Head-to-head studies evaluating efficacy of pharmaco-therapy for obesity: a systematic review and meta-analysis

Discovery of triterpenoids as potent dual inhibitors of pancreatic lipase and human carboxylesterase 1

Pancreatic lipase (PL) is a well-known key target for the prevention and treatment of obesity. Human carboxylesterase 1A (hCES1A) has become an important target for the treatment of hyperlipidaemia. Thus, the discovery of potent dual-target inhibitors based on PL and hCES1A hold great potential for the development of remedies for treating related metabolic diseases. In this study, a series of natural triterpenoids were collected and the inhibitory effects of these triterpenoids on PL and hCES1A were determined using fluorescence-based biochemical assays. It was found that oleanolic acid (OA) and ursolic acid (UA) have the excellent inhibitory effects against PL and hCES1A, and highly selectivity over hCES2A. Subsequently, a number of compounds based on the OA and UA skeletons were synthesised and evaluated. Structure–activity relationship (SAR) analysis of these compounds revealed that the acetyl group at the C-3 site of UA (compound 41) was very essential for both PL and hCES1A inhibition, with IC₅₀ of 0.75 µM and 0.014 µM, respectively. In addition, compound 39 with 2-enol and 3-ketal moiety of OA also has strong inhibitory effects against both PL and hCES1A, with IC₅₀ of 2.13 µM and 0.055 µM, respectively. Furthermore, compound 39 and 41 exhibited good selectivity over other human serine hydrolases including hCES2A, butyrylcholinesterase (BChE) and dipeptidyl peptidase IV (DPP-IV). Inhibitory kinetics and molecular docking studies demonstrated that both compounds 39 and 41 were effective mixed inhibitors of PL, while competitive inhibitors of hCES1A. Further investigations demonstrated that both compounds 39 and 41 could inhibit adipocyte adipogenesis induced by mouse preadipocytes. Collectively, we found two triterpenoid derivatives with strong inhibitory ability on both PL and hCES1A, which can be served as promising lead compounds for the development of more potent dual-target inhibitors targeting on PL and hCES1A.

Views and Experiences of Adults who are Overweight and Obese on the Barriers and Facilitators to Weight Loss in Southeast Brazil: A Qualitative Study

Background: Obesity in Brazil is increasing with 54% of the Brazilian population being overweight, of which 20% is obese. Obesity is a risk factor for non-communicable diseases such as cardiovascular disease: the leading cause of mortality in Brazil. This study aims to identify the barriers and facilitators to weight loss as perceived by patients with a view to reducing the burden of obesity-related diseases on patients and healthcare services. Methods: Fifteen qualitative, semi-structured, in-depth interviews were conducted in the preventive medicine department in a private health clinic in Bauru, Southeast Brazil. Inductive thematic analysis was conducted. Results: The barriers and facilitators were classified into three themes: lifestyle, motivation and education. Barriers include cost of a healthy lifestyle, time management, personal safety, mobility, junk food advertising, sustaining weight loss, mental health, lack of support and health education. Facilitators include change in eating habits, sleep quality, cooperative food networks, access to the multidisciplinary team and expert patients as health educators. Conclusion: Expert patients should be utilized as an education method, as they increase motivation, promote the facilitators and provide realistic expectations of the weight loss process. Barriers such as junk food advertising and accessibility to treatment need to be addressed. Abbreviations: BMI: Body Mass Index; NCD: Non-Communicable Disease; SUS: Sistema Único de Saúde; WHO: World Health Organization.

Evaluation of Some Biological Applications of Pleurotus citrinopileatus and Boletus edulis Fruiting Bodies

BACKGROUND

Mushrooms are deemed as a special delicacy in many countries. They are considered an important cuisine due to their bioactive ingredients and possible health benefits.

METHODS

Herein, we measured selected biological properties of methanol extracts of Pleurotus citrinopileatus and Boletus edulis fruiting bodies including; in vitro antimicrobial activity, anti-α- glucosidase activity, antioxidant activity, anti-lipase activity and cytotoxic activity against different cancer cells and normal cells.

