Small weight loss on long-term acarbose therapy with no change in dietary pattern or nutrient intake of individuals with non-insulin-dependent diabetes

The effects of subcutaneous Tirzepatide on obesity and overweight: a systematic review and meta-regression analysis of randomized controlled trials

Background

Despite the fact that obesity and overweight are serious major health problems worldwide, fighting against them is also considered a challenging issue. Several interventional studies have evaluated the potential weight-reduction effect of Tirzepatide. In order to obtain a better viewpoint from them, this study aimed to comprehensively investigate the effects of subcutaneous Tirzepatide on obesity and overweight.

Methods

Scopus, PubMed/Medline, Web of Science, Cochrane, and Embase databases were searched using standard keywords to identify all controlled trials investigating the weight loss effects of Tirzepatide. Pooled weighted mean difference and 95% confidence intervals were achieved by random-effects model analysis for the best estimation of outcomes. The statistical heterogeneity and publication bias were determined using the Cochran's Q test and I2 statistics and using the funnel plot and Egger's test, respectively.

Results

Twenty three treatments arm with 7062 participants' were included in this systematic review and meta-regression analysis. The pooled findings showed that Tirzepatide vs placebo significantly reduced body weight (weighted mean difference (WMD): -11.34 kg, 95% confidence interval (CI): -12.79 to -9.88, P< 0.001), body mass index (BMI) (WMD: -3.11 kg/m2, 95% CI: -4.36 to -1.86, P< 0.001), and waist circumference (WC) (WMD: -7.24 cm, 95% CI -10.12 to -4.36, P< 0.001). These reductions were even greater, especially with higher doses and duration of Tirzepatide.

Conclusions

Tirzepatide medication had significant effects on weight management with the reduction of body weight, BMI, and WC. Administration of Tirzepatide can be considered a therapeutic strategy for overweight or obese people.

Anti-diabetic drugs and weight loss in patients with type 2 diabetes

INTRODUCTION

Obesity is frequently a comorbidity of type 2 diabetes. Even modest weight loss can significantly improve glucose homeostasis and lessen cardiometabolic risk factors in patients with type 2 diabetes, but lifestyle-based weight loss strategies are not long-term effective. There is an increasing need to consider pharmacological approaches to assist weight loss in the so called diabesity syndrome. Aim of this review is to analyze the weight-loss effect of non-insulin glucose lowering drugs in patients with type 2 diabetes.

MATERIAL AND METHODS

A systematic analysis of the literature on the effect of non-insulin glucose lowering drugs on weight loss in patients with type 2 diabetes was performed. For each class of drugs, the following parameters were analyzed: kilograms lost on average, effect on body mass index and body composition.

RESULTS

Our results suggested that anti-diabetic drugs can be stratified into 3 groups based on their efficacy in weight loss: metformin, acarbose, empagliflozin and exenatide resulted in a in a mild weight loss (less than 3.2% of initial weight); canagliflozin, ertugliflozin, dapagliflozin and dulaglutide induces a moderate weight loss (between 3.2% and 5%); liraglutide, semaglutide and tirzepatide resulted in a strong weight loss (greater than 5%).

CONCLUSIONS

This study shows that new anti-diabetic drugs, particularly GLP1-RA and Tirzepatide, are the most effective in inducing weight loss in patients with type 2 diabetes. Interestingly, exenatide appears to be the only GLP1-RA that induces a mild weight loss.

Efficacy and Safety of Voglibose Plus Metformin in Patients with Type 2 Diabetes Mellitus: A Randomized Controlled Trial

BACKGROUND

Combination of metformin to reduce the fasting plasma glucose level and an α-glucosidase inhibitor to decrease the postprandial glucose level is expected to generate a complementary effect. We compared the efficacy and safety of a fixed-dose combination of voglibose plus metformin (vogmet) with metformin monotherapy in drug-naïve newly-diagnosed type 2 diabetes mellitus.

METHODS

A total of 187 eligible patients aged 20 to 70 years, with a glycosylated hemoglobin (HbA1c) level of 7.0% to 11.0%, were randomized into either vogmet or metformin treatments for 24 weeks. A change in the HbA1c level from baseline was measured at week 24.

RESULTS

The reduction in the levels of HbA1c was -1.62%±0.07% in the vogmet group and -1.31%±0.07% in the metformin group (P=0.003), and significantly more vogmet-treated patients achieved the target HbA1c levels of <6.5% (P=0.002) or <7% (P=0.039). Glycemic variability was also significantly improved with vogmet treatment, estimated by M-values (P=0.004). Gastrointestinal adverse events and hypoglycemia (%) were numerically lower in the vogmet-treated group. Moreover, a significant weight loss was observed with vogmet treatment compared with metformin (-1.63 kg vs. -0.86 kg, P=0.039).

CONCLUSION

Vogmet is a safe antihyperglycemic agent that controls blood glucose level effectively, yields weight loss, and is superior to metformin in terms of various key glycemic parameters without increasing the risk of hypoglycemia.

Associations between changes in glucagon-like peptide-1 and bodyweight reduction in patients receiving acarbose or metformin treatment

BACKGROUND

The present post hoc analysis investigated whether changes in endogenous glucagon-like peptide-1 (∆GLP-1) levels are associated with weight loss in newly diagnosed diabetes patients.

METHODS

In all, 784 subjects from the Metformin and AcaRbose in Chinese as initial Hypoglycemic treatment (MARCH) study were stratified according to ∆GLP-1. Changes in clinical and physiological parameters were evaluated across ∆GLP-1 subgroups (low, medium, and high) to assess correlations between ∆GLP-1 and weight loss in acarbose- versus metformin-treated groups.

RESULTS

After 24 weeks treatment, greater ∆GLP-1 was associated with significantly greater weight loss (-2 vs -1 kg in the medium/high vs low ∆GLP-1 groups, respectively) and reduction in body mass index (BMI; -0.88, -0.83, and -0.69 kg/m² in the high, medium, and low ∆GLP-1 groups, respectively). In the acarbose-treated group, there was a significant association between ∆GLP-1 and BMI reductions, and greater ∆GLP-1 across the high, medium, and low ∆GLP-1 groups was correlated with greater weight loss (-2.8, -2.1, and -1.9 kg, respectively) and reductions in fasting plasma glucose (-1.57, -1.28, and -1.02 mmol/L, respectively) at Week 24. No significant differences were found across ∆GLP-1 subgroups in metformin-treated patients (P > 0.05). Multivariate linear regression analysis revealed that gender, baseline BMI, and ∆GLP-1 at Week 24 were associated with weight loss. Baseline BMI and ∆GLP-1 in the acarbose-treated group and baseline BMI in the metformin-treated group predicted weight loss at Week 24.

CONCLUSION

Changes in GLP-1 levels are associated with weight loss in newly diagnosed Chinese diabetes patients receiving acarbose.

