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The Journal of the American Board of... 2005Type 2 diabetes is a serious, costly, and increasingly common disease. Several conditions commonly seen in family medicine settings confer increased risk of developing... (Review)
Review
Type 2 diabetes is a serious, costly, and increasingly common disease. Several conditions commonly seen in family medicine settings confer increased risk of developing diabetes. Among these conditions are impaired glucose tolerance, impaired fasting glucose, obesity, gestational diabetes, hypertension, hyperlipidemia, and menopause. We here present the results of a systematic review of the literature examining the evidence for different strategies aimed at preventing type 2 diabetes in patients with these conditions. The strongest evidence supports an intensive lifestyle intervention designed to induce modest weight loss. The greatest degree of prevention, based on lesser quality evidence, may be imparted by bariatric surgery. Metformin and troglitazone have appreciable evidence in specific populations, and orlistat and acarbose have slightly less evidence among obese patients, for preventing diabetes. Ramipril, captopril, losartan, pravastatin, and estrogens show some very preliminary promise for preventing diabetes in patients treated for hypertension, hyperlipidemia, and menopause, but each needs a more rigorous evaluation. Although more questions remain to be answered, family physicians now have tools available to help our patients lead lives free of diabetes.
Topics: Bariatrics; Diabetes Mellitus, Type 2; Female; Hormone Replacement Therapy; Humans; Hyperlipidemias; Hypertension; Male; Menopause; Obesity
PubMed: 15709062
DOI: 10.3122/jabfm.18.1.37 -
The Cochrane Database of Systematic... Jan 2005Obesity is closely related to type 2 diabetes and long-term weight reduction is an important part of the care delivered to obese persons with diabetes. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Obesity is closely related to type 2 diabetes and long-term weight reduction is an important part of the care delivered to obese persons with diabetes.
OBJECTIVES
To assess the efficacy of pharmacotherapy for weight loss in adults with type 2 diabetes.
SEARCH STRATEGY
Computerized searches were performed of MEDLINE (January 1966 to May 2004), EMBASE (January 1974 to May 2004, Web of Science (January 1981 to May 2004, and other electronic bibliographic databases, supplemented with hand searches of reference lists and selected journals.
SELECTION CRITERIA
Randomized, controlled trials were included where pharmacotherapy was used as the primary strategy for weight loss among adults with type 2 diabetes. Published and unpublished literature in any language and with any study design was included.
DATA COLLECTION AND ANALYSIS
Two reviewers abstracted data and the quality of included studies was evaluated by assessing potential attrition, as well as selection and measurement bias, and a Jadad score was obtained. Effects were combined using a random effects model.
MAIN RESULTS
A sufficient number of studies were available for a quantitative synthesis for fluoxetine, orlistat, and sibutramine. Twenty two randomized controlled trials were included in the review, with a total of 296 participants for fluoxitine, 2036 for orlistat, and 1047 for sibutramine. Pharmacotherapy produced modest reductions in weight for fluoxetine (5.1 kg (95% confidence interval [CI], 3.3 - 6.9) at 24 to 26 weeks follow up; orlistat 2.0 kg (CI, 1.3 - 2.8) at 12 to 57 weeks follow-up, and sibutramine 5.1 kg (CI, 3.2 - 7.0) at 12 to 52 weeks follow-up. Glycated hemoglobin also modestly and significantly reduced for fluoxetine and orlistat. Gastrointestinal side effects were common with orlistat; tremor, somnolence and sweating with fluoxetine; and palpitations with sibutramine. Some studies, using a variety of study designs, were available on other drugs and a significant decrease in weight was noted in three studies of mazindol, one of phenmetrazine, two of phentermine. No studies were identified that fit inclusion criteria for pseudophedrine, ephedra, sertraline, yohimbine, amphetamine or its derivatives, bupropion, topiramate, benzocaine, threachlorocitric acid, sertraline, and bromocriptine.
AUTHORS' CONCLUSIONS
Fluoxetine, orlistat, and sibutramine can achieve statistically significant weight loss over 12 to 57 weeks. The magnitude of weight loss is modest, however, and the long-term health benefits remain unclear. The safety of sibutramine is uncertain. There is a paucity of data on other drugs for weight loss or control in persons with type 2 diabetes.
Topics: Adult; Anti-Obesity Agents; Appetite Depressants; Cyclobutanes; Diabetes Mellitus, Type 2; Fluoxetine; Humans; Lactones; Obesity; Orlistat; Randomized Controlled Trials as Topic; Weight Loss
PubMed: 15674929
DOI: 10.1002/14651858.CD004096.pub2 -
The American Journal of Clinical... Dec 2004Obesity is a growing health concern in Canada and the United States, and pharmacologic therapies such as orlistat are being more commonly prescribed to assist with... (Meta-Analysis)
Meta-Analysis Review
Changes in body weight and serum lipid profile in obese patients treated with orlistat in addition to a hypocaloric diet: a systematic review of randomized clinical trials.