RESULTS

B. edulis methanol extracts showed high antimicrobial and anti-α-glucosidase activity. In contrast, P. citrinopileatus methanol extracts showed superior antioxidant activity indicated by (1,1- diphenyl-2-picrylhydrazyl) DPPH radical scavenging with half maximal inhibitory concentration of IC50 37.4 µg/ml, anti-lipase activities with IC50 65.2 µg/ml and high cytotoxicity activity against HepG2 and HeLa cell lines with IC50 22.8 and 36.7 µg/ml, respectively. Flow cytometric analysis of the cell cycle was used to show apoptotic effects of methanol extracts against HepG2 and HeLa cells.

CONCLUSION

P. citrinopileatus and B. edulis methanolic extracts appear to contain biologically active compounds that might be used to treat some common human diseases.

Phentermine: A Systematic Review for Plastic and Reconstructive Surgeons

PURPOSE

Phentermine is the most prescribed antiobesity drug in America, with 2.43 million prescriptions written in 2011. Case reports suggest there are anesthetic risks, such as refractory hypotension, involved with its perioperative use. Despite these risks and the frequency of phentermine use among plastic surgery patients, there are no published guidelines for the perioperative management of phentermine use in the plastic surgery literature. To address this patient safety issue, we performed a systematic review and provide management recommendations.

METHODS

A systematic review of the pharmacology of phentermine and the anesthetic risks involved with its perioperative use was undertaken using the search engines PubMed/MEDLINE, EMBASE, and Scopus.

RESULTS

A total of 251 citations were reviewed, yielding 4 articles that discussed perioperative phentermine use and complications with anesthesia. One was a review article, 2 were case reports, and 1 was a letter. Complications included hypotension, hypertension, hypoglycemia, hyperthermia, bradycardia, cardiac depression, and acute pulmonary edema.

CONCLUSIONS

The relationship between phentermine and anesthesia, if any, is unclear. Hypotension on induction of general anesthesia is the most reported complication of perioperative phentermine use. Specifically, phentermine-induced hypotension may be unresponsive to vasopressors that rely on catecholamine release, such as ephedrine. Therefore, the decision to perform surgery, especially elective surgery, in a patient taking phentermine should be made with caution. Because of the half-life of phentermine, we recommend discontinuing phentermine for at least 4 days prior to surgery. This differs from the classic 2-week discontinuation period recommended for "fen-phen." The patient should be made aware of the increased risk of surgery, and a skilled anesthesiologist should monitor intraoperative blood pressure and body temperature for signs of autonomic derailment.

Antiobesity and Antioxidant Potentials of Selected Palestinian Medicinal Plants

We evaluated the antioxidant and porcine pancreatic lipase inhibition (PPLI) activities of 90 plants extracts. The antioxidant activity was measured using the free-radical scavenging capacity (DPPH) and reducing power (RP) assays. The pancreatic lipase inhibition assay was used to determine the PPLI activity of plant extracts. Among the 90 plant extracts examined, 41.0 % crude extracts showed antilipase activity of more than 50%. The most active plants by means of IC₅₀ value were Camellia sinensis (0.5 mg/ml), Ceratonia siliqua (leaves) (0.8 mg/mL), Curcuma longa (0.8 mg/mL), Sarcopoterium spinosum (1.2 mg/mL), and Mentha spicata (1.2 mg/mL). The antioxidant activity of plant extracts using the DPPH and RP assays reveals comparable results. The most active antioxidant extracts using both assays were the leaves and fruit epicarp of Rhus coriaria, areal parts of Sarcopoterium spinosum, and leaves of Ceratonia siliqua. Our results suggest natural resources that possess strong antioxidant and pancreatic lipase inhibitory activities with potential applications in the treatment and prevention of obesity and overweight. The extracts of Camellia sinensis, Ceratonia siliqua, Curcuma longa, Sarcopoterium spinosum, and Mentha spicata were proved to have a great potential as antioxidants and antiobesity agents.

A systematic review and meta-analysis of interventions for weight management using text messaging

BACKGROUND

Obesity prevalence continues to increase worldwide, with significant associated chronic disease and health cost implications. Among more recent innovations in health service provision is the use of text messaging for health behaviour change interventions including weight management. This review investigates the efficacy of weight management programmes incorporating text messaging.

