Different effects of insulin and oral antidiabetic agents on glucose and energy metabolism in type 2 (non-insulin-dependent) diabetes mellitus

Acute Effect of Metformin on Postprandial Hypertriglyceridemia through Delayed Gastric Emptying

Postprandial hypertriglyceridemia is a potential target for cardiovascular disease prevention in patients with diabetic dyslipidemia. Metformin has been reported to reduce plasma triglyceride concentrations in the postprandial states. However, little is known about the mechanisms underlying the triglyceride-lowering effect of metformin. Here, we examined the effects of metformin on lipid metabolism after olive oil-loading in 129S mice fed a high fat diet for three weeks. Metformin administration (250 mg/kg) for one week decreased postprandial plasma triglycerides. Pre-administration (250 mg/kg) of metformin resulted in a stronger triglyceride-lowering effect (approximately 45% lower area under the curve) than post-administration. A single administration (250 mg/kg) of metformin lowered plasma postprandial triglycerides comparably to administration for one week, suggesting an acute effect of metformin on postprandial hypertriglyceridemia. To explore whole body lipid metabolism after fat-loading, stomach size, fat absorption in the intestine, and fat oxidation (¹³C/¹²C ratio in expired CO₂ after administration of glyceryl-1-¹³C tripalmitate) were measured with and without metformin (250 mg/kg) pre-treatment. In metformin-treated mice, larger stomach size, lower fat oxidation, and no change in lipid absorption were observed. In conclusion, metformin administration before fat loading reduced postprandial hypertriglyceridemia, most likely by delaying gastric emptying.

WITHDRAWN: Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because of the involvement of one author (SS Lund) being employed in a pharmaceutical company. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the author. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide. Whether sulphonylureas show better, equal or worse therapeutic effects in comparison with other antidiabetic interventions for patients with T2DM remains controversial.

OBJECTIVES

To assess the effects of sulphonylurea monotherapy versus placebo, no intervention or other antidiabetic interventions for patients with T2DM.

SEARCH METHODS

We searched publications in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS and CINAHL (all until August 2011) to obtain trials fulfilling the inclusion criteria for our review.

SELECTION CRITERIA

We included clinical trials that randomised patients 18 years old or more with T2DM to sulphonylurea monotherapy with a duration of 24 weeks or more.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias. The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes were other patient-important outcomes and metabolic variables. Where possible, we used risk ratios (RR) with 95% confidence intervals (95% CI) to analyse the treatment effect of dichotomous outcomes. We used mean differences with 95% CI to analyse the treatment effect of continuous outcomes. We evaluated the risk of bias. We conducted trial sequential analyses to assess whether firm evidence could be established for a 10% relative risk reduction (RRR) between intervention groups.

MAIN RESULTS

We included 72 randomised controlled trials (RCTs) with 22,589 participants; 9707 participants randomised to sulphonylureas versus 12,805 participants randomised to control interventions. The duration of the interventions varied from 24 weeks to 10.7 years. We judged none of the included trials as low risk of bias for all bias domains. Patient-important outcomes were seldom reported.First-generation sulphonylureas (FGS) versus placebo or insulin did not show statistical significance for all-cause mortality (versus placebo: RR 1.46, 95% CI 0.87 to 2.45; P = 0.15; 2 trials; 553 participants; high risk of bias (HRB); versus insulin: RR 1.18, 95% CI 0.88 to 1.59; P = 0.26; 2 trials; 1944 participants; HRB). FGS versus placebo showed statistical significance for cardiovascular mortality in favour of placebo (RR 2.63, 95% CI 1.32 to 5.22; P = 0.006; 2 trials; 553 participants; HRB). FGS versus insulin did not show statistical significance for cardiovascular mortality (RR 1.36, 95% CI 0.68 to 2.71; P = 0.39; 2 trials; 1944 participants; HRB). FGS versus alpha-glucosidase inhibitors showed statistical significance in favour of FGS for adverse events (RR 0.63, 95% CI 0.52 to 0.76; P = 0.01; 2 trials; 246 participants; HRB) and for drop-outs due to adverse events (RR 0.28, 95% CI 0.12 to 0.67; P = 0.004; 2 trials; 246 participants; HRB).Second-generation sulphonylureas (SGS) versus metformin (RR 0.98, 95% CI 0.61 to 1.58; P = 0.68; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 0.92, 95% CI 0.60 to 1.41; P = 0.70; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.79 to 1.18; P = 0.72; 4 trials; 1642 participants; HRB), meglitinides (RR 1.44, 95% CI 0.47 to 4.42; P = 0.52; 7 trials; 2038 participants; HRB), or incretin-based interventions (RR 1.39, 95% CI 0.52 to 3.68; P = 0.51; 2 trials; 1503 participants; HRB) showed no statistically significant effects regarding all-cause mortality in a random-effects model. SGS versus metformin (RR 1.47; 95% CI 0.54 to 4.01; P = 0.45; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 1.30, 95% CI 0.55 to 3.07; P = 0.55; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.73 to 1.28; P = 0.80; 4 trials; 1642 participants; HRB) or meglitinide (RR 0.97, 95% CI 0.27 to 3.53; P = 0.97; 7 trials, 2038 participants, HRB) showed no statistically significant effects regarding cardiovascular mortality. Mortality data for the SGS versus placebo were sparse. SGS versus thiazolidinediones and meglitinides did not show statistically significant differences for a composite of non-fatal macrovascular outcomes. SGS versus metformin showed statistical significance in favour of SGS for a composite of non-fatal macrovascular outcomes (RR 0.67, 95% CI 0.48 to 0.93; P = 0.02; 3018 participants; 3 trials; HRB). The definition of non-fatal macrovascular outcomes varied among the trials. SGS versus metformin, thiazolidinediones and meglitinides showed no statistical significance for non-fatal myocardial infarction. No meta-analyses could be performed for microvascular outcomes. SGS versus placebo, metformin, thiazolidinediones, alpha-glucosidase inhibitors or meglitinides showed no statistical significance for adverse events. SGS versus alpha-glucosidase inhibitors showed statistical significance in favour of SGS for drop-outs due to adverse events (RR 0.48, 95% CI 0.24 to 0.96; P = 0.04; 9 trials; 870 participants; HRB). SGS versus meglitinides showed no statistical significance for the risk of severe hypoglycaemia. SGS versus metformin and thiazolidinediones showed statistical significance in favour of metformin (RR 5.64, 95% CI 1.22 to 26.00; P = 0.03; 4 trials; 3637 participants; HRB) and thiazolidinediones (RR 6.11, 95% CI 1.57 to 23.79; P = 0.009; 6 trials; 5660 participants; HRB) for severe hypoglycaemia.Third-generation sulphonylureas (TGS) could not be included in any meta-analysis of all-cause mortality, cardiovascular mortality or non-fatal macro- or microvascular outcomes. TGS versus thiazolidinediones showed statistical significance regarding adverse events in favour of TGS (RR 0.88, 95% CI 0.78 to 0.99; P = 0.03; 3 trials; 510 participants; HRB). TGS versus thiazolidinediones did not show any statistical significance for drop-outs due to adverse events. TGS versus other comparators could not be performed due to lack of data.For the comparison of SGS versus FGS no meta-analyses of all-cause mortality, cardiovascular mortality, non-fatal macro- or microvascular outcomes, or adverse events could be performed.Health-related quality of life and costs of intervention could not be meta-analysed due to lack of data.In trial sequential analysis, none of the analyses of mortality outcomes, vascular outcomes or severe hypoglycaemia met the criteria for firm evidence of a RRR of 10% between interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support the decision as to whether to initiate sulphonylurea monotherapy. Data on patient-important outcomes are lacking. Therefore, large-scale and long-term randomised clinical trials with low risk of bias, focusing on patient-important outcomes are required.

