Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). UK Prospective Diabetes Study (UKPDS) Group

Aldose reductase inhibitors: therapeutic implications for diabetic complications

The 'late complications' of diabetes mellitus, i.e., nephropathy, neuropathy and retinopathy are firmly rooted in inadequate control of blood glucose: hyperglycaemia. Hyperglycaemia causes elevated cytosolic glucose and/or rates of glucose metabolism, i.e., 'hyperglysolia,' within cells of vulnerable tissues. Although the molecular basis for the pathogenic effects of hyperglysolia remains to be proven, substantial evidence points to a key role for increased glucose metabolism through a cytosolic enzyme, aldose reductase (AR). Recent human genetic and biochemical data link polymorphisms of the AR gene (technically called the AR2 gene) and elevated tissue levels of AR with strongly altered risks for diabetic complications. Despite several genetic reports failing to confirm such an association, there are now ten concordant reports from five continents that certain polymorphisms of the AR gene are associated with an ~ 3- to 20-fold higher risk for diabetic complications. Moreover, in US and European diabetic study populations the principle allele of the AR gene associated with elevated disease risk, the Z-2 allele, correlates with an ~ 2- to 3-fold increase in AR expression. These results, together with recent clinical, experimental and pharmacological data, provide powerful new support for the rationale for research and development of aldose reductase inhibitors (ARIs) targeted at slowing the progression of diabetic complications. Although past clinical trials of ARIs have been disappointing, this has stemmed from overly optimistic expectations, inadequate trial designs and lack of pharmacological robustness and/or acceptable systemic toleration of the agents tested. However, a more realistic and encouraging perspective for therapeutic expectations for ARIs has arisen from recent data revealing that the seemingly modest short-term effects of intensified glycaemic control and of pancreatic transplantation are followed by substantial long-term benefits on diabetic complications. In addition, robust inhibition of AR in human nerve has recently yielded dose-dependent efficacy on nerve structure and function. Thus, the quest for well-tolerated, potent ARIs continues to be a worthy and more urgent objective than ever before.

Effects of 3-week oral treatment with the antioxidant thioctic acid (alpha-lipoic acid) in symptomatic diabetic polyneuropathy

AIMS

To evaluate the efficacy and safety of short-term oral treatment with the antioxidant thioctic acid (TA) on neuropathic symptoms and deficits in patients with Type 2 diabetes mellitus with symptomatic polyneuropathy.

METHODS

Patients were randomly assigned to oral treatment with 600 mg of TA t.i.d. (n = 12) or placebo (n = 12) for 3 weeks. Neuropathic symptoms (pain, burning, paraesthesiae, and numbness) in the feet were scored at weekly intervals and summarized as a Total Symptom Score (TSS). The Hamburg Pain Adjective List (HPAL) and the Neuropathy Disability Score (NDS) were assessed at baseline and day 19.

RESULTS

At baseline the TSS, HPAL, and NDS were not significantly different between the groups. The TSS in the foot decreased from baseline to day 19 by -3.75 +/- 1.88 points (-47%) in the TA group and by -1.94 +/- 1.50 points (-24%) in the placebo group (P= 0.021 for TA vs. placebo). The total HPAL score decreased from baseline to day 19 by -2.20 +/- 1.65 points (-60%) in the TA group and by -0.96 +/- 1.32 points (-29%) in the placebo group (P = 0.072 for TA vs. placebo). The NDS decreased by -0.27 +/- 0.47 points in the TA group, whereas it slightly increased by +0.18 +/- 0.4 points in the placebo group (P = 0.025 for TA vs. placebo). No differences between the groups were noted regarding the rates of adverse events.

CONCLUSIONS

These preliminary findings indicate that oral treatment with 600 mg of TA t.i.d. for 3 weeks may improve symptoms and deficits resulting from polyneuropathy in Type 2 diabetic patients, without causing significant adverse reactions.

