UK Prospective Diabetes Study (UKPDS) Group. Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34). Lancet. 1998;352:854-865. [PMID: 9742977 DOI: 10.1016/s0140-6736(98)07037-8]

Reaction of metformin with dicarbonyl compounds. Possible implication in the inhibition of advanced glycation end product formation

Dicarbonyl compounds such as methylglyoxal and glyoxal are extremely reactive glycating agents involved in the formation of advanced glycation end products (AGEs), which in turn are associated with diabetic vascular complications. Guanidino compounds such as aminoguanidine appear to inhibit AGE formation by reacting with alpha-dicarbonyl compounds. The aim of this work was to study whether the antihyperglycemic agent metformin (a guanidine-like compound) might react with reactive alpha-dicarbonyls. Metformin was incubated at pH 7.4 and 37 degrees in the presence of either methylglyoxal or glyoxal and reaction products analysed by HPLC coupled to mass tandem spectrometry. AGE formation on albumin by methylglyoxal and glyoxal in the presence or absence of metformin was also studied by measuring the fluorescence at 370/440 nm after albumin-AGE isolation by ultrafiltration. As a standard for mass spectra analysis, a metformin-methylglyoxal adduct was chemically synthesised and characterised as a triazepinone (2-amino-4-(dimethyl-amino)-7-methyl-5,7-dihydro-6H-[1,3,5]triazepin+ ++-6-one). The results obtained showed that metformin strongly reacted with methylglyoxal and glyoxal, forming original guanidine-dicarbonyl adducts. Reaction kinetic studies as well as mass fragmentation spectra of the reaction products were compatible with the presence of triazepinone derivatives. In the presence of metformin, AGE-related fluorescence after albumin incubation with either glyoxal or methylglyoxal was decreased by 37% and 45%, respectively. These results suggest that besides its known antihyperglycemic effect, metformin could also decrease AGE formation by reacting with alpha-dicarbonyl compounds. This is relevant to a potential clinical use of metformin in the prevention of diabetic complications by inhibition of carbonyl stress.

Fibrates, dyslipoproteinaemia and cardiovascular disease

Recent epidemiological data have reaffirmed that elevated plasma triglyceride and low HDL-cholesterol levels are important risk factors for atherosclerotic vascular disease. The rationale for the clinical use of fibric acid derivatives, which are designed to correct this metabolic nexus, is now on firmer ground. The mechanism of action of fibrates on lipoprotein metabolism has recently been elucidated at the molecular level and involves the activation of peroxisome proliferator-activated receptor-alpha 1 in the liver, with the net effect of improving the plasma transport rates of several lipoproteins. Other potential anti-atherothrombotic effects include the inhibition of coagulation and enhancement of fibrinolysis, as well as the inhibition of inflammatory mediators involved in atherogenesis. These consequences probably underpin the favourable effects of fibrates seen in recent angiographic and clinical trials. Two important clinical trials on the effect of gemfibrozil (Veterans Administration-HDL-Cholesterol Intervention Trial) and bezafibrate (Bezafibrate Infarction Prevention Study) have recently been completed in subjects with elevated triglyceride, low HDL and normal or near-normal LDL-cholesterol levels. The results testify to the efficacy of these agents in decreasing the incidence of cardiovascular events, particularly in patients with multiple risk factors and plasma triglyceride levels of over 2.2 mmol/l. The findings of these trials are compared with the statin-based Air Force/Texas Coronary Atherosclerosis Prevention Study, with a recommendation that future studies in appropriately selected patients should examine the synergistic effect of the fibrate/statin combination. The absolute risk reduction in the incidence of coronary events in the Veterans Administration-HDL-Cholesterol Intervention Trial compares favourably with the statin trials. The therapeutic aspects of the efficacy and safety of fibrates are reviewed. Besides primary mixed hyperlipidaemias, particular indications for the clinical use of fibrates include type 2 diabetes, the metabolic syndrome and renal insufficiency. The St Mary's, Ealing, Northwick Park Diabetes Cardiovascular Disease Prevention Study has suggested that fibrates may decrease the incidence of coronary events in type 2 diabetes, but this hypothesis will be more extensively tested in the Diabetes Atherosclerosis Intervention Study, Fenofibrate in Event Lowering in Diabetes Study and Lipids in Diabetes Study projects. Although significant new knowledge has accrued over the past few years concerning the fundamental and clinical aspects of fibrates, the success of these agents in clinical practice depends on the availability of methods for assessing cardiovascular risk as well as on treatment guidelines, which as presently designed and recommended may be inaccurate and suboptimal.

Prader-Willi syndrome, diabetes mellitus and hypogonadism

Diabetes mellitus is not a diagnostic criterion for Prader-Willi syndrome (PWS), but it is often found in PWS patients. The etiology for diabetes mellitus in PWS may be related to the morbid obesity and consequent insulin resistance, because a decrease of oxytocin neurons and leptin resistance in PWS may cause hyperphagia, inducing obesity. However, treatment with growth hormone (GH) is beneficial for the majority of GH-deficient PWS children, because relative decreased fat mass and increased fat-free mass could prevent obesity and concomitant insulin resistance. Hypogonadism is thought to be due to hypogonadotrophic hypogonadism in a majority of PWS patients. Hypergonadotrophic hypogonadism secondary to cryptorchidism and its treatment is shown in other cases. Low luteinizing hormone and high follicle-stimulating hormone levels in PWS cases in young men with idiopathic oligospermia or in the early stages of puberty is less frequently reported.

Prevention and treatment of microvascular and neuropathic complications of diabetes

The most important factors that influence development of the eye, kidney, and nerve complications of diabetes are the duration and degree of exposure to hyperglycemia. Hypertension is also very important. The risk of complications appears to be similar for all patients with diabetes; differences in complication rates between patients with type 1 and type 2 diabetes are largely due to differences in duration of diabetes and glycemic control. The benefits of lowering blood sugar are also similar for patients with diabetes, regardless of the type. Significant reductions in complications can be seen with relatively short-term treatment of hyperglycemia.

