Surgical vs conventional therapy for weight loss treatment of obstructive sleep apnea: a randomized controlled trial

CONTEXT

Obstructive sleep apnea (OSA) is strongly related to obesity. Weight loss is recommended as part of the overall management plan for obese patients diagnosed with OSA.

OBJECTIVE

To determine whether surgically induced weight loss is more effective than conventional weight loss therapy in the management of OSA.

DESIGN, SETTING, AND PATIENTS

A randomized controlled trial of 60 obese patients (body mass index: >35 and <55) with recently diagnosed (<6 months) OSA and an apnea-hypopnea index (AHI) of 20 events/hour or more. These patients had been prescribed continuous positive airway pressure (CPAP) therapy to manage OSA and were identified via accredited community sleep clinics. The trial was conducted between September 2006 and March 2009 by university- and teaching hospital-based clinical researchers in Melbourne, Australia. Patients with obesity hypoventilation syndrome, previous bariatric surgery, contraindications to bariatric surgery, or significant cardiopulmonary, neurological, vascular, gastrointestinal, or neoplastic disease were excluded.

INTERVENTIONS

Patients were randomized to a conventional weight loss program that included regular consultations with a dietitian and physician, and the use of very low-calorie diets as necessary (n = 30) or to bariatric surgery (laparoscopic adjustable gastric banding; n = 30).

MAIN OUTCOME MEASURES

The primary outcome was baseline to 2-year change in AHI on diagnostic polysomnography scored by staff blinded to randomization. Secondary outcomes were changes in weight, CPAP adherence, and functional status.

RESULTS

Patients lost a mean of 5.1 kg (95% CI, 0.8 to 9.3 kg) in the conventional weight loss program compared with 27.8 kg (95% CI, 20.9 to 34.7 kg) in the bariatric surgery group (P < .001). The AHI decreased by 14.0 events/hour (95% CI, 3.3 to 24.6 events/hour) in the conventional weight loss group and by 25.5 events/hour (95% CI, 14.2 to 36.7 events/hour) in the bariatric surgery group. The between-group difference was -11.5 events/hour (95% CI, -28.3 to 5.3 events/hour; P = .18). CPAP adherence did not differ between the groups. The bariatric surgery group had greater improvement in the Short Form 36 physical component summary score (mean, 9.3 [95% CI, 0.5 to 18.0]; P = .04).

CONCLUSION

Among a group of obese patients with OSA, the use of bariatric surgery compared with conventional weight loss therapy did not result in a statistically greater reduction in AHI despite major differences in weight loss.

TRIAL REGISTRATION

anzctr.org Identifier: 12605000161628.

Bariatric surgery for type 2 diabetes

Bariatric surgery provides substantial, sustained weight loss and major improvements in glycaemic control in severely obese individuals with type 2 diabetes. However, uptake of surgery in eligible patients is poor, and the barriers are difficult to surmount. We examine the indications for and efficacy and safety of conventional bariatric surgical procedures and their effect on glycaemic control in type 2 diabetes. How surgical gastrointestinal interventions achieve these changes is of great research interest, and is evolving rapidly. Old classifications about restriction and malabsorption are inadequate, and we explore understanding of putative mechanisms. Some bariatric procedures improve glycaemic control in people with diabetes beyond that expected for weight loss, and understanding this additional effect could provide insights into the pathogenesis of type 2 diabetes and assist in the development of new procedures, devices, and drugs both for obese and non-obese patients.

Bariatric surgery: an IDF statement for obese Type 2 diabetes

The International Diabetes Federation Taskforce on Epidemiology and Prevention of Diabetes convened a consensus working group of diabetologists, endocrinologists, surgeons and public health experts to review the appropriate role of surgery and other gastrointestinal interventions in the treatment and prevention of Type 2 diabetes. The specific goals were: to develop practical recommendations for clinicians on patient selection; to identify barriers to surgical access and suggest interventions for health policy changes that ensure equitable access to surgery when indicated; and to identify priorities for research. Bariatric surgery can significantly improve glycaemic control in severely obese patients with Type 2 diabetes. It is an effective, safe and cost-effective therapy for obese Type 2 diabetes. Surgery can be considered an appropriate treatment for people with Type 2 diabetes and obesity not achieving recommended treatment targets with medical therapies, especially in the presence of other major co-morbidities. The procedures must be performed within accepted guidelines and require appropriate multidisciplinary assessment for the procedure, comprehensive patient education and ongoing care, as well as safe and standardized surgical procedures. National guidelines for bariatric surgery need to be developed for people with Type 2 diabetes and a BMI of 35 kg/m² or more.