Emerging diabetes therapies and technologies

The prevalence of diabetes is increasing globally and is expected to increase to 439 million people by the year 2030. Several studies have shown that improved glycemic control measured by glycosylated hemoglobin (A1c) in patients with type 1 and type 2 diabetes results in a reduction of both the micro- and macrovascular complications associated with the disease. The recent introduction of new oral medications, insulin analogs (long and rapid acting), insulin pens and pumps, better SMBG meters and continuous glucose monitoring (CGM) have all resulted in improvement of glycemic control. Closed-loop devices currently in development aim to integrate the CGM and pump system in order to more closely mimic the human pancreas. The other upcoming new basal insulin (Degludec), prandial insulin, other new technologies and improved oral therapies will significantly improve patient acceptance of intensive therapy, glycemic control and quality of life in patients with diabetes.

Insulin detemir for the treatment of obese patients with type 2 diabetes

The risk for developing type 2 diabetes (T2DM) is greater among obese individuals. Following onset of the disease, patients with T2DM become more likely to be afflicted with diabetic micro- and macrovascular complications. Decreasing body weight has been shown to lower glycosylated hemoglobin and improve other metabolic parameters in patients with T2DM. Medications used to lower blood glucose may increase body weight in patients with T2DM and this has been repeatedly shown to be the case for conventional, human insulin formulations. Insulin detemir is a neutral, soluble, long-acting insulin analog in which threonine-30 of the insulin B-chain is deleted, and the C-terminal lysine is acetylated with myristic acid, a C14 fatty acid chain. Insulin detemir binds to albumin, a property that enhances its pharmacokinetic/pharmacodynamic profile. Results from clinical trials have demonstrated that treatment with insulin detemir is associated with less weight gain than either insulin glargine or neutral protamine Hagedorn insulin. There are many potential reasons for the lower weight gain observed among patients treated with insulin detemir, including lower risk for hypoglycemia and therefore decreased defensive eating due to concern about this adverse event, along with other effects that may be related to the albumin binding of this insulin that may account for lower within-patient variability and consistent action. These might include faster transport across the blood-brain barrier, induction of satiety signaling in the brain, and preferential inhibition of hepatic glucose production versus peripheral glucose uptake. Experiments in diabetic rats have also indicated that insulin detemir increases adiponectin levels, which is associated with both weight loss and decreased eating.

Management of diabetes across the course of disease: minimizing obesity-associated complications

Obesity increases the risk for developing type 2 diabetes mellitus (T2DM) and this in turn correlates with an elevated probability of long-term diabetes complications once diabetes is established. Interventions aimed at lowering weight via changes in diet and lifestyle have repeatedly been shown to improve glycemic control in patients with T2DM and even to reverse early disease. Weight gain, a potential side effect of treatment for patients with T2DM, is also an important concern, and it has been noted that weight increases associated with antidiabetes therapy may blunt cardiovascular risk reductions achieved by decreasing blood glucose. Among older agents, metformin and acarbose have the lowest risk for weight gain, while sulfonylureas, meglitinides, and thiazolidinediones are all associated with weight increases. Clinical trial results have also consistently demonstrated that treatment with glucagon-like peptide-1 receptor agonists and amylin lowers weight, and that dipeptidyl peptidase-4 inhibitors are weight neutral in patients with T2DM. Conventional human insulin formulations are known to increase weight in patients with T2DM. However, some insulin analogs, particularly insulin detemir, have lower liability for this adverse event. The use of both pharmacologic and surgical therapies aimed at treating obesity rather than lowering blood glucose have the potential to improve glycemic control and even resolve T2DM in some patients.

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.

Direct comparison among oral hypoglycemic agents and their association with insulin resistance evaluated by euglycemic hyperinsulinemic clamp: the 60's study

The aim of the study was to compare the long-term effect of 4 antidiabetic treatment protocols on insulin resistance evaluated by euglycemic hyperinsulinemic clamp in type 2 diabetes mellitus patients. Two hundred seventy-one type 2 diabetes mellitus patients with poor glycemic control and who were overweight were enrolled in this study. Patients were randomized and titrated to take pioglitazone, metformin, pioglitazone + metformin, or glimepiride + metformin for 15 months. They underwent a euglycemic hyperinsulinemic clamp at baseline, after 3 months, and after 15 months. Anthropometric and metabolic measurements were assessed at baseline, after 3 months, and after 15 months. There was a decrease in glycated hemoglobin in all groups, but glycated hemoglobin value was lower in the group treated with pioglitazone + metformin compared with the groups treated with metformin alone and with pioglitazone alone. There was a decrease in fasting plasma glucose and postprandial plasma glucose values in all groups, but values obtained with pioglitazone + metformin were lower compared with values in the groups treated with metformin alone and with pioglitazone alone. Fasting plasma insulin and postprandial plasma insulin values were higher in the group treated with glimepiride + metformin compared with the other groups. After 15 months, glucose infusion rate and total glucose requirement values observed in the groups treated with pioglitazone alone and with pioglitazone + metformin were higher compared with the values in the group treated with metformin alone and with glimepiride + metformin; furthermore, values obtained in the group treated with pioglitazone + metformin were higher than the value obtained with pioglitazone alone. Pioglitazone-metformin-based therapeutic control is associated with the most quantitatively relevant improvement in insulin resistance-related parameters, whereas the sulfonylurea-metformin-including protocol has less relevant effects.

A rice bran oil diet improves lipid abnormalities and suppress hyperinsulinemic responses in rats with streptozotocin/nicotinamide-induced type 2 diabetes

The aim of this study was to determine the effects of rice bran oil (RBO) on lipid metabolism and insulin resistance in rats with streptozotocin/nicotinamide-induced type 2 diabetes mellitus (T2DM). Rats were divided into two groups: the control group (15% soybean oil, contains 0 g γ-oryzanol and 0 g γ-tocotrienol/150 g oil for 5 weeks) and the RBO group (15% RBO, contains 5.25 g γ-oryzanol and 0.9 g γ-tocotrienol/150 g oil for 5 weeks). Compared with the control group, the RBO group had a lower plasma nonesterified fatty acid concentration, ratio of total to high-density-lipoprotein cholesterol, hepatic cholesterol concentration, and area under the curve for insulin. The RBO group had a higher high-density-lipoprotein cholesterol concentration and greater excretion of fecal neutral sterols and bile acid than did the control group. RBO may improve lipid abnormalities, reduce the atherogenic index, and suppress the hyperinsulinemic response in rats with streptozotocin/nicotinamide-induced T2DM. In addition, RBO can lead to increased fecal neutral sterol and bile acid excretion.

Weight gain in type 2 diabetes mellitus--not all uphill

OBJECTIVE

The goal of this study, of type 2 diabetes mellitus patients, treated in a referral community setting, was to follow the history of weight changes, in relation to the changing treatment modalities, and to detect independent risk factor and predictors for weight gain.

RESEARCH METHODS

366 outpatients with type 2 diabetes (T2DM) were followed longitudinally for at least 5 years. 310 patients were treated with oral hypoglycemic agents and 56 patients had insulin treatment added to the oral therapy.

RESULTS

The two groups did no differ significantly in the duration of diabetes, age of onset and admission HbA1c. The mean weight at admission was 78.9+/-15.1 and 76.7+/-15.0 kg (ns) respectively. No significant weight changes were noted on initiation of oral treatment and at final visit. The commencing of insulin therapy was the only step associated with a significant 3.7 kg increase in body weight (p<0.001) with a significant reduction in HbA1c (-1.4%, p<0.001). These changes however, followed a decrease in body weight that preceded insulin therapy. Mean weight at follow-up did not exceed the self-reported weight prior to the diagnosis of diabetes.

DISCUSSION

The results show that weight gain does not necessarily accompany treatment of T2DM. Insulin therapy in T2DM is associated with some weight gain, mostly due to correction of glycemia and improvement of weight loss prior to insulin treatment. This should encourage the timely addition and combining of appropriate therapeutic modalities in order to achieve good glycemic control.

Short-term effects of metformin in type 2 diabetes

BACKGROUND

Although metformin is widely used in the management of type 2 diabetes, its mechanism(s) of action is not fully known, and there have been remarkably few reports on short-term effects of the drug. Here, we examined the early effects on glucose and lipid metabolism and on certain adipose tissue and inflammatory markers during treatment for 28 days.

