Adding metformin versus insulin dose increase in insulin-treated but poorly controlled Type 2 diabetes mellitus: an open-label randomized trial

The effect of Madhumeha Kusumakar Rasa - an Ayurved medicine - in insulin resistance

OBJECTIVES

Madhumeha Kusumakar Rasa (MKR) is an Ayurved formulation having a strong pharmacological base for diabetes management. This study aimed to validate MKR's efficacy in dexamethasone-induced insulin resistance (IR).

METHODS

Albino Wistar rats were divided into four groups. Group 1 served as the normal control, Group 2 received dexamethasone 1.5 mg/kg (i.p.), Group 3 received dexamethasone and metformin 200 mg/kg (p.o.), and Group 4 received dexamethasone and MKR 236 mg/kg (p.o.). Animals were evaluated for serum glucose levels and glucose tolerance, serum insulin, Homeostatic model assessment of insulin resistance (HOMA-IR), Homeostatic model assessment of insulin sensitivity (HOMA-IS), fasting glucose to insulin ratio (FGIR), and lipid parameters. Pancreas, liver, and kidneys were evaluated for reduced Glutathione (GSH) and Malondialdehyde (MDA) levels. These tissues were also evaluated for histopathological changes.

RESULTS

MKR showed significant improvement in serum glucose and glucose tolerance, serum insulin and HOMA-IR, HOMA-IS, and FGIR. It also showed a significant improvement in lipid parameters as compared to the dexamethasone-treated group. It prevented depletion of GSH levels and elevation in MDA levels. These effects were supported by histopathological analysis.

CONCLUSIONS

MKR treatment significantly attenuated dexamethasone-induced IR. This study validates the mechanism of the anti-diabetic potential of MKR.

Changes in metformin use and other antihyperglycemic therapies after insulin initiation in patients with type 2 diabetes

AIMS

When patients with type 2 diabetes initiate insulin, metformin should be continued while continuation of other antihyperglycemics has unclear benefit. We aimed to identify practice patterns in antihyperglycemic therapy during the insulin transition, and determine factors associated with metformin continuation.

METHODS

We performed a retrospective analysis of the Look AHEAD (Action for Health in Diabetes) trial which randomized overweight/obese adults under ambulatory care for type 2 diabetes to an intensive lifestyle intervention or diabetes support and education. Among the 931 participants who initiated insulin over ten years, we described longitudinal changes in antihyperglycemic medications during the insulin transition, and performed multivariable logistic regression to estimate the association between patient characteristics and metformin continuation.

RESULTS

Before insulin initiation, 81.0% of patients used multiple antihyperglycemics, the most common being metformin, sulfonylureas, and thiazolidinediones. After insulin initiation, metformin was continued in 80.3% of patients; other antihyperglycemics were continued less often, yet 58.0% of patients were treated with multiple non-insulin antihyperglycemics. Metformin continuation was inversely associated with age (fully adjusted (a) OR 0.60 per 10 years [0.42-0.86]), serum creatinine above safety thresholds (aOR 0.09 [0.02-0.36]), lower income (P = 0.025 for trend), taking more medications (aOR 0.92 per medication [0.86-0.98]), and initiating rapid, short, or premixed insulin (aOR 0.59 [0.39-0.89]).

CONCLUSIONS

The vast majority of patients with type 2 diabetes continue metformin after insulin initiation, consistent with guidelines. Other antihyperglycemics are frequently continued along with insulin, and further research is needed to determine which, if any, patients may benefit from this.

Insulin Monotherapy Versus Insulin Combined with Other Glucose-Lowering Agents in Type 2 Diabetes: A Narrative Review

CONTEXT

Insulin can be prescribed as a monotherapy or a combined therapy with other anti-diabetic medications. In this narrative review, the authors aimed to gather data related to comparison of insulin monotherapy versus combination of insulin and other anti-diabetic treatments with regards to different outcome measures in type 2 diabetes.

EVIDENCE ACQUISITION

This study searched and focused on the most recently published systematic reviews and their references investigating issues related to the primary aim.