METHODS

Medical and scientific databases were searched from January 1993 to October 2013. Eligibility criteria included randomised controlled trials (RCTs), pseudoRCTs and before and after studies of weight management, among healthy children and adults, that used text messaging and included a nutrition component. Data extraction and quality assessment followed guidelines from PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) and the Evidence Analysis Manual of the American Academy of Nutrition and Dietetics.

RESULTS

From 512 manuscripts retrieved, 14 met the inclusion criteria (five manuscripts in children and nine in adults). Duration of interventions ranged from 1 to 24 months. Frequency of text messaging was from daily to fortnightly. Six studies in adults were included in a meta-analysis with mean body weight change as the primary outcome. The weighted mean change in body weight in intervention participants was -2.56 kg (95% confidence interval = -3.46 to -1.65) and in controls -0.37 kg (95% confidence interval = -1.22 to 0.48).

CONCLUSIONS

The small body of evidence indicates that text messaging interventions can promote weight loss. However, lack of long-term results indicate that further efficacy studies are required. Future investigations should elucidate the determinants, such as intervention duration, text message frequency and level of interactivity that maximise the success and cost effectiveness of the delivery medium.

The effect of antiobesity drugs on waist circumference: a mixed treatment comparison

AIM

To use meta-analytic techniques to quantitatively evaluate the efficacy of orlistat and lorcaserin in the treatment of people who are overweight and obese.

METHODS

We identified publications from searches of electronic databases and extracted data from studies that compared orlistat or lorcaserin to lifestyle advice (standard care), placebo, sibutramine, rimonabant or metformin and collected information on waist circumference change or withdrawals due to adverse events (AEs). A mixed treatment comparison (MTC) meta-analysis was performed on the data extracted.

RESULTS

Orlistat was found to be significantly better than placebo and standard care in reducing waist circumference at 6 and 12 months; orlistat reduced waist circumference by -6.96 cm [95% credible interval (CrI): -8.93, -4.96 cm] compared to standard care at 6 months. The results suggested that lorcaserin reduced waist circumference by a greater amount than all other interventions at 12 months, for example, lorcaserin lead to a greater reduction of -2.45 cm (95% CrI: -4.99, 0.08 cm) in comparison to placebo, although these differences were not statistically significant. Although data were very limited, metformin reduced waist circumference by a greater amount (-2.11 cm, 95% CI: -1.00, -3.22 cm) than orlistat at 6 months. On average, 6.5% of patients on orlistat and 5.4% of those on lorcaserin discontinued their treatment due to AEs at 12 months.

CONCLUSIONS

Orlistat should be considered as an addition to lifestyle interventions in the treatment of obesity. Lorcaserin has recently been approved by the US Food and Drug Administration (FDA) and these results suggest that it is similar in both efficacy and safety compared to orlistat.

[Determinant factors associated with weight loss in adults on diet interventions]

OBJECTIVE

To analyze the determinants for weight loss (> 5%) resulting from outpatient individual appointments.

SUBJECTS AND METHODS

A retrospective cohort study was conduct in 318 overweight/obese patients seeking individual care to lose weight.

RESULTS

Fifteen percent of the patients did not lose weight; 35.1% had lost < 5%; 35.4% had lost between 5 and 10%; and 13.9% had lost > 10%. Patients who lost > 5% body weight (-7.6 ± 3.3 kg, n = 156) had a greater number of visits at a shorter interval, and greater frequency of visits with a registered dietitian and multidisciplinary care. This group had a lower prescription of anti-obesity drugs and their total calorie intake was higher than the other patients. In multivariate Cox regression, only the interval between appointments and the total number of visits remained inversely associated with weight loss.

CONCLUSIONS

The determinants of > 5% weight loss were fewer visits with a shorter interval between appointments.

Connecting type 1 and type 2 diabetes through innate immunity

The escalating epidemic of obesity has driven the prevalence of both type 1 and 2 diabetes mellitus to historically high levels. Chronic low-grade inflammation, which is present in both type 1 and type 2 diabetics, contributes to the pathogenesis of insulin resistance. The accumulation of activated innate immune cells in metabolic tissues results in release of inflammatory mediators, in particular, IL-1β and TNFα, which promote systemic insulin resistance and β-cell damage. In this article, we discuss the central role of innate immunity and, in particular, the macrophage in insulin sensitivity and resistance, β-cell damage, and autoimmune insulitis. We conclude with a discussion of the therapeutic implications of this integrated understanding of diabetic pathology.