Targeting glucose metabolism for healthy aging

Advancing age is the greatest single risk factor for numerous chronic diseases. Thus, the ability to target the aging process can facilitate improved healthspan and potentially lifespan. Lack of adequate glucoregulatory control remains a recurrent theme accompanying aging and chronic disease, while numerous longevity interventions result in maintenance of glucoregulatory control. In this review, we propose targeting glucose metabolism to enhance regulatory control as a means to ameliorate the aging process. We highlight that calorie restriction improves glucoregulatory control and extends both lifespan and healthspan in model organisms, but we also indicate more practical interventions (i.e., calorie restriction mimetics) are desirable for clinical application in humans. Of the calorie restriction mimetics being investigated, we focus on the type 2 diabetes drug acarbose, an α-glucosidase inhibitor that when taken with a meal, results in reduced enzymatic degradation and absorption of glucose from complex carbohydrates. We discuss alternatives to acarbose that yield similar physiologic effects and describe dietary sources (e.g., sweet potatoes, legumes, and berries) of bioactive compounds with α-glucosidase inhibitory activity. We indicate future research should include exploration of how non-caloric compounds like α-glucosidase inhibitors modify macronutrient metabolism prior to disease onset, which may guide nutritional/lifestyle interventions to support health and reduce age-related disease risk.

Acarbose reduces body weight irrespective of glycemic control in patients with diabetes: results of a worldwide, non-interventional, observational study data pool

OBJECTIVE

The objective of this study is to examine the effect of acarbose, an alpha-glucosidase inhibitor, on body weight in a real-life setting by pooling data from post-marketing surveillance.

METHODS

Data from 10 studies were pooled (n=67,682) and the effect of acarbose on body weight was analysed taking into account baseline body weight, glycemic parameters and other baseline characteristics.

RESULTS

The mean relative reduction in body weight was 1.45 ± 3.24% at the 3-month visit (n=43,510; mean baseline 73.4 kg) and 1.40 ± 3.28% at the last visit (n=54,760; mean baseline 73.6 kg) (both p<0.0001). These reductions were dependent on baseline body weight (overweight: -1.33 ± 2.98% [n=13,498; mean baseline 71.6 kg]; obese: -1.98 ± 3.40% [n=20,216; mean baseline 81.3 kg]). When analysed by baseline glycemic parameter quartiles, the reduction was independent of fasting plasma glucose (FPG), postprandial plasma glucose (PPG), glycated hemoglobin (HbA1c) and postprandial glucose excursion (PPGE). A bivariate analysis of covariance identified female sex, South East Asian and East Asian ethnicity, younger age, higher body mass index, short duration of diabetes, and no previous treatment as factors likely to impact positively on body weight reduction with acarbose.

CONCLUSIONS

This post-hoc analysis showed that acarbose treatment reduces body weight independent of glycemic control status but dependent on baseline body weight.

Pancreatic regulation of glucose homeostasis

In order to ensure normal body function, the human body is dependent on a tight control of its blood glucose levels. This is accomplished by a highly sophisticated network of various hormones and neuropeptides released mainly from the brain, pancreas, liver, intestine as well as adipose and muscle tissue. Within this network, the pancreas represents a key player by secreting the blood sugar-lowering hormone insulin and its opponent glucagon. However, disturbances in the interplay of the hormones and peptides involved may lead to metabolic disorders such as type 2 diabetes mellitus (T2DM) whose prevalence, comorbidities and medical costs take on a dramatic scale. Therefore, it is of utmost importance to uncover and understand the mechanisms underlying the various interactions to improve existing anti-diabetic therapies and drugs on the one hand and to develop new therapeutic approaches on the other. This review summarizes the interplay of the pancreas with various other organs and tissues that maintain glucose homeostasis. Furthermore, anti-diabetic drugs and their impact on signaling pathways underlying the network will be discussed.

Comparison of glucose lowering effect of metformin and acarbose in type 2 diabetes mellitus: a meta-analysis

BACKGROUND

Metformin is the first-line oral hypoglycemic agent for type 2 diabetes mellitus recommended by international guidelines. However, little information exists comparing it with acarbose which is also commonly used in China. This study expanded knowledge by combining direct and indirect evidence to ascertain the glucose lowering effects of both drugs.

METHODS

PubMed (1980- December 2013) and China National Knowledge Infrastructure databases (1994-January 2014) were systematically searched for eligible randomized controlled trials from Chinese and English literatures. Meta-analysis was conducted to estimate the glucose lowering effects of metformin vs. acarbose, or either of them vs. common comparators (placebo or sulphonylureas), using random- and fixed-effect models. Bucher method with indirect treatment comparison calculator was applied to convert the summary estimates from the meta-analyses into weighted-mean-difference (WMD) and 95% confidence intervals (CIs) to represent the comparative efficacy between metformin and acarbose.

RESULTS

A total of 75 studies were included in the analysis. In direct comparison (8 trials), metformin reduced glycosylated hemoglobin (HbA1c) by 0.06% more than acarbose, with no significant difference (WMD,-0.06%; 95% CI, -0.32% to 0.20%). In indirect comparisons (67 trials), by using placebo and sulphonylureas as common comparators, metformin achieved significant HbA1c reduction than acarbose, by -0.38% (WMD,-0.38%, 95% CI, -0.736% to -0.024%) and -0.34% (WMD, -0.34%, 95% CI, -0.651% to -0.029%) respectively.

CONCLUSION

The glucose lowering effects of metformin monotherapy and acarbose monotherapy are the same by direct comparison, while metformin is a little better by indirect comparison. This implies that the effect of metformin is at least as good as acarbose's.

Acarbose monotherapy and weight loss in Eastern and Western populations with hyperglycaemia: an ethnicity-specific meta-analysis

OBJECTIVE

To demonstrate if weight loss achieved with acarbose in individuals with hyperglycaemia differs between Eastern and Western populations.

METHODS

Databases and reference lists of clinical trials on acarbose were searched. Eligible studies were randomised controlled trials of acarbose monotherapy in populations with hyperglycaemia of more than 12-week duration that provided data on body weight (BW) or body mass index (BMI).

RESULTS

A total of 34 trials (6082 participants) were included. The effect of acarbose on BW was superior to that of placebo [weighted mean difference (WMD) = -0.52, 95% confidence interval (CI) -0.78 to -0.25], nateglinide (WMD = -1.33, 95% CI -1.51 to -0.75) and metformin (WMD = -0.67, 95% CI -1.14 to -0.20). Compared with placebo, there was a significantly greater weight loss of 0.92 kg (p < 0.05, I(2)  = 88.8%) with acarbose in Eastern populations (WMD = -1.20, 95% CI -1.51 to -0.75) than that in Western populations (WMD = -0.28, 95% CI -0.59 to 0.03). Across all studies, the acarbose group achieved a significantly larger absolute weight loss of (change from baseline) 1.35 kg (p < 0.05, I(2)  = 94.3%) in Eastern populations (WMD = -2.26, 95% CI -2.70 to -1.81) than in Western populations (WMD = -0.91, 95% CI -1.36 to -0.47). Nevertheless, the possible risk of bias in Eastern studies may influence the results.

