Pharmacotherapy of obesity

Porcine Pancreatic Lipase Inhibitory Agent Isolated from Medicinal Herb and Inhibition Kinetics of Extracts from Eleusine indica (L.) Gaertner

Eleusine indica (Linnaeus) Gaertner is a traditional herb known to be depurative, febrifuge, and diuretic and has been reported with the highest inhibitory activity against porcine pancreatic lipase (PPL) among thirty two plants screened in an earlier study. This study aims to isolate and identify the active components that may possess high potential as an antiobesity agent. Of the screened solvent fractions of E. indica, hexane fraction showed the highest inhibitory activity of 27.01 ± 5.68% at 100 μg/mL. Bioactivity-guided isolation afforded three compounds from the hexane fraction of E. indica, namely, β-sitosterol, stigmasterol, and lutein. The structures of these compounds were elucidated using spectral techniques. Lutein showed an outstanding inhibitory activity against PPL (55.98 ± 1.04%), with activity 60% higher than that of the reference drug Orlistat. The other compounds isolated and identified were β-sitosterol (2.99 ± 0.80%) and stigmasterol (2.68 ± 0.38%). The enzyme kinetics of E. indica crude methanolic extract on PPL showed mixed inhibition mechanism.

Effects of leptin replacement alone and with exendin-4 on food intake and weight regain in weight-reduced diet-induced obese rats

Weight loss in obese humans produces a relative leptin deficiency, which is postulated to activate potent orexigenic and energy conservation mechanisms to restrict weight loss and promote weight regain. Here we determined whether leptin replacement alone or with GLP-1 receptor agonist exendin-4 attenuates weight regain or promotes greater weight loss in weight-reduced diet-induced obese (DIO) rats. Forty percent restriction in daily intake of a high-fat diet in DIO rats for 4 wk reduced body weight by 12%, body fat by 29%, and plasma leptin by 67% and normalized leptin sensitivity. When food restriction ended, body weight, body fat, and plasma leptin increased rapidly. Daily administration of leptin [3-h intraperitoneal (ip) infusions (4 nmol·kg(-1)·h(-1))] at onset and end of dark period for 3 wk did not attenuate hyperphagia and weight regain, nor did it affect mean daily meal sizes or meal numbers. Exendin-4 (50 pmol·kg(-1)·h(-1)) infusions during the same intervals prevented postrestriction hyperphagia and weight regain by normalizing meal size. Coadministration of leptin and exendin-4 did not reduce body weight more than exendin-4 alone. Instead, leptin began to attenuate the inhibitory effects of exendin-4 on food intake, meal size, and weight regain by the end of the second week of administration. Plasma leptin in rats receiving leptin was sevenfold greater than in rats receiving vehicle and 17-fold greater than in rats receiving exendin-4. Together, these results do not support the hypothesis that leptin replacement alone or with exendin-4 attenuates weight regain or promotes greater weight loss in weight-reduced DIO rats.

Taking Orlistat: Predicting Weight Loss over 6 Months

This study explored the predictors of weight loss following orlistat with a focus on both baseline variables and changes in beliefs and behaviours occurring over the course of taking the drug. Patients (n = 566) prescribed orlistat completed a questionnaire at baseline and after 6 months concerning their weight, beliefs and behaviours. By 6 months the majority had lost some weight and showed improvements in diet. Many had also stopped taking the drug and a large minority reported using it flexibly as a lifestyle drug. Those who lost most weight showed a decrease in beliefs in a medical solution, a decrease in unhealthy eating, an increased belief in treatment control and an increased belief that the unpleasant consequences are both due to their eating behaviour and just part of the drug. When taken with fatty food orlistat causes symptoms such as anal leakage and oily stools. These may encourage some patients to focus on the behavioural aspects of their weight problem thus promoting the dietary changes needed for both short and longer term weight loss. When prescribing orlistat, clinicians should encourage patients to see the consequences as an education as a means to promote the effectiveness of this form of medical management.