RESULTS

The current data available on this topic is heterogeneous and suffers from low quality with respect to most combination treatments. Considering the efficacy and safety of combination therapy of insulin with older hypoglycemic agents, in general metformin and pioglitazone have the best and worst profiles, respectively. Compared to insulin monotherapy, combination of insulin and metformin is associated with better glycemic control, reduced daily insulin dose, less hypoglycemia, and weight gain; combination of insulin and pioglitazone results in greater hypoglycemia and weight gain and is associated with increased risk of edema and heart failure. Regarding sulphonylurea, there is some concern regarding hypoglycemia and weight gain. Addition of dipeptidyl peptidase-4 inhibitors to insulin seems to be beneficial with respect to glycemic control without any significant adverse effects. New drugs, including glucagon-like peptide-1 agonists and sodium glucose co-transporter 2 inhibitors, have acceptable profiles with significant benefits regarding weight reduction when added on insulin therapy.

CONCLUSIONS

Considering the quality and longevity of evidence, compared to insulin monotherapy, insulin combined with metformin and pioglitazone has the best and worst profiles, respectively. New anti-diabetic medications have acceptable profiles yet are expensive. It is important for clinicians to meticulously weigh the advantages of combination therapy against the possible adverse effects with each drug class in every patient, individually.

Insulin monotherapy compared with the addition of oral glucose-lowering agents to insulin for people with type 2 diabetes already on insulin therapy and inadequate glycaemic control

BACKGROUND

It is unclear whether people with type 2 diabetes mellitus on insulin monotherapy who do not achieve adequate glycaemic control should continue insulin as monotherapy or can benefit from adding oral glucose-lowering agents to the insulin therapy.

OBJECTIVES

To assess the effects of insulin monotherapy compared with the addition of oral glucose-lowering agents to insulin monotherapy for people with type 2 diabetes already on insulin therapy and inadequate glycaemic control.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and reference lists of articles. The date of the last search was November 2015 for all databases.

SELECTION CRITERIA

Randomised controlled clinical trials of at least two months' duration comparing insulin monotherapy with combinations of insulin with one or more oral glucose-lowering agent in people with type 2 diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias, extracted data and evaluated overall quality of the evidence using GRADE. We summarised data statistically if they were available, sufficiently similar and of sufficient quality. We performed statistical analyses according to the statistical guidelines in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 37 trials with 40 treatment comparisons involving 3227 participants. The duration of the interventions ranged from 2 to 12 months for parallel trials and two to four months for cross-over trials.The majority of trials had an unclear risk of bias in several risk of bias domains. Fourteen trials showed a high risk of bias, mainly for performance and detection bias. Insulin monotherapy, including once-daily long-acting, once-daily intermediate-acting, twice-daily premixed insulin, and basal-bolus regimens (multiple injections), was compared to insulin in combination with sulphonylureas (17 comparisons: glibenclamide = 11, glipizide = 2, tolazamide = 2, gliclazide = 1, glimepiride = 1), metformin (11 comparisons), pioglitazone (four comparisons), alpha-glucosidase inhibitors (four comparisons: acarbose = 3, miglitol = 1), dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) (three comparisons: vildagliptin = 1, sitagliptin = 1, saxagliptin = 1) and the combination of metformin and glimepiride (one comparison). No trials assessed all-cause mortality, diabetes-related morbidity or health-related quality of life. Only one trial assessed patients' treatment satisfaction and showed no substantial differences between the addition of either glimepiride or metformin and glimepiride to insulin compared with insulin monotherapy.Insulin-sulphonylurea combination therapy (CT) compared with insulin monotherapy (IM) showed a MD in glycosylated haemoglobin A1c (HbA1c) of -1% (95% confidence interval (CI) -1.6 to -0.5); P < 0.01; 316 participants; 9 trials; low-quality evidence. Insulin-metformin CT compared with IM showed a MD in HbA1c of -0.9% (95% CI -1.2 to -0.5); P < 0.01; 698 participants; 9 trials; low-quality evidence. We could not pool the results of adding pioglitazone to insulin. Insulin combined with alpha-glucosidase inhibitors compared with IM showed a MD in HbA1c of -0.4% (95% CI -0.5 to -0.2); P < 0.01; 448 participants; 3 trials; low-quality evidence). Insulin combined with DPP-4 inhibitors compared with IM showed a MD in HbA1c of -0.4% (95% CI -0.5 to -0.4); P < 0.01; 265 participants; 2 trials; low quality evidence. In most trials the participants with CT needed less insulin, whereas insulin requirements increased or remained stable in participants with IM.We did not perform a meta-analysis for hypoglycaemic events because the included studies used different definitions.. In most trials the insulin-sulphonylurea combination resulted in a higher number of mild episodes of hypoglycaemia, compared to the IM group (range: 2.2 to 6.1 episodes per participant in CT versus 2.0 to 2.6 episodes per participant in IM; low-quality evidence). Pioglitazone CT also resulted in more mild to moderate hypoglycaemic episodes compared with IM (range 15 to 90 episodes versus 9 to 75 episodes, respectively; low-quality evidence. The trials that reported hypoglycaemic episodes in the other combinations found comparable numbers of mild to moderate hypoglycaemic events (low-quality evidence).The addition of sulphonylureas resulted in an additional weight gain of 0.4 kg to 1.9 kg versus -0.8 kg to 2.1 kg in the IM group (220 participants; 7 trials; low-quality evidence). Pioglitazone CT caused more weight gain compared to IM: MD 3.8 kg (95% CI 3.0 to 4.6); P < 0.01; 288 participants; 2 trials; low-quality evidence. Metformin CT was associated with weight loss: MD -2.1 kg (95% CI -3.2 to -1.1), P < 0.01; 615 participants; 7 trials; low-quality evidence). DPP-4 inhibitors CT showed weight gain of -0.7 to 1.3 kg versus 0.6 to 1.1 kg in the IM group (362 participants; 2 trials; low-quality evidence). Alpha-glucosidase CT compared to IM showed a MD of -0.5 kg (95% CI -1.2 to 0.3); P = 0.26; 241 participants; 2 trials; low-quality evidence.Users of metformin CT (range 7% to 67% versus 5% to 16%), and alpha-glucosidase inhibitors CT (14% to 75% versus 4% to 35%) experienced more gastro-intestinal adverse effects compared to participants on IM. Two trials reported a higher frequency of oedema with the use of pioglitazone CT (range: 16% to 18% versus 4% to 7% IM).