Implications of the United Kingdom prospective diabetes study

The United Kingdom Prospective Diabetes Study (UKPDS) is the largest ever study to clarify the role of glycemia and blood pressure control in improving morbidity and mortality in patients with type 2 diabetes. The study examined the impact of glycemia and blood pressure control on microvascular and macrovascular risk, and if any particular therapy was advantageous for these patients. This articles discusses the background, methodology and results of the UKPDS and develops recommendations for treatment and management of patients with type 2 diabetes in the clinical setting.

The use of insulin secretagogues in the treatment of type 2 diabetes

Secretatogues are a class of agents that achieve their hypoglycemic effects through stimulating insulin release. They include the sulfonylureas, repaglinide, and the investigational agent glucagon-like peptide. The secretagogue agents have been studied extensively as monotherapy and in conjunction with other classes of oral agents, including alpha-glucosidase inhibitors, bijuanides, and thiazolidinediones, for the treatment of type 2 diabetes. This article reviews the pharmacodynamic and pharmacokinetic differences of the secretagogues, as well as the most recent clinical trials. Such information should be helpful when deciding which agent or agents will yield the best glycemic control for an individual patient.

Insulin resistance and antidiabetic drugs

Insulin resistance describes an impaired biological response to insulin, which underpins the development of type 2 (non-insulin-dependent) diabetes mellitus (T2DM). Initially, insulin resistance causes a compensatory hyperinsulinaemia, which gives way to pancreatic beta-cell failure. Insulin resistance and hyperinsulinaemia conspire together in the development of a diverse collection of risk factors for coronary heart disease, namely obesity, T2DM, dyslipidaemia, hypertension, atherosclerosis, and a pro-coagulant state. This collection of factors is commonly found in T2DM patients, and is recognised as the Insulin Resistance Syndrome or Syndrome X. By targeting insulin resistance as a treatment strategy for T2DM, it should be possible to broaden the potential benefits, so that improved glycaemic control is complemented with improvements to other components of Syndrome X. At present, metformin and thiazolidinediones are the only therapies for T2DM that directly address aspects of insulin resistance. Increasing awareness of the clinical implications of insulin resistance, and increasing knowledge of the cellular basis of insulin resistance, provide the rationale and a means for developing an anti-insulin resistance approach to the treatment of T2DM.

Insulin lispro for the treatment of type 2 diabetes

Tight control can prevent complications in type 2 diabetes, and many patients will require insulin therapy to achieve this. Newer insulin formulations may offer some advantages with regard to patient convenience and a reduction in hypoglycaemia.

The assessment of endothelial function in the cardiac catheterization laboratory in patients with risk factors for atherosclerotic coronary artery disease

In the last 2 decades the endothelium has emerged as an active modulator of many local and systemic functions. The intact endothelium synthesizes and releases a variety of autocrine and paracrine substances that affect cell growth and proliferation, platelet aggregation and adhesion, inflammatory processes, and vascular tone. The aims of the present review are to present the current technique for the assessment of coronary artery endothelial function in the cardiac catheterization laboratory and to describe the current knowledge regarding risk factor modification on endothelial dysfunction.

Reversal of increased lymphocyte PC-1 activity in patients with type 2 diabetes treated with metformin

BACKGROUND

The plasma cell differentiation antigen (PC-1) is an inhibitor of insulin receptor tyrosine kinase activity, and has been implicated in the pathogenesis of insulin resistance in Type 2 diabetes. Metformin increases peripheral insulin sensitivity and, therefore, we have studied the effect of metformin treatment on lymphocyte PC-1 (ecto-alkaline phosphodiesterase I, APD) in patients with Type 2 diabetes.

METHODS

Basal, concanavalin A (Con A)-, and phorbol-12-myristate-13-acetate (PMA)-stimulated lymphocyte PC-1, aminopeptidase N (APN), and dipeptidylpeptidase IV (DPP IV) activities were determined in 16 patients with Type 2 diabetes before and after 3 months of metformin treatment.

RESULTS

Lymphocyte PC-1 in patients with Type 2 diabetes was increased significantly (p<0.001) over control; however, metformin treatment brought its activity in unstimulated and Con A-stimulated lymphocytes to the control level. PMA-stimulated PC-1 in patients with Type 2 diabetes was 17-times higher than in controls, and was reduced to near the control level by 3-month metformin treatment. In Type 2 diabetes, PMA-stimulated ecto-DPP IV was significantly (p<0. 005) increased over control, but was reduced after metformin treatment.

CONCLUSION

This study has shown an increased activity of lymphocyte PC-1 in Type 2 diabetes and its reversal by 3-month metformin treatment, corresponding to the improvement of insulin sensitivity. Data obtained are consistent with a role of PC-1 in insulin resistance and suggest a new mechanism of action for metformin via PC-1 inhibition.

Contribution of fasting hyperinsulinemia to prediction of atherosclerotic cardiovascular disease status in 293 hyperlipidemic patients