Effects of different intermittent peptide YY (3-36) dosing strategies on food intake, body weight, and adiposity in diet-induced obese rats

Chronic administration of anorexigenic substances to experimental animals by injections or continuous infusion typically produces either no effect or a transient reduction in food intake and body weight. Our aim here was to identify an intermittent dosing strategy for intraperitoneal infusion of peptide YY(3-36) [PYY(3-36)] that produces a sustained reduction in daily food intake and adiposity in diet-induced obese rats. Rats (665+/-10 g body wt, 166+/-7 g body fat) with intraperitoneal catheters tethered to infusion swivels had free access to a high-fat diet. Vehicle-treated rats (n=23) had relatively stable food intake, body weight, and adiposity during the 9-wk test period. None of 15 PYY(3-36) dosing regimens administered in succession to a second group of rats (n=22) produced a sustained 15-25% reduction in daily food intake for >5 days, although body weight and adiposity were reduced across the 9-wk period by 12% (594+/-15 vs. 672+/-15 g) and 43% (96+/-7 vs. 169+/-9 g), respectively. The declining inhibitory effect of PYY(3-36) on daily food intake when the interinfusion interval was >or=3 h appeared to be due in part to an increase in food intake between infusions. The declining inhibitory effect of PYY(3-36) on daily food intake when the interinfusion interval was <3 h suggested possible receptor downregulation and tolerance to frequent PYY(3-36) administration; however, food intake significantly increased when PYY(3-36) treatments were discontinued for 1 day following apparent loss in treatment efficacies. Together, these results demonstrate the development of a potent homeostatic response to increase food intake when PYY(3-36) reduces food intake and energy reserves in diet-induced obese rats.

Gut hormones and appetite control

Many peptides are synthesized and released from the gastrointestinal tract. Although their roles in the regulation of gastrointestinal function have been known for some time, it is now evident that they also physiologically influence eating behavior. Our understanding of how neurohormonal gut-brain signaling regulates energy homeostasis has advanced significantly in recent years. Ghrelin is an orexigenic peptide produced by the stomach, which appears to act as a meal initiator. Satiety signals derived from the intestine and pancreas include peptide YY, pancreatic polypeptide, glucagon-like peptide 1, oxyntomodulin, and cholecystokinin. Recent research suggests that gut hormones can be manipulated to regulate energy balance in humans, and that obese subjects retain sensitivity to the actions of gut hormones. Gut hormone-based therapies may thus provide an effective and well-tolerated treatment for obesity.

Efficacy of Slim339® in reducing body weight of overweight and obese human subjects

A double-blind, randomized, parallel-group, placebo-controlled study has been carried out in order to evaluate the effect of orally self-administered Slim339, a proprietary fixed combination of Garcinia cambogia extract with calcium pantothenate (standardized for the content of hydroxycitric acid and pantothenic acid) and extracts of Matricaria chamomilla, Rosa damascena, Lavandula officinalis and Cananga odorata, on body weight in overweight and obese volunteers. During a 60-day treatment period, the average reduction in body weight for the group receiving Slim339 (n = 30) was 4.67% compared with 0.63% for the placebo group (n = 28) (p < 0.0001). Weight losses of >or=3 kg were recorded for 23 subjects in the treatment group and only one in the placebo group. It is concluded that Slim339 represents a potential therapy for obesity.

The obesity pipeline: current strategies in the development of anti-obesity drugs

This review provides a summary of currently available pharmaceutical therapies for the treatment of obesity, along with an overview of the pipeline of products currently in development, and the key mechanisms on which the major development candidates are based. In particular, the recent increase in understanding of the role of gut peptides in energy homeostasis is highlighted as a promising source of potential future obesity therapies.

