orlistat

Orlistat (Xenical) is a reversible inhibitor of gastric and pancreatic lipases. In conjunction with a hypocaloric diet and moderate exercise, orlistat is an effective drug for use in the management of obesity in adults with or without comorbidities. Recent data have shown that orlistat is also effective as a component of weight management strategies in obese adolescents. In addition to its well established efficacy in achieving modest weight loss, orlistat has been shown to improve glycaemic parameters in obese adults with type 2 diabetes mellitus as well as some features of the metabolic syndrome. Orlistat is generally well tolerated. Thus, orlistat is an option for the treatment of obese patients with or without type 2 diabetes and also has a role in the management of obese patients with the metabolic syndrome, associated comorbidities or concomitant disorders.

Nutrition therapy for overweight children and adolescents with type 2 diabetes

The increased number of children and adolescents diagnosed with type 2 diabetes presents new challenges to pediatricians, nurses, and dietitians. Treatment with medications and lifestyle changes is similar to that for adults with type 2 diabetes, but must be developmentally appropriate for children and adolescents. Registered dieticians must apply knowledge from treatment for overweight children and adolescents without diabetes with treatment for adults with type 2 diabetes to provide effective nutrition therapy for this population.

Pediatric obesity and insulin resistance: chronic disease risk and implications for treatment and prevention beyond body weight modification

The study of childhood obesity has continued to grow exponentially in the past decade. This has been driven in part by the increasing prevalence of this problem and the widespread potential effects of increased obesity in childhood on lifelong chronic disease risk. The focus of this review is on recent findings regarding the link between obesity and disease risk during childhood and adolescence. We describe recent reports relating to type 2 diabetes in youth (2), prediabetes (69, 166), metabolic syndrome (33, 35), polycystic ovarian syndrome (77), and nonalcoholic fatty liver disease (58, 146), and the mediating role of insulin resistance in these conditions. In addition, we review the implications of this research for the design of more effective treatment and prevention strategies that focus more on the improvement of obesity-related metabolic abnormalities and chronic disease risk reduction than on the conventional energy balance approach that focuses on weight management.