METHODS

Twenty-one patients were randomized to metformin (n = 16) or placebo (n = 5) and studied at baseline, 1, 2 and 4 weeks with blood sampling and oral glucose tolerance tests (OGTT). The active group received 500 mg metformin daily in the first week, 500 mg twice daily during week 2 and 1000 mg twice daily during weeks 3 and 4.

RESULTS

After 7 days of treatment, a reduced area under curve (AUC) for glucose at OGTT with no change in AUC for insulin levels was observed compared to baseline. Insulin sensitivity, as derived from the OGTT by Gutt's index, was increased. Reductions in fasting plasma glucose, total cholesterol and low-density lipoprotein cholesterol appeared after 14 days, and reductions in triglycerides, plasminogen activator inhibitor-1 (PAI-1) and leptin after 28 days of treatment. There were no changes in body weight, adiponectin or C-reactive protein. Compared with placebo, the changes between day 0 and day 28 differed significantly with regard to AUC for glucose at OGTT and Gutt's index, and showed strong trends for PAI-1 and leptin.

CONCLUSIONS

The data demonstrate that in type 2 diabetes, metformin rapidly affects glucose handling without changing the concentrations of insulin. Reductions in PAI-1 and leptin levels indicate that the early effects of metformin involve also the adipose tissue.

Short-term effects of metformin in type 2 diabetes

BACKGROUND

Although metformin is widely used in the management of type 2 diabetes, its mechanism(s) of action is not fully known, and there have been remarkably few reports on short-term effects of the drug. Here, we examined early effects on glucose and lipid metabolism, and on certain adipose tissue and inflammatory markers during treatment for 28 days.

METHODS

Twenty-one patients were randomized to metformin (n = 16) or placebo (n = 5) and studied at baseline, 1, 2 and 4 weeks with blood sampling and oral glucose tolerance tests (OGTT). The active group received 500 mg metformin daily in week 1, 500 mg twice daily in week 2 and 1000 mg twice daily in week 3 and 4.

RESULTS

After 7 days of treatment, a reduced area under curve (AUC) for glucose at OGTT with no change in AUC for insulin levels was observed compared with baseline. Insulin sensitivity, as derived from the OGTT by Gutt's index, was increased. Reductions in fasting plasma glucose, total and LDL-cholesterol appeared after 14 days, and reductions in triglycerides, plasminogen activator inhibitor-1 (PAI-1) and leptin after 28 days of treatment. There were no changes in body weight, adiponectin or C-reactive protein. Compared with placebo, the changes between day 0 and day 28 differed significantly with regard to AUC for glucose at OGTT and Gutt's index, and showed strong trends for PAI-1 and leptin.

CONCLUSIONS

The data demonstrate that in type 2 diabetes metformin rapidly affects glucose handling without changing the concentrations of insulin. Reductions in PAI-1 and leptin levels indicate that the early effects of metformin involve also the adipose tissue.

Changes in patient weight and the impact of antidiabetic therapy during the first 5 years after diagnosis of diabetes mellitus

AIMS/HYPOTHESIS

It is generally thought difficult for type 2 diabetic patients to lose weight. We monitored changes in patients' weight during the first 5 years after diabetes diagnosis in relation to initiation of antidiabetic treatment.

SUBJECTS AND METHODS

Data from 711 newly diagnosed diabetic patients aged 40 or over were analysed with a random-effect linear-regression model. Patients were included consecutively from a well-defined patient list in general practice.

RESULTS

In 245 patients whose only treatment was advice on diet, an initial weight loss of 6 to 7 kg was largely maintained over 5 years. Patients receiving metformin (n=86) or sulfonylureas (n=330) maintained an average weight loss of 2 to 4 kg that was dependent on age and sex. Patients' weight did not change on initiation of treatment with sulfonylureas or metformin. Over 5 years, median HbA(1c) increased from 7.0 to 7.8% (reference range 5.4-7.4%) in the diet-alone group. HbA(1c) was approximately 1 percentage point higher for most of the other treatment groups.

CONCLUSIONS/INTERPRETATION

In newly diagnosed type 2 diabetic patients, long-term weight loss was common and weight loss was not affected by sulfonylurea treatment. The measurements in the study are taken from treatment results achieved in the general population of diabetic patients, who are rarely treated in secondary care and seldom the subject of research; the results thus indicate that weight reduction is a practicable treatment in diabetic patients.

Glycaemic control without weight gain in insulin requiring type 2 diabetes: 1-year results of the GAME regimen

INTRODUCTION

Weight gain appears to be unavoidable in patients with type 2 diabetes who are switched from oral agents to insulin therapy. Peripheral hyperinsulinism induced by the use of long-acting insulin may be the key to explain this adverse effect.

AIM

The aim of this study was to investigate whether a regimen free of long-acting insulin can provide long-term glycaemic control without causing weight gain.

PATIENTS AND METHODS

This is an uncontrolled, 1-year study comprising 58 patients with type 2 diabetes and secondary failure, age 30-75 years, BMI 25-35 kg/m(2), HbA1c > 7.5% and fasting C-peptide level > 0.3 mmol/l. All patients were treated with the GAME regimen, a combination of glimepiride administered at 20:00 hours for nocturnal glycaemic control, insulin aspart three times daily for meal-related glucose control and metformin.

RESULTS

Seventy-one per cent of the patients were considered evaluable. HbA1c decreased from 10.0 +/- 0.3 to 7.4 +/- 0.1% (p < 0.001). Fifty-nine per cent reached HbA1c levels <or= 7.5%. Symptomatic nocturnal hypoglycaemia was not reported. Body weight tended to decrease during the first 3 months (-1.0 +/- 0.5 kg, p = 0.06), but then gradually rose to a value 0.8 +/- 0.5 kg higher than at baseline (p = 0.12). This is 4.4 +/- 0.6 kg less than predicted for conventional regimens employing long-acting insulin (p < 0.001).

CONCLUSION

The GAME regimen provides long-term glycaemic control as well as stabilization of body weight in about 60% of type 2 patients presenting with secondary failure.

Effects of metformin on the glycemic control, lipid profile, and arterial blood pressure of type 2 diabetic patients with metabolic syndrome already on insulin

Fifty-seven type 2 diabetic patients with metabolic syndrome and on insulin were assessed by a paired analysis before and 6 months after addition of metformin as combination therapy to evaluate the impact of the association on glycemic control, blood pressure, and lipid profile. This was a historical cohort study in which the files of type 2 diabetic patients with metabolic syndrome on insulin were reviewed. The body mass index (BMI), waist circumference, lipid profile, A1C level, fasting blood glucose level, daily dose of NPH insulin, systolic blood pressure, and diastolic blood pressure were assessed in each patient before the start of metformin and 6 months after the initiation of combination therapy. Glycemic control significantly improved (P < 0.001) after the addition of metformin (1404.4 +/- 565.5 mg/day), with 14% of the 57 patients reaching A1C levels up to 7%, and 53% reaching values up to 8%. There was a statistically significant reduction (P < 0.05) of total cholesterol (229.0 +/- 29.5 to 214.2 +/- 25.0 mg/dL), BMI (30.7 +/- 5.4 to 29.0 +/- 4.0 kg/m2), waist circumference (124.6 +/- 11.7 to 117.3 +/- 9.3 cm), and daily necessity of insulin. The reduction of total cholesterol occurred independently of the reductions of A1C (9.65 +/- 1.03 to 8.18 +/- 1.01%) and BMI and the reduction of BMI and WC did not interfere with the improvement of A1C. In conclusion, our study showed the efficacy of the administration of metformin and insulin simultaneously without negative effects. No changes were detected in HDL-cholesterol or blood pressure.

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.

