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Comparison of results from different imputation techniques for missing data from an anti-obesity drug trial.
Jørgensen, AW, Lundstrøm, LH, Wetterslev, J, Astrup, A, Gøtzsche, PC
PloS one. 2014;(11):e111964
Abstract
BACKGROUND In randomised trials of medical interventions, the most reliable analysis follows the intention-to-treat (ITT) principle. However, the ITT analysis requires that missing outcome data have to be imputed. Different imputation techniques may give different results and some may lead to bias. In anti-obesity drug trials, many data are usually missing, and the most used imputation method is last observation carried forward (LOCF). LOCF is generally considered conservative, but there are more reliable methods such as multiple imputation (MI). OBJECTIVES To compare four different methods of handling missing data in a 60-week placebo controlled anti-obesity drug trial on topiramate. METHODS We compared an analysis of complete cases with datasets where missing body weight measurements had been replaced using three different imputation methods: LOCF, baseline carried forward (BOCF) and MI. RESULTS 561 participants were randomised. Compared to placebo, there was a significantly greater weight loss with topiramate in all analyses: 9.5 kg (SE 1.17) in the complete case analysis (N = 86), 6.8 kg (SE 0.66) using LOCF (N = 561), 6.4 kg (SE 0.90) using MI (N = 561) and 1.5 kg (SE 0.28) using BOCF (N = 561). CONCLUSIONS The different imputation methods gave very different results. Contrary to widely stated claims, LOCF did not produce a conservative (i.e., lower) efficacy estimate compared to MI. Also, LOCF had a lower SE than MI.
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Can medical therapy mimic the clinical efficacy or physiological effects of bariatric surgery?
Miras, AD, le Roux, CW
International journal of obesity (2005). 2014;(3):325-33
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Abstract
The number of bariatric surgical procedures performed has increased dramatically. This review discusses the clinical and physiological changes, and in particular, the mechanisms behind weight loss and glycaemic improvements, observed following the gastric bypass, sleeve gastrectomy and gastric banding bariatric procedures. The review then examines how close we are to mimicking the clinical or physiological effects of surgery through less invasive and safer modern interventions that are currently available for clinical use. These include dietary interventions, orlistat, lorcaserin, phentermine/topiramate, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, pramlintide, dapagliflozin, the duodenal-jejunal bypass liner, gastric pacemakers and gastric balloons. We conclude that, based on the most recent trials, we cannot fully mimic the clinical or physiological effects of surgery; however, we are getting closer. A 'medical bypass' may not be as far in the future as we previously thought, as the physician's armamentarium against obesity and type 2 diabetes has recently got stronger through the use of specific dietary modifications, novel medical devices and pharmacotherapy. Novel therapeutic targets include not only appetite but also taste/food preferences, energy expenditure, gut microbiota, bile acid signalling, inflammation, preservation of β-cell function and hepatic glucose output, among others. Although there are no magic bullets, an integrated multimodal approach may yield success. Non-surgical interventions that mimic the metabolic benefits of bariatric surgery, with a reduced morbidity and mortality burden, remain tenable alternatives for patients and health-care professionals.
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A comparative study of five centrally acting drugs on the pharmacological treatment of obesity.
Suplicy, H, Boguszewski, CL, dos Santos, CM, do Desterro de Figueiredo, M, Cunha, DR, Radominski, R
International journal of obesity (2005). 2014;(8):1097-103
Abstract
CONTEXT No long-term studies have compared centrally acting drugs for treating obesity. OBJECTIVE To compare the efficacy and safety of diethylpropion (DEP), fenproporex (FEN), mazindol (MZD), fluoxetine (FXT) and sibutramine (SIB) in promoting weight loss. DESIGN AND SETTING A prospective, randomized, placebo (PCB)-controlled study conducted at a single academic institution. PATIENTS A total of 174 obese premenopausal women. INTERVENTION Participants randomly received DEP 75 mg (n=28), FEN 25 mg (n=29), MZD 2 mg (n=29), SIB 15 mg (n=30), FXT 20 mg (n=29) or PCB (n=29) daily over 52 weeks. Diet and physical activity were encouraged. MAIN OUTCOME MEASURES The primary endpoints were changes in body weight and the proportion of women who achieved at least 5% weight loss by week 52 in the intent-to-treat population. Other measurements included anthropometry, safety, metabolic and cardiovascular parameters. RESULTS Weight loss was greater than PCB (-3.1±4.3 kg) with DEP (-10.0±6.4 kg; P<0.001), SIB (-9.5±5.9 kg; P<0.001), FEN (-7.8±6.9 kg; P<0.01) and MZD (-7.4±4.9 kg; P<0.01) but not with FXT (-2.5±4.1 kg). Ten (33.3%) women lost⩾5% of their initial weight with PCB, compared with 20 (71.4%; P<0.001) with DEP, 20 (69%; P<0.02) with FEN, 21 (72.4%; P<0.01) with MZD, 22 (73.3%; P<0.001) with SIB and 10 (35.5%) with FXT. Each medically treated group experienced more adverse events compared with PCB (P<0.001). Compared with PCB, constipation was more prevalent with DEP, SIB and MZD (P<0.01); anxiety was more prevalent with DEP (P=0.01); and irritability occurred more frequently with DEP and FEN (P=0.02). Significant improvements in the depression and anxiety scores, binge-eating episodes and quality of life correlated with weight loss. CONCLUSION The centrally acting drugs DEP, FEN, MZD and SIB were more effective than PCB in promoting weight loss in obese premenopausal women, with a satisfactory benefit-risk profile.