BACKGROUND
Obesity is a growing health concern in Canada and the United States, and pharmacologic therapies such as orlistat are being more commonly prescribed to assist with weight loss.
OBJECTIVE
Our goal was to assess the efficacy and safety of orlistat compared with either placebo or an active control with regard to weight loss and serum lipid changes in overweight patients.
DESIGN
We performed a systematic literature search of MEDLINE (1966 through December 2003) and the Cochrane Central Register of Controlled Trials. Relevant trials and reviews were searched by hand. Randomized trials comparing orlistat and a control and reporting changes in weight loss, serum lipids (total cholesterol, LDL cholesterol, HDL cholesterol, LDL:HDL, and triacylglycerols), or both in overweight and obese patients [body mass index (in kg/m2) > or =25] were included.
RESULTS
Twenty-eight randomized trials met our inclusion criteria. Seventeen studies including 10,041 patients compared 3 x 120 mg orlistat/d with placebo or an inactive control along with a hypocaloric diet over a 1-y period. Relative risks (RRs) associated with clinically significant weight losses of 5% and 10% were 1.74 (95% CI: 1.57, 1.91) and 1.96 (1.74, 2.21), both favoring orlistat. Improvement in total cholesterol, LDL cholesterol, HDL cholesterol, and LDL:HDL were also greater with orlistat. Gastrointestinal events were more common with orlistat than with placebo [RR: 1.46 (1.37, 1.55)].
CONCLUSION
Our findings suggest that 3 x 120 mg orlistat/d is effective for improving both weight loss and serum lipid profiles in obese patients at low and high cardiovascular disease risk and in obese patients with type 2 diabetes.
Topics: Adult; Anti-Obesity Agents; Body Weight; Diet, Reducing; Energy Intake; Female; Humans; Lactones; Lipids; Male; Middle Aged; Obesity; Orlistat; Randomized Controlled Trials as Topic; Safety; Treatment Outcome; Weight Loss
PubMed: 15585756
DOI: 10.1093/ajcn/80.6.1461 -
The Cochrane Database of Systematic... 2004Worldwide prevalence rates of obesity and overweight are rising and safe and effective treatment strategies are urgently needed. A number of anti-obesity agents have... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Worldwide prevalence rates of obesity and overweight are rising and safe and effective treatment strategies are urgently needed. A number of anti-obesity agents have been studied in short-term clinical trials, but long-term efficacy and safety need to be established.
OBJECTIVES
To assess/compare the effects and safety of approved anti-obesity medications in clinical trials of at least one-year duration.
SEARCH STRATEGY
MEDLINE, EMBASE, the Cochrane Controlled Trials Register, the Current Science Meta-register of Controlled Trials, and reference lists of original studies and reviews were searched. Date of last search was December 2002. Drug manufacturers and two obesity experts were contacted in to detect unpublished trials. No language restrictions were imposed.
SELECTION CRITERIA
Double-blind, randomised controlled weight loss and weight maintenance trials of approved anti-obesity agents that 1) enrolled adult overweight or obese patients, 2) included a placebo control group or compared two or more anti-obesity drugs 3) used an intention-to-treat analysis, and 4) had a minimum follow-up period of one year. Abstracts and pseudo-randomised trials were not included.
DATA COLLECTION AND ANALYSIS
Two reviewers independently assessed all potentially relevant citations for inclusion and methodological quality. The primary outcome measure was weight loss.
MAIN RESULTS
Of the eight anti-obesity agents investigated, only orlistat and sibutramine trials met inclusion criteria. Eleven orlistat weight loss studies (four of which reported a second year weight maintenance phase) and five sibutramine studies (three weight loss and two weight maintenance trials) were included. Attrition rates averaged 33% during the weight loss phase of orlistat trials and 43% in sibutramine studies. All patients received lifestyle modification as a co-intervention. Compared to placebo, orlistat-treated patients lost 2.7 kg (95% CI: 2.3 kg to 3.1 kg) or 2.9% (95% CI: 2.3 % to 3.4%) more weight and patients on sibutramine experienced 4.3 kg (95% CI: 3.6 kg to 4.9 kg) or 4.6% (95% CI: 3.8% to 5.4%) greater weight loss. The number of patients achieving ten percent or greater weight loss was 12% (95% CI: 8% to 16%) higher with orlistat and 15% (95% CI: 4% to 27%) higher with sibutramine therapy. Weight loss maintenance results were similar. Orlistat caused gastrointestinal side effects and sibutramine was associated with small increases in blood pressure and pulse rate.