'Glucose control-related' and 'non-glucose control-related' effects of insulin on weight gain in newly insulin-treated type 2 diabetic patients

Insulin use is common in type 2 diabetes and is frequently accompanied by weight gain, the composition of which is poorly understood. The present study evaluates insulin-induced body composition changes. Body weight and composition of thirty-two type 2 diabetic patients undergoing their first 12 months of insulin therapy were compared with those observed in thirty-two type 2 diabetic patients previously treated on insulin (minimum 1 year). Body composition was determined by simultaneous body water spaces (bioelectrical impedance analysis) and body density measurements. After 6 months, glycosylated Hb (HbA1c) significantly improved in the newly treated group (P<0.0001), but remained stable in those treated previously. HbA1c did not differ between 6 and 12 months in the two groups. Body weight significantly (P=0.04) changed over 12 months in those newly treated only (+2.8 kg), essentially comprising fat-free mass (P=0.044). Fat mass remained unchanged (P=0.85) as did total body water, while extracellular: total body water ratio tended to increase in those newly treated (P=0.059). Weight changes correlated with HbA1c changes (R2 0.134, P=0.002) in the initial 6 months only. Insulin therapy leads to weight gain (2.8 kg), predominantly fat-free mass, over 12 months. After 6 months, newly treated patients continued gaining weight despite an unchanged HbA1c, suggesting the potential anabolic role of insulin in subsequent gains. Therefore, in the initial 6 months, weight gain can be attributed to a 'glucose control-related effect' and further gain appears to be due to a 'non-glucose control-related' effect of insulin treatment.

Combination therapy using metformin or thiazolidinediones and insulin in the treatment of diabetes mellitus

The biguanide, metformin, sensitizes the liver to the effect of insulin, suppressing hepatic glucose output. Thiazolidinediones such as rosiglitazone and pioglitazone enhance insulin-mediated glucose disposal, leading to reduced plasma insulin concentrations. These classes of drugs may also have varying beneficial effects on features of insulin resistance such as lipid levels, blood pressure and body weight. Metformin in combination with insulin has been shown to significantly improve blood glucose levels while lowering total daily insulin dose and body weight. The thiazolidinediones in combination with insulin have also been effective in lowering blood glucose levels and total daily insulin dose. Triple combination therapy using insulin, metformin and a thiazolidinedione improves glycaemic control to a greater degree than dual therapy using insulin and metformin or insulin and a thiazolidinedione. There is insufficient evidence to recommend the use of metformin or thiazolidinediones in type 1 diabetic patients. Although these agents are largely well tolerated, some subjects experience significant gastrointestinal problems while using metformin. Metformin is associated with a low risk of lactic acidosis, but should not be used in patients with elevated serum creatinine or those being treated for congestive heart failure. The thiazolidinediones are associated with an increase in body weight, although this can be avoided with careful lifestyle management. Thiazolidinediones may also lead to oedema and are associated with a low incidence of hepatocellular injury. Thiazolidinediones are contraindicated in patients with underlying heart disease who are at risk of congestive heart failure and in patients who have abnormal hepatic function. The desired blood glucose-lowering effect and adverse event profiles of these agents should be considered when recommending these agents to diabetic patients. The potential for metformin or the thiazolidinediones to impact long-term cardiovascular outcomes remains under investigation.

Metformin revisited: re-evaluation of its properties and role in the pharmacopoeia of modern antidiabetic agents

BACKGROUND

The usefulness of metformin as an oral antidiabetic agent is widely accepted. However, several other classes of oral antidiabetic agents have been recently introduced, raising the need to evaluate the role of metformin as initial therapy and in combination with these newer drugs for treatment of type 2 diabetes mellitus (DM).

METHODS

Synthesis of information was preceded by a comprehensive review of the English language literature using Medline. We also reviewed bibliographies of relevant articles. The studies most pertinent to the mechanism of action, efficacy, toxicity and administration of metformin were selected for citation in this review.

RESULTS

Metformin acts by increasing tissue sensitivity to insulin, principally in the liver. Beneficial properties of metformin include weight reduction, favourable effects on the lipid profile and the fibrinolytic pathway, and improvement of ovarian function in some insulin-resistant women. It does not cause hyperinsulinaemia or hypoglycaemia. Metformin is effective as monotherapy and, in combination with both insulin secretagogues and thiazolidinediones (TZDs), may obviate the need for insulin treatment. Several fixed-dose combination pills containing metformin and other agents are available. A protocol for the initiation of therapy with contemporary oral agents for type 2 DM is presented, with emphasis on the continuing central role of metformin.

CONCLUSIONS

Metformin remains a safe and effective agent for the therapy of patients with type 2 DM. It is useful as monotherapy or in combination regimens with the newer insulin secretagogues, TZDs or insulin. It is still in most circumstances the agent of choice for initial therapy of the typical obese patient with type 2 DM and mild to moderate hyperglycaemia.

Insulin pump therapy vs. multiple daily injections in obese Type 2 diabetic patients

AIMS

To compare the efficacy of insulin pump treatment with multiple daily injections in the treatment of poorly controlled obese Type 2 diabetic patients already receiving two or more daily injections of insulin plus metformin.

METHODS

Forty obese Type 2 diabetic subjects (using insulin) were randomized to treatment with continuous subcutaneous infusion pump (CSII) (Minimed) or multiple daily insulin injections (MDI). At the end of the first 18-week treatment period, patients underwent a 12-week washout period during which they were treated with MDI plus metformin. They were then crossed-over to the other treatment for an 18-week follow-up period. Patients performed 4-point daily self blood-glucose monitoring (SBGM) on a regular basis and 7-point monitoring prior to visits 2, 8, 10 and 16. A subset of patients underwent continuous glucose monitoring using the Minimed(R) continuous glucose monitoring system (CGMS) at visits 2, 8, 10 and 16. A standard meal test was performed in which serum glucose was tested at fasting and once each hour for 6 h following a test meal. Glucose levels were plotted against time and the area under the curve (AUC) was calculated. HbA(1c), weight, daily insulin dose and hypoglycaemic episodes were recorded.

RESULTS

In obese Type 2 diabetic patients already treated with insulin, treatment with CSII significantly reduced HbA(1c) levels compared with treatment with MDI. An additional CSII treatment benefit was demonstrated by reduced meal-test glucose AUC. Initial reduction of daily insulin requirement observed in CSII-treated subjects during the first treatment period was attributable to a period effect and did not persist over time.

CONCLUSIONS

In the intent-to-treat analysis, CSII appeared to be superior to MDI in reducing HbA(1c) and glucose AUC values without significant change in weight or insulin dose in obese, uncontrolled, insulin-treated Type 2 diabetic subjects.

Metformin monotherapy for type 2 diabetes mellitus

BACKGROUND

Metformin is an anti-hyperglycaemic agent used for the treatment of type 2 diabetes mellitus. Type 2 diabetes may present long-term complications: micro- (retinopathy, nephropathy and neuropathy) and macrovascular (stroke, myocardial infarction and peripheral vascular disease). Two meta-analyses have been published before, although only secondary outcomes were assessed.

OBJECTIVES

To assess the effects of metformin monotherapy on mortality, morbidity, quality of life, glycaemic control, body weight, lipid levels, blood pressure, insulinaemia, and albuminuria in patients with type 2 diabetes mellitus.

SEARCH STRATEGY

Studies were obtained from computerised searches of multiple electronic databases and hand searches of reference lists of relevant trials identified. Date of last search: September 2003.

SELECTION CRITERIA

Trials fulfilling the following inclusion criteria: Diabetes mellitus type 2, metformin versus any other oral intervention, assessment of relevant clinical outcome measures, use of random allocation.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data, using a standard data extraction form. Data were summarised under a random effects model. Dichotomous data were expressed as relative risk. We calculated the risk difference (RD), and the Number Needed to Treat, when it was possible. We collected data of mean and standard deviation from changes to baseline. However many trials reported end point data. This limitation lead to the expression of the results as standardised mean differences (SMD) and an overall SMD was calculated. Heterogeneity was tested for using the Z score and the I-squared statistic. Subgroup, sensitivity analysis and meta-regression were used to explore heterogeneity.