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Diet and physical activity "defeated" Tuberil® in treatment of childhood obesity.
Ferrara, P, Del Bufalo, F, Ianniello, F, Franceschini, A, Paolini Paoletti, F, Massart, F, Saggese, G
Minerva endocrinologica. 2013;(2):181-5
Abstract
AIM: Childhood obesity is remarkably spreading worldwide, involving both industrialized and low-income countries. Its prevalence, outcome and socioeconomic impact call for the attention of medical community. We conducted a monocentric, open, two-arm, parallel-group study to evaluate the efficacy at reducing appetite and increasing dietary compliance of obese children of Tuberil®, a weight-loss supplement derived from potato and devoid of side effects. METHODS We recruited participants, children with BMI ≥ 85th, through direct referrals in pediatrician's surgeries. Children were randomized to receive Tuberil® (group A) or nothing (group B), following a chronological order (A-B-A-B). Every child received a nutritionally balanced diet and had to record their appetite and to describe their meals in a diary. RESULTS Even if we found a significant reduction in BMI, weight and waist circumference in both groups, no statistically significant differences between groups were noted. We did not found any significant differences in appetite between group A and B. CONCLUSION Our data show that Tuberil® has no efficacy neither in reducing appetite in children nor in increasing dietary compliance. We believe that only a nutritionally balanced diet and our attention in verifying their compliance led to the reduction in BMI, weight and waist circumferences noted in our series.
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A randomized trial of a low-carbohydrate diet vs orlistat plus a low-fat diet for weight loss.
Yancy, WS, Westman, EC, McDuffie, JR, Grambow, SC, Jeffreys, AS, Bolton, J, Chalecki, A, Oddone, EZ
Archives of internal medicine. 2010;(2):136-45
Abstract
BACKGROUND Two potent weight loss therapies, a low-carbohydrate, ketogenic diet (LCKD) and orlistat therapy combined with a low-fat diet (O + LFD), are available to the public but, to our knowledge, have never been compared. METHODS Overweight or obese outpatients (n = 146) from the Department of Veterans Affairs primary care clinics in Durham, North Carolina, were randomized to either LCKD instruction (initially, <20 g of carbohydrate daily) or orlistat therapy, 120 mg orally 3 times daily, plus low-fat diet instruction (<30% energy from fat, 500-1000 kcal/d deficit) delivered at group meetings over 48 weeks. Main outcome measures were body weight, blood pressure, fasting serum lipid, and glycemic parameters. RESULTS The mean age was 52 years and mean body mass index was 39.3 (calculated as weight in kilograms divided by height in meters squared); 72% were men, 55% were black, and 32% had type 2 diabetes mellitus. Of the study participants, 57 of the LCKD group (79%) and 65 of the O + LFD group (88%) completed measurements at 48 weeks. Weight loss was similar for the LCKD (expected mean change, -9.5%) and the O + LFD (-8.5%) (P = .60 for comparison) groups. The LCKD had a more beneficial impact than O + LFD on systolic (-5.9 vs 1.5 mm Hg) and diastolic (-4.5 vs 0.4 mm Hg) blood pressures (P < .001 for both comparisons). High-density lipoprotein cholesterol and triglyceride levels improved similarly within both groups. Low-density lipoprotein cholesterol levels improved within the O + LFD group only, whereas glucose, insulin, and hemoglobin A(1c) levels improved within the LCKD group only; comparisons between groups, however, were not statistically significant. CONCLUSION In a sample of medical outpatients, an LCKD led to similar improvements as O + LFD for weight, serum lipid, and glycemic parameters and was more effective for lowering blood pressure. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00108524.