In a cross-sectional study of 293 nondiabetic patients (169 men and 124 women) referred for the diagnosis and treatment of hyperlipidemia, our specific aim was to determine whether fasting serum insulin independently contributes to the prediction of atherosclerotic cardiovascular disease (ASCVD) status. Of the 169 men and 124 women, 65 (38%) and 44 (35%), respectively, had ASCVD with at least one of the following: unstable angina, myocardial infarction (MI), angioplasty, coronary artery bypass graft (CABG), claudication, transient ischemic attack, or ischemic stroke. In addition, 42% and 38% had fasting hyperinsulinemia (> or =20 microU/mL). Fasting serum insulin of 20 microU/mL or higher was very common in women (59% to 100%) and men (67% to 88%) when hypertension, obesity, top-decile triglyceride (TG), and bottom-decile high-density lipoprotein cholesterol (HDLC) were concurrent in various combinations. ASCVD events (present or absent) were dependent variables in a stepwise logistic regression model with explanatory variables including age, gender, race, hypertension, cigarette smoking, ASCVD in first-degree relatives at age 55 years or less, Quetelet Index, fasting serum insulin, a gender x insulin interaction term, anticardiolipin antibodies (ACLAs) IgG and IgM, total cholesterol to HDLC ratio, TG, lipoprotein(a) [Lp(a)], and homocysteine. The risk odds ratio for ASCVD (109 events and 184 nonevents) for subjects with top-decile insulin (vthe bottom nine deciles) was 3.71, with a 95% confidence interval (CI) of 1.62 to 8.9 (P = .002). For patients with MI and/or CABG and/or angioplasty ([MCA] 63 events and 184 nonevents), the risk odds ratio for top-decile insulin versus the rest was 5.07 (95% CI, 1.83 to 14.8, P = .002). For patients with MCA at age 55 or less, the gender x insulin interaction term was significant (P = .0004); the risk odds ratio for men with top-decile insulin was 13.28 (95% CI, 3.82 to 51.65, P = .0001). Hyperinsulinemia is very common in nondiabetic hyperlipidemic women and men. Fasting serum insulin, a crude, simple, practical, and inexpensive measure, independently and uniformly improved the prediction of ASCVD status beyond traditional risk factors and lipid variables in patients referred for treatment of hyperlipidemia.

Antihyperglycemic treatment in diabetics with coronary disease: increased metformin-associated mortality over a 5-year follow-up

Mortality rates are considerably higher in chronic ischemic heart disease (IHD) patients with non-insulin-dependent diabetes mellitus (NIDDM) than in those who are nondiabetics. The relationship between different types of antihyperglycemic pharmacological therapy and mortality rate in this NIDDM population is uncertain. We aimed to examine the survival in NIDDM patients with IHD using various types of oral antidiabetic treatments over a 5-year follow-up period. The study sample comprised 11,440 patients with a previous myocardial infarction and/or stable anginal syndrome, aged 45-74 years, who were screened, but not included in the Bezafibrate Infarction Prevention study. Among them, 9,045 were nondiabetics and 2,395 diabetics. The diabetic patients were divided into four groups on the basis of their therapeutic regimen at screening: diet alone (n = 990), sulfonylureas (n = 1,041), metformin (n = 78) and a combination of a sulfonylurea and metformin (n = 266). All NIDDM groups were similar with regard to age, gender, hypertension, smoking, heart failure, angina and prior myocardial infarction. Crude mortality rate was lower in the nondiabetic group (11.21 vs. 21.8%; p < 0.001). In the diabetic group, mortality was 18.5% for patients on diet alone, 22.5% for those on sulfonylureas, 25.6% for patients on metformin, and 31.6% for the combined sulfonylurea/metformin group (p < 0.01). When analyzing age-adjusted mortality rate and actuarial survival curves, the lowest mortality was found in patients on diet alone and the highest in patients on metformin (alone or in combination with sulfonylureas). After adjustment for variables connected with long-term prognosis, the use of metformin was associated with increased relative risk (RR) for all-cause mortality of 1.42 (95% CI 1.10-1.85), whereas the use of sulfonylureas alone was not [RR 1.11 (95% CI 0.90-1.36)]. NIDDM patients with IHD using metformin, alone or in combination with sulfonylureas, exhibited a significantly increased mortality. Until the results of problem-oriented prospective studies on oral control of NIDDM will be available, alternative therapeutic approaches should be investigated in these patients.

A systematic review of foot ulcer in patients with Type 2 diabetes mellitus. I: prevention

AIM

To evaluate the role of preventative strategies in reducing foot ulcers in patients with Type 2 diabetes mellitus, both in the general population and those identified to be at a raised risk.

METHOD

A systematic review of interventions to prevent diabetic foot ulcers.

RESULTS

Available studies are generally unsatisfactory in their ability to answer the important questions relating to prevention. However, where people with diabetes receive well-organized and regular care with rapid referral to appropriate specialist multidisciplinary teams when problems (or their precursors) occur, ulcer morbidity can be substantially reduced.

CONCLUSION

Foot ulcers are common in people with diabetes and are costly in terms of both patient morbidity and the use of healthcare resources. Although it is nearly a decade since the St Vincent Declaration called for a marked reduction in morbidity to be achieved through better patient management, available evidence suggests that the process of care in Britain is still very variable in quality. Foot care for people with diabetes must be organized to provide monitoring, education and referral in a manner acceptable to patients and realistic for local healthcare providers.

Rosiglitazone: a new therapy for Type 2 diabetes

Rosiglitazone (Avandiatrade mark) is a new generation thiazolidinedione used in the treatment of Type 2 diabetes. As with other thiazolidinediones, it binds to the gamma-isoform of the peroxisome proliferator-activated receptor (PPAR), a nuclear hormone receptor. Subsequent to PPAR-gamma activation, rosiglitazone increases insulin suppression of hepatic glucose output and increases peripheral glucose uptake in the muscles, thereby improving the glycaemic state of the individual. In rodent models of obesity and Type 2 diabetes, rosiglitazone has been shown to have positive effects in the main target organs responsible for the condition, namely the liver, pancreas, skeletal muscle and adipose tissue. These studies also suggest that rosiglitazone may help in preserving renal and pancreatic function that deteriorates in chronic hyperinsulinaemia. In clinical studies, rosiglitazone has been shown to be effective, safe and well-tolerated, not only when used as monotherapy, but also when used in combination with sulphonylureas, metformin or insulin. Unlike troglitazone, rosiglitazone is not metabolised via CYP3A4 and is thus unlikely to be subject to clinically important drug interactions. In addition, no evidence of hepatotoxicity has been associated with rosiglitazone to date. Rosiglitazone should therefore be strongly considered as part of the overall management of Type 2 diabetes.