Managing obesity--from childhood and onwards

It is unclear whether the obesity epidemic has come to a halt. Perhaps the incidence is declining, at least in pre-school children. However, the obesity rate is higher than ever before. Prevention is a priority, especially in children, but has not been very successful to date. Treatment has basically offered the same tools for decades. The recent development of obesity pharmacotherapy has regressed with--in most countries--only one drug of modest effect available. Bariatric surgery has therefore been considered one of the few solutions in the adult setting and is gaining increasing attention as a treatment option, even in pediatric extreme obesity. In some countries, government action for prevention has been taken, but too often resources have not been set aside. This review addresses new and old strategies to manage obesity--from childhood and onwards.

An update on less invasive and endoscopic techniques mimicking the effect of bariatric surgery

Obesity (BMI 30-35 kg/m(2)) and its associated disorders such as type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular disease have reached pandemic proportions worldwide. For the morbidly obese population (BMI 35-50 kg/m(2)), bariatric surgery has proven to be the most effective treatment to achieve significant and sustained weight loss, with concomitant positive effects on the metabolic syndrome. However, only a minor percentage of eligible candidates are treated by means of bariatric surgery. In addition, the expanding obesity epidemic consists mostly of relatively less obese patients who are not (yet) eligible for bariatric surgery. Hence, less invasive techniques and devices are rapidly being developed. These novel entities mimic several aspects of bariatric surgery either by gastric restriction (gastric balloons, gastric plication), by influencing gastric function (gastric botulinum injections, gastric pacing, and vagal nerve stimulation), or by partial exclusion of the small intestine (duodenal-jejunal sleeve). In the last decade, several novel less invasive techniques have been introduced and some have been abandoned again. The aim of this paper is to discuss the safety, efficacy, complications, reversibility, and long-term results of these latest developments in the treatment of obesity.

Cardiovascular risk-benefit profile of sibutramine

Sibutramine is a combined norepinephrine and serotonin reuptake inhibitor used as an antiobesity agent to reduce appetite and promote weight loss in combination with diet and exercise. At a daily dose of 10-20 mg, it was initially considered to have a good safety profile, as it does not induce primary pulmonary hypertension or adverse effects on cardiac valves, in contrast to previous reports relating to some other antiobesity agents. However, it exerts disparate effects on cardiovascular risk factors. On the one hand, sibutramine may have antiatherogenic activities, as it improves insulin resistance, glucose metabolism, dyslipidemia, and inflammatory markers, with most of these effects resulting from weight loss rather than from an intrinsic effect of the drug. On the other hand, because of its specific mode of action, sibutramine exerts a peripheral sympathomimetic effect, which induces a moderate increase in heart rate and attenuates the reduction in BP attributable to weight loss or even slightly increases BP. It may also prolong the QT interval, an effect that could induce arrhythmias. Because of these complex effects, it is difficult to conclude what the final impact of sibutramine on cardiovascular outcomes might be. Sibutramine has been shown to exert favorable effects on some surrogate cardiovascular endpoints such as reduction of left ventricular hypertrophy and improvement of endothelial dysfunction. A good cardiovascular safety profile was demonstrated in numerous 1- to 2-year controlled trials, in both diabetic and nondiabetic well selected patients, as well as in several observational studies. However, since 2002, several cardiovascular adverse events (hypertension, tachycardia, arrhythmias, and myocardial infarction) have been reported in sibutramine-treated patients. This led to a contraindication of the use of this antiobesity agent in patients with established coronary heart disease, previous stroke, heart failure, or cardiac arrhythmias. SCOUT (Sibutramine Cardiovascular and Diabetes Outcome Study) was designed to prospectively evaluate the efficacy/safety ratio of sibutramine in a high-risk population. The efficacy/safety results of the first 6-week lead-in open period of treatment with sibutramine 10 mg/day were reassuring in 10 742 overweight/obese high-risk subjects (97% had cardiovascular disease, 88% had hypertension, and 84% had type 2 diabetes mellitus). However, the final results of SCOUT showed that long-term (5 years') treatment with sibutramine (10-15 mg/day) exposed subjects with pre-existing cardiovascular disease to a significantly increased risk for nonfatal myocardial infarction and nonfatal stroke, but not cardiovascular death or all-cause mortality. Because the benefit of sibutramine as a weight-loss aid seems not to outweigh the cardiovascular risks, the European Medicines Agency recommended the suspension of marketing authorizations for sibutramine across the EU. The US FDA stated that the drug should carry a 'black box' warning due to an increased risk of stroke and heart attack in patients with a history of cardiovascular disease. In conclusion, concern still persists about the safety profile of sibutramine regarding cardiovascular outcomes, and the drug should not be prescribed for overweight/obese patients with a high cardiovascular risk profile.