CONCLUSION

The effect of acarbose on weight loss seems to be more pronounced in Eastern than in Western populations with hyperglycaemia, and is superior to that of placebo, nateglinide and metformin across both ethnicities.

Pharmacotherapy for childhood obesity: present and future prospects

Pediatric obesity is a serious medical condition associated with significant comorbidities during childhood and adulthood. Lifestyle modifications are essential for treating children with obesity, yet many have insufficient response to improve health with behavioral approaches alone. This review summarizes the relatively sparse data on pharmacotherapy for pediatric obesity and presents information on obesity medications in development. Most previously studied medications demonstrated, at best, modest effects on body weight and obesity-related conditions. It is to be hoped that the future will bring new drugs targeting specific obesity phenotypes that will allow clinicians to use etiology-specific, and therefore more effective, anti-obesity therapies.

Antioxidant and anti-α-glucosidase compounds from the rhizome of Peltiphyllum peltatum (Torr.) Engl

The antioxidant, anti-α-glucosidase and anticholinesterase effects of the alcohol extract of fresh underground rhizomes of Peltiphyllum peltatum were studied. A potent antioxidant activity accompanied by a selective α-glucosidase effect was observed for the crude extract. Further activity-guided fractionation (petroleum ether, chloroform, ethyl acetate, n-butanol and water) resulted in the identification of the ethyl acetate fraction with the highest antioxidant effect. Gallic acid, methyl-3-O-methyl gallate, catechin, gallocatechin, bergenin and 11-O-galloylbergenin were isolated from the ethyl acetate fraction. While all the isolated compounds did show a variable degree of radical scavenging effect, 11-O-galloylbergenin was identified as the selective α-glucosidase inhibitor. The isolation, structural elucidation and biological effects of these compounds are discussed.

Second-line therapy in patients with type 2 diabetes inadequately controlled with metformin monotherapy: a systematic review and mixed-treatment comparison meta-analysis

BACKGROUND

Although there is general agreement that metformin should be used as first-line pharmacotherapy in patients with type 2 diabetes, uncertainty remains regarding the choice of second-line therapy once metformin is no longer effective. We conducted a systematic review and meta-analysis to assess the comparative safety and efficacy of all available classes of antihyperglycemic therapies in patients with type 2 diabetes inadequately controlled on metformin monotherapy.

METHODS

MEDLINE, EMBASE, BIOSIS Previews, PubMed and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials published in English from 1980 to October 2009. Additional citations were obtained from grey literature and conference proceedings and through stakeholder feedback. Two reviewers independently selected studies, extracted data and assessed risk of bias. Key outcomes of interest were hemoglobin A1c, body weight, hypoglycemia, quality of life, long-term diabetes-related complications, serious adverse drug events and mortality. Mixed-treatment comparison and pairwise meta-analyses were conducted to pool trial results, when appropriate.

RESULTS

We identified 49 active and non-active controlled randomized trials that compared 2 or more of the following classes of antihyperglycemic agents and weight-loss agents: sulfonylureas, meglitinides, thiazolidinediones (TZDs), dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) analogues, insulins, alpha-glucosidase inhibitors, sibutramine and orlistat. All classes of second-line antihyperglycemic therapies achieved clinically meaningful reductions in hemoglobin A1c (0.6% to 1.0%). No significant differences were found between classes. Insulins and insulin secretagogues were associated with significantly more events of overall hypoglycemia than the other agents, but severe hypoglycemia was rarely observed. An increase in body weight was observed with the majority of second-line therapies (1.8 to 3.0 kg), the exceptions being DPP-4 inhibitors, alpha-glucosidase inhibitors and GLP-1 analogues (0.6 to -1.8 kg). There were insufficient data available for diabetes complications, mortality or quality of life.

INTERPRETATION

DPP-4 inhibitors and GLP-1 analogues achieved improvements in glycemic control similar to those of other second-line therapies, although they may have modest benefits in terms of weight gain and overall hypoglycemia. Further long-term trials of adequate power are required to determine whether newer drug classes differ from older agents in terms of clinically meaningful outcomes.

The role of lipid and carbohydrate digestive enzyme inhibitors in the management of obesity: a review of current and emerging therapeutic agents

Obesity is a global epidemic associated with significant morbidity and mortality in adults and ill health in children. A proven successful approach in weight management has been the disruption of nutrient digestion, with orlistat having been used to treat obesity for the last 10 years. Although orlistat-induced weight loss remains modest, it produces meaningful reductions in risk factors for obesity-related conditions such as diabetes and cardiovascular disease. Moreover, this lipase inhibitor is free of the serious side effects that have dogged appetite-suppressing drugs. This success had driven investigation into new generation nutraceuticals, supplements and pharmaceutical agents that inhibit the breakdown of complex carbohydrates and fats within the gut. This review focuses on agents purported to inhibit intestinal enzymes responsible for macronutrient digestion. Except for some synthetic products, the majority of agents reviewed are either botanical extracts or bacterial products. Currently, carbohydrate digestion inhibitors are under development to improve glycemic control and these may also induce some weight loss. However, colonic fermentation induced side effects, such as excess gas production, remain an issue for these compounds. The α-glucosidase inhibitor acarbose, and the α-amylase inhibitor phaseolamine, have been used in humans with some promising results relating to weight loss. Nonetheless, few of these agents have made it into clinical studies and without any clinical proof of concept or proven efficacy it is unlikely any will enter the market soon.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators.

SELECTION CRITERIA

Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy.

DATA COLLECTION AND ANALYSIS

The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data.

MAIN RESULTS

Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies.

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators.

SELECTION CRITERIA

Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy.

DATA COLLECTION AND ANALYSIS

The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data.

MAIN RESULTS

Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies.

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.

Diabetes medications and body weight

Tight diabetes control sometimes comes with a price: weight gain and hypoglycemia. Two of the three major recent trials that looked at the relationship between intensive diabetes control and cardiovascular events reported significant weight gain among the intensively treated groups. There is a growing concern that the weight gain induced by most diabetes medications diminishes their clinical benefits. On the other hand, there is a claim that treating diabetes with medications that are weight neutral or induces weight loss or less weight gain while minimizing those that increase body weight may emerge as the future direction for treating overweight and obese patients with diabetes. This review clarifies the weight effect of each of the currently available diabetes medications, and explains the mechanism of action behind this effect. Despite the great variability among reviewed clinical trials, the currently available evidence is quite sufficient to demonstrate the change in body weight in association with most of the currently available medications. This review also provides some guidelines on using diabetes medications during weight management programs.

Comparison of vildagliptin and acarbose monotherapy in patients with Type 2 diabetes: a 24-week, double-blind, randomized trial

AIMS

To compare the efficacy and tolerability of the dipeptidyl peptidase-4 inhibitor, vildagliptin, with the alpha glucosidase inhibitor, acarbose, in drug-naive patients with Type 2 diabetes.