Bromocriptine improves glycaemic control and serum lipid profile in obese Type 2 diabetic subjects: a new approach in the treatment of diabetes

Bromocriptine, a potent dopamine D(2) receptor agonist, has been shown to reduce insulin resistance, glucose intolerance and hyperlipidaemia in both numerous animal studies and in Phase II studies. Bromocriptine has been used worldwide for over 20 years to treat Parkinson's disease, macroprolactinoma and other disorders; it has been found to be generally safe. We therefore investigated the possible beneficial effects of Ergoset(R) (Ergo Science Corp.), a new quick release formulation of bromocriptine, on glycaemic control and serum lipid profile in obese Type 2 diabetic subjects in two large Phase III studies. A large, randomised, double-blind placebo-controlled study was conducted in which Ergoset was given once daily at 8 am. (4.8 mg maximum dose) for 24 weeks as adjunctive therapy to sulphonylurea (485 subjects) to obese Type 2 diabetics held on a weight- maintaining diet. Treatment efficacy parameters included change from baseline in glycated haemoglobin A(1c) (HbA(1c)), fasting and post-prandial serum glucose, insulin, triglyceride and free fatty acid levels. Baseline glycated haemoglobin, fasting glucose, insulin, triglyceride and free fatty acid levels did not differ between treatment groups. and on average were 9.4 +/- 0.05%, 222 +/- 2 mg/dl, 24 +/- 1 µU/ml, 248 +/- 11 mg/dl, and 850 +/- 32 µEq/l, respectively. A similarly designed study of Ergoset as monotherapy in Type 2 diabetics (154 subjects) with similar baseline clinical characteristics was conducted. Addition of Ergoset treatment to sulphonylurea reduced percent glycated HbA(1c) by 0.55 (P < 0.0001) (approximately 1.0 for responders, 65% of population), fasting and post-prandial glucose by 23 and 26 mg/dl (P < 0.0002), fasting and post-prandial triglycerides by 72 and 63 mg/dl (P < 0.005) and fasting and post-prandial free fatty acids by 150 and 165 µEq/l (P < 0.05), relative to placebo. Twelve percent of all Ergoset subjects, compared to 3% of placebo subjects, withdrew from the study due to adverse events. The most common events causing withdrawal were nausea, dizziness, asthenia, and rhinitis (representing 4.5, 3.3, 2.0, and 0.8% of the total Ergoset populations, respectively). The incidence of serious adverse events did not differ between Ergoset- (3.4%) and placebo- (4.3%) treated subjects. Ergoset as monotherapy also improved glycaemic control (0.56 HbA(1c) decrease relative to placebo after 24 weeks of treatment; P < 0.02). Once daily Ergoset treatment improves glycaemic control and serum lipid profile and is well-tolerated in obese Type 2 diabetics.

Impaired endothelium-mediated relaxation in coronary arteries from insulin-resistant rats

OBJECTIVE

The insulin resistance syndrome is associated with atherosclerosis and cardiovascular events; however, the underlying mechanism of vascular dysfunction is unknown. The purpose of the current study was to assess endothelium- and smooth-muscle-mediated vasodilation in isolated coronary arteries from insulin-resistant rats and to determine whether insulin resistance alters the activity of the specific endothelium-derived relaxing factors.

METHODS

Male Sprague-Dawley rats were randomized to insulin resistance or control. Insulin resistance was induced by a fructose-rich diet. After 4 weeks of diet, coronary arteries were removed and vascular function was assessed in vitro using videomicroscopy. Acetylcholine (10(-9)-3 x 10(-5) M)- or sodium-nitroprusside (10(-9)-3 x 10(-4) M)-induced relaxations were determined. To evaluate the role of the specific endothelium-derived relaxing factors, several inhibitors were used, including N-nitro-L-arginine (LNNA), charybdotoxin/apamin (CTX/apamin), and indomethacin.

RESULTS

Studies with nitroprusside showed that smooth-muscle-dependent relaxation did not differ between insulin resistance and control groups. In contrast, maximal relaxation (E(max)) to acetylcholine was decreased in the insulin resistance group (56 +/- 7%) versus control (93 +/- 3%). LNNA pretreatment further impaired E(max) in the IR group from 56 +/- 7 to 17 +/- 2% (p < 0.01). In control, E(max) was only slightly impaired by LNNA (93 +/- 3 to 63 +/- 6%; p < 0.05). The addition of CTX/apamin also decreased relaxation in the control group (93 +/- 3 to 47 +/- 7%; p < 0.05), whereas relaxation in insulin-resistant rats was not affected (45 +/- 5% with CTX/apamin vs. 56 +/- 7% with acetylcholine alone, NS). Pretreatment with indomethacin did not affect relaxation in either group, while pretreatment with the combination of LNNA and CTX/ apamin completely abolished relaxation in both groups.

CONCLUSIONS

Endothelium-dependent relaxation is impaired in small coronary arteries from insulin-resistant rats. The mechanism of this defect is related to a decrease in an endothelium-dependent, nitric oxide/prostanoid-independent relaxing factor or endothelium-derived hyperpolarizing factor.

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.

Effects of metformin in patients with poorly controlled, insulin-treated type 2 diabetes mellitus. A randomized, double-blind, placebo-controlled trial

BACKGROUND

Patients with type 2 diabetes are often obese and require large doses of insulin to achieve glycemic control. Weight gain often accompanies insulin therapy and results in increasing insulin requirements.

OBJECTIVE

To evaluate the efficacy of metformin in combination with insulin in patients with type 2 diabetes poorly controlled with insulin therapy alone.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Outpatient diabetes clinic at a university medical center.

PATIENTS

43 patients with poorly controlled type 2 diabetes who were receiving insulin therapy.

INTERVENTION

Patients were randomly assigned to receive placebo or metformin in combination with insulin for 24 weeks.