Increase of neuronal histamine in obese rats is associated with decreases in body weight and plasma triglycerides

OBJECTIVE

The purpose of the present study was to examine the metabolic effects of a specific histamine H(3) receptor antagonist, the cinnamic amide NNC 0038-0000-1202 (NNC 38-1202).

RESEARCH METHODS AND PROCEDURES

Effects of NNC 38-1202 on paraventricular levels of histamine and acute effects on food intake were followed in normal rats, whereas effects on body weight homeostasis and lipid metabolism were studied in a rat model of diet-induced obesity (DIO).

RESULTS

NNC 38-1202, administered as single oral doses of 15 and 30 mg/kg, significantly (p < 0.01) increased paraventricular histamine by 339 +/- 54% and 403 +/- 105%, respectively, compared with basal levels. The same doses produced significant (p < 0.01) reductions in food intake. In DIO rats receiving NNC 38-1202 in a daily dose of 5 mg/kg for 22 days, a decrease in food intake was associated with a significant (p < 0.001) net loss of body weight (-11.0 +/- 4.8 grams), compared with rats receiving vehicle, which gained 13.6 +/- 3.0 grams. Also, NNC 38-1202 significantly (p < 0.05) reduced plasma triglycerides by approximately 42%, in parallel with increases in plasma free fatty acids and beta-hydroxybutyrate levels. Despite reductions in food intake and body weight following administration of NNC 38-1202, no sign of a decrease in energy expenditure was observed, and whole-body lipid oxidation was significantly (p < 0.05) increased in the period after dosing.

DISCUSSION

The present study suggests that antagonistic targeting of the histamine H(3) receptor decreases food intake, body weight, and plasma TG levels and, thus, represents an interesting approach to treatment of obesity and associated hyperlipidemia.

Adherence, behavior change, and visualization: a qualitative study of the experiences of taking an obesity medication

OBJECTIVE

Our objective was to examine patients' experiences of taking orlistat as a means to explore adherence and behavior change.

METHOD

We performed qualitative interviews with 12 participants who had taken orlistat in the past 2 years.

RESULTS

Their experiences were described in terms of beliefs about the causes of their obesity, their motivations for taking orlistat, and highly visual side effects. These themes have implications for understanding adherence and behavior change. For some, the side effects led to nonadherence and absence of behavior change. These individuals seemed to be motivated by routine effects of being overweight, such as lowered self-esteem. In contrast, those who were motivated by a life crisis seemed to tolerate the side effects of the drug, leading to adherence. In turn, these highly visual side effects enabled them to make an explicit link between food consumed and weight, creating a shift in their beliefs about the causes of obesity and making behavior change more likely.

CONCLUSION

Orlistat use illustrates how treatment and illness beliefs interact to create both adherence and behavior change, particularly in the context of a life crisis and particularly when symptoms can be visualized.

An update on the pharmacological treatment of obesity

OBJECTIVE

To review the commonly utilized pharmacological options for the treatment of overweight and obese patients in the United States.

METHODS

A MEDLINE and EMBASE search, in English, between January 1995 and November 2005 was conducted using the terms, "anti-obesity agents", "orlistat", "sibutramine", and "phentermine". References cited in relevant studies and reviews were also examined for additional clinical trials to be included in the review.

RESULTS

There are several pharmacological options currently available for the treatment of overweight and obese individuals in the United States, including phentermine, sibutramine, and orlistat, with only sibutramine and orlistat being indicated for use in the long term (> 6 months). However, none of these medications have proven to be more effective than another for the indication of weight loss, each with a very similar maximum weight loss potential. Therefore choosing a weight loss medication should be patient specific and based on its pharmacological profile, including mechanism of action and potential adverse effects. Most importantly, it is imperative to realize that these agents are only indicated for use when combined with lifestyle modifications. Most studies have indicated that maximum benefits from any of these medications are only shown when taken in addition to a hypocaloric diet.