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Efficacy and safety of ezetimibe plus orlistat or rimonabant in statin-intolerant nondiabetic overweight/obese patients with dyslipidemia.
Florentin, M, Kostapanos, MS, Nakou, ES, Elisaf, M, Liberopoulos, EN
Journal of cardiovascular pharmacology and therapeutics. 2009;(4):274-82
Abstract
AIMS: To compare the effects of ezetimibe plus orlistat or rimonabant on anthropometric and lipid parameters in nondiabetic statin-intolerant overweight/obese patients with dyslipidemia. METHODS AND RESULTS Thirty participants received a hypocaloric diet and were randomized to open-label combination of ezetimibe (10 mg/day) with orlistat (120 mg, 3 times a day with meals; ezetimibe/orlistat [EO], n = 15) or rimonabant (20 mg/day; ezetimibe/rimonabant [ER], n = 15). Anthropometric and metabolic variables were assessed at baseline and 3 months posttreatment. Similar reductions in body weight, body mass index, and waist circumference were recorded in both groups (-8.3%, -8.6%, and -5.2% in the EO group and -7.3%, -7.2%, and -7.0% in the ER group, P < .01 vs baseline for all). Low-density lipoprotein cholesterol (LDL-C) levels decreased in both treatment groups, but this reduction tended to be more pronounced in the EO group (28.4% vs 15.3%, respectively; P < .01 vs baseline for both). Triglycerides tended to decrease more in the ER compared with the EO group (-20.4% vs -14.1%, P < .01 vs baseline for both). High-density lipoprotein cholesterol (HDL-C) levels tended to decrease in EO group, but remained unaltered with ER treatment. Apolipoprotein B levels were equally reduced in both treatment groups. CONCLUSION For similar body weight reduction, the combination of ezetimibe with orlistat may be more efficient in LDL-C lowering, whereas the combination of ezetimibe with rimonabant may be more potent in terms of improving HDL-C and triglycerides.
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A randomized double-blind study comparing the efficacy and safety of orlistat versus placebo in obese patients with mild to moderate hypercholesterolemia.
de Castro, JJ, Dias, T, Chambel, P, Carvalheiro, M, Correia, LG, Guerreiro, L, Marques, O, Medina, JL, Nobre, E, Nunes, JS, et al
Revista portuguesa de cardiologia : orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology. 2009;(12):1361-74
Abstract
INTRODUCTION Obesity is a chronic disease and a serious health problem that leads to increased prevalence of diabetes, hypertension, dyslipidemia and gallbladder disease. OBJECTIVE To evaluate the efficacy of orlistat for weight loss and improved lipid profile compared to placebo in obese patients with hypercholesterolemia, treated over a period of 6 months. METHODOLOGY In a 6-month, multicenter (10 centers in Portugal), double-blind, parallel, placebo-controlled study, 166 patients, aged 18-65 years, body mass index (BMI) > or = 27 kg/m2, LDL cholesterol > 155 mg/dl, were randomized to a reduced calorie diet (600 kcal/day deficit) plus orlistat three times a day or placebo. Exclusion criteria included triglycerides > 400 mg/dl, severe cardiovascular disease, uncontrolled hypertension, type 1 or 2 diabetes under pharmacological treatment, and gastrointestinal or pancreatic disease. RESULTS The mean difference in weight from baseline was 5.9% (5.6 kg) in the orlistat group vs. 2.3% (2.2 kg) in the placebo group. In the orlistat group 49% of patients achieved 5-10% weight loss and 8.8% achieved > 10%. The orlistat group showed a significant reduction in total and LDL cholesterol, with similar changes for HDL in both treatment groups. The frequency of gastrointestinal adverse events was slightly higher in the orlistat group than in the placebo group, leading to discontinuation in 7 patients. CONCLUSION Treatment with orlistat plus a reduced calorie diet for 6 months achieved significant reductions in weight, BMI and lipid parameters.
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The use of a Cissus quadrangularis/Irvingia gabonensis combination in the management of weight loss: a double-blind placebo-controlled study.