Pharmacotherapies for obesity: past, current, and future therapies

Past therapies for the treatment of obesity have typically involved pharmacological agents usually in combination with a calorie-controlled diet. This paper reviews the efficacy and safety of pharmacotherapies for obesity focusing on drugs approved for long-term therapy (orlistat), drugs approved for short-term use (amfepramone [diethylpropion], phentermine), recently withdrawn therapies (rimonabant, sibutamine) and drugs evaluated in Phase III studies (taranabant, pramlintide, lorcaserin and tesofensine and combination therapies of topiramate plus phentermine, bupropion plus naltrexone, and bupropion plus zonisamide). No current pharmacotherapy possesses the efficacy needed to produce substantial weight loss in morbidly obese patients. Meta-analyses support a significant though modest loss in bodyweight with a mean weight difference of 4.7 kg (95% CI 4.1 to 5.3 kg) for rimonabant, 4.2 kg (95% CI 3.6 to 4.8 kg) for sibutramine and 2.9 kg (95% CI 2.5 to 3.2 kg) for orlistat compared to placebo at ≥12 months. Of the Phase III pharmacotherapies, lorcaserin, taranabant, topiramate and bupropion with naltrexone have demonstrated significant weight loss compared to placebo at ≥12 months. Some pharmacotherapies have also demonstrated clinical benefits. Further studies are required in some populations such as younger and older people whilst the long term safety continues to be a major consideration and has led to the withdrawal of several drugs.

Long-term changes in blood pressure following orlistat and sibutramine treatment: a meta-analysis

Previous meta-analyses investigating blood pressure effects of anti-obesity drugs have included studies using non-licensed doses, but not data from head-to-head studies. Furthermore, although diabetes is an important comorbidity in obesity, variation in blood pressure effects across diabetes status has not been investigated. The objective of this study was to estimate the effects on systolic (SBP) and diastolic blood pressure (DBP) of orlistat and sibutramine. Medline, EMBASE, the Cochrane controlled trials register and reference lists of identified articles from 1990 to February 2009 were searched. All placebo-controlled randomized controlled trials of 12-month duration or randomized head-to-head studies of any duration on adults using standard doses were included. Studies/study arms were excluded if they only evaluated weight maintenance after weight loss. Randomized controlled trials were identified, subjected to inclusion and exclusion criteria, and reviewed. Random effects models were used for assessment of weighted mean differences. Eighteen placebo-controlled (12 orlistat, 5540 patients; 6 sibutramine, 1495 patients) and four head-to-head trials (348 patients) met the inclusion criteria. Three orlistat and three sibutramine studies examined overweight subjects with type 2 diabetes (T2DM), as did two head-to-head trials. Mean baseline SBP ranged from 119 to 153 mmHg, and mean DBP from 69 to 98 mmHg. Overall, the placebo-controlled SBP change was -1.9 (95% CI; -2.7, -1.1) mmHg for orlistat, and 0.5 (-1.1, 2.1) mmHg for sibutramine. The corresponding values for DBP were -1.5 (-2.2, -0.8) and 1.7 (0.7, 2.6). Compared with patients without diabetes, diabetic patients treated with orlistat experienced smaller and non-significant reductions of SBP (-0.9; -2.6, 0.7 vs. -2.2; -3.0, -1.3) and DBP (-1.0; -2.4, 0.3 vs. -1.6; -2.4, -0.8). For sibutramine, higher on-treatment elevations in SBP (1.6; -1.3, 4.5 vs. 0.1; -1.8, 2.0) and DBP (2.4; 0.6, 4.1 vs. 1.4; 0.3, 2.5) were seen in patients with vs. without diabetes. In head-to-head trials, the overall differences between sibutramine and orlistat were small and non-significant for both SBP (1.0; -2.3, 4.3) and DBP (-0.2; -2.9, 2.5). In conclusion, in the studies using approved sibutramine doses, the drug caused significant elevations in DBP, while the overall SBP effect was near null. Moreover, absence of a blood pressure-lowering effect of orlistat ad a higher DBP elevation by sibutramine were observed for persons with diabetes. Head-to-head studies indicated that an indirect comparison of placebo-adjusted blood pressure effects may overestimate the adverse effects associated with sibutramine, but these studies were small, of shorter duration and of lower quality.