CONCLUSION

It has been shown that the combination of lifestyle changes and pharmacological treatment leads to a greater decrease in total body weight loss. Treatment with anti-obesity agents is associated with side effects and an increased cost in health care. These factors must be weighed prior to initiating anti-obesity treatment.

The use of orlistat in the treatment of obesity, dyslipidaemia and Type 2 diabetes

Orlistat (tetrahydrolipstatin) is an inhibitor of gastrointestinal lipases, especially pancreatic lipase. It is used as an adjunct to diet and exercise in order to achieve weight loss in obese individuals (body mass index > 30 kg/m2) or in overweight individuals (body mass index > 27 kg/m2) with other risk factors for atherosclerotic vascular disease, such as hypertension, dyslipidaemia or diabetes. Short- and long-term studies of up to 4 years duration have shown the drug to have significant benefits in weight loss, as well as in the reduction in lipids, glucose and haemoglobin A1c, and in time to onset of Type 2 diabetes compared with diet alone or placebo groups. The incremental amount of weight loss that orlistat produces is modest, but sufficient to result in improvement in obesity comorbidities such as elevated blood pressure, dyslipidaemia and hyperglycaemia compared with diet and exercise alone. Orlistat should only be prescribed for individuals who are motivated to adhere to lifestyle modifications, especially dietary fat restriction.

Efficacy and safety of topiramate in combination with metformin in the treatment of obese subjects with type 2 diabetes: a randomized, double-blind, placebo-controlled study

OBJECTIVE

To investigate the efficacy and safety of topiramate in obese subjects with type 2 diabetes treated with metformin.

DESIGN

This was a multicenter, double-blind, placebo-controlled trial. All subjects received a non-pharmacological program of diet, exercise and behavioral modification throughout the study; the assigned diet was 600 kcal/day less than the subject's individually calculated energy expenditure. After a 6-week single-blind placebo run-in, subjects were randomized to placebo, topiramate 96 mg/day or topiramate 192 mg/day. Following an 8-week titration period, subjects remained on their assigned dose for 52 weeks. However, the sponsor ended the study early in order to develop a new controlled-release formulation with the potential to enhance tolerability and simplify dosing in this patient population. A total of 646 obese men and women (age: 18-75 years, body mass index: 27-50 kg/m(2)) with an established history of type 2 diabetes mellitus controlled by metformin monotherapy were randomized. Efficacy was assessed in a pre-determined modified intent-to-treat (MITT) population of 307 subjects whose randomization date would have allowed them to complete 24 weeks on study medication before the announcement of study termination.

MEASUREMENTS

Joint primary efficacy parameters were mean percent change in weight and change in glycosylated hemoglobin (HbA(1c)) from baseline to week 24.

RESULTS

Subjects in the placebo, topiramate 96 mg/day and topiramate 192 mg/day groups lost 1.7%, 4.5% (P<0.001) and 6.5% (P<0.001), respectively, of their baseline body weight and had absolute decreases in HbA(1c) of 0.1%, 0.4% (P<0.001) and 0.6% (P<0.001) (MITT, last observation carried forward). Topiramate-treated subjects also experienced statistically significant decreases in systolic blood pressure. Most common adverse events were paresthesia and events related to the central nervous system.

CONCLUSIONS

Topiramate was effective for weight reduction and improvement in glycemic control in obese subjects with type 2 diabetes treated with metformin monotherapy. Further study in obese diabetics is warranted.

Tamoxifen-induced anorexia is associated with fatty acid synthase inhibition in the ventromedial nucleus of the hypothalamus and accumulation of malonyl-CoA