MAIN RESULTS

We included for analysis 29 trials with 37 arms (5259 participants), comparing metformin (37 arms and 2007 participants) with sulphonylureas (13 and 1167), placebo (12 and 702), diet (three and 493), thiazolidinediones (three and 132), insulin (two and 439), meglitinides (two and 208), and glucosidase inhibitors (two and 111). Nine studies reported data on primary outcomes. Obese patients allocated to intensive blood glucose control with metformin showed a greater benefit than chlorpropamide, glibenclamide, or insulin for any diabetes-related outcomes (P = 0.009), and for all-cause mortality (P = 0.03). Obese participants assigned to intensive blood glucose control with metformin showed a greater benefit than overweight patients on conventional treatment for any diabetes-related outcomes (P = 0.004), diabetes-related death (P = 0.03), all-cause mortality (P = 0.01), and myocardial infarction (P = 0.02). Patients assigned to metformin monotherapy showed a significant benefit for glycaemia control, weight, dyslipidaemia, and diastolic blood pressure. Metformin presents a strong benefit for HbA1c when compared with placebo and diet; and a moderated benefit for: glycaemia control, LDL cholesterol, and BMI or weight when compared with sulphonylureas.

AUTHORS' CONCLUSIONS

Metformin may be the first therapeutic option in the diabetes mellitus type 2 with overweight or obesity, as it may prevent some vascular complications, and mortality. Metformin produces beneficial changes in glycaemia control, and moderated in weight, lipids, insulinaemia and diastolic blood pressure. Sulphonylureas, alpha-glucosidase inhibitors, thiazolidinediones, meglitinides, insulin, and diet fail to show more benefit for glycaemia control, body weight, or lipids, than metformin.

Use of a reference four-component model to define the effects of insulin treatment on body composition in type 2 diabetes: the 'Darwin study'

AIMS

To define the effects of insulin treatment on body composition and fat distribution, and investigate the potential role of body weight (BWt) gain predictors in patients with poorly controlled type 2 diabetes.

METHODS

Assessments of body composition, using a four-component model, and biochemical indices were obtained in 19 patients [mean (SD): age, 60 (8.3) years; BMI, 25.3 (3.3) kg/m(2)] with poorly controlled type 2 diabetes, despite maximal oral hypoglycaemic agents, receiving insulin [40 (12.2) units/day] at baseline and after 1, 3 and 6 months.

RESULTS

Insulin therapy significantly reduced plasma glucose [-6.0 (4.3) mmol/l], improved [HbA(1)c [-1.9 (1.8)%], and reversed the BWt lost [3.3 (1.8) kg] before treatment. The 6-month BWt gain [+5.2 (2.7) kg] consisted of body fat [+2.9 (2.7) kg] and fat-free mass [FFM; +2.3 (1.8) kg], with the FFM increase due solely to total body water [TBW; +2.4 (1.5) l], as there were no detectable changes in total body protein or bone mineral, thereby increasing FFM hydration by 1.3%. More body fat was deposited centrally in patients receiving insulin alone than those receiving insulin with an oral hypoglycaemic agent (metformin). Daily insulin dose, HbA(1)c and hip circumference were independent predictors of BWt gain.

CONCLUSIONS

Insulin treatment increased fat and FFM similarly in poorly controlled type 2 diabetes patients, with the FFM gain due entirely to TBW. The possible role of metformin in reducing central fat accumulation following insulin treatment warrants further investigation into its mechanism and potential long-term benefits.

Effect of insulin treatment on the body composition of Type 2 diabetic patients

OBJECTIVE

Insulin is used commonly in Type 2 diabetes and is often accompanied by weight gain. The composition of this weight gain is poorly understood. Predominant increases in fat mass could increase cardiovascular risks. The aim of the study was to evaluate insulin-induced body composition changes.

RESEARCH DESIGN AND METHODS

Body weight and composition of 35 Type 2 diabetic patients during their first 6 months of insulin therapy was compared with those in 34 Type 2 diabetic individuals treated with insulin for at least 1 year prior to commencing the study. Body composition was determined by the simultaneous measurement of body water spaces and body density.

RESULTS

Over 6 months, glycaemic control improved in the new treatment group only (HbA(1c): 7.26 +/- 0.81 vs. 9.66 +/- 1.60%; P < 0.0001), remaining stable in the previously treated group (7.67 +/- 1.25 vs. 7.76 +/- 1.26%; P = NS). Weight significantly increased over time in the newly treated group (+1.7 kg; P = 0.04), but not in the previously treated group (-0.3 kg). It comprised of both fat (+0.85 kg) and fat-free mass (+0.55 kg). Total body water remained unchanged. Using bioelectrical impedance analysis, the gain in fat mass was +2.2 kg; P = 0.048.

CONCLUSIONS

Over 6 months, insulin therapy leads to a weight gain of 1.7 kg because of an increase in both fat and fat-free mass. When body composition is determined by bioelectrical impedance analysis, the results are biased by fluctuations in hydration.

Insulin monotherapy versus combinations of insulin with oral hypoglycaemic agents in patients with type 2 diabetes mellitus

BACKGROUND

It is unclear whether patients with type 2 diabetes who have poor glycaemic control despite maximal oral hypoglycaemic agents (OHAs) should be commenced on insulin as monotherapy, or insulin combined with oral hypoglycaemic agents (insulin-OHA combination therapy).

OBJECTIVES

To assess the effects of insulin monotherapy versus insulin-OHA combinations therapy.

SEARCH STRATEGY

Eligible studies were identified by searching MEDLINE, EMBASE, and The Cochrane Library. Date of last search: May 2004.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with 2 months minimum follow-up duration comparing insulin monotherapy (all schemes) with insulin-OHA combination therapy.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of study quality were undertaken by three reviewers in pairs.

MAIN RESULTS

Twenty RCTs (mean trial duration 10 months) including 1,811 participants, with mean age 59.8 years and mean known duration of diabetes 9.6 years. Overall, study methodological quality was low. Twenty-eight comparisons in 20 RCTs were ordered according to clinical considerations. No studies assessed diabetes-related morbidity, mortality or total mortality. From 13 studies (21 comparisons), sufficient data were extracted to calculate pooled effects on glycaemic control. Insulin-OHA combination therapy had statistically significant benefits on glycaemic control over insulin monotherapy only when the latter was applied as a once-daily injection of NPH insulin. Conversely, twice-daily insulin monotherapy (NPH or mixed insulin) provided superior glycaemic control to insulin-OHA combination therapy regimens where insulin was administered as a single morning injection. In more conventional comparisons, regimens utilising OHAs with bedtime NPH insulin provided comparable glycaemic control to insulin monotherapy (administered as twice daily, or multiple daily injections). Overall, insulin-OHA combination therapy was associated with a 43% relative reduction in total daily insulin requirement compared to insulin monotherapy. Of the 14 studies (22 comparisons) reporting hypoglycaemia, 13 demonstrated no significant difference in the frequency of symptomatic or biochemical hypoglycaemia between insulin and combination therapy regimens. No significant differences in quality of life related issues were detected. Combination therapy with bedtime NPH insulin resulted in statistically significantly less weight gain compared to insulin monotherapy, provided metformin was used +/-sulphonylurea. In all other comparisons no significant differences with respect to weight gain were detected.

REVIEWERS' CONCLUSIONS

Bedtime NPH insulin combined with oral hypoglycaemic agents provides comparable glycaemic control to insulin monotherapy and is associated with less weight gain if metformin is used.

The effect of metformin on blood pressure, plasma cholesterol and triglycerides in type 2 diabetes mellitus: a systematic review

BACKGROUND

The UKPDS 34 showed that intensive treatment with metformin significantly reduces macrovascular end-points and mortality in individuals with newly diagnosed type 2 diabetes compared with intensive treatment with insulin or sulphonylurea derivatives, despite similar glycaemic control. How this should be explained is as yet unclear. We hypothesized that metformin may have a glucose-lowering independent effect on blood pressure and lipid profile. In order to test this hypothesis we systematically reviewed the literature and pooled the data obtained in a meta-analysis.

METHODS

Included were randomized-controlled trials in patients with type 2 diabetes mellitus and metformin treatment lasting at least 6 weeks. To identify all eligible trials we conducted electronic searches using the bibliographic databases Medline and Embase, contacted the manufacturer and checked obtained publications for cross-references.