METHODS

This multi-centre, randomized, double-blind, parallel-arm study compared the efficacy and tolerability of vildagliptin (100 mg daily, given as 50 mg twice daily, n = 441) and acarbose (up to 300 mg daily, given as three equally divided doses, n = 220) during 24-week treatment in drug-naive patients with Type 2 diabetes.

RESULTS

Monotherapy with vildagliptin or acarbose decreased glycated haemoglobin (HbA(1c)) (baseline approximately 8.6%) to a similar extent during 24-week treatment. The adjusted mean change from baseline to end-point (AMDelta) in HbA(1c) was -1.4 +/- 0.1% and -1.3 +/- 0.1% in patients receiving vildagliptin and acarbose, respectively, meeting the statistical criterion for non-inferiority (upper limit of 95% confidence interval for between-treatment difference < or = 0.4%). The decrease in fasting plasma glucose was similar with acarbose (-1.5 +/- 0.2 mmol/l) and vildagliptin (-1.2 +/- 0.1 mmol/l). Body weight did not change in vildagliptin-treated patients (-0.4 +/- 0.1 kg) but decreased in acarbose-treated patients (-1.7 +/- 0.2 kg, P < 0.001 vs. vildagliptin). The proportion of patients experiencing any adverse event (AE) was 35% vs. 51% in patients receiving vildagliptin or acarbose, respectively; gastrointestinal AEs were significantly more frequent with acarbose (25.5%) than vildagliptin (12.3%, P < 0.001). No hypoglycaemia was reported for either group.

CONCLUSIONS

Vildagliptin is effective and well tolerated in patients with Type 2 diabetes, demonstrating similar glycaemic reductions to acarbose, but with better tolerability.

Acarbose: oral anti-diabetes drug with additional cardiovascular benefits

Acarbose is an alpha-glucosidase inhibitor acting specifically at the level of postprandial glucose excursion. This compound lowers HbA(1c) by 0.5-1% in patients with Type 2 diabetes, either drug naive or in combination with other antidiabetic drugs. In those with impaired glucose tolerance (IGT), it reduces the incidence of newly diagnosed diabetes by 36.4%. Furthermore, it has beneficial effects on overweight, reduces blood pressure and triglycerides, and downregulates biomarkers of low-grade inflammation. In the Study To Prevent Non-Insulin-Dependent-Diabetes-Mellitus (STOP-NIDDM) trial, acarbose significantly reduced the progression of intima media thickness, incidence of cardiovascular events and of newly diagnosed hypertension. In a meta-analysis of patients with Type 2 diabetes (MERIA), acarbose intake was associated with a reduction of cardiovascular events by 35%. Acarbose is a very safe drug but in approximately 30% of patients, it can cause gastrointestinal complaints due to its mode of action, which in the majority disappear after 1-2 months. Acarbose is approved for treatment of IGT in 25 countries. It can be given alone or in combination with other oral antidiabetics and insulin. Acarbose is particularly effective in those with IGT and early diabetes and patients with comorbidities of the metabolic syndrome.

Metabolic syndrome and type 2 diabetes: can we stop the weight gain with diabetes?

Many patients with type 2 diabetes also have the metabolic syndrome with its cardinal features of central adiposity, insulin resistance, dyslipidemia, and hypertension. Although there is strong evidence for the importance of tight glycemic control in minimizing the microvascular complications of diabetes, many of the current therapies used for optimizing glycemic control also cause weight gain. With this treatment-induced weight gain, there is a risk of worsening the patient's insulin resistance. Physicians need to be aware of this vicious cycle in their overweight type 2 diabetic patients. This article reviews the strategies currently available to achieve glycemic control while at the same time minimizing weight gain and the associated complications.

Cardiovascular benefits and safety profile of acarbose therapy in prediabetes and established type 2 diabetes

Dysglycaemic disease is one of the most important health issues facing the world in the 21^st century. Patients with type 2 diabetes and individuals with prediabetes are at risk of developing macrovascular and microvascular complications. Long-term management strategies are therefore required that are effective at controlling dysglycaemia, well tolerated and, ideally, offer additional cardiovascular disease (CVD) risk-reduction benefits. The efficacy, safety and tolerability of the α-glucosidase inhibitor acarbose have been well-established in a wide range of patient populations in both clinical and community trials. In addition, acarbose has been shown to reduce cardiovascular complications in type 2 diabetes and prevent hypertension and CVD in individuals with impaired glucose tolerance (IGT). Acarbose has a very good safety profile and, owing to its straightforward, non-systemic mode of action, avoids most adverse events. The most common side-effects of acarbose are mild-to-moderate gastrointestinal complaints that subside as treatment continues. They can be minimised through the use of an appropriate stepwise dosing regimen and careful choice of diet. Acarbose is therefore a valuable option for the management of type 2 diabetes and, as the only oral antidiabetes agent approved for the treatment of prediabetes, can help to improve clinical management across the dysglycaemic disease continuum.

Weight management for type 2 diabetes mellitus: global cardiovascular risk reduction

Most patients with type 2 diabetes mellitus are overweight or obese, and the relation between obesity, especially of the visceral compartment, and the risk for developing diabetes is well recognized. Excessive adipose tissue is associated with insulin resistance as well as the increased expression of proinflammatory cytokines and prothrombotic factors, all of which contribute to elevating the risk for coronary artery disease (CAD). In particular, abdominal obesity, or excess visceral adiposity, has been linked to a cluster of risk factors (high blood pressure, hypertriglyceridemia, low levels of high-density lipoprotein cholesterol, and impaired fasting glucose) that constitute the metabolic syndrome, the presence of which confers an increased risk for type 2 diabetes and cardiovascular disease. In fact, a large waist circumference, a surrogate measure of abdominal adiposity, is 1 of the main criteria for diagnosing the metabolic syndrome. Lifestyle modification is the first-line approach to the management of obesity and the metabolic syndrome. However, if patients are unable to achieve a weight loss of 5%-10% of initial body weight and improve cardiometabolic risk factors with lifestyle modification alone, physicians should consider using adjunctive long-term pharmacotherapy. A variety of approved and investigational pharmacologic agents, including sibutramine, orlistat, metformin, and rimonabant, have been shown to reduce weight and ameliorate metabolic syndrome components, thereby reducing cardiovascular risk. Such global risk reduction is crucial for patients with diabetes, in whom CAD is a major cause of mortality.

Lack of association between the Pro12Ala polymorphism in PPAR-gamma2 gene and body weight changes, insulin resistance and chronic diabetic complications in obese patients with type 2 diabetes

BACKGROUND

It is generally accepted that the Pro12Ala polymorphism in peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) is associated with an increased risk of type 2 diabetes. However, studies on an association between the polymorphism and obesity have yielded inconsistent findings. Also, a role of PPAR-gamma receptors in development of chronic diabetic complications cannot be excluded. The aim of this study was to investigate an association between Pro12Ala polymorphism and body weight changes, insulin resistance, insulin secretion and incidence of diabetic complications in obese patients with long-lasting type 2 diabetes.