RESULTS

Hemoglobin A1c levels decreased by 2.5 percentage points (95% CI, 1.8 to 3.1 percentage points) in the metformin group, a significantly greater change (P = 0.04) than the decrease of 1.6 percentage points in the placebo group. Average final hemoglobin A1c levels were 6.5% in the metformin group and 7.6% in the placebo group (difference, 11%). For patients who received placebo, the insulin dose increased 22.8 units (CI, 11 to 44 units) or 29% more than did the dose for patients who received metformin (P = 0.002); for these patients, the insulin dose decreased slightly. Patients in the placebo group gained an average of 3.2 kg of body weight (CI, 1.2 to 5.1 kg); patients in the metformin group gained an average of 0.5 kg of body weight (P = 0.07). Total cholesterol and low-density lipoprotein cholesterol levels decreased in both groups. High-density lipoprotein cholesterol and triglyceride levels did not change.

CONCLUSIONS

The addition of metformin to insulin therapy resulted in hemoglobin A1c concentrations that were 10% lower than those achieved by insulin therapy alone. This improvement in glycemic control occurred with the use of 29% less insulin and without significant weight gain. Metformin is an effective adjunct to insulin therapy in patients with type 2 diabetes.

Type 2 Diabetes: An Overview

Type 2 diabetes is a heterogeneous disorder. Clinical expression of the disorder requires both genetic and environmental factors. One theory concerning its etiology is that it is the result of the evolution of a thrifty genotype that had survival benefits in the past but is detrimental in the current environment. An opposing theory is that it represents an adult metabolic response to fetal malnutrition. Hyperglycemia in type 2 diabetes results from absolute or relative insulin deficiency. Most often relative insulin deficiency is attributable to an inability to adequately compensate for insulin resistance. Insulin resistance may be caused by a variety of genetic or metabolic factors. The most common etiological factor in insulin resistance is central obesity. Insulin resistance is associated with a cluster of metabolic abnormalities that include glucose intolerance, hypertension, a unique dyslipidemia, a procoagulant state, and an increase in macrovascular disease. Clinical intervention studies have demonstrated that reduction in the chronic microvascular and macrovascular complications of type 2 diabetes requires treatment of hyperglycemia to achieve hemoglobin A1c &lt;7.0%, blood pressure ≤130/80 mmHg, and plasma LDL-cholesterol ≤2.6 mmol/L (≤100 mg/dL). Oral antihyperglycemic agents increase endogenous insulin secretion, decrease insulin resistance, or lower postprandial plasma glucose rise by delaying absorption of complex carbohydrates. Long-term glycemic control in type 2 diabetes requires progressive, stepwise, combination treatment with oral agents and eventually combination treatment with oral agents and insulin.

Drug selection and the management of corticosteroid-related diabetes mellitus

Glucocorticoid use is associated with the risk of hyperglycemia in patients without known diabetes mellitus and worsened glycemic control in diabetic patients. The effects are greater in the fed than fasting state. Management includes use of diet and exercise (as appropriate for the individual) in all patients. Mild hyperglycemia can often be managed with oral agents, especially those with rapid onset of action. Marked hyperglycemia, especially in diabetic patients or patients with liver or renal disease, requires insulin. Adjustments in insulin can be done both in anticipation of the glucocorticoid effect and based on home glucose monitoring. The effects of glucocorticoids on hyperglycemia usually remit within 48 hours of discontinuation of oral administration.

Diabetes and periodontal diseases

This position paper on diabetes mellitus was prepared by the Research, Science and Therapy Committee of The American Academy of Periodontology. It is intended to: 1) update members of the dental profession on the diagnosis and medical management of patients with diabetes mellitus; 2) summarize current knowledge on the relation between diabetes mellitus and periodontal diseases; 3) provide an overview of factors in diabetic patients relevant to understanding the pathogenesis of periodontal diseases in these subjects; 4) outline special considerations associated with treatment of periodontal diseases in diabetic patients; and 5) discuss possible approaches to the management of diabetic emergencies in the dental office.

Contra-indications to metformin therapy are largely disregarded

AIMS

To investigate the current metformin treatment practice and in particular to examine the consideration given to its contraindications.

METHODS

A cross-sectional analysis of 308 consecutive Type 2 diabetic patients (mean age 66+/-11.3 years) previously treated with metformin on an outpatient basis and admitted to a German general hospital during the period from 1 January 1995 to 31 May 1998 because of acute disease or in order to optimize their diabetes management. All patients underwent a basic investigation comprising a documentation of their medical history, a physical examination, an electrocardiogram, and an extensive laboratory profile; 34% also had acute coronary angiography.

RESULTS

On admission to hospital, 73% of the patients were found to have contra-indications, risk factors, or intercurrent illnesses necessitating discontinuation of metformin; 51% of these patients had several of these conditions. As major contra-indications to metformin, renal impairment was present in 19% of all patients, heart failure in 25%, respiratory insufficiency in 6.5%, and hepatic impairment in 1.3%. The risk factors to metformin included advanced coronary heart disease in 51%, atrial fibrillation in 9.8%, chronic alcohol abuse in 3.3%, advanced peripheral vascular disease in 2%, and pregnancy in 0.7%. As intercurrent illnesses, cerebral ischaemia occurred in 9.8% under metformin treatment and malignancies were diagnosed in 6.5%. The patients with contra-indications or requiring caution to metformin were significantly older and had previously been treated with more cardiovascular medication than those without such reservations (P<0.001).

CONCLUSIONS

Despite the considerable risk of lactic acidosis in the majority of patients, no cases were observed.