Clinical and economic considerations of antiobesity treatment: a review of orlistat

The objective of this study was to review the current knowledge about the use of orlistat from clinical and economic perspectives, and to assess this drug's public health impact. Weight reduction by current antiobesity drugs, compared to placebo, is at most around 5 kg. Orlistat, the most studied antiobesity drug, is associated with the least-severe adverse effects, but compared with other drugs in its class it also delivers the most modest weight loss versus placebo (less than 3 kg). Orlistat appears to have a favorable risk/benefit profile, and cost-effectiveness ratios seem to be within a range that is generally considered acceptable. In the short-term, orlistat is related to reduced diabetes incidence and to slightly improved blood pressure and lipid profiles. Long-term clinical effects have been largely unstudied, however, and this study did not find reports that considered mortality as an endpoint. Given a very low continuation with orlistat treatment in the population and very modest and, apparently, only short-term clinical effects, orlistat is not likely to have a significant impact on the population health. Public health approaches of improving environmental and social factors to foster healthier food choices and increase physical activity remain essential for addressing the obesity epidemic.

Sleep-disordered breathing and obesity: pathophysiology, complications, and treatment

Sleep-disordered breathing (SDB) is a medical condition that has increasingly recognized adverse health effects. Obesity is the primary risk factor for the development of SDB and contributes to cardiovascular and metabolic abnormalities in this population. However, accumulating evidence suggests that SDB may be related to the development of these abnormalities independent of obesity. Periodic apneas and hypopneas during sleep result in intermittent hypoxemia, arousals, and sleep disturbances. These pathophysiologic characteristics of SDB are likely mechanisms underlying cardiovascular and metabolic abnormalities including hypertension and other cardiovascular diseases, altered adipokines, inflammatory cytokines, insulin resistance, and glucose intolerance. Treatment of SDB with continuous positive airway pressure reverses some but not all of these abnormalities; however, studies to date have demonstrated inconsistent findings. Weight loss strategies, including diet, exercise, medications, and bariatric surgery, have been evaluated as a treatment strategy for SDB. In preliminary studies, dietary intervention and exercise reduced severity of SDB. One study demonstrated improvements in SDB severity using the weight-reducing medication sibutramine. In morbidly obese subjects, bariatric surgery effectively induces weight loss and improvement in SDB severity and symptoms, but long-term benefits remain uncertain. Large randomized trials are required to determine the utility of these strategies as long-term approaches to improving SDB and reducing associated complications.

Pharmacologic therapies for obesity

This article examines the transitions in pharmacological therapy for obesity. It reviews the current options approved by the Food and Drug Administration and several drugs approved for other indications that can be used to treat obesity as well. Because weight regulation is complex and redundant systems protect against perceived starvation, optimal treatment of obesity in individual patients will likely require different combinations of behavioral, nutritional, pharmacologic, endoscopic, and surgical therapies.

