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Objective To quantify the overall effects of bariatric surgery compared with non-surgical treatment for obesity.Design Systematic review and meta-analysis based on a random effects model. Data sourcesSearches of Medline, Embase, and the Cochrane Library from their inception to December 2012 regardless of language or publication status.Eligibility criteria Eligible studies were randomised controlled trials with ≥6 months of follow-up that included individuals with a body mass index ≥30, compared current bariatric surgery techniques with non-surgical treatment, and reported on body weight, cardiovascular risk factors, quality of life, or adverse events. ResultsThe meta-analysis included 11 studies with 796 individuals (range of mean body mass index at baseline 30-52). Individuals allocated to bariatric surgery lost more body weight (mean difference −26 kg (95% confidence interval −31 to −21)) compared with non-surgical treatment, had a higher remission rate of type 2 diabetes (relative risk 22.1 (3.2 to 154.3) in a complete case analysis; 5.3 (1.8 to 15.8) in a conservative analysis assuming diabetes remission in all non-surgically treated individuals with missing data) and metabolic syndrome (relative risk 2.4 (1.6 to 3.6) in complete case analysis; 1.5 (0.9 to 2.3) in conservative analysis), greater improvements in quality of life and reductions in medicine use (no pooled data). Plasma triglyceride concentrations decreased more (mean difference −0.7 mmol/L (−1.0 to −0.4) and high density lipoprotein cholesterol concentrations increased more (mean difference 0.21 mmol/L (0.1 to 0.3)). Changes in blood pressure and total or low density lipoprotein cholesterol concentrations were not significantly different. There were no cardiovascular events or deaths reported after bariatric surgery. The most common adverse events after bariatric surgery were iron deficiency anaemia (15% of individuals undergoing malabsorptive bariatric surgery) and reoperations (8%).Conclusions Compared with non-surgical treatment of obesity, bariatric surgery leads to greater body weight loss and higher remission rates of type 2 diabetes and metabolic syndrome. However, results are limited to two years of follow-up and based on a small number of studies and individuals.Systematic review registration PROSPERO CRD42012003317 (www. crd.york.ac.uk/PROSPERO). IntroductionObesity is one of the greatest public health problems in industrialised countries.1 2 In the US, UK, and Australia, for instance, the prevalence of obesity (body mass index (weight (kg) /(height (m) 2 ) >30) has more than doubled in the past 25 years.2 Currently, 67% of the US population is either overweight or obese, and in most European countries the prevalence ranges between 40% and 50%.3 Obesity is associated with an increased risk for type 2 diabetes, hypertension, dyslipidaemia, cardiovascular diseases, musculoskeletal disorders (such as osteoarthritis), certain types of cancer, and mortality. 4 This entails huge healthcare costs due to obesity. 5Treatment options f...

Background: Low-carbohydrate diets have become increasingly popular for weight loss. However, evidence from individual trials about benefits and risks of these diets to achieve weight loss and modify cardiovascular risk factors is preliminary. Methods: We used the Cochrane Collaboration search strategy to identify trials comparing the effects of lowcarbohydrate diets without restriction of energy intake vs low-fat diets in individuals with a body mass index (calculated as weight in kilograms divided by the square of height in meters) of at least 25. Included trials had to report changes in body weight in intention-to-treat analysis and to have a follow-up of at least 6 months. Two reviewers independently assessed trial eligibility and quality of randomized controlled trials. Results: Five trials including a total of 447 individuals fulfilled our inclusion criteria. After 6 months, individuals assigned to low-carbohydrate diets had lost more weight than individuals randomized to low-fat diets (weighted mean difference,-3.3 kg; 95% confidence interval [CI], −5.3 to −1.4 kg). This difference was no longer obvious after 12 months (weighted mean difference, −1.0 kg; 95% CI, −3.5 to 1.5 kg). There were no differences in blood pressure. Tri-glyceride and high-density lipoprotein cholesterol values changed more favorably in individuals assigned to lowcarbohydrate diets (after 6 months, for triglycerides, weighted mean difference, −22.1 mg/dL [−0.25 mmol/L]; 95% CI, −38.1 to −5.3 mg/dL [−0.43 to −0.06 mmol/L]; and for high-density lipoprotein cholesterol, weighted mean difference, 4.6 mg/dL [0.12 mmol/L]; 95% CI, 1.5-8.1 mg/dL [0.04-0.21 mmol/L]), but total cholesterol and lowdensity lipoprotein cholesterol values changed more favorably in individuals assigned to low-fat diets (weighted mean difference in low-density lipoprotein cholesterol after 6 months, 5.4 mg/dL [0.14 mmol/L]; 95% CI, 1.2-10.1 mg/dL [0.03-0.26 mmol/L]). Conclusions: Low-carbohydrate, non-energy-restricted diets appear to be at least as effective as low-fat, energyrestricted diets in inducing weight loss for up to 1 year. However, potential favorable changes in triglyceride and highdensity lipoprotein cholesterol values should be weighed against potential unfavorable changes in low-density lipoprotein cholesterol values when low-carbohydrate diets to induce weight loss are considered.

In this sample of trials based on RCT protocols from 6 research ethics committees, discontinuation was common, with poor recruitment being the most frequently reported reason. Greater efforts are needed to ensure the reporting of trial discontinuation to research ethics committees and the publication of results of discontinued trials.

Objective To investigate the association between treatment induced change in high density lipoprotein cholesterol and total death, coronary heart disease death, and coronary heart disease events (coronary heart disease death and non-fatal myocardial infarction) adjusted for changes in low density lipoprotein cholesterol and drug class in randomised trials of lipid modifying interventions. Design Systematic review and meta-regression analysis of randomised controlled trials. Data sources Medline, Embase, Central, CINAHL, and AMED to October 2006 supplemented by contact with experts in the field. Study selection In teams of two, reviewers independently determined eligibility of randomised trials that tested lipid modifying interventions to reduce cardiovascular risk, reported high density lipoprotein cholesterol and mortality or myocardial infarctions separately for treatment groups, and treated and followed participants for at least six months. Data extraction and synthesis Using standardised, prepiloted forms, reviewers independently extracted relevant information from each article. The change in lipid concentrations for each trial and the weighted risk ratios for clinical outcomes were calculated.