AUTHORS' CONCLUSIONS

The addition of all oral glucose-lowering agents in people with type 2 diabetes and inadequate glycaemic control who are on insulin therapy has positive effects on glycaemic control and insulin requirements. The addition of sulphonylureas results in more hypoglycaemic events. Additional weight gain can only be avoided by adding metformin to insulin. Other well-known adverse effects of oral glucose-lowering agents have to be taken into account when prescribing oral glucose-lowering agents in addition to insulin therapy.

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.

Addressing insulin resistance in Type 1 diabetes

Type 1 diabetes is recognised to include an element of insulin resistance. Insulin resistance is an independent risk factor for the development of macro- and microvascular complications of Type 1 diabetes and may also contribute to the development of the disease. This understanding comes at a time when the incidence of Type 1 diabetes appears to be rising and the public health burden from its vascular complications is high. A variety of safe and efficacious manoeuvres are available to redress insulin resistance in Type 2 diabetes. So far however, clinical trials addressing insulin resistance in Type 1 diabetes have been small with only short periods of follow-up. Regardless, these trials have yielded promising results. This review examines the evidence for insulin resistance in the pathophysiology of Type 1 diabetes and its complications, the problems associated with its measurement, and summarizes the trials aimed at reducing insulin resistance in Type 1 diabetes. This includes a meta-analysis of controlled trials of adjuvant metformin in Type 1 diabetes.

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.

A comparison of mealtime insulin aspart and human insulin in combination with metformin in type 2 diabetes patients

This randomized, open-label, cross-over study compares the efficacy of mealtime rapid-acting analog insulin aspart with human insulin, in combination with metformin. A total of 30 patients with type 2 diabetes, inadequately controlled (HbA(1c)>7.5%) with oral hypoglycemic agents (OHAs), were assigned to human insulin 30 min before meals or aspart immediately before meals, both with metformin 500 mg t.i.d. for 90 days. Patients then switched to the alternate insulin. At 90 and 180 days, blood glucose and lipids were measured at baseline and every 30 min after test meals, for 3h. HbA(1c) and hypoglycemic events were also assessed. After 3 months, HbA(1c) was significantly reduced with aspart, but not human insulin (-0.4+/-0.7% versus +0.1+/-0.7%, p<0.05). During meal tests, blood glucose area under the curve (AUC) was significantly lower with aspart than human insulin (1240+/-476 min/mmol/l versus 1588+/-766 min/mmol/l, p<0.01). AUCs for lipids were similar for both treatments. Neither group experienced serious hypoglycemic events. These results encourage treatment with mealtime insulin aspart plus metformin, in type 2 diabetes patients with postprandial hyperglycemia inadequately controlled by OHAs alone.