Discontinuation due to adverse events in randomized trials of orlistat, sibutramine and rimonabant: a meta-analysis

The objective of this article was to estimate the risk of discontinuation due to adverse events in trials of orlistat, sibutramine and rimonabant. Medline, EMBASE, the Cochrane controlled trials register and reference lists of identified articles were searched from 1990 to May 2008. All randomized placebo-controlled trials of 12-24 months of duration on adults using licensed doses were included. Studies/study arms were excluded if they evaluated weight maintenance after weight loss. Trials were identified, subjected to inclusion and exclusion criteria and reviewed. Data on participants, interventions and discontinuation were extracted and trials rated for quality based on established criteria. A random effects model was used to estimate pooled risk ratios, risk differences and number needed to harm (NNH). A total of 28 trials met the inclusion criteria (16 orlistat, 7 sibutramine and 5 rimonabant). The risk ratios for discontinuation due to adverse events were significantly elevated for rimonabant (2.00; 1.66-2.41) and orlistat (1.59; 1.21-2.08), but not sibutramine (0.98, 0.68-1.41). Compared with placebo, the risk difference was the largest for rimonabant (7%, 5-9%; NNH 14, 11-19), followed by orlistat (3%, 1-4%; NNH 39, 25-83), while no significant difference was seen for sibutramine (0.2%, -3 to 4%; NNH 500). The most common adverse events leading to withdrawal were gastrointestinal for orlistat (40%) and psychiatric for rimonabant (47%). Corresponding information was unavailable for sibutramine. In conclusion, available weight loss drugs differ markedly regarding risk of discontinuation due to adverse events, as well as in underlying causes of these events. Given the large number of patients eligible for treatment, the low NNH for rimonabant is a concern.

The use of sibutramine in the management of obesity and related disorders: an update

Aims:

To review the major trials that evaluated the efficacy and safety of the use of sibutramine for weight loss and the impact of this agent on obesity-related disorders.

Methods and results:

The most important articles on sibutramine up to January 2009 were located by a PubMed and Medline search. Sibutramine reduces food intake and body weight more than placebo and has positive effects on the lipid profile (mainly triglycerides and high density lipoprotein cholesterol), glycemic control and inflammatory markers in studies for up to one year. Preliminary studies showed that sibutramine may also improve other obesity-associated disorders such as polycystic ovary syndrome, left ventricular hypertrophy, binge eating disorder and adolescent obesity. The high discontinuation rates and some safety issues mainly due to the increase in blood pressure and pulse rate have to be considered. Additionally, it has not yet been established that treatment with sibutramine will reduce cardiovascular events and total mortality.

Conclusions:

Sibutramine, in conjunction with lifestyle measures, is a useful drug for reducing body weight and improving associated cardiometabolic risk factors and obesity-related disorders. Studies of longer duration are required to determine the precise indications of the drug, to evaluate safety issues and to assess its efficacy on cardiovascular mortality.

Cost-effectiveness of pharmacological anti-obesity treatments: a systematic review

AIM

To review economic evaluations of weight loss drugs and compare reported incremental cost-effectiveness ratios (ICERs).

METHODS

A literature search was conducted for cost-effectiveness (CEAs) and cost-utility analyses (CUAs) of sibutramine, orlistat and rimonabant.

RESULTS

Fourteen unique articles were identified (11 CUAs and 3 CEAs; 9 orlistat, 4 sibutramine and 1 rimonabant). All used diet and exercise as comparator, whereas none included indirect costs. Time horizons varied from treatment period only (1-4 years) to 80 years (median 7.5 years). Longer studies modeled effects on diabetes, micro- and macrovascular complications, coronary heart disease and death. Of the CUAs, the median ICER was 16,000 euro(2007)/QALY (quality-adjusted life-year; range 10,000-88,000), with the worst cost-effectiveness when recommended stop rules for non-responding patients were not applied. All studies but three were funded by the manufacturing company, and the median ICER was considerably higher for independent than for sponsored analyses (62,000 euro vs 15,000 euro/QALY). However, two of the three independent CUAs did not use recommended stop rules, as compared with one of eight manufacturer-sponsored analyses. The results were most sensitive to assumptions regarding weight loss sustainability and utility per kilogram lost. Side effects and dropout because of reasons other than lack of efficacy were generally not incorporated.

CONCLUSION

Published economic evaluations indicate that orlistat, sibutramine and rimonabant are within the range of what is generally regarded as cost-effective. Uncertainty remains about weight loss sustainability, utility gain associated with weight loss and extrapolations from transient weight loss to long-term health benefits. Modeling of head-to-head comparisons and attrition is needed, as are analyses conducted independently of manufacturing companies.