[Current status of the treatment of type 2 diabetes mellitus. The revival of insulin-resistance drugs]

The relief of insulin resistance is one of the two therapeutic targets of the treatment of type 2 diabetes. Insulin-sensitizers are therefore complemental with other oral diabetic drugs. The treatment of insulin resistance was for a long time limited to dietary and exercise programmes, a biguanide, metformine, and benfluorex, a phenylethylamine derivative; the mechanisms of action of both drugs are now better understood and their indications more precisely targeted. A new therapeutic class, the thiazolidinediones (troglitazone, rosiglitazone, pioglitazone) has recently completed the family of insulin-sensitizing agents. These drugs, which should be soon available in France, act by a different way than metformin, which has been recently identified as the peroxisomes proliferator-activated receptor. The role of antilipolytic agents, which might increase glucose uptake by reducing free fatty acid production and oxidation is under evaluation, as well as the potential benefit of orlistat, an inhibitor of lipid digestion which has been proved effective, in addition to hypocaloric diet, in the management of obese patients.

Prevalence and prognostic significance of unrecognized systemic hypertension in patients with diabetes mellitus and healed myocardial infarction and/or stable angina pectoris

Few data are available regarding the prevalence and prognostic significance of the triple coexistence of undiagnosed systemic hypertension, diabetes mellitus, and coronary heart disease. This study aimed to evaluate the prevalence and prognostic significance of unrecognized hypertension in cardiac diabetic patients previously defined as "normotensives" over a 5-year follow-up period. The study sample comprised 11,515 patients aged 45 to 74 years with a previous myocardial infarction and/or anginal syndrome who were screened but not included in the Bezafibrate Infarction Prevention study. Among them, 9,033 were nondiabetics and 2,482, diabetics. The diabetics were divided into 3 groups: (1) 1,272 normotensives, (2) 152 patients without history of hypertension but with elevated blood pressure ("unrecognized hypertensives"), and (3) 1,058 hypertensives with established diagnosis. The prevalence of both diagnosed and unrecognized hypertension in diabetics pooled together increased from 49% to 69% when World Health Organization and new Joint National Committee-VI criteria were compared. Crude all-cause mortality was lower in nondiabetics than in diabetics (11.2% vs 22.0%; p <0.001). Among diabetics the lowest all-cause mortality was documented for normotensives (19.3%), whereas the highest mortality was observed in unrecognized hypertensives (26.3%, p = 0.003). Both unrecognized and established hypertensives demonstrated a significant stroke-related mortality excess: about four- and threefold increases in cerebrovascular accident-related death, respectively, were observed (p = 0.002). On multivariate analysis, both unrecognized and diagnosed hypertension were consistent predictors of increased all-cause mortality, with a hazard ratio of 1.28 (95% confidence interval 0.90 to 1.82) and 1.24 (95% confidence interval 1.03 to 1.49), respectively. Our findings demonstrate widespread undiagnosed hypertension in diabetic coronary patients; their 5-year mortality was significantly increased compared with normotensives, and tended to be even higher than in diabetics previously identified as hypertensives.

Using baseline data to improve care of the patient with type 2 diabetes mellitus

Diabetes mellitus affects approximately 16 million people in the United States. Despite the publication of multiple guidelines, the delivery of care has not substantially changed. This article describes a program at Advocate Health Care to improve the delivery of care to individuals with Type 2 diabetes mellitus in an ambulatory setting. Using a variety of continuous quality improvement tools, this project enhances partnerships between patients and health care providers.

[Current status of the treatment of type 2 diabetes mellitus. Alpha-glucosidase inhibitors]

The development of antidiabetic drugs with complementary mechanisms of action appears more and more necessary in order to achieve durable glycaemic control in type 2 diabetes. By inhibiting in a reversible way the hydrolysis of disaccharides and the ultimate steps of the digestion of dietary polysaccharides, alpha-glucosidase inhibitors reduce postprandial blood glucose raise in diabetics. This therapeutic class, limited in Europe until recently to acarbose, has been enlarged with the marketing of miglitol, whose pharmacokinetic properties might lead to better long term tolerance. The improvement of glycaemic control obtained with alpha-glucosidase inhibitors is now better evaluated and appears similar whatever the combinations with other antidiabetic drugs, including insulin. The role of alpha-glucosidase inhibitors in the overall therapeutic strategy of type 2 diabetes and their benefit on the evolution of long term complications remains to be clarified.

Effect of metformin on advanced glycation endproduct formation and peripheral nerve function in streptozotocin-induced diabetic rats

The effects of metformin treatment on advanced glycation endproduct formation and peripheral nerve function in streptozotocin-induced diabetic rats were examined. Streptozotocin-induced diabetic rats were treated with low dose metformin (50-65 mg kg(-1) daily) or high dose metformin (500-650 mg kg(-1) daily) for 10 weeks. While the metformin-untreated diabetic group showed a significant increase of advanced glycation endproducts (6.1-fold in the lens, 1.6-fold in the sciatic nerve, 2.3-fold in the renal cortex, and 1.9-fold in plasma; all P < 0.01) compared with the healthy control group, both metformin-treated groups had significantly less advanced glycation endproduct deposition. The % decrease in the diabetes-induced increase in advanced glycation endproduct formation by low and high dose metformin treatment was 25% and 72% in the lens (both P < 0.01), 31% and 42% in the sciatic nerve (both P < 0.05), and 16% and 33% in the renal cortex (P < 0.05 and P < 0.01), respectively. However, the plasma advanced glycation endproduct level showed no significant difference from that in the untreated diabetic group, in spite of slight decrease in plasma glucose and glycated hemoglobin levels in the metformin-treated groups. The diabetes-induced sciatic nerve conduction velocity deficits were improved by 46% and 42% by low and high dose metformin treatment, respectively (both P < 0.01). These data suggest that metformin may have a direct antiglycative action, which in turn contributes to amelioration of peripheral nerve function. Thus, metformin treatment may be effective in the prevention of diabetic complications through not only lowering plasma glucose, but also directly inhibiting advanced glycation endproduct formation.