General practice research--does gender affect the decision to participate?

BACKGROUND

Recruitment of general practitioners for research in Australia is problematic. We aimed to explore general practice demographics and recent research experience for effects on research attitudes and enablers and inhibitors of research participation.

METHODS

A survey was developed and distributed to GPs via two divisions of general practice in Melbourne, Victoria.

RESULTS

Seven hundred and fifty-six questionnaires were mailed and 215 (28%) returned; 50% of respondents were women and 51% of all GPs had previously participated in general practice research. Gender differences were found in factors affecting the decision to participate. Women were significantly more concerned about out-of-hours commitment (p<0.001), paperwork volume (p<0.001), recruitment criteria (p=0.009) and research methodology complexity (p=0.016). They were more likely to want to work as a general practice group (p=0.007) and to be inhibited by having to present results to peers (OR 2.4, 95% CI: 1.5-3.8).

CONCLUSION

Research challenges, reduced interest in research participation and feminisation of the workforce have major implications for the future of research in general practice. Systemic changes are needed to address these issues.

Baseline sympathetic nervous system activity predicts dietary weight loss in obese metabolic syndrome subjects

CONTEXT

The sympathetic nervous system is an important physiological modulator of basal and postprandial energy expenditure.

OBJECTIVE

Our objective was to investigate whether the variability of weight loss attained during hypocaloric dietary intervention is related to individual differences in baseline sympathetic drive and nutritional sympathetic nervous system responsiveness.

PARTICIPANTS AND METHODS

Untreated obese subjects (n = 42; body mass index = 32.1 ± 0.5 kg/m(2)), aged 57 ± 1 yr, who fulfilled Adult Treatment Panel III metabolic syndrome criteria participated in a 12-wk weight loss program using a modified Dietary Approaches to Treat Hypertension (DASH) diet. Muscle sympathetic nerve activity (MSNA) was measured by microneurography at rest and in a subset of subjects during a standard 75-g oral glucose tolerance test.

RESULTS

Weight loss (6.7 ± 0.5 kg) was independently predicted by baseline resting MSNA burst incidence (r = 0.38; P = 0.019), which accounted for 14.3% of the variance after adjustment for age and baseline body weight. Weight loss-resistant subjects in the lower tertile of weight loss (4.4 ± 0.3%) had significantly blunted MSNA responses to oral glucose at baseline compared with successful weight losers (9.6 ± 0.8%). Absolute Δ MSNA averaged -7 ± 2, -6 ± 5, and -3 ± 3 bursts per 100 heartbeats at 30, 60, and 90 min after glucose in the weight loss-resistant group. Corresponding values in the successful weight loss group were 9 ± 3, 12 ± 3, and 15 ± 4 bursts per 100 heartbeats (time × group interaction, P = 0.004).

CONCLUSIONS

These findings indicate that baseline sympathetic drive and nutritional sympathetic responsiveness may be important prognostic biological markers for weight loss outcome.

The effects of dietary weight loss with or without exercise training on liver enzymes in obese metabolic syndrome subjects

AIM

Insulin resistance and visceral adiposity are predisposing factors for fatty liver disease. The main objectives of this study were (i) to compare the effects of caloric restriction (CR) alone or together with moderate-intensity aerobic exercise training (CR+EX) on liver enzymes, a surrogate marker of liver injury, in obese metabolic syndrome (MetS) subjects and (ii) to identify anthropometric, metabolic, cardiovascular and dietary predictors of changes in liver enzymes.