Fatty acid metabolism in the hypothalamus has recently been shown to regulate feeding. The selective estrogen receptor modulator tamoxifen (TMX) exerts a potent anorectic effect. Here, we show that the anorectic effect of TMX is associated with the accumulation of malonyl-CoA in the hypothalamus and inhibition of fatty acid synthase (FAS) expression specifically in the ventromedial nucleus of the hypothalamus (VMN). Furthermore, we demonstrate that FAS mRNA expression is physiologically regulated by fasting and refeeding in the VMN but not in other hypothalamic nuclei. Thus, the VMN appears to be the hypothalamic site where regulation of FAS and feeding converge. Supporting the potential clinical relevance of these observations, reanalysis of a primary breast cancer prevention study showed that obese women treated with TMX gained significantly less body weight over a 6-year period than obese women given placebo. The finding that TMX can modulate appetite through alterations in FAS expression and malonyl-CoA levels suggests a link between hypothalamic sex steroid receptors, fatty acid metabolism, and feeding behavior.

The therapeutic potential of gut hormone peptide YY3-36 in the treatment of obesity

Many peptides are synthesised and released from the gastrointestinal tract. Although their roles in the regulation of gastrointestinal function have been known for some time, it has become increasingly evident that they also influence eating behaviour. Peptide YY (PYY) is released postprandially from gastrointestinal L-cells with glucagon-like peptide 1 (GLP-1) and oxyntomodulin. Following peripheral administration of PYY3-36, the circulating form of PYY, to mouse, rat or human there is marked inhibition of food intake. Obese subjects have lower basal fasting PYY levels and have a smaller postprandial rise. However, obesity does not appear to be associated with resistance to PYY (as it is with leptin) and exogenous infusion of PYY3-36 results in a reduction in food intake by 30% in an obese group and 31% in a lean group at a buffet meal. Overall PYY significantly reduced 24-h caloric intake in both obese (16.5%) and lean groups (23.5%). Obesity is the current major cause of premature death in the UK, killing almost 1000 people a week. Worldwide its prevalence is accelerating. The administration of the naturally occurring gut hormone may offer a long-term therapeutic approach to weight control. Here, the therapeutic potential of PYY is considered.

Gut hormones ghrelin, PYY, and GLP-1 in the regulation of energy balance [corrected] and metabolism

The first hormone discovered in the gastrointestinal tract was secretin, isolated from duodenal mucosa. Some years later, two additional gastrointestinal hormones, gastrin and cholecystokinin (CCK), were discovered, but it was not until the 1970s that gastrointestinal endocrinology studies became more prevalent, resulting in the discovery of many more hormones. Here, we examine the role of gut hormones in energy balance regulation and their possible use as pharmaceutical targets for obesity.

Oxyntomodulin

The prevalence of obesity is increasing rapidly and the associated morbidity and mortality has led to an urgent need for potential therapeutic targets to reduce appetite and food intake. Gut hormones released after eating that coordinate digestive activity and promote satiety are novel potential treatments for obesity. Oxyntomodulin is a gut hormone that is produced by the L cells in the small intestine and reduces food intake. It is timely to review some of the original literature on oxyntomodulin, to evaluate what is already known about the peptide, and also to set the recent findings on its effects on food intake and bodyweight into context.Recent studies have shown that long-term peripheral administration of oxyntomodulin to rats leads to reduced food intake and reduced weight gain. Studies in humans have demonstrated that acute administration reduces food intake by 19%. When given preprandially by subcutaneous injection three times daily, oxyntomodulin resulted in a reduction in food intake and mean weight loss of 2.8kg over 4 weeks. Oxyntomodulin thus represents a potential therapy for obesity.The mechanism of action of oxyntomodulin is not known. Current evidence suggests that it acts via the glucagon-like peptide 1 (GLP-1) receptor. There may be an additional receptor in the gastric mucosa mediating its effects on gastric acid secretion. Although oxyntomodulin probably acts via the GLP-1 receptor, the two peptides differentially regulate food intake and energy expenditure in the mouse.Oxyntomodulin represents a potential therapy for obesity. Further work will help to clarify its mechanisms of action.