RESULTS

Forty-one studies (3074 patients) provided data on blood pressure and/or lipid profile. When compared with control treatment, metformin associated effects on systolic and diastolic blood pressure and HDL cholesterol were small and statistically not significant [-1.09 mmHg 95% confidence interval (-3.01-0.82), P = 0.30; -0.97 (-2.15-0.21) mmHg, P = 0.11 and +0.01 (-0.02-0.03) mmol L(-1), P = 0.50, respectively]. Compared with control treatment, however, metformin decreased plasma triglycerides, total cholesterol and LDL cholesterol significantly [-0.13 (-0.21--0.04) mmol L(-1), P = 0.003; -0.26 (-0.34--0.18) mmol L(-1), P < 0.0001 and -0.22 (-0.31--0.13) mmol L(-1), P < 0.00001, respectively]. We found no indications for publication bias. Of note, glycaemic control as assessed by HbA1c was better with metformin than with control treatment [-0.74 (-0.84--0.65) percentage point; P < 0.00001]. When studies were subdivided into tertiles according to increasing difference in glycaemic control between metformin and control treatment, it appeared that in case of near similar glycaemic control metformin had no effect versus control treatment on triglycerides, whereas still there was a significant effect on total and LDL cholesterol.

CONCLUSIONS

This meta-analysis of randomized-controlled clinical trials suggests that metformin has no intrinsic effect on blood pressure, HDL cholesterol and triglycerides in patients with type 2 diabetes. This drug, however, independent of its effect on glycaemia, reduces total and LDL cholesterol significantly, but the reductions in these variables are relatively small.

Prevention of weight gain in type 2 diabetes requiring insulin treatment

BACKGROUND

Patients with type 2 diabetes who are failing on oral agents will generally gain a large amount of body fat when switched to insulin treatment. This adverse effect may be related to chronic hyperinsulinism induced by long-acting insulin compounds.

AIM

To test the concept that regain of glycaemic control can be achieved without causing weight gain, using a regimen free of long-acting insulin.

METHODS

In a 3-month open-label pilot study including 25 patients with moderate overweight and secondary failure, we investigated whether nocturnal glycaemic control could be achieved with glimepiride administered at 20:00 hours. The starting dose was 1-2 mg, with subsequent titration up to a maximum of 6 mg. Rapid-acting insulin analogues were used three times daily to regain postprandial glucose control.

RESULTS

Glycaemic control at 3 months was established with glimepiride in a dose of 4.4 +/- 0.3 mg/day (mean +/- standard error of the mean), and a total daily insulin dose of 24.1 +/- 2.6 IU. Fasting glucose levels decreased from 12.7 +/- 0.6 mmol/l to 8.1 +/- 0.3 mmol/l (p < 0.001), and target levels were reached in 14 of 25 patients (56%). Mean HbA1c decreased from 10.5 +/- 0.4 to 7.7 +/- 0.2% (p < 0.001). Symptomatic nocturnal hypoglycaemia was not reported. Body weight did not change (85.7 +/- 3.6 kg vs. 85.7 +/- 3.3 kg, p = 0.99).

CONCLUSION

The data suggest that this new approach may be useful in about 50% of type 2 diabetes patients presenting with failure on maximal oral treatment.

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.

Comparison of insulin monotherapy and combination therapy with insulin and metformin or insulin and troglitazone in type 2 diabetes

OBJECTIVE

To evaluate the safety and efficacy of treatment with insulin alone, insulin plus metformin, or insulin plus troglitazone in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 88 type 2 diabetic subjects using insulin monotherapy (baseline HbA(lc) 8.7%) were randomly assigned to insulin alone (n = 31), insulin plus metformin (n = 27), or insulin plus troglitazone (n = 30) for 4 months. The insulin dose was increased only in the insulin group. Metformin was titrated to a maximum dose of 2,000 mg and troglitazone to 600 mg.

RESULTS

HbA(lc) levels decreased in all groups, the lowest level occurring in the insulin plus troglitazone group (insulin alone to 7.0%, insulin plus metformin to 7.1%, and insulin plus troglitazone to 6.4%, P < 0.0001). The dose of insulin increased by 55 units/day in the insulin alone group (P < 0.0001) and decreased by 1.4 units/day in the insulin plus metformin group and 12.8 units/day in the insulin plus troglitazone group (insulin plus metformin versus insulin plus troglitazone, P = 0.004). Body weight increased by 0.5 kg in the insulin plus metformin group, whereas the other two groups gained 4.4 kg (P < 0.0001 vs. baseline). Triglyceride and VLDL triglyceride levels significantly improved only in the insulin plus troglitazone group. Subjects taking metformin experienced significantly more gastrointestinal side effects and less hypoglycemia.

CONCLUSIONS

Aggressive insulin therapy significantly improved glycemic control in type 2 diabetic subjects to levels comparable with those achieved by adding metformin to insulin therapy. Troglitazone was the most effective in lowering HbA(lc), total daily insulin dose, and triglyceride levels. However, treatment with insulin plus metformin was advantageous in avoiding weight gain and hypoglycemia.

Insulin therapy in type 2 diabetes

OBJECTIVE

To review the increasingly common use of insulin therapy in patients with type 2 diabetes and the practical aspects of initiating insulin therapy in these patients.

DATA SOURCES

Recent scientific and clinical literature identified through MEDLINE searches for the years 1995-2001 using the terms oral agents, type 2 diabetes, insulin therapy, glycemic control and diabetic complications, glucose toxicity, insulin lispro, insulin aspart, and insulin glargine. STUDY SECTION: Reports of key large (1,000 patients or more) and significant smaller, randomized, controlled clinical trials were reviewed. For studies comparing insulin analogs, the authors reviewed a sampling of the identified trials for their characteristics and clinical importance.

DATA SYNTHESIS

Tight blood glucose control can help reduce the risk of diabetes complications. Evidence suggests that early insulin therapy can help correct the underlying pathogenetic abnormalities in type 2 diabetes and improve long-term glycemic control. For these reasons, some diabetes experts advocate the initiation of insulin therapy earlier in the course of type 2 diabetes than has been common in the past. Insulin regimens should be designed to mimic the body's natural physiologic secretion of insulin, including the basal amounts released continuously by the pancreas and the insulin surges produced in response to glucose loads. Using new insulin analogs is a useful approach to achieving this ideal. Insulin glargine provides a nearly constant, peakless release of insulin when injected subcutaneously once daily. Two new rapid-acting insulin analogs, insulin lispro (Humalog--Lilly) and insulin aspart (NovoLog--Novo Nordisk), enhance patients' flexibility in terms of meals by permitting injection immediately before meals, rather than 30 minutes before meals, as with regular insulin.

CONCLUSION

Patients should be reassured that early initiation of insulin therapy is a positive event that should improve their long-term health and does not represent a decline in the course of their disease.

Treatment with metformin of non-diabetic men with hypertension, hypertriglyceridaemia and central fat distribution: the BIGPRO 1.2 trial

BACKGROUND

In the BIGPRO 1 trial, one year of treatment with metformin in non-diabetic obese subjects with a central fat distribution had no significant effect on fasting plasma triglyceride concentration or on blood pressure despite a decrease in weight, fasting plasma insulin and glucose concentrations. To re-evaluate the effect of metformin on fasting triglyceride concentration and on blood pressure, the BIGPRO 1.2 trial included non-diabetic men (n=168) with a fasting plasma triglyceride concentration > or =1.7 and < or =6.5 mmol/l, high blood pressure (systolic > or =140 and < or =180 and/or diastolic > or =90 and < or =105 mmHg, or treatment for hypertension) and a waist-to-hip ratio > or =0.95.

METHODS

A randomised double-blind trial comparing metformin treatment (850 mg bid) with placebo.

RESULTS

Metformin had no significant effect either on blood pressure or plasma triglyceride concentration. In comparison with the placebo group, fasting plasma insulin (p<0.04), total cholesterol (p<0.05) and Apo B (p<0.008) concentrations decreased more in the metformin group in the BIGPRO 1. 2 trial, confirming most of the previous results of the BIGPRO 1 trial. Tissue plasminogen activator antigen concentration decreased significantly (p<0.01) only in the metformin group, but this was not significantly different from the placebo group (p<0.12); further, there were no significant differences in the change in plasminogen activator inhibitor 1.