METHODS

Sedentary men and women (n = 63), aged 55 ± 6 (s.d.) years with body mass index 32.7 ± 4.1 kg/m(2) and confirmed MetS, were randomized to 12-week CR, CR+EX or no treatment (Control).

RESULTS

Weight loss averaged 7.6% in the CR and 9.1% in the CR+EX group (time effect, p < 0.001; group effect, p = 0.11); insulin sensitivity improved by 49 and 45%, respectively (both p < 0.001). Fitness (maximal oxygen consumption) increased by 19% in the CR+EX group only (p < 0.001). Alanine aminotransferase (ALT) levels decreased by 20% in the CR and 24% in the CR+EX group (time effect, both p < 0.001; group effect, p = 0.68); corresponding values for γ-glutamyltransferase (GGT) were -28 and -33%, respectively (time effect, both p < 0.001; group effect, p = 0.28). Reduction in abdominal fat mass (measured by DXA from L1 to L4) independently predicted ΔALT (r = 0.42, p = 0.005) and ΔGGT (r = 0.55, p < 0.001), whereas change in dietary saturated fat intake was independently associated with ΔALT (r = 0.35, p = 0.03).

CONCLUSIONS

Reductions in central adiposity and saturated fat intake are key drivers of improvement in liver enzymes during lifestyle interventions. Exercise training did not confer significant incremental benefits in this study.

First Australian experiences with an oral volume restriction device to change eating behaviors and assist with weight loss

Eating behaviors impact satiety and caloric intake so should be considered in any weight-loss program. A novel custom-made oral device has been designed to be worn in the upper palate while eating in order to slow eating-rate and aid weight loss. The aim of this study was to assess the device's potential impact on weight-loss and gain first impressions among overweight/obese Australians. Twenty participants (M: 6, F: 14, mean age 36 years, BMI 27-33 kg/m(2)) were enrolled in a 4-month open-label trial. Each received a device and nutritionist-delivered diet plan. Weight, compliance, and acceptability were assessed fortnightly. Anthropometry, biochemical and clinical outcomes were measured at baseline and 16 weeks. Sixteen participants completed the study. Mean weight-loss was 4.9 ± 0.9 kg, or 5.2 ± 0.9% initial bodyweight (P < 0.001, n = 20, intention-to-treat). There were no significant adverse events (AEs), but 65% of participants required device adjustment by the dentist. Compliance (defined as >5 uses/week) was achieved by 80% of participants and correlated positively with weight-loss (R = 0.68, P = 0.001). All reported that the device was comfortable and reduced bite-size, promoted chewing and slowed eating-rate. Most observed either no change, or increased satiety, despite reduced meal sizes. For most, speech difficulties discouraged device use in social settings. All reported greater awareness of food choices, portion sizes and eating-rate. Subjective control of dietary behaviors, measured by the Three Factor Eating Questionnaire (TFEQ), improved significantly. The device should be explored as an adjunct to dietary composition change in weight-management programs, to assist patients to modify eating behaviors and achieve successful weight-loss.

Impact of laparoscopic adjustable gastric banding on type 2 diabetes

Bariatric surgery is becoming an accepted option for obese people with type 2 diabetes. Our aim was to assess the impact of laparoscopic adjustable gastric banding (LAGB) through a systematic review of the literature. Data was sourced from Scopus, MEDLINE and EMBASE published from 2000 through May 2011, and five unpublished studies that were performed by industry for regulatory approval were also included. Studies were selected on the basis that they provide some detail of diabetes status before and after LAGB. There were 35 studies meeting the inclusion criteria. There was considerable heterogeneity in study design, sample size, length of follow-up, attrition rates and classification of diabetes status. Weight loss was progressive over the first 2 years with a weighted average of 47% excess weight loss at 2 years. Remission or improvement in diabetes varied from 53% to 70% over different time periods. Results were broadly consistent, demonstrating clinically relevant improvements in diabetes outcomes with sustained weight loss in obese people with type 2 diabetes following LAGB surgery. However, there were significant shortcomings in the reviewed literature with few high-quality studies, inconsistent reporting of diabetes outcomes and high attrition rates. Long-term studies that address these limitations are needed.