METHODS

In 216 obese patients with at least a 10-year history of type 2 diabetes, a detailed medical history was taken and a physical examination with assessment of diabetic complications was performed as well as evaluation of insulin resistance (homeostatic model assessment-HOMA), insulin secretion and other biochemical parameters. PCR-RFLP was used to assess Pro12Ala polymorphism. Two subgroups of patients were compared: homozygotic Pro/Pro and Ala allele carriers (Ala/Ala + Ala/Pro).

RESULTS

No differences between the analyzed groups in body weight changes, insulin resistance and insulin secretion were found, but Ala allele was significantly more frequent in males than in females. There was no difference in incidence and progression of diabetic complications with only a trend towards higher incidence of diabetic retinopathy in patients with Ala allele.

CONCLUSIONS

There is no association between Pro12Ala PPAR-gamma2 polymorphism and body mass changes observed during a course of type 2 diabetes, differences in peripheral insulin resistance and incidence and progression of diabetic complications in obese patients with long-lasting type 2 diabetes.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent used in the treatment of type 2 diabetes mellitus. The results of the UK Prospective Diabetes Study indicate that metformin treatment is associated with a reduction in total mortality compared to other anti-hyperglycemic treatments. Metformin, however, is thought to increase the risk of lactic acidosis, and is considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis with metformin use compared to placebo and other glucose-lowering treatments in patients with type 2 diabetes mellitus. A secondary objective was to evaluate the blood lactate levels for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A search was performed of The Cochrane Library (up to 8/2005), MEDLINE (up to 8/2005), EMBASE (up to 11/2000), OLD MEDLINE, and REACTIONS (up to 8/2005), in order to identify all studies of metformin treatment from 1966 to August 2005. The Cumulated Index Medicus was used to search relevant articles from 1959 to 1965. The search was augmented by scanning references of identified articles, and by contacting principal investigators. Date of latest search: August 2005.

SELECTION CRITERIA

Prospective trials in patients with type 2 diabetes that lasted longer than one month were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. Observational cohort studies of metformin treatment lasting greater than one month were also included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials to be included, assessed study quality and extracted data. The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for placebo or other treatments. The upper limit for the true incidence of cases in the metformin and non-metformin groups were calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed effect model for continuous data.

MAIN RESULTS

Pooled data from 206 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 47,846 patient-years of metformin use or in 38,221 patients-years in the non-metformin group. Using Poisson statistics with 95% confidence intervals the upper limit for the true incidence of metformin-associated lactic acidosis was 6.3 cases per 100,000 patient-years, and the upper limit for the true incidence of lactic acidosis in the non-metformin group was 7.8 cases per 100,000 patient-years. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to placebo or other non-biguanide therapies. The mean lactate levels were slightly lower for metformin treatment compared to phenformin (WMD -0.75 mmol/L, 95% CI -0.86 to -0.15).

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments if prescribed under the study conditions.

Medications as Adjunct Therapy for Weight Loss: Approved and Off-Label Agents in Use

Although a nutritionally balanced, energy-controlled diet and regular exercise form the cornerstone of weight management, supporting therapies may include antiobesity medications when a clinician determines that pharmacologic assistance could contribute to treatment success. The US Food and Drug Administration has approved certain medications for helping achieve weight loss in patients with obesity or overweight who have comorbidities. However, some clinicians prescribe medications not approved for weight loss for this purpose. Evidence from clinical trials indicates that weight loss resulting from the use of many of these off-label pharmaceutical agents is modest, but in a range that correlates with favorable modification of cardiovascular risk factors, and significant when compared with placebo plus diet and lifestyle modification. Clinical trials also demonstrate a slight but significant effect in the weight-maintenance phases following weight loss. Pharmacotherapy alone, without behavior modification, is not effective; patients who respond to medication typically regain weight when the drug is discontinued. The fact that many weight-loss medications are sold over the Internet without a prescription suggests that they are being used without medical supervision. The purpose of this review is to present evidence for and against the obesity medications currently used in clinical practice, and the possible role for these agents in a person's overall weight loss plan.

Alpha-glucosidase inhibitors for type 2 diabetes mellitus

BACKGROUND

Alpha-glucosidase inhibitors such as acarbose or miglitol, have the potential to improve glycemic control in type 2 diabetes mellitus. The true value of these agents, especially in relation to diabetes related mortality and morbidity, has never been investigated in a systematic literature review and meta-analysis.

OBJECTIVES

To assess the effects of alpha-glucosidase inhibitors s in patients with type 2 diabetes mellitus.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, EMBASE, Current Contents, LILACS, databases of ongoing trials, reference lists of reviews on the topic of alpha-glucosidase inhibitors and we contacted experts and manufacturers for additional trials. Date of most recent search: December 2003 (Current Contents) and April 2003 (other databases).

SELECTION CRITERIA

Randomised controlled trials of at least 12 weeks duration comparing alpha-glucosidase inhibitor monotherapy in patients with type 2 diabetes with any other intervention and that included at least one of the following outcomes: mortality, morbidity, quality of life, glycemic control, lipids, insulin levels, body weight, adverse events.

DATA COLLECTION AND ANALYSIS

Two reviewers read all abstracts, assessed quality and extracted data independently. Discrepancies were resolved by consensus or by the judgement of a third reviewer. A statistician checked all extracted data entrance in the database. We attempted to contact all authors for data clarification.

MAIN RESULTS

We included 41 trials (8130 participants), 30 investigated acarbose, seven miglitol, one trial voglibose and three trials compared different alpha-glucosidase inhibitors. Study duration was 24 weeks in most cases and only two studies lasted amply longer than one year. We found only few data on mortality, morbidity and quality of life. Acarbose had a clear effect on glycemic control compared to placebo: glycated haemoglobin -0.8% (95% confidence interval -0.9 to -0.7), fasting blood glucose -1.1 mmol/L (95% confidence interval -1.4 to -0.9), post-load blood glucose -2.3 mmol/L (95% confidence interval -2.7 to -1.9). The effect on glycated haemoglobin by acarbose was not dose-dependent. We found a decreasing effect on post-load insulin and no clinically relevant effects on lipids or body weight. Adverse effects were mostly of gastro-intestinal origin and dose dependent. Compared to sulphonylurea, acarbose decreased fasting and post-load insulin levels by -24.8 pmol/L (95% confidence interval -43.3 to -6.3) and -133.2 pmol/L (95% confidence interval -184.5 to -81.8) respectively and acarbose caused more adverse effects.