CONCLUSIONS

The consistency of the two BIGPRO trials supports the conclusion that metformin affects several cardiovascular risk factors favourably in non-diabetic subjects with a central fat distribution.

The role of sulphonylurea in combination therapy assessed in a trial of sulphonylurea withdrawal. Scandinavian Insulin-Sulphonylurea Study Group Research Team

AIMS

To evaluate the effect of adding insulin to sulphonylurea (SU) and the effect of SU withdrawal on glycaemic control in Type 2 diabetic patients who failed on treatment with SU alone.

METHOD

One hundred and seventy-five patients were included in a placebo-controlled multicentre study. During phase I (4 months), premixed insulin was added to glibenclamide therapy; during phase II (1-4 months, depending on response) the insulin dose was fixed, while placebo or glibenclamide replaced the open SU therapy. Insulin sensitivity (KITT), beta-cell function (C-peptide) and metabolic control (HbA1c) were monitored.

RESULTS

HbA1c improved from 9.65% to 7.23% (P < 0.0001) during phase I. A high HbA1c value (P < 0.0001) and a high KITT-value (P = 0.045) at baseline were associated with a beneficial response to combination treatment. During phase II, glycaemic control was unchanged in the control (glibenclamide) group. In the placebo group, after SU withdrawal, fasting blood glucose (FBG) increased by 10% or more within 4 weeks in 79% of the patients. Patients (67 of 112) with an FBG increase > or =40% during phase II were defined as 'SU responders' by protocol. In a multivariate analysis only a long duration of diabetes was associated with SU response. There were more GAD-antibody-positive patients among non-responders (18% vs. 4%, P = 0.0263).

CONCLUSIONS

Poor glycaemic control in combination with preserved insulin sensitivity and lack of GAD antibodies predicts a beneficial response to combination therapy, which can be achieved in 75% of patients with SU failure.

Pharmacologic therapy for type 2 diabetes mellitus

Type 2 diabetes mellitus is a chronic metabolic disorder that results from defects in both insulin secretion and insulin action. An elevated rate of basal hepatic glucose production in the presence of hyperinsulinemia is the primary cause of fasting hyperglycemia; after a meal, impaired suppression of hepatic glucose production by insulin and decreased insulin-mediated glucose uptake by muscle contribute almost equally to postprandial hyperglycemia. In the United States, five classes of oral agents, each of which works through a different mechanism of action, are currently available to improve glycemic control in patients with type 2 diabetes. The recently completed United Kingdom Prospective Diabetes Study (UKPDS) has shown that type 2 diabetes mellitus is a progressive disorder that can be treated initially with oral agent monotherapy but will eventually require the addition of other oral agents, and that in many patients, insulin therapy will be needed to achieve targeted glycemic levels. In the UKPDS, improved glycemic control, irrespective of the agent used (sulfonylureas, metformin, or insulin), decreased the incidence of microvascular complications (retinopathy, neuropathy, and nephropathy). This review examines the goals of antihyperglycemic therapy and reviews the mechanism of action, efficacy, nonglycemic benefits, cost, and safety profile of each of the five approved classes of oral agents. A rationale for the use of these oral agents as monotherapy, in combination with each other, and in combination with insulin is provided.

A risk-benefit assessment of metformin in type 2 diabetes mellitus

Metformin has been used for over 40 years as an effective glucose-lowering agent in type 2 (noninsulin-dependent) diabetes mellitus. Typically it reduces basal and postprandial hyperglycaemia by about 25% in more than 90% of patients when either given alone or coadministered with other therapies including insulin during a programme of managed care. Metformin counters insulin resistance and offers benefits against many features of the insulin resistance syndrome (Syndrome X) by preventing bodyweight gain, reducing hyperinsulinaemia and improving the lipid profile. In contrast to sulphonylureas, metformin does not increase insulin secretion or cause serious hypoglycaemia. Treatment of type 2 diabetes mellitus with metformin from diagnosis also offers greater protection against the chronic vascular complications of type 2 diabetes mellitus. The most serious complication associated with metformin is lactic acidosis which has an incidence of about 0.03 cases per 1000 patients years of treatment and a mortality risk of about 0.015 per 1000 patient-years. Most cases occur in patients who are wrongly prescribed the drug, particularly patients with impaired renal function (e.g. serum creatinine level > 130 micromol/L or > 1.5 g/L). Other major contraindications include congestive heart failure, hypoxic states and advanced liver disease. Serious adverse events with metformin are predictable rather than spontaneous and are potentially preventable if the prescribing guidelines are respected. Gastrointestinal adverse effects, notably diarrhoea, occur in less than 20% of patients and remit when the dosage is reduced. The life-threatening risks associated with metformin are rare and could mostly be avoided by strict adherence to the prescribing guidelines. Given the 4 decades of clinical experience with metformin, its antihyperglycaemic efficacy and benefits against Syndrome X, metformin offers a very favourable risk-benefit assessment when compared with the chronic morbidity and premature mortality among patients with type 2 diabetes mellitus.

Insulin resistance: site of the primary defect or how the current and the emerging therapies work

Insulin resistance is one of the cardinal pathophysiological components of the metabolic syndrome, type 2 diabetes, and frequently co-exists with essential hypertension. Although insulin resistance is defined as inadequate target organ (muscle, liver and fat) responsiveness and/or sensitivity to insulin, the primary defect may be located in the target organs themselves or at their remote controller--the central nervous system. One of the ways of resolving this dilemma is studying the mechanisms of action of drugs that have insulin-sensitizing properties. In this brief review we discuss how the known and potential insulin sensitizers: metformin, appetite suppressants, thiazolidinediones, and the new class of centrally acting antihypertensive drugs, I1-receptor agonists, may work.

Preperitoneal fat deposition estimated by ultrasonography in patients with non-insulin-dependent diabetes mellitus

Preperitoneal fat is an indicator of visceral fat deposition, which is closely related to atherosclerosis and coronary heart disease in obese patients. We assessed the relationship of preperitoneal fat deposition and various clinical characteristics in 90 patients with non-insulin-dependent diabetes mellitus (NIDDM). Preperitoneal and subcutaneous fat deposition were measured by ultrasonography. In both the male and female diabetics, preperitoneal fat levels were significantly higher than in age-matched healthy subjects. We also determined blood pressures, fasting plasma glucose, glycosylated hemoglobin A1c, serum lipids, fasting immunoreactive insulin (FIRI), daily urinary C-peptide (CPR), serum leptin, urinary albumin excretion and body mass index (BMI). Of these parameters, BMI, FIRI, leptin and daily urinary CPR were positively correlated with preperitoneal fat deposition. Patients with diet therapy alone showed significantly higher preperitoneal fat levels than those receiving insulin therapy. In female, patients with increased preperitoneal fat showed higher prevalence of hypertension than those with decreased fat. Macroalbuminuric patients had a lower preperitoneal fat than microalbuminuric and normoalbuminuric patients. Patients with proliferative retinopathy exhibited lower preperitoneal fat than did those without retinopathy. Preperitoneal fat levels were positively correlated with motor or sensory nerve conduction velocity.

CONCLUSION

The present findings suggest that in NIDDM patients, increased preperitoneal fat deposition is closely associated with obesity, hypertension and hyperinsulinemia, and negatively modulates diabetic microangiopathy including nephropathy, retinopathy and neuropathy.