Metformin and body weight

Most patients with type 2 diabetes are overweight or obese, overweight or obesity increases the risk of developing type 2 diabetes and obesity per se is strongly associated with multiple cardiometabolic risk factors. However, many antidiabetic treatments increase body weight. The oral antidiabetic agent, metformin, has been evaluated in hundreds of clinical studies in diverse patient populations during approximately five decades of clinical use. This review summarizes the effects of metformin on body weight, with special reference to studies of longer duration (>/=6 months) as both diabetes and obesity are long-term conditions. Approximately half of studies in drug-naive type 2 diabetic patients demonstrated significant weight loss with metformin compared with baseline or comparator drugs, although pooled analyses have suggested no significant effect versus placebo. Similarly, metformin has been shown to induce weight loss in obese nondiabetic populations, although studies of long duration in this population are scarce. Metformin does appear to mitigate the adverse effects of insulin on body weight. The weight-neutral or weight-sparing effects of metformin constitute a therapeutic advantage in diabetes management where other first-line oral antidiabetic treatments often promote clinically significant weight gain.

A randomized controlled trial examining combinations of repaglinide, metformin and NPH insulin

AIMS

To compare combination use of repaglinide, metformin and bedtime Neutral Protamine Hagedorn (NPH) insulin with conventional approaches of insulin initiation in patients with Type 2 diabetes (T2DM).

METHODS

Eighty-two patients with T2DM with suboptimal glycaemic control on oral glucose-lowering agents were randomized to one of three treatment regimens for 4 months. Group 1 received metformin and twice daily biphasic 30/70 human insulin mixture (n = 27), group 2 metformin and bedtime NPH insulin (n = 26) and group 3 metformin, bedtime NPH insulin and mealtime repaglinide (n = 25).

RESULTS

Seventy-five patients completed the study. Baseline and end-point mean HbA1c levels fell from 9.0 +/- 1.1 to 7.9 +/- 1.1% in group 1, 10.0 +/- 2.2 to 9.2 +/- 1.4% group 2 and 10.0 +/- 1.7 to 8.1 +/- 1.5% in group 3, respectively. All groups showed improvements in HbA1c. There was no significant difference between groups in the proportions of patients experiencing hypoglycaemia (29.6, 25.0 and 16.7%, respectively; P = 0.55) or in mean weight gain (2.9, 0.7 and 2.2 kg, respectively; P = 0.06). By 4 months, insulin doses were 0.63 +/- 0.32 IU/kg in group 1, 0.58 +/- 0.21 IU/kg in group 2 and 0.37 +/- 0.22 IU/kg in group 3 (group 3 vs. groups 1 and 2: P < 0.002).

CONCLUSIONS

The approach using repaglinide, metformin and NPH insulin improved glycaemic control with a similar safety profile to conventional insulin initiation in T2DM and produced final glycaemic control similar to metformin and a twice daily biphasic insulin mixture.

Predictors of metabolic control at one year in a population of pediatric patients with type 2 diabetes mellitus: a retrospective study

BACKGROUND/OBJECTIVES

The rising prevalence of pediatric type 2 diabetes mellitus (DM2) and non-adherence to diabetes regimens pose challenges to obtaining optimal control. This study evaluated factors that may impact glycemic control (HbA1c): age, Tanner stage, body mass index (BMI), total daily insulin (TDD), metformin dose (MET), activity level, frequency of clinic visits and adherence.

METHODS

One-year data from 72 patients (ages 8.6-17.8 years) were collected retrospectively. From that sample, 57 patients who continued to attend clinic for the entire year were assessed and divided into optimal and suboptimal HbA1c control groups.

RESULTS

All factors measured were similar in the two groups, except for lower initial and 1.0-year HbA1c, TDD, and rates of missing MET and insulin in the optimal HbA1c control group.

CONCLUSIONS

Initial glycemic status and adherence rate predicted metabolic control at one year. Early identification of DM2 may improve metabolic outcome, which may improve medical regimen adherence.

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.

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.