Management of the metabolic/bariatric surgery patient

There is currently a global pandemic of obesity and obesity-engendered comorbidities; in particular, certain major chronic metabolic diseases (eg, type 2 diabetes) which markedly reduce life expectancy and quality of life. This review is predicated on the fact that management of the obese patient is a primary concern of all physicians and health care providers, and that metabolic/bariatric surgery is a highly successful therapeutic option for this disease.

Bariatric surgery for diabetes: the International Diabetes Federation takes a position

Type 2 diabetes (T2D) and obesity are both complex and chronic medical disorders, each with an escalating worldwide prevalence. When obesity is severe, and/or available medical therapies fail to control the diabetes, bariatric surgery becomes a cost-effective therapy for T2D. When there are other major comorbidities and cardiovascular risk, the option of bariatric surgery becomes even more worthy of consideration. National guidelines for bariatric surgery need to be developed and implemented for people with T2D. With this in mind, the International Diabetes Federation convened a multidisciplinary working group to develop a position statement. The key recommendations cover describing those eligible for surgery and who should be prioritized, incorporating bariatric surgery into T2D treatment algorithms, performing surgery in centers with multidisciplinary teams that are experienced in the management of both obesity and diabetes, and developing bariatric surgery registries and reporting standards.

Impact of laparoscopic adjustable gastric banding on type 2 diabetes

Bariatric surgery is becoming an accepted option for obese people with type 2 diabetes. Our aim was to assess the impact of laparoscopic adjustable gastric banding (LAGB) through a systematic review of the literature. Data was sourced from Scopus, MEDLINE and EMBASE published from 2000 through May 2011, and five unpublished studies that were performed by industry for regulatory approval were also included. Studies were selected on the basis that they provide some detail of diabetes status before and after LAGB. There were 35 studies meeting the inclusion criteria. There was considerable heterogeneity in study design, sample size, length of follow-up, attrition rates and classification of diabetes status. Weight loss was progressive over the first 2 years with a weighted average of 47% excess weight loss at 2 years. Remission or improvement in diabetes varied from 53% to 70% over different time periods. Results were broadly consistent, demonstrating clinically relevant improvements in diabetes outcomes with sustained weight loss in obese people with type 2 diabetes following LAGB surgery. However, there were significant shortcomings in the reviewed literature with few high-quality studies, inconsistent reporting of diabetes outcomes and high attrition rates. Long-term studies that address these limitations are needed.

Surgical approaches to the treatment of obesity

Bariatric surgery, through its efficacy and improved safety, is emerging as an important and broadly available treatment for people with severe and complex obesity that has not responded adequately to other therapy. Established procedures, such as Roux-en-Y gastric bypass and adjustable gastric banding, account for more than 80% of bariatric surgical procedures globally. Sleeve gastrectomy has emerged as a stand-alone procedure. Truly malabsoptive procedures, such as biliopancreatic diversion and its duodenal switch variant, have a diminishing role as primary procedures, but remain an option for patients who do not respond adequately to less disruptive procedures. The procedures vary considerably in their postoperative morbidity and mortality; pattern and extent of weight loss; nature and severity of long-term complications; and nutritional requirements and risks. There is no perfect procedure--an informed risk and benefit assessment should be made by each patient. Gastroenterologists also need to be familiar with the risks and benefits of current and emerging procedures as they are likely to be increasingly involved in the integrated care of these patients.