Oben, JE, Ngondi, JL, Momo, CN, Agbor, GA, Sobgui, CS
Lipids in health and disease. 2008;:12
Abstract
AIM: To evaluate the effects of two formulations, Cissus quadrangularis-only and a Cissus quadrangularis/Irvingia gabonensis combination, on weight loss in overweight and obese human subjects. METHODS The study was a 10 week randomized, double-blind, placebo-controlled design involving 72 obese or overweight participants (45.8% male; 54.2% female; ages 21-44; mean age = 29.3). The participants were randomly divided into three equal (n = 24) groups: placebo, Cissus quadrangularis-only, and Cissus quadrangularis/Irvingia gabonensis combination. Capsules containing the placebo or active formulations were administered twice daily before meals; no major dietary changes nor exercises were suggested during the study. A total of six anthropomorphic and serological measurements (body weight, body fat, waist size; total plasma cholesterol, LDL cholesterol, fasting blood glucose level) were taken at baseline and at 4, 8 and 10 weeks. RESULTS Compared to the placebo group, the two active groups showed a statistically significant difference on all six variables by week 10. The magnitude of the differences was noticeable by week 4 and continued to increase over the trial period. CONCLUSION Although the Cissus quadrangularis-only group showed significant reductions on all variables compared to the placebo group, the Cissus quadrangularis/Irvingia gabonensis combination resulted in even larger reductions. This apparently synergistic formulation should prove helpful in the management of obesity and its related complications.
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[Cardiometabolic effects of rimonabant in obese/overweight subjects with dyslipidaemia or type 2 diabetes].
Scheen, AJ, Van Gaal, LF
Revue medicale de Liege. 2007;(2):81-5
Abstract
Rimonabant (Acomplia) is the first selective CB1 receptor blocker of the endocannabinoid system. It has been evaluated in the RIO ("Rimonabant In Obesity and related disorders") programme including above 6.600 overweight/obese patients with or without comorbidities followed for 1 to 2 years. Compared to placebo, rimonabant 20 mg/day consistently increases weight loss, reduces waist circumference, increases HDL cholesterol, lowers triglyceride levels, diminishes insulin resistance, and reduces the prevalence of metabolic syndrome. In patients with type 2 diabetes, rimonabant also diminishes HbA1c levels, an effect confirmed in the recent SERENADE trial. Almost half of the metabolic effects occurs beyond weight loss, suggesting direct peripheral effects of rimonabant. Rimonabant is indicated in Europe as an adjunct to diet and exercise for the treatment of obese patients, or overweight patients with associated risk factor(s), such as type 2 diabetes or dyslipidaemia.
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Combination therapy of zonisamide and bupropion for weight reduction in obese women: a preliminary, randomized, open-label study.
Gadde, KM, Yonish, GM, Foust, MS, Wagner, HR
The Journal of clinical psychiatry. 2007;(8):1226-9
Abstract
OBJECTIVE Zonisamide and bupropion have been investigated for weight reduction in obese adults. We conducted a preliminary study comparing the effect on body weight of the combination of these 2 drugs versus zonisamide monotherapy. METHOD This was a 12-week, randomized, open-label, parallel-group comparison of 2 active interventions conducted from October 2003 to June 2004. Eighteen obese women (mean [SE] body mass index of 36.8 [1.2] kg/m(2)) were randomly assigned to receive the combination of zonisamide and bupropion (N = 9) or zonisamide alone (N = 9). All subjects were prescribed a balanced hypocaloric diet (500 kcal/day deficit) and compliance was monitored with self-rated food diaries. Zonisamide therapy was started at 100 mg/day, with a gradual increase to 400 mg/day over 4 weeks for both groups. In addition, the group assigned to combination therapy received bupropion, which was started at 100 mg/day, with an increase to 200 mg/day after 2 weeks. Zonisamide was administered at night and bupropion in the morning. Body weight in kilograms was the primary outcome measure. RESULTS In an intent-to-treat analysis, carrying the last observation forward for all randomly assigned participants with at least 1 postbaseline assessment, the combination group lost more body weight than the zonisamide group (mean [SE] = 7.2 [1.2] kg [7.5%] vs. 2.9 [0.7] kg [3.1%]; F = 4.7, df = 4,56; p = .003) during the 12-week period. For the subset of 12 patients (combination, N = 7; zonisamide, N = 5) that completed the full 12-week treatment, the mean (SE) weight loss was 8.1 (1.4) kg (8.5%) for the combination group versus 3.0 (0.9) kg (3.3%) for the zonisamide group (F = 4.6, df = 4,40; p = .004). Six subjects in the combination group and 2 in the zonisamide group lost at least 5% of body weight. CONCLUSION In this short-term, open-label, preliminary trial, combination treatment of zonisamide and bupropion resulted in more weight loss than treatment with zonisamide alone.