Efficacy of glimepiride in patients with poorly controlled insulin-treated type 2 diabetes mellitus

We retrospectively investigated the effects of adding glimepiride in patients with type 2 diabetes showing suboptimal control by insulin therapy. Of 63 patients with poorly controlled insulin-treated type 2 diabetes (baseline HbA1c, 8.4 +/- 0.6%), 32 were treated with insulin alone and 31 were given glimepiride in addition to insulin. HbA1c values, daily insulin dose, body weight, blood pressure, plasma lipid concentrations, and the number of hypoglycemic events were recorded at weeks 0, 12, 24, 36, 48, 60, and 72. HbA1c decreased by 1.1%, from 8.5 +/- 0.6% to 7.4 +/- 0.8% (P<0.0001) in patients treated with insulin plus glimepiride at 12 weeks, and improved glycemic control continued throughout the study. Required insulin dose was reduced significantly in patients treated with insulin plus glimepiride (from 29.4 +/- 14.5 to 22.3 +/- 12.1 units/day, P = 0.0187). Body weight increased significantly in patients treated with insulin plus glimepiride (from 57.0 +/- 8.7 to 59.5 +/- 9.2 kg, P = 0.0232). Adding glimepiride showed little effect on blood pressure, plasma total cholesterol, triglyceride, or HDL-cholesterol. Serum C peptide concentrations increased significantly in patients treated with insulin plus glimepiride (from 1.01 +/- 0.71 to 1.28 +/- 0.65 ng/ml, P = 0.0367). The number of hypoglycemic events did not differ between groups. Adding glimepiride to insulin therapy resulted in sustained improvement of glycemic control in patients with poorly controlled type 2 diabetes.

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.

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.

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.

The implementation of nutritional advice for people with diabetes

These consensus-based recommendations emphasize the practical implementation of nutritional advice for people with diabetes, and describe the provision of services required to provide the information. Important changes from previous recommendations include greater flexibility in the proportions of energy derived from carbohydrate and monounsaturated fat, further liberalization in the consumption of sucrose, more active promotion of foods with a low glycaemic index, and greater emphasis on the provision of nutritional advice in the context of wider lifestyle changes, particularly physical activity. Monounsaturated fats are now promoted as the main source of dietary fat because of their lower susceptibility to lipid peroxidation and consequent lower atherogenic potential. Consumption of sucrose for patients who are not overweight can be increased up to 10% of daily energy provided that this is eaten in the context of a healthy diet and distributed throughout the day [corrected]. Evidence is presented for the effectiveness of advice provided by trained dieticians. The increasing evidence for the importance of good metabolic control and the growing requirement for measures to prevent Type 2 diabetes in an increasingly obese population will require major expansion of dietetic services if the standards in National Service Frameworks are to be successfully implemented.

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.

Combination of insulin and metformin in the treatment of type 2 diabetes

OBJECTIVE

To investigate the metabolic effects of metformin, as compared with placebo, in type 2 diabetic patients intensively treated with insulin.

RESEARCH DESIGN AND METHODS

Metformin improves glycemic control in poorly controlled type 2 diabetic patients. Its effect in type 2 diabetic patients who are intensively treated with insulin has not been studied. A total of 390 patients whose type 2 diabetes was controlled with insulin therapy completed a randomized controlled double-blind trial with a planned interim analysis after 16 weeks of treatment. The subjects were selected from three outpatient clinics in regional hospitals and were randomly assigned to either the placebo or metformin group, in addition to insulin therapy. Intensive glucose monitoring with immediate insulin adjustments according to strict guidelines was conducted. Indexes of glycemic control, insulin requirements, body weight, blood pressure, plasma lipids, hypoglycemic events, and other adverse events were measured.

RESULTS

Of the 390 subjects, 37 dropped out (12 in the placebo and 25 in the metformin group). Of those who completed 16 weeks of treatment, metformin use, as compared with placebo, was associated with improved glycemic control (mean daily glucose at 16 weeks 7.8 vs. 8.8 mmol/l, P = 0.006; mean GHb 6.9 vs. 7.6%, P < 0.0001); reduced insulin requirements (63.8 vs. 71.3 IU, P < 0.0001); reduced weight gain (-0.4 vs. +1.2 kg, P < 0.01); and decreased plasma LDL cholesterol (-0.21 vs. -0.02 mmol/l, P < 0.01). Risk of hypoglycemia was similar in both groups. CONCLUSIONS-In type 2 diabetic patients who are intensively treated with insulin, the combination of insulin and metformin results in superior glycemic control compared with insulin therapy alone, while insulin requirements and weight gain are less.