Hormonal regulation of food intake

Our knowledge of the physiological systems controlling energy homeostasis has increased dramatically over the last decade. The roles of peripheral signals from adipose tissue, pancreas, and the gastrointestinal tract reflecting short- and long-term nutritional status are now being described. Such signals influence central circuits in the hypothalamus, brain stem, and limbic system to modulate neuropeptide release and hence food intake and energy expenditure. This review discusses the peripheral hormones and central neuronal pathways that contribute to control of appetite.

Subcutaneous oxyntomodulin reduces body weight in overweight and obese subjects: a double-blind, randomized, controlled trial

This study investigated the effect of subcutaneously administered oxyntomodulin on body weight in healthy overweight and obese volunteers. Participants self-administered saline or oxyntomodulin subcutaneously in a randomized, double-blind, parallel-group protocol. Injections were self-administered for 4 weeks, three times daily, 30 min before each meal. The volunteers were asked to maintain their regular diet and level of physical exercise during the study period. Subjects' body weight, energy intake, and levels of adipose hormones were assessed at the start and end of the study. Body weight was reduced by 2.3 +/- 0.4 kg in the treatment group over the study period compared with 0.5 +/- 0.5 kg in the control group (P = 0.0106). On average, the treatment group had an additional 0.45-kg weight loss per week. The treatment group demonstrated a reduction in leptin and an increase in adiponectin. Energy intake by the treatment group was significantly reduced by 170 +/- 37 kcal (25 +/- 5%) at the initial study meal (P = 0.0007) and by 250 +/- 63 kcal (35 +/- 9%) at the final study meal (P = 0.0023), with no change in subjective food palatability. Oxyntomodulin treatment resulted in weight loss and a change in the levels of adipose hormones consistent with a loss of adipose tissue. The anorectic effect was maintained over the 4-week period. Oxyntomodulin represents a potential therapy for obesity.

Efficacy and safety comparative evaluation of orlistat and sibutramine treatment in hypertensive obese patients

AIM

The aim of our study was to comparatively evaluate the efficacy and safety of orlistat and sibutramine treatment in obese hypertensive patients, with a specific attention to cardiovascular effects and to side effects because of this treatment.

METHODS

Patients were enrolled, evaluated and followed at three Italian Centres of Internal Medicine. We evaluated 115 obese and hypertensive patients. (55 males and 60 females; 26 males and 29 females, aged 50 +/- 4 with orlistat; 28 males and 30 females, aged 51 +/- 5 with sibutramine). All patients took antihypertensive therapy for at least 6 months before the study. We administered orlistat or sibutramine in a randomized, controlled, double-blind clinical study. We evaluated anthropometric variables, blood pressure and heart rate (HR) during 12 months of this treatment.

RESULTS

A total of 113 completed the 4 weeks with controlled energy diet and were randomized to double-blind treatment with orlistat (n = 55) or sibutramine (n = 58). Significant body mass index (BMI) improvement was present after 6 (p < 0.05), 9 (p < 0.02), and 12 (p < 0.01) months in both groups, and body weight (BW) improvement was obtained after 9 (p < 0.05) and 12 (p < 0.02) months in both groups. Significant waist circumference (WC), hip circumference (HC) and waist/hip ratio (W/H ratio) improvement was observed after 12 months (p < 0.05, respectively) in both groups. Significant systolic blood pressure (SBP) and diastolic blood pressure (DBP) improvement (p < 0.05) was present in orlistat group after 12 months. Lipid profile [total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and triglycerides] reduction (p < 0.05, respectively) was observed in orlistat group and triglyceride reduction (p < 0.05) in sibutramine group after 12 months. No significant change was observed in sibutramine group during the study. No significant HR variation was obtained during the study in both groups. Of the 109 patients who completed the study, 48.1% of patients in the orlistat group and 17.5% of patients in the sibutramine group had side effects (p < 0.05 vs. orlistat group). Side-effect profiles were different in the two treatment groups. All orlistat side effects were gastrointestinal events. Sibutramine caused an increase in blood pressure (both SBP and DBP) in two patients, but it has been controlled by antihypertensive treatment. The vitamin changes were small and all mean vitamin and beta-carotene values stayed within reference ranges. No patients required vitamin supplementation.