AUTHORS' CONCLUSIONS

It remains unclear whether alpha-glucosidase inhibitors influence mortality or morbidity in patients with type 2 diabetes. Conversely, they have a significant effect on glycemic control and insulin levels, but no statistically significant effect on lipids and body weight. These effects are less sure when alpha-glucosidase inhibitors are used for a longer duration. Acarbose dosages higher than 50 mg TID offer no additional effect on glycated hemoglobin but more adverse effects instead. Compared to sulphonylurea, alpha-glucosidase inhibitors lower fasting and post-load insulin levels and have an inferior profile regarding glycemic control and adverse effects.

"Low dose" metformin improves hyperglycemia better than acarbose in type 2 diabetics

OBJECTIVES

"High dose" metformin therapy (2,550 mg/day) is reported to improve glycemic control in type 2 diabetic patients with obesity (body mass index (BMI) > or = 30). Some have reported that metformin therapy, even in low doses (500-750 mg/day), improves glycemic control in non-obese type 2 diabetic patients (BMI approximately 25). However, it is unclear whether "low dose" metformin improves glycemic control better than acarbose in non-obese type 2 diabetic patients, which has been shown to improve glycemic control in type 2 diabetes with obesity.

METHODS

We randomly divided 22 non-obese type 2 diabetic patients (mean BMI approximately 25) into two groups (A = 11, B = 11). Group A was treated with "low dose" metformin (500-750 mg/day) for 3 months, and switched to acarbose (150-300 mg/day) for another 3 months. Group B was treated with acarbose first, and then switched to "low dose" metformin.

RESULTS

"Low dose" metformin significantly decreased the fasting plasma glucose (FPG) and HbA1c level in both groups A and B, whereas acarbose decreased HbA1c levels in group B but not in group A. Overall, "low dose" metformin significantly decreased HbA1c (p=0.0165) levels as compared to acarbose.

CONCLUSION

In conclusion, "low dose" metformin therapy improved glycemic control better than acarbose in non-obese diabetics.

The management of the obese diabetic patient

The prevalence of obesity and diabetes is increasing in the United States and worldwide. These diseases are predicted to explode to epidemic proportions, unless appropriate counteractive measures are taken. Several large studies (DCCT, UKPDS, Kumamoto) clearly showed that intensive glycemic control in the diabetic patient reduced microvascular complications and improved mortality. Despite this, the NHANES III showed that only 50% of diabetics have been able to achieve a HgbAic level that is less than 7%; this suggests the need for a re-evaluation of our approach to these patients. The management of the obese diabetic patient involves glycemic control and weight reduction. These goals are particularly difficult to achieve in the obese diabetic patient because progressive beta-cell dysfunction and increasing insulin resistance necessitates the administration of increasingly higher dosages of insulin, which, in turn, promotes weight gain. A vicious cycle may ensue. Lifestyle modifications with diet and exercise are an essential part of the management of the obese diabetic patient. These measures alone are often insufficient and concomitant pharmacologic therapy is usually required to achieve glycemic and weight control. Oral agents that improve glycemia, decrease insulin resistance, and limit weight gain are desirable. Because of the progressive nature of diabetes, glycemic control with monotherapy often deteriorates over time, which necessitates the addition of other pharmacologic agents, including insulin. When insulin therapy is required in the treatment of the obese diabetic patient, combinations with oral agents that have been shown to minimize the amount of exogenous insulin that is required, may minimize weight gain. In addition, the obese diabetic patient who is poorly controlled with maximum oral hypoglycemic therapy may benefit from weight-reducing agents, such as sibutramine or orlistat. The introduction of these agents at other points in the management of the obese diabetic patients have been successful. Finally, for the severely obese diabetic patient, bariatric surgery may be the only effective treatment. Gastric bypass has been unequivocally shown to produce significant weight loss and improve glycemic control on a long-term basis in the obese diabetic patient. It is recommended that physicians avail themselves of all of these strategies in the management of the obese patient who has type 2 diabetes.

Is there a role for alpha-glucosidase inhibitors in the prevention of type 2 diabetes mellitus?

Type 2 diabetes mellitus is a major health problem associated with excess morbidity and mortality. As the prevalence of this metabolic disorder is rapidly increasing and current treatment fails to stabilise the disease in most patients, prevention should be considered as a key objective in the near future. People who develop type 2 diabetes pass through a phase of impaired glucose tolerance (IGT). Defects in the action and/or secretion of insulin are the two major abnormalities leading to development of glucose intolerance. Any intervention in the impaired glucose tolerance phase that reduces resistance to insulin or protects the beta-cells, or both, should prevent or delay progression to diabetes.Acarbose, miglitol and voglibose act by competitively inhibiting the alpha-glucosidases, a group of key intestinal enzymes involved in the digestion of carbohydrates. They decrease both postprandial hyperglycaemia and hyperinsulinaemia, and thereby may improve sensitivity to insulin and release the stress on beta-cells. These compounds do not induce hypoglycaemia and have a good safety profile, although gastrointestinal adverse effects may limit long-term compliance to therapy. The recent placebo-controlled prospective STOP-noninsulin-dependent diabetes mellitus (STOP-NIDDM) trial demonstrated that acarbose 100mg three times daily reduces the risk of developing type 2 diabetes in patients with IGT (relative risk reduction of 25% after a mean follow-up of 3.3 years). The 6-year Early Diabetes Intervention Trial (EDIT), comparing the effect of acarbose 50mg three times daily to that of metformin, showed a trend to a positive effect of acarbose compared with placebo, in a mid-term 3-year analysis, which should be confirmed in the final analysis. To our knowledge, no such prevention intervention trials have been or are currently being performed with miglitol or voglibose. In conclusion, because of its absence of toxicity and its particular mechanism of action on gastrointestinal tract and indirect consequences on both insulin action and beta-cell function, acarbose may be used to prevent type 2 diabetes. If the ongoing EDIT trial confirms the positive results of the recent STOP-NIDDM trial, acarbose could be used, either as an alternative or in addition to changes in lifestyle, to delay development of diabetes in patients with IGT. However, the best dosage of acarbose for this specific indication remains to be specified, especially when all three important parameters, efficacy, tolerance and cost, are taken into consideration.