The contribution of metformin to glycaemic control in patients with Type 2 diabetes mellitus receiving combination therapy with insulin

Combination therapy of oral hypoglycaemic agents and insulin is a therapeutic option for those who have deterioration in glycaemic control. We examined the contribution of metformin by withdrawing it from Type 2 diabetic patients who had been stabilised on combination therapy. Fifty-one subjects with Type 2 diabetes and secondary oral hypoglycaemic agent failure were studied in a randomised, open and parallel study. In the first phase of 36 weeks, subjects were stabilised on combined therapy of sulphonylureas and nocturnal insulin, with or without metformin. During the second phase, metformin was withdrawn. The primary variables for efficacy were HbA(1c), fasting plasma glucose and 3-point capillary blood glucose profiles. After stabilisation with combination therapy, those subjects on metformin used less insulin to maintain glycaemic control (13.7+/-6.8 vs. 23.0+/-9.4 U/day, P=0.001) and had lower HbA(1c) values (8.13+/-0.89 vs. 9.05+/-1.30%, P=0.003) compared with those not given metformin. Withdrawal of metformin therapy caused deterioration in HbA(1c) (P=0.001). This study confirms that metformin plays an important role in the success of the combination therapy. The rational use of metformin and sulphonylurea together with insulin will help to improve metabolic control in Type 2 diabetes patients who have secondary drug failure.

[Treatment of diabetes mellitus: general goals, and clinical practice management]

Diabetes mellitus is associated with a marked increased of cardiovascular events. The treatment strategy of diabetes has to be based on the knowledge of its pathophysiology. Thus, insulin is essential for treatment of type 1 diabetic patients because there is a defect in insulin secretion. However, treatment of type 2 diabetic patients is more complex because a defect in both insulin secretion and insulin action exists. Therefore, the treatment selection will depend on the stage of the disease and the individual characteristics of the patient. This article examines the general goals of the treatment and reviews the management of type 2 diabetes.

[Role and modalities of insulin treatment in type 2 diabetics]

INTRODUCTION

The natural history of type 2 diabetes mellitus is characterized by an inescapable and gradual worsening of a decrease in insulin secretion. Thus after several years of progress, less than half of type 2 diabetic patients have good glycemic control. This explains the increase in insulin prescription to type 2 diabetic patients in France in recent years. This work's objective is to take into account recent publication data to clarify the status of and adjustments in insulin therapy.

CURRENT KNOWLEDGE AND KEY POINTS

The benefit of insulin treatment-mediated glycemic control optimization on microvascular complications is now proven. However, there is still controversy concerning macrovascular complications. Hypoglycemic risk in type 2 diabetic patients is limited and the main problem with insulin treatment is weight gain. Following failure with treatment by tablets, the most suitable treatment in terms of metabolic improvement, weight gain limitation and treatment adhesion is to add an intermediate insulin injection at bedtime. The next step remains several injections a day, with metformine addition if possible.

FUTURE PROSPECTS AND PROJECTS

Therapeutic treatment in type 2 diabetes mellitus may become an earlier start of insulin therapy to preserve the remaining pancreatic insulin reserve. The role of brief and long-lasting insulin analogues, as well as inhaled insulin, which will soon be available, should be specified.

Recent advances in the pharmacologic management of diabetes mellitus

The importance of glucose control in reducing the complications of diabetes mellitus has been clearly demonstrated. The emergency physician routinely is expected to treat a wide range of problems related to this disease, including making the initial diagnosis of type 2 and occasionally type 1 diabetes. Also common are patients with poorly controlled diabetes. The recent introduction of new classes of agents to lower blood glucose, especially in type 2 diabetes, should improve the control in this category of patient and reduce the complication rate. Some of these agents, such as troglitazone, have potentially fatal complications and require careful monitoring. Emergency physicians should be aware of the common complications of these drugs because patients can present to the ED with them. Hypoglycemia, a common cause of 911 calls and emergency visits, is not a side effect of either metformin or acarbose. Insulin lispro has improved postprandial glycemic control for type 1 and some insulin-requiring type 2 diabetics. Hypoglycemia is less of a risk with insulin lispro, and quality of life is better with this rapidly acting insulin. Newer methods of insulin delivery, such as continuous subcutaneous infusion, have greatly improved glucose control, given greater freedom to patients, and reduced the risks of hypoglycemia.

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.

Treating obese patients with poorly controlled diabetes: confessions of an insulin therapist

How to treat the obese, poorly controlled patient with diabetes is a common and vexed question. Using insulin without giving thought to ameliorating the inevitable weight gain will cause desperation in the physician and despondency in the patient. Novel attempts at dietary manipulation before commencing insulin can be beneficial provided there is close scrutiny of short-term changes in weight and metabolic parameters. Combinations of insulin and metformin can also be helpful at an early stage. It may be helpful to use insulin as a therapeutic trial provided the goals of therapy are agreed with the patient at the outset. Above all it is important to avoid therapeutic nihilism - a minority of fat people may be jolly but few are truly happy.