Diabetes and myocardial infarction

Myocardial infarction (MI) is a common cause of mortality in people with diabetes. The case fatality from MI is high and may be reduced by thrombolysis and treatment with aspirin, beta-blockers and angiotensin-converting enzyme inhibitors. Poor metabolic control is common among diabetic patients with MI, but the importance of controlling blood glucose during and following an MI is debatable. Treatment with statins reduces cardiovascular end-points in diabetic patients with previous MI (secondary prevention). Large studies in diabetic patients without existing heart disease have shown statistically insignificant reductions in heart disease and MI with improved glycaemic control of the diabetes (primary prevention). The treatment of hypertension in people with diabetes prevents cardiovascular end-points, and studies on whether the treatment of hyperlipidaemia reduces heart disease and MI are proceeding.

1999 World Health Organization-International Society of Hypertension Guidelines for the management of hypertension. Guidelines sub-committee of the World Health Organization

The present Guidelines were prepared by the Guidelines Sub-Committee of the World Health Organization-International Society of Hypertension (WHO-ISH) Mild Hypertension Liaison Committee, the members of which are listed at the end of the text. These guidelines represent the fourth revision of the WHO-ISH Guidelines and were finalised after presentation and discussion at the 7th WHO-ISH Meeting on Hypertension, Fukuoka, Japan, 29th Sept-1st Oct, 1998. Previous versions of the Guidelines were published in Bull WHO 1993, 71:503-517 and J Hypertens 1993, 11:905-918.

Obesity and diabetes

Obesity, particularly truncal obesity, is closely correlated to the prevalence of diabetes and cardiovascular disease. Plasma leptin, tumour necrosis factor-alpha and non-esterified fatty acid levels are all elevated in obesity and play a role in causing insulin resistance. Diabetic glycaemic control and insulin resistance improve with reductions in obesity, but the treatment of obesity is difficult, and sustained weight reduction rarely occurs with dietary management alone. Hypocaloric diets should be combined with education and low-impact exercise, as well as behavioural techniques used to encourage long-term changes. Weight-reducing drugs have a role in the management of obesity but only as part of such a total package. Newer anti-obesity drugs such as orlistat and sibutramine are well tolerated and have been shown to improve glycaemic control in diabetes. It is probable that drugs developed in the future will act at different sites in the pathways regulating body weight, but they may have to be used in combination.

Preventing diabetic foot complications. Tight glucose control and patient education are the keys

Foot disease is a common complication of diabetes that can have tragic consequences. Tight glucose control can reduce microvascular diabetic complications, including peripheral sensory neuropathy and thus development of foot ulcers. Patient education is essential for risk-factor reduction and early recognition of foot complications. Awareness and training of healthcare providers in diagnosing and treating diabetic foot disease are paramount and may begin with such simple measures as adding a wall poster or chart reminder to conduct foot examinations in all diabetic patients at every office visit.

Drug treatment for hypertensive patients in special situations: diabetes and hypertension

Diabetes mellitus and hypertension is often associated, but with a different type of development in type 1 and type 2 diabetes. Type 1 diabetes, renal disease, starting with microalbuminuria, is associated with increasing blood pressure or hypertension, whereas the patient without renal disease is most often normotensive. Poor metabolic control is a predictor of microalbuminuria or incipient nephropathy, but with microalbuminuria hypertension is an important risk factor for progression along with poor glycemic control. The same is the case for overt renal disease, and metabolic control is important in all stages of renal disease in type 1 diabetes. It has also been shown that good metabolic control as well as antihypertensive treatment, especially with ACE-inhibitors, often combined with other agents is quite effective in preventing progression in renal disease in all its stages. In type 2 diabetes, blood pressure elevation is often found as early as at the actual diagnosis, and blood pressure significantly increases according to the degree of albuminuria, normo-microalbuminuria and clinical proteinuria (macroalbuminuria). Elevated blood pressure is an important risk for renal disease but more importantly so also for cardiovascular disease. Several studies document that antihypertensive treatment in particular with ACE-inhibitors is important in preventing microalbuminuria, in treating microalbuminuria and thus preventing progression, also in overt renal disease. Near-normalization of blood pressure is vital. Regarding cardiovascular disease, a series of studies now document that antihypertensive treatment with various antihypertensive agents is able to significantly reduce a number of major cardiovascular complications in diabetes, such as cardiac disease, stroke, and also microvacular disease, including retinopathy. Several studies show that antihypertensive treatment should be started at a level higher than 140-150/90. The blood pressure to be achieved during treatment is probably around 140/85 mmHg or even 130/80 mmHg as a pragmatic goal. However, there is no sign of a J-shaped curve in any of the studies, and therefore even lower blood pressure could be advantageous. Even mortality, at least from diabetes-related causes can be effected by antihypertensive treatment. With more advanced renal disease, normalization of blood pressure is increasingly difficult, especially systolic blood pressure, and therefore it is recommendable to screen patients much earlier on with focus on blood pressure recordings and measurements of albuminuria, including microalbuminuria, and to treat early.

Evidence supporting secondary prevention strategies

Currently 14 million individuals in the United States have coronary disease. Within the next 2 decades, this number is expected to increase to 21 million persons. To minimize the excessive risk of recurrent cardiac events in these people, evidence-based, cost-effective prevention strategies must be developed. This review highlights the evidence supporting commonly used means of secondary prevention and is divided into two major sections: lifestyle modifications and pharmacologic interventions. Lifestyle changes discussed include smoking cessation, especially newer pharmacologic adjuncts; the efficacy of dietary interventions; and current inroads into the treatment of depression in recurrent events. Pharmacologic innovations include reexamination of a role for warfarin; continued advances in the treatment of hyper- and dyslipidemias, new roles for beta-blockade in congestive heart failure, and finally a view of future measures, risk and targets of risk intervention.