Meformin, plasma glucose and free fatty acids in type II diabetic out-patients: results of a clinical study

Abnormalities in free fatty acid (FFA) metabolism are an intrinsic feature of type II diabetes mellitus and may even play a role in the development of glycaemic imbalance. This study investigated whether the anti-diabetic drug metformin can reduce FFA levels in clinical practice and whether this correlates with its anti-diabetic effect. For 6 months metformin was added to sulfonylurea therapy in 68 type II diabetic outpatients with poor glycaemic control, being administered before meals and at bed-time. Basal and daily area-under-the-curve (AUC) glucose levels dropped (both P < 0.0005) like basal and daily AUC FFA levels (P < 0.004 and P < 0.001 respectively) reductions were all correlated (P < 0.001 and P < 0.003 respectively). Reductions in fasting and daily AUC glucose correlated more closely with body fat distribution, expressed by waist-hip ratio (WHR) (P < 0.006 and P < 0.004 respectively), than with the body mass index (BMI) (P < 0.02 and P < 0.04 respectively). Similarly fasting and daily AUC FFA correlated with WHR (P < 0.007 and P < 0.01 respectively) but not with BMI (both P = ns). Subdividing male and female diabetic patients into groups with low and high WHRs, fasting and daily AUC glucose were reduced in men (P < 0.01 and P < 0.02) and in women (P < 0.02 and P < 0.04 respectively) with low WHRs less than in men and in women with higher WHRs (for each gender P < 0.0001 and P < 0.0002, respectively). Decreases in fasting and daily AUC FFA, which did not reach significance in either men or women with low WHRs, were statistically significant in men (P < 0.03 and P < 0.01 respectively) and in women (P < 0.02 and P < 0.005 respectively) with high WHRs. These findings suggest that an improvement in FFA plasma levels might contribute to metformin's anti-diabetic activity which appears to be more marked in patients with high WHRs. Moreover adding a bed-time dosage to the standard administration at meal times seems to be an effective therapeutical strategy.

Bodyweight change as an adverse effect of drug treatment. Mechanisms and management

A number of drugs are capable of changing bodyweight as an adverse effect of their therapeutic action. Bodyweight gain is more of a problem than bodyweight loss. As bodyweight gain during drug treatment for any kind of disease may be the reflection of improvement of the disease itself, we will try to separate these effects from those due to drug-induced alterations of the mechanisms regulating bodyweight. Bodyweight gain may jeopardise patient compliance to the prescribed regimen and it may pose health risks. The body mass index (BMI) is determined by dividing bodyweight in kilograms by height in metres squared. A BMI of > or = 27 kg/m2 warrants therapeutic action; nutritional counselling and programmed physical exercise can be used as a basis. In general, if basic therapeutic measures are unsuccessful at controlling bodyweight gain then a change of drug might help. Finally, an anoretic drug may serve to support dietary measures. However, safety and efficacy has been demonstrated for only a few anorectic drugs when used as an adjunct to caloric restriction in the treatment of drug-induced obesity. Bodyweight is determined by complex mechanisms regulating energy balance. A number of neurotransmitter systems acting in several hypothalamic nuclei are pivotal to the regulation of body fat stores. Most drugs that are capable of changing bodyweight interfere with these neurotransmitter systems. The increment is dependent on the type and dose of the drug concerned. Some antidepressant drugs induce bodyweight gain, which may amount to 20 kg over several months of treatment. Monoamine oxidase inhibitors appear to cause less bodyweight change than tricyclic antidepressants. Selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors cause bodyweight loss instead of bodyweight gain. Lithium may cause large increases in bodyweight. Generally speaking, the bodyweight change induced by antipsychotics is more often of clinical significance than the bodyweight change associated with the use of antidepressants. Again, the changes of bodyweight are dependent upon the type and dose of the antipsychotic drug involved. Although almost all antipsychotics induce bodyweight gain, molindone and loxapine appear to induce bodyweight loss. Anticonvulsants, especially valproic acid (sodium valproate) and carbamazepine, induce bodyweight gain in a considerable percentage of patients. Treatment with corticosteroids is associated with dose-dependent bodyweight gain in many patients. Corticosteroid-induced obesity aggravates other corticosteroid-associated health risks. Insulin therapy in diabetic patients usually increases bodyweight. Finally, sulphonurea derivatives, antineoplastic agents used for the treatment of breast cancer and several drugs used in migraine prophylaxis may cause bodyweight gain as well.

Metformin: Actions and Indications for Use in Non-Insulin-Dependent Diabetes Mellitus

Metformin (N,N-dimethylbiguanide) is about to be introduced into the United States. The drug, a potent blood glucose-lowering agent, is rapidly absorbed through the small intestine, has a circulating t 1/2 in plasma of 1.7 to 2.5 hours, and is 90% cleared through the kidneys in 12 hours. The drug does not cause hypoglycemia in nondiabetic patients and is effective in both obese and nonobese patients with non-insulin-dependent diabetes mellitus (NIDDM). The drug does not act through stimulation of endogenous insulin secretion. It seems to act at multiple sites, with a small effect on the inhibition of intestinal glucose transport, a moderate effect on inhibition of hepatic glucose output, and a major effect on enhancement of peripheral glucose uptake by muscle and adipose tissues. In addition to its glucose-lowering potency, metformin causes weight loss in obese patients with NIDDM and lowers total cholesterol, very-low-density lipoprotein cholesterol, total triglycerides, and very-low-density lipoprotein triglyceride levels as well as causing an increase in high-density lipoprotein cholesterol level. The drug is ideally suited for obese patients with NIDDM who are unresponsive to diet alone, and it is effective in combination with sulfonylureas. The major risk associated with use of metformin is the development of lactic acidosis. Patients predisposed toward the development of lactic acidosis are those with hepatic or renal disease or with tissue ischemia, in whom the drug should not be prescribed.

Energy expenditure in type 2 diabetic patients on metformin and sulphonylurea therapy

Insulin and sulphonylurea therapies have both been reported to cause weight gain in Type 2 diabetic patients whereas metformin does not have this adverse effect. The mechanism for this difference is unclear. We have investigated in a cross-over study the effect of sulphonylurea and metformin therapy on energy expenditure and body composition in 10 Type 2 diabetic patients (7 females, 3 males) of various weights (mean body mass index 33.4 (SD 7.6 kg m-2)). Free living total energy expenditure was measured over 14 days by the doubly labelled water method adjusted for urinary glucose energy losses and resting energy expenditure by ventilated hood indirect calorimetry. Overall, total energy expenditure (12.88 +/- 4.17 vs 13.1 +/- 3.69 MJ 24 h-1) and resting metabolic rate (7.30 +/- 1.75 vs 7.23 +/- 1.74 MJ 24 h-1) were similar on metformin and sulphonylurea therapy, respectively. When adjusted for differences in fat free mass, resting metabolic rate on sulphonylurea therapy was slightly but significantly lower (mean difference -5.5 kJ 24 h-1 kg-1, 95% CI -1.2, -9.9 kJ 24 h-1 kg-1, p < 0.05). Fat free mass also increased significantly by 1.3 kg (95% CI 0.4, 2.4 kg, p < 0.05) when on sulphonylurea therapy, thus compensating for the lower resting metabolic rate per kg fat free mass to leave overall resting metabolic rate unchanged compared to metformin therapy. We also investigated the effect of adding metformin to six Type 2 diabetic patients already on insulin. This did not lead to any measurable changes in any of the components of energy expenditure.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihyperglycaemic efficacy, response prediction and dose-response relations of treatment with metformin and sulphonylurea, alone and in primary combination

The short-term (2-12 weeks) antihyperglycaemic efficacy of metformin (M), glibenclamide (G), and their primary combination (MG) was assessed in a double-blind study including 165 unselected patients with Type 2 diabetes. Patients with diet failure were randomized to M, G or MG. The dose was titrated with a fasting blood glucose concentration (FBG) of < 6.7 mmol l-1 as the target, using at most six dose levels, the first three comprising increasing monotherapy (M or G) or low-dose primary combination (MGL), and the second three add-on therapies (M/G and G/M) and primary combination therapy escalated to high dose (MGH). Success rates were higher on MGL than on monotherapy. The difference in achieving acceptable control (FBG < or = 7.8 mmol 1(-1)) was 70% versus 51% (95% confidence interval 3-36%, p = 0.032). When the drugs were combined, a slightly greater FBG reduction (p = 0.026) was observed, at lower dosage (p = 0.013). The response could not be predicted from body weight, but depended upon initial FBG (p = 0.019) and meal-stimulated C-peptide (p = 0.007). FBG declined progressively with increasing doses of metformin, whereas glibenclamide exerted most of its effect at low dose. Primary combination therapy with metformin and sulphonylurea may be clinically useful.