REVIEWERS' CONCLUSIONS
Studies evaluating the long-term efficacy of anti-obesity agents are limited to orlistat and sibutramine. Both drugs appear modestly effective in promoting weight loss; however, interpretation is limited by high attrition rates. Longer and more methodologically rigorous studies of anti-obesity drugs that are powered to examine endpoints such as mortality and cardiovascular morbidity are required to fully evaluate any potential benefit of such agents.
Topics: Anti-Obesity Agents; Appetite Depressants; Body Weight; Cyclobutanes; Humans; Lactones; Obesity; Orlistat; Randomized Controlled Trials as Topic; Weight Loss
PubMed: 15266516
DOI: 10.1002/14651858.CD004094.pub2 -
Health Technology Assessment... May 2004To undertake a systematic review of the long-term effects of obesity treatments on body weight, risk factors for disease, and disease. (Review)
Review
OBJECTIVES
To undertake a systematic review of the long-term effects of obesity treatments on body weight, risk factors for disease, and disease.
METHODS
The study encompassed three systematic reviews that examined different aspects of obesity treatments. (1) A systematic review of obesity treatments in adults where the methods of the Cochrane Collaboration were applied and randomised controlled trials (RCTs) with a follow-up of at least 1 year were evaluated. (2) A systematic epidemiological review, where studies were sought on long-term effects of weight loss on morbidity and/or mortality, and examined through epidemiological modelling. (3) A systematic economic review that sought reports with both costs and outcomes of treatment, including recent reports that assessed the cost-effectiveness of pharmaceutical and surgical interventions. A Markov model was also adopted to examine the cost-effectiveness of a low-fat diet and exercise intervention in adults with obesity and impaired glucose tolerance.
RESULTS
The addition of the drugs orlistat or sibutramine was associated with weight loss and generally improved risk factors, apart from diastolic blood pressure for sibutramine. Metformin was associated with decreased mortality after 10 years in obese people with type 2 diabetes. Low-fat diets were associated with continuing weight loss for 3 years and improvements in risk factors, as well as prevention of type 2 diabetes and improved control of hypertension. Insufficient evidence was available to demonstrate the benefits of low calorie or very low calorie diets. The addition of an exercise or behaviour programme to diet was associated with improved weight loss and risk factors for at least 1 year. Studies combining low-fat diets, exercise and behaviour therapy suggested improved hypertension and cardiovascular disease. Family therapy was associated with improved weight loss for 2 years compared to individual therapy. There was insufficient evidence to conclude that individual therapy was more beneficial than group therapy. Weight lost more quickly (within 1 year), from the epidemiology review, may be more beneficial with respect to the risk of mortality. The effects of intentional weight loss need further investigation. Weight loss from surgical and non-surgical interventions for people suffering from obesity was associated with decreased risk of development of diabetes, and a reduction in low-density lipoprotein cholesterol, total cholesterol and blood pressure, in the long term. Targeting high-risk individuals with drugs or surgery was likely to result in a cost per additional life-year or quality-adjusted life-year (QALY) of no more than 13,000 British pounds. There was also suggestive evidence of cost saving from treatment of people with type 2 diabetes with metformin. Targeting surgery on people with severe obesity and impaired glucose tolerance was likely to be more cost-effective at 2329 British pounds per additional life-year. Economic modelling over 6 years for diet and exercise for people with impaired glucose tolerance was associated with a high initial cost per additional QALY, but by the sixth year the cost per QALY was 13,389 British pounds. Results did not include cost savings from diseases other than diabetes, and therefore may be conservative.
CONCLUSIONS
The drugs orlistat and sibutramine appear beneficial for the treatment of adults with obesity, and metformin for obese patients with type 2 diabetes. Exercise and/or behaviour therapy appear to improve weight loss when added to diet. Low-fat diets with exercise, or with exercise and behaviour therapy are associated with the prevention of type 2 diabetes and hypertension. Long-term weight loss in epidemiological studies was associated with reduced risk of type 2 diabetes, and may be beneficial for cardiovascular disease. Low-fat diets and exercise interventions in individuals at risk of obesity-related illness are of comparable cost to drug treatments. Long-term pragmatic RCTs of obesity treatments in populations with obesity-related illness or at high risk of developing such illness are needed (to include an evaluation of risk factors, morbidity, quality of life and economic evaluations). Drug trials that include dietary advice, plus exercise and/or behaviour therapy are also needed. Research exploring effective types of exercise, diet or behaviour and also interventions to prevent obesity in adults is required.
Topics: Anti-Obesity Agents; Behavior Therapy; Caloric Restriction; Cost-Benefit Analysis; Cyclobutanes; Diet, Fat-Restricted; Humans; Hypoglycemic Agents; Lactones; Markov Chains; Metformin; Obesity; Orlistat; Physical Fitness; Randomized Controlled Trials as Topic; Risk Factors
PubMed: 15147610
DOI: 10.3310/hta8210 -
Health Technology Assessment... 2001The prevalence of obesity in developed societies is increasing. Obesity is associated with an increased risk of co-morbidity, including cardiovascular disease and... (Review)
Review
BACKGROUND
The prevalence of obesity in developed societies is increasing. Obesity is associated with an increased risk of co-morbidity, including cardiovascular disease and diabetes. Following the withdrawal of fenfluramine and dexfenfluramine, interest has focused on a novel anti-obesity drug orlistat.