Bariatric surgery: an IDF statement for obese Type 2 diabetes

The International Diabetes Federation Taskforce on Epidemiology and Prevention of Diabetes convened a consensus working group of diabetologists, endocrinologists, surgeons and public health experts to review the appropriate role of surgery and other gastrointestinal interventions in the treatment and prevention of Type 2 diabetes. The specific goals were: to develop practical recommendations for clinicians on patient selection; to identify barriers to surgical access and suggest interventions for health policy changes that ensure equitable access to surgery when indicated; and to identify priorities for research. Bariatric surgery can significantly improve glycaemic control in severely obese patients with Type 2 diabetes. It is an effective, safe and cost-effective therapy for obese Type 2 diabetes. Surgery can be considered an appropriate treatment for people with Type 2 diabetes and obesity not achieving recommended treatment targets with medical therapies, especially in the presence of other major co-morbidities. The procedures must be performed within accepted guidelines and require appropriate multidisciplinary assessment for the procedure, comprehensive patient education and ongoing care, as well as safe and standardized surgical procedures. National guidelines for bariatric surgery need to be developed for people with Type 2 diabetes and a BMI of 35 kg/m(2) or more.

Bariatric surgery: an IDF statement for obese Type 2 diabetes

The International Diabetes Federation Taskforce on Epidemiology and Prevention of Diabetes convened a consensus working group of diabetologists, endocrinologists, surgeons and public health experts to review the appropriate role of surgery and other gastrointestinal interventions in the treatment and prevention of Type 2 diabetes. The specific goals were: to develop practical recommendations for clinicians on patient selection; to identify barriers to surgical access and suggest interventions for health policy changes that ensure equitable access to surgery when indicated; and to identify priorities for research. Bariatric surgery can significantly improve glycaemic control in severely obese patients with Type 2 diabetes. It is an effective, safe and cost-effective therapy for obese Type 2 diabetes. Surgery can be considered an appropriate treatment for people with Type 2 diabetes and obesity not achieving recommended treatment targets with medical therapies, especially in the presence of other major co-morbidities. The procedures must be performed within accepted guidelines and require appropriate multidisciplinary assessment for the procedure, comprehensive patient education and ongoing care, as well as safe and standardized surgical procedures. National guidelines for bariatric surgery need to be developed for people with Type 2 diabetes and a BMI of 35 kg/m(2) or more.

Obesity and global warming: are they similar "canaries" in the same "mineshaft"?

Obesity, linked to chronic disease, and global warming, linked to climate change, may be indicators of serious problems with our consumption-based economic system.

Barriers to recruitment of professionals into a general practice childhood obesity program

Recruiting general practitioners to take part in research in primary care is important and challenging. This paper describes the process, barriers and achievements experienced by a research team whilst recruiting Divisions and general practitioners (GPs)/practices into a project related to management of obesity in children, which used Breakthrough Series methodology in the intervention arm. The research team chose to recruit GPs through Divisions of General Practice, because of the existing positive relationship between the research team and the Divisions, and the Divisions’ positive relationships with the GPs/practices in their area. The project aimed to recruit four Divisions of General Practice, who in turn would recruit a total of 24 GPs/practices. Four Divisions (two rural, two metropolitan) were recruited initially, but the two rural Divisions withdrew before the project commenced and were replaced by two metropolitan Divisions. As Divisions were unable to recruit sufficient GPs/practices, two additional strategies were used, but despite all efforts, only 17 practices were recruited. Reflection on recruitment failure focussed on reasons from the perspective of Divisions, GPs, other projects using the Breakthrough Series methodology with a chronic disease focus and other projects conducted in Australia where the focus was childhood obesity. The results showed that even Divisions who were enthusiastic about joining a project may be unable to recruit sufficient GPs and practices, for reasons including staff changeover and GP reluctance. Caution is suggested when setting recruitment targets where the condition is sensitive, is not the presenting problem, is not routinely tackled in general practice, involves minors, where treatment is perceived to be of doubtful effectiveness, or where major government policies may need to be considered.

The effect of obesity on health outcomes

The prevalence of obesity has progressively increased globally over the last 30 years. The determinants of this pandemic are many, poorly defined and priorities debated. While public health measures to prevent obesity have largely failed we are presented with a growing burden of disease and disability. Cardiovascular disease, type-2 diabetes, obesity related cancers, osteoarthritis and psychological disturbance generate much of the morbidity and years of life lost associated with increasing levels of obesity. Obesity has a clearly measurable impact on physical and mental health, health related quality of life, and generates considerable direct and indirect costs. The evolving obesity pandemic is exacting a considerable toll on those affected, the treating health services, and on our communities. Weight loss appears to be the most effective therapy for obesity and obesity related comorbidity. As health care researchers and providers we are likely to play a peripheral role in the prevention of obesity, but a central role in effectively treating those afflicted by the obesity pandemic.