Acarbose improves glycemic control in insulin-treated Asian type 2 diabetic patients: results from a multinational, placebo-controlled study

The purpose of the study was to determine the efficacy and tolerability of acarbose in Asian type 2 diabetic patients insufficiently controlled by insulin. Asian type 2 diabetic patients on stable insulin dosages were enrolled into a multinational, double-blind, placebo-controlled parallel arm study. After a 2-week screening phase, patients were randomly assigned to 50 mg acarbose t.i.d. or matching placebo for 6 weeks, followed by 100 mg acarbose t.i.d. or placebo for 12 weeks. The primary efficacy parameter was change from baseline in HbA(1c); secondary variables included the changes in fasting and postprandial blood glucose. After 18 weeks of treatment there was a difference in HbA(1c) levels between the two treatment groups (-0.69%, 95% CI (-1.18; -0.2), P=0.008) in favour of acarbose. Reductions in 1-h postprandial glucose levels from baseline to endpoint were observed with acarbose treatment (P=0.029). There were no differences in fasting blood glucose, total triglyceride and cholesterol between the two groups. Safety profiles were similar for both treatment arms except for the higher incidence of flatulence in the acarbose group (28.6% vs. 16.4% for placebo). Adjunctive acarbose therapy offers an efficacious and safe means for improvement of glycemic control in Asian type 2 diabetic patients insufficiently controlled by insulin.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent used in the treatment of type 2 diabetes mellitus. The results of the UK Prospective Diabetes Study indicate that metformin treatment is associated with a reduction in total mortality compared to other anti-hyperglycemic treatments. Metformin, however, is thought to increase the risk of lactic acidosis, and is considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis with metformin use compared to placebo and other glucose-lowering treatments in patients with type 2 diabetes mellitus. A secondary objective was to evaluate the blood lactate levels for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A search was performed of the Cochrane Controlled Trials Register and the Database of Abstracts of Reviews of Effectiveness (up to 4/2000), Medline (up to 11/2000), Embase (up to 11/2000), Oldmedline, and Reactions (up to 5/2000), in order to identify all studies of metformin treatment from 1966 to November 2000. The Cumulated Index Medicus was used to search relevant articles from 1959 to 1965. The search was augmented by scanning references of identified articles, and by contacting principal investigators. Date of latest search: November 2000.

SELECTION CRITERIA

Prospective trials in patients with type 2 diabetes that lasted longer than one month were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. Observational cohort studies of metformin treatment lasting greater than one month were also included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials to be included, assessed study quality and extracted data. The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for placebo or other treatments. The upper limit for the true incidence of cases in the metformin and non-metformin groups were calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed effects model for continuous data.

MAIN RESULTS

Pooled data from 176 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 35,619 patient-years of metformin use or in 30,002 patients-years in the non-metformin group. Using Poisson statistics with 95% confidence intervals the upper limit for the true incidence of metformin-associated lactic acidosis was 8.4 cases per 100,000 patient-years, and the upper limit for the true incidence of lactic acidosis in the non-metformin group was 9 cases per 100,000 patient-years. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to placebo or other non-biguanide therapies. The mean lactate levels were slightly lower for metformin treatment compared to phenformin (WMD -0.75 mmol/L, 95% CI -0.86 to -0.15).

REVIEWER'S CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments if prescribed under the study conditions, taking into account contra-indications.

Should obese patients be counselled to follow a low-glycaemic index diet? Yes

A reduction in dietary fat has been widely advocated for the prevention and treatment of obesity and related complications. However, the efficacy of low-fat diets has been questioned in recent years. One potential adverse effect of reduced dietary fat is a compensatory increase in the consumption of high glycaemic index (GI) carbohydrate, principally refined starchy foods and concentrated sugar. Such foods can be rapidly digested or transformed into glucose, causing a large increase in post-prandial blood glucose and insulin. Short-term feeding studies have generally found an inverse association between GI and satiety. Medium-term clinical trials have found less weight loss on high GI or high glycaemic load diets compared to low GI or low glycaemic load diets. Epidemiological analyses link GI to multiple cardiovascular disease risk factors and to the development of cardiovascular disease and type 2 diabetes. Physiologically orientated studies in humans and animal models provide support for a role of GI in disease prevention and treatment. This review examines the mechanisms underlying the potential benefits of a low GI diet, and whether such diets should be recommended in the clinical setting.

Orlistat use in type 2 diabetes

OBJECTIVE

To review the use of orlistat in type 2 diabetes.

DATA SOURCES

A MEDLINE search of the English-language literature (1990-August 2001) was performed using the key terms orlistat, obesity, glucose, and diabetes.

DATA EXTRACTION

All articles pertaining to orlistat were considered for inclusion, with emphasis placed on randomized, placebo-controlled, double-blind clinical trials.

DATA SYNTHESIS

In April 1999, orlistat was approved by the Food and Drug Administration for the treatment of obesity. Of 13 randomized, placebo-controlled studies, only 2 reported specific data in individuals with type 2 diabetes. Both reported significant weight reduction and improved glycemic control over placebo.

CONCLUSIONS

Since weight loss is a difficult goal to achieve in patients with type 2 diabetes, orlistat can be a safe, effective addition to a multidisciplinary approach.

Chronic acarbose-feeding increases GLUT1 protein without changing intestinal glucose absorption function

As alpha-glucosidase inhibitor, the antidiabetic drug acarbose reduces postprandial glucose levels by retarding the intestinal digestion of polysaccharides. However, it is unknown if acarbose also affects the expression of intestinal glucose transporters, especially the Na(+)-glucose cotransporter (SGLT1) and the glucose transporters GLUT1 and GLUT2. To unravel this question, Wistar rats received standard powdered chow either without (control) or with acarbose (40 mg acarbose/100 g chow) for 40 days. While food intake was slightly enhanced by acarbose, the drug had no influence on weight gain or plasma glucose and insulin levels. The acarbose-treatment did not alter the SGLT1 and GLUT2 gene expression in both upper and middle small intestine, whereas GLUT1 protein was increased by 75% in middle small intestine. Despite the territorial change in GLUT1 protein, the intestinal glucose absorption in an acarbose-free perfusion study was unaltered. In conclusion, the chronic use of acarbose did not alter the acarbose-free glucose absorption profile.

Effect of acarbose on weight maintenance after dietary weight loss in obese subjects

AIMS

Acarbose is a well established antidiabetic drug and is known to exert a modest weight-lowering effect. The aim of this study was to assess the potential of acarbose to improve weight maintenance after a substantial weight loss by dietary measures in obese subjects.

DESIGN

Randomised, double-blind, placebo-controlled trial of the effect of acarbose on weight change over a 6-month follow-up period.

PATIENTS AND METHODS

One hundred and ten obese subjects with a BMI > or = 32 and < or = 38 kg/m2 were included in the study and underwent a 10-16-week very-low-calorie diet programme to initiate weight loss. Then, subjects were randomised to receive either acarbose or placebo for 26 +/- 2 weeks. The primary variable was body weight. The primary efficacy analysis was performed in the per-protocol population (n = 75).

RESULTS

After an initial mean weight loss of 10.0 +/- 3.4 kg, 54 subjects received acarbose at increasing dosage and 56 subjects received placebo treatment. After 14 weeks of follow-up, there was no change in body weight in the two groups. After 26 weeks, completed by 37 subjects in the acarbose group and by 38 subjects in the placebo group, a small weight regain of 0.6 kg was documented in the latter, whereas no weight increase was observed under acarbose treatment (p = 0.38, analysis of covariance with initial body weight as covariable).

CONCLUSION

In obese individuals who undergo a hypocaloric diet and achieve a substantial loss of body weight, acarbose treatment provides only a very modest, not significant benefit to stabilise weight reduction. Thus, acarbose is not a useful adjunct to improve weight maintenance in obese subjects after weight loss.