OBJECTIVE
To systematically assess the clinical effectiveness and cost-effectiveness of orlistat in the management of obesity. METHODS - SEARCH STRATEGY: Nineteen electronic databases were searched from inception to June 2000. Additionally, Internet searches were carried out, bibliographies of retrieved articles were examined and submissions were received from the manufacturer of orlistat. METHODS - INCLUSION AND EXCLUSION CRITERIA: Randomised controlled trials (RCTs) evaluating the effectiveness of orlistat used for weight loss or maintenance of weight loss in overweight or obese patients were eligible for inclusion. Primary outcome measures were changes in body weight, fat content or fat distribution. Secondary outcomes were changes in obesity-related risk-factor profiles, such as lipid levels, indicators of glycaemic control and blood pressure. Studies recruiting people with eating disorders such as anorexia nervosa and bulimia nervosa were excluded. METHODS - PROCESS OF STUDY SELECTION: Assessment of titles and abstracts was performed independently by two reviewers. If either reviewer considered a reference to be relevant, the full paper was retrieved. Full papers were assessed against the review selection criteria by two independent reviewers, and disagreements were resolved through discussion. METHODS - DATA EXTRACTION: Data were extracted by one reviewer into structured summary tables and checked by a second reviewer. Any disagreements about data were resolved by discussion. METHODS - QUALITY ASSESSMENT: Each included trial was assessed against a comprehensive checklist for methodological quality. Quality assessment was performed independently by two reviewers with disagreements resolved by discussion. METHODS - METHODS OF ANALYSIS/SYNTHESIS: This report is a narrative summary, with results grouped according to study endpoint. Statistical pooling was undertaken in groups of trials that were considered to be sufficiently similar. METHODS - ESTIMATION OF QUALITY OF LIFE, COSTS AND COST-EFFECTIVENESS AND/OR COST PER QUALITY-ADJUSTED LIFE-YEAR: Relevant economic evaluations were identified from the search strategy described above. Assessment of methodological quality was undertaken using principles outlined in published guidelines. METHODS - COMPANY SUBMISSIONS: Data from company submissions were subject to the same selection and appraisal processes as other studies considered for inclusion in the review, except that only RCTs with a duration of at least 1 year were selected. RESULTS - RESULTS OF THE SEARCH STRATEGY: Fourteen RCTs (including three company submissions) and two economic evaluations (including one company submission) were included in the review. RESULTS - RESULTS OF THE QUALITY ASSESSMENT: Methodological quality of trials was moderate to good. The main problems were lack of detail on methods used to produce true randomisation, small sample sizes in some cases and failure to use intention-to-treat analysis. It is likely that maintenance of blinding was difficult due to adverse effects associated with the study medication. RESULTS - EVIDENCE OF CLINICAL EFFECTIVENESS AND COST-EFFECTIVENESS: Most of the trials showed greater weight loss and better weight maintenance with orlistat compared to placebo at all endpoints (statistically significant differences for both outcomes). Orlistat 120 mg three times daily was the optimum regimen in terms of weight loss. Most trials showed significant improvement in at least some lipid concentration parameters, and, in three RCTs, orlistat produced statistically significant reductions in blood pressure relative to placebo. In obese patients with type 2 diabetes, orlistat resulted in a significantly greater weight loss at 1 year compared with placebo, and some parameters of glycaemic control and lipid concentration also showed significantly greater improvements compared with placebo. The incidence of gastrointestinal adverse events was consistently higher in orlistat groups compared with placebo, and orlistat use was associated with lower serum levels of fat-soluble vitamins. The cost per quality-adjusted life-year for orlistat was 45,881 UK pounds. CONCLUSIONS - IMPLICATIONS FOR CLINICAL PRACTICE: Although many trials have demonstrated statistically significant differences between groups in terms of weight loss in favour of orlistat versus placebo, the differences may not always be of clinical significance. The clinical significance of between-group differences for secondary outcomes may also be debatable. Possible adverse effects should be taken into account when prescribing orlistat, particularly gastrointestinal effects. (ABSTRACT TRUNCATED)
Topics: Anti-Obesity Agents; Cost-Benefit Analysis; Drug Evaluation; Humans; Lactones; Obesity; Orlistat; Randomized Controlled Trials as Topic; Technology Assessment, Biomedical; Treatment Outcome; United Kingdom
PubMed: 11399238
DOI: 10.3310/hta5180