Sympathetic nervous activation in obesity and the metabolic syndrome--causes, consequences and therapeutic implications

The world wide prevalence of obesity and the metabolic syndrome is escalating. Contrary to earlier experimental evidence, human obesity is characterised by sympathetic nervous activation, with the outflows to both the kidney and skeletal muscle being activated. While the mechanisms responsible for initiating the sympathetic activation remain to be unequivocally elucidated, hyperinsulinemia, obstructive sleep apnoea, increased circulating adipokines, stress and beta adrenergic receptor polymorphisms are implicated. The pattern of sympathetic activation may be the pathophysiological mechanism underpinning much obesity-related illnesses with the consequences including, amongst others, the development of hypertension, insulin resistance, diastolic dysfunction and renal impairment. While diet and exercise are the first line therapy for the treatment of obesity and the metabolic syndrome, pharmacological interventions targeting the sympathetic nervous system, either directly or indirectly are also likely to be of benefit. Importantly, the benefit may not necessarily be weight related but may be associated with a reduction in end organ damage.

Laparoscopic adjustable gastric banding in severely obese adolescents: a randomized trial

CONTEXT

Adolescent obesity is a common and serious health problem affecting more than 5 million young people in the United States alone. Bariatric surgery is being evaluated as a possible treatment option. Laparoscopic adjustable gastric banding (gastric banding) has the potential to provide a safe and effective treatment.

OBJECTIVE

To compare the outcomes of gastric banding with an optimal lifestyle program on adolescent obesity.

DESIGN, SETTING, AND PATIENTS

A prospective, randomized controlled trial of 50 adolescents between 14 and 18 years with a body mass index (BMI) higher than 35, recruited from the Melbourne, Australia, community, assigned either to a supervised lifestyle intervention or to undergo gastric banding, and followed up for 2 years. The study was performed between May 2005 and September 2008.

MAIN OUTCOME MEASURES

Weight loss. Secondary outcomes included change in metabolic syndrome, insulin resistance, quality of life, and adverse outcomes.

RESULTS

Twenty-four of 25 patients in the gastric banding group and 18 of 25 in lifestyle group completed the study. Twenty-one (84%) in the gastric banding and 3 (12%) in the lifestyle groups lost more than 50% of excess weight, corrected for age. Overall, the mean changes in the gastric banding group were a weight loss of 34.6 kg (95% CI, 30.2-39.0), representing an excess weight loss of 78.8% (95% CI, 66.6%-91.0%), 12.7 BMI units (95% CI, 11.3-14.2), and a BMI z score change from 2.39 (95% CI, 2.05-2.73) to 1.32 (95% CI, 0.98-1.66). The mean losses in the lifestyle group were 3.0 kg (95% CI, 2.1-8.1), representing excess weight loss of 13.2% (95% CI, 2.6%-21.0%), 1.3 BMI units (95% CI, 0.4-2.9), and a BMI z score change from 2.41 (95% CI, 2.21-2.66) to 2.26 (95% CI, 1.91-2.43). At entry, 9 participants (36%) in the gastric banding group and 10 (40%) in the lifestyle group had the metabolic syndrome. At 24 months, none of the gastric banding group had the metabolic syndrome (P = .008; McNemar chi(2)) compared with 4 of the 18 completers (22%) in the lifestyle group (P = .13). The gastric banding group experienced improved quality of life with no perioperative adverse events. However, 8 operations (33%) were required in 7 patients for revisional procedures either for proximal pouch dilatation or tubing injury during follow-up.

CONCLUSIONS

Among obese adolescent participants, use of gastric banding compared with lifestyle intervention resulted in a greater percentage achieving a loss of 50% of excess weight, corrected for age. There were associated benefits to health and quality of life.

TRIAL REGISTRATION

ANZCTR Identifier: 12605000160639.