Pharmacotherapy of type 2 diabetes mellitus

OBJECTIVE

To review the drug treatments and some of the popular, nontraditional remedies now available for type 2 diabetes mellitus, as well as selected investigational agents; to describe each medication's place in the overall approach to treatment.

DATA SOURCES

English-language journals, abstracts, review articles, and newspaper accounts.

DATA SYNTHESIS

In the past five years, there has been tremendous progress in the pharmacotherapy of diabetes, particularly type 2 diabetes. Several new agents have entered the clinical arena, and many more are in the late stages of investigation leading to approval. Sulfonylureas stimulate the production and release of insulin; these drugs must be used in patients with an intact pancreas. The meglitinides are nonsulfonylurea agents that are also insulin secretagogues. Unlike the sulfonylureas, repaglinide appears to require the presence of glucose to close the adenosine triphosphate-sensitive potassium channels and induce calcium influx. Metformin reduces hepatic glucose production in some patients and increases peripheral glucose utilization, but its use is hampered by a high percentage of adverse reactions. Disaccharidase inhibitors effectively compensate for the defective early-phase insulin release by slowing the production of sugars from carbohydrates. Thiazolidinediones appear to activate peroxisome proliferator-activated receptor gamma, which is involved in the metabolism of lipids. Short-acting insulin and the role of weight-loss agents are also discussed.

CONCLUSIONS

The availability of new options for diabetes therapy provides a chance for successful therapy in a larger number of patients. However, it is important to consider how much true benefit these new forms of treatment will have on the diabetic community. The best choice for a patient remains controversial.

The insulin-sensitizing activity of moderate alcohol consumption may promote leanness in women

Cross-sectional epidemiology reveals that women who drink alcohol regularly and moderately, on average, tend to have a decidedly lower body-mass index (BMI) than non-drinking women, despite slightly higher caloric intakes. In men, moderate drinkers are no heavier than non-drinkers, yet they consume considerably more calories. The thermogenic effect which this implies is not explained by the modest acute thermic effect of ethanol ingestion. However, there is indirect evidence that regular alcohol consumption has an insulin-sensitizing effect on skeletal muscle that down-regulates insulin secretion. Decreased insulin activity on adipocytes and the liver may discourage fat storage and promote hepatic mechanisms of ketogenesis, gluconeogenesis, and associated thermogenesis, thus possibly accounting for the relative leanness of female drinkers. The possibility that prescribing moderate alcohol intake could aid weight control in non-drinking overweight females should receive clinical evaluation. The impact of moderate drinking on risk for diabetes in women appears to be quite dramatic.

Combining insulin and oral agents

Type 2 diabetes mellitus is a progressive disorder, and maintenance of near-normal glycemic control has been demonstrated to reduce the risk of its associated long-term vascular complications. This treatment goal can be achieved in most patients with use of single oral agents, combinations of oral agents, or insulin. Secondary failure rates for intensive oral or injected therapy are high, however, especially in patients with long-standing disease. A substantial body of evidence indicates that combination therapy with insulin and oral antidiabetic agents can safely establish excellent glycemic control in most patients, while it reduces the required dosage of insulin and, in some combinations, mitigates the weight gain associated with insulin therapy. The availability of more convenient insulin-delivery systems may render the addition of insulin to oral drug therapy more acceptable to patients and clinicians. The most-studied combination is that of insulin and the sulfonylurea drugs. Randomized, prospective clinical trials have documented the benefits of thiazolidinediones, metformin, and acarbose in combination with insulin. To date, however, clinical trial data are insufficient for use in determining the optimal combination of agents, insulin formulations, and dosages among the many currently available possibilities.

Acarbose treatment does not change the habitual diet of patients with Type 2 diabetes mellitus. The Finnish Acargbos Study Group

AIMS

It has been speculated that acarbose treatment in patients with Type 2 diabetes mellitus might induce changes in diet as a result of its adverse gastrointestinal effects. The aim of this study was to determine whether poor metabolic control can be improved by acarbose, and whether this might be because the acarbose supplementation provokes changes in diet.

METHODS

Poorly controlled Type 2 diabetic patients treated with oral hypoglycaemic agents (OHA) were randomized into either acarbose (100 mg t.d.s.) or placebo treatment. The double-blind treatment lasted for 24 weeks. Four-day food diaries and blood samples for efficacy analysis were collected at 0, 4, 12, and 24 weeks. Thirty-six acarbose and 39 placebo-treated patients completed the trial and were included in the final analyses.

RESULTS

At 24 weeks the baseline adjusted means of fasting, 1 and 2-h postprandial blood glucose values were 9.3 vs. 10.5 (P=0.02), 11.6 vs. 14.5 (P<0.001) and 11.0 vs. 13.7 mmol/l (P<0.001) and HbA1 9.3% vs. 10.2% (P=0.002) in the acarbose and placebo groups, respectively. No significant differences in nutrient intakes between groups were observed. The energy intake and energy proportion of fat and carbohydrates remained unchanged in both groups.

CONCLUSIONS

Acarbose significantly improves metabolic control in Type 2 diabetic patients poorly controlled with oral hypoglycaemic agents. This effect seems not to be a result of concomitant involuntary dietary changes, since acarbose did not induce modifications in diet during the study.

The use of insulin alone and in combination with oral agents in type 2 diabetes

To achieve optimal outcomes in patients with type 2 diabetes, clinical trial data suggest that near normal glycemic control should be targeted. Insulin is arguably the most effective treatment available for diabetes and yet many patients remain poorly controlled without the benefit of insulin therapy. Discussion of its putative risks and benefits as well as the barriers to its wider use both in the context of monotherapy and in combination with oral antidiabetic agents is provided. Application of the strategies and principles of insulin therapy in type 2 diabetes should minimize the burden of complications in patients with the disease.

Obesity medications and the treatment of type 2 diabetes

Obesity is a chronic disease and requires ongoing treatment. Type 2 diabetes is associated with obesity and improves with weight loss. Diets of 800 kcal/d induce twice the weight loss induced by weight loss medications. The strength of weight loss medication, which should be used with diet and a lifestyle change program, is the maintenance of weight loss. Sibutramine and orlistat are the only two medications approved for the long-term treatment of obesity. Orlistat gives a reduction of low-density lipoprotein (LDL) cholesterol in excess of that expected with weight loss, and the drop in blood pressure expected with weight loss is not seen with sibutramine. Except in newly diagnosed patients with diabetes subjects, patients with diabetes lose half the weight of subjects who do not have diabetes when treated with weight loss medications. Metformin and, to a lesser extent, acarbose cause weight loss, making them attractive choices for the treatment of obese type 2 diabetic subjects. Repaglinide appears to be weight-neutral, but other medications for patients with diabetes can be associated with weight gain. Many new medications are in development for the treatment of obesity. These new medications act through a variety of mechanisms and will surely play an increasingly important role in the treatment of obese patients with type 2 diabetes.