Effects of gliclazide versus metformin on the clinical profile and lipid peroxidation markers in type 2 diabetes

The sulfonylurea gliclazide and the biguanide metformin have different mechanisms to reduce glycemia. We performed a randomized study to compare these two agents with respect to glycemic control and effects on lipid peroxidation markers in 36 adult patients with type 2 diabetes. Both agents significantly decreased glycosylated hemoglobin ([HbA1c] P < .05), fructosamine (P < .05), and the glucose-excursion curve during the oral glucose tolerance test ([OGTT] P < .01). With regard to the insulin curve during this test, no significant change was observed with metformin and a significant increase was measured with gliclazide (P < .05). Considering the small number of events, no significant difference was detected in the number of hypoglycemic episodes between the two agents. More upper-gastrointestinal (GI) symptoms were observed with metformin compared with gliclazide (P < .05). Even with no change in the standard lipid profile, both agents increased serum vitamin E (P < .01 for gliclazide and P < .05 for metformin) and decreased the level of lipid peroxidation markers in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles (P < .05). Despite different mechanisms of action, gliclazide and metformin demonstrated comparable levels of efficacy and complementary effects on lipid peroxidation markers.

Diabetes mellitus and anaesthesia

Diabetes mellitus is the most common endocrinological problem encountered by an anaesthetist and its prevalence will increase greatly in the next decade. This review focuses on the relevance of a new classification and diagnostic criteria for diabetes and the results of the important UK prospective diabetes study group trial. Other key areas of interest are the acute treatment of non-insulin-dependent diabetes (type 2), the management of coronary heart disease and vascular reactivity in patients with diabetes.

Does social medicine still matter in an era of molecular medicine?

To ask whether social medicine still matters may seem to be in poor taste at a symposium to honor Martin Cherkasky, but social medicine has always had the courage to take on difficult questions. There is all the more reason to do so when its legitimacy is challenged. The extraordinary findings emerging from the human genome project will revolutionize diagnostic and therapeutic methods in medicine. The power of medical interventions, for good and for harm, will increase enormously. However, in the next millennium, as in this one, social factors will continue to be decisive for health status. The distribution of health and disease in human populations reflects where people live, what they eat, the work they do, the air and the water they consume, their activity, their interconnectedness with others, and the status they occupy in the social order. Virchow's aphorism is as true today as it was in 1848: "If disease is an expression of individual life under unfavorable conditions, then epidemics must be indicative of mass disturbances of mass life." Increasing longevity resulting from major economic transformations has made ours the age of chronic disease. Changes in diet and behavior transform genes that once conferred selective biologic advantage into health hazards. Although disease risk varies with social status, medical care makes an important difference for health outcomes. Access to care and the quality of care received are functions of social organization, the way care is financed, and political beliefs about the "deserving" and the "underserving" poor. It is a moral indictment of the US that ours is the only industrialized society without universal health care coverage. In educating the American public about the social determinants of health, a goal Martin Cherkasky championed, the very power of the new molecular biology will help make our case. Social medicine is alive and well.

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.

Rosiglitazone monotherapy improves glycaemic control in patients with type 2 diabetes: a twelve-week, randomized, placebo-controlled study

AIM

Rosiglitazone is the most potent of the thiazolidinediones, a novel class of oral antidiabetic agents that reduce blood glucose levels by sensitizing peripheral tissues to insulin. This study was designed to identify doses of rosiglitazone that would lower fasting plasma glucose (FPG) in patients with type 2 diabetes.

METHODS

In this 12-week, double-blind, multicentre study, 380 patients with FPG values > or =7.8 mmol/L (140 mg/dL) and < or =13.3 mmol/L (240 mg/dL) were randomly assigned to receive treatment with placebo or rosiglitazone, 0.05, 0.25, 1.0, or 2.0 mg twice daily. The primary efficacy parameter was changed in FPG from baseline after 12 weeks of treatment. Secondary endpoints were changes in HbA1c, fructosamine, C peptide, insulin, lipid levels, and body weight (b.w.). Safety monitoring included clinical laboratory evaluations, electrocardiography, and echocardiography.

RESULTS

Rosiglitazone 1.0 and 2.0 mg b.i.d. produced significant decreases in FPG (p=0.0001). Fructosamine also decreased in patients treated with these two dosages (p=0.003 in the 2.0 mg b.i.d. group). Rosiglitazone 2.0 mg b.i.d. significantly reduced plasma insulin levels (p=0.0044) and free fatty acids (p=0.0014) compared with placebo. Total cholesterol (p=0.0001), HDL (p=0.0009), and LDL (p=0.0001) increased in the rosiglitazone 2.0 mg b.i.d. group, but there was no significant change in the total cholesterol/HDL ratio or triglyceride levels in any rosiglitazone treatment group. Clinically insignificant dose-dependent increases in b.w. were observed in the rosiglitazone 1.0 and 2.0 mg b.i.d. treatment groups.

CONCLUSIONS

Twelve weeks of treatment with rosiglitazone 2.0 mg b.i.d. significantly decreases fasting plasma glucose, fructosamine, plasma insulin, and free fatty acids in patients with type 2 diabetes. Longer studies using higher doses will be needed to assess the efficacy and safety of rosiglitazone in patients with type 2 diabetes mellitus.

Type 2 diabetes towards the new millennium--the relative importance of glycaemic versus lipid control

The prevalence of type 2 diabetes is set to increase. The UKPDS has shown that better average glycaemic control over time leads to a reduction in microvascular complications. Macrovascular outcomes are also reduced in overweight subjects treated with metformin. The UKPDS and our own data, however, show that the natural history of type 2 diabetes is one of progressive deterioration in glycaemic control despite treatment. Lipid parameters emerges as the strongest predictors of outcomes in type 2 diabetes and suggest where therapeutic endeavours might best be directed. Ongoing trials of lipid-modifying therapies in type 2 diabetes will help to substantiate this. In the meantime, efforts to improve glycaemic control should not be pursued to the exclusion of other abnormalities that may have a greater relevance to outcomes of type 2 diabetes. There is an urgent need for better prevention and intervention strategies as we approach the new millennium.