CONCLUSIONS

Both orlistat and sibutramine are effective on anthropometric variables during the 12-month treatment; in our sample, orlistat has been associated to a mild reduction in blood pressure, while sibutramine assumption has not be associated to any cardiovascular effect and was generically better tolerated than orlistat.

Minireview: Gut peptides regulating satiety

The gastrointestinal tract and the pancreas release hormones regulating satiety and body weight. Ghrelin stimulates appetite, and glucagon-like peptide-1, oxyntomodulin, peptide YY, cholecystokinin, and pancreatic polypeptide inhibit appetite. These gut hormones act to markedly alter food intake in humans and rodents. Obesity is the current major cause of premature death in the United Kingdom, killing almost 1000 people per week. Worldwide, its prevalence is accelerating. There is currently no effective answer to the pandemic of obesity, but replacement of the low levels of peptide YY observed in the obese may represent an effective antiobesity therapy.

Pharmacoeconomics of obesity management in childhood and adolescence

The level of fatness of a child at which morbidity acutely increases is operationally determined by calculating the body mass index (BMI). An increased risk of death from cardiovascular disease in adults has been found in subjects whose BMI had been > 75(th) percentile as adolescents. Childhood obesity seems to substantially increase the risk of subsequent morbidity whether or not obesity persists into adulthood. Among the most common sequelae of primary childhood obesity are hypertension, dyslipidaemia, back pain and psychosocial problems. Environmental/exogenous factors largely contribute to the development of body fatness early in life. Therapeutic strategies include psychological and family therapy, lifestyle/behaviour modification and nutrition education. The role of regular exercise and exercise programmes is emphasised. Surgical procedures and drugs used in adult obesity are not generally recommended in children and adolescents. Appetite suppressants and thermogenic drugs have not been approved for use in children. Digestive inhibitors such as lipase inhibitors and fat substitutes have been used in children and adolescents in off-label use and in only a few clinical studies. As obesity is the most common chronic disorder in the industrialised societies, its impact on individual lives, as well as on health economics, has to be recognised more widely. One should aim to increase public awareness of the ever increasing health burden and economic dimension of the childhood obesity epidemic that is present around the globe.

Prevention of type 2 diabetes: data from recent trials

All four main studies of lifestyle intervention on diabetes incidence found a clear benefit for diet and exercise intervention compared with usual care. Although the study populations differed by race and ethnicity, the mean BMI, and the intensity of the lifestyle intervention provided, all investigators found substantial diabetes risk reduction with modest weight loss and increased physical activity. Results of these trials give health care providers useful and heartening information to share with patients at risk for diabetes. The challenge remains to find feasible and cost-efficient methods to identify people at risk and to deliver effective lifestyle interventions. Findings from trials of pharmacologic agents such as metformin, acarbose, and troglitazone are encouraging; however, the ADA recommends that drug therapy should not be used routinely to prevent diabetes until more information regarding the cost-effectiveness of such intervention is known [20]. Results from trials that found a lower incidence of diabetes among those randomly assigned to angiotensin-converting enzyme inhibitors, statins, or hormone therapy are intriguing but must be viewed with caution because they are based on post hoc analyses. Because it is difficult to conduct randomized controlled trials of major operative procedures such as bariatric surgery, observational studies that compare surgical interventions for weight loss with traditional weight-loss management may be the best evidence available. These studies have the potential for healthy-person bias in that people who choose bariatric surgery may have other healthy behaviors that are often difficult to measure and control for; such behaviors could account for their lower incidence of diabetes. Undeniably, the best test to diagnose those at high risk for diabetes is not yet known. New strategies that identify those with pre-diabetes and that overcome the limitations of the current tests, particularly the 2-hour post-challenge glucose test, are needed.