Z-4 allele upstream of the aldose reductase gene is associated with proliferative retinopathy in Japanese patients with NIDDM, and elevated luciferase gene transcription in vitro

We determined by PCR the number of (A-C)n repeats in the 2. 1 kb upstream of the aldose reductase (AR2) gene in healthy control subjects and in patients with NIDDM in Japanese. Sixty-one patients were recruited based on the severity of retinopathy and subdivided into two groups with proliferative retinopathy and without retinopathy. Japanese exhibited 10 different alleles in this region. The most prevalent allele was designated Z ((A-C)24 repeats) allele. The Z-4 allele was significantly associated with patients with proliferative retinopathy, whereas the Z+2 allele was significantly associated with patients without retinopathy. Erythrocyte AR2 protein levels were significantly elevated in patients exhibiting the Z-4 allele compared to those exhibiting other alleles. When Z-4 allele was ligated in transfection experiments to luciferase vector containing the promoter region of the AR2 gene, the construct showed significantly higher transcription of the reporter gene compared to constructs without (A-C) repeat or with Z-2, Z or Z+2 alleles. Our results suggest that the Z-4 allele in the 2. 1 kb upstream of the AR2 gene may enhance gene transcription and may be a genetic risk factor, which determines the predisposition to retinopathy in Japanese patients with NIDDM.

Hyperglycemia as a risk factor for cardiovascular disease in type 2 diabetes

According to several prospective population-based studies, glycemic control influences the risk for cardiovascular disease, including coronary heart disease, independently of conventional risk factors in patients with type 2 diabetes. Recent clinical trials, particularly the United Kingdom Prospective Diabetes Study, have shown that microvascular complications and macrovascular complications, although to a lesser extent, can be prevented in patients with type 2 diabetes with correction of glycemic control. However, in the treatment and prevention of cardiovascular disease in type 2 diabetes, all known cardiovascular risk factors should be attacked simultaneously.

Early diabetes-related complications in children and adolescents with type 1 diabetes. Implications for screening and intervention

Although children and adolescents with type 1 diabetes are faced with the threat of the acute complications of hypoglycemia and ketoacidosis on a day-to-day basis, in the long-term, the microvascular and macrovascular complications of the disease place them at greatest risk for serious morbidity and earlier than expected mortality. The families of children with diabetes should be provided with information about the complications of diabetes beginning at the time of diagnosis, and this information needs to be reinforced throughout the follow-up period. Appropriate surveillance for the earliest evidence of microvascular disease should begin at the onset of puberty and after 3 to 5 years of diabetes. Therapeutic interventions, particularly excellent metabolic control, may be exceedingly effective in preventing complication onset or significantly retarding the rate of progression.

Systolic hypertension and duration of diabetes mellitus are important determinants of retinopathy and microalbuminuria in young diabetics

This cross-sectional study looked at the prevalence of microalbuminuria and retinopathy in a cohort of 926 young, Type 1 and Type 2 diabetes mellitus (DM) patients, and determined the factors which were associated with these microvascular complications. The prevalence of microalbuminuria, defined as the albumin:creatinine ratio > or = 2.5 (for males) or > or = 3.5 mg/mmol (for females), was 13.4% in Type 1 DM, 69.5% in insulin-requiring Type 2 DM and 16% in Type 2 DM treated only with oral hypoglycemic agents. Compared to those with normal renal functions, these patients were older (P < or = 0.01), had significantly elevated blood pressures (P < 0.01 or P = 0.0001), and in the case of Type 1 DM, with a higher body mass index (P = 0.0001) and waist-hip ratio (P < 0.01). The prevalence of diabetic retinopathy in Type 1 DM was found to increase with the duration of diabetes, from 1.4% in the newly-onset (< 5 years), to 9.9% in those with 5-10 years disease, to 35% among patients with more than 10 years of diabetes (P < 0.0001). In this study, it was also observed that 10% of the Type 2 DM patients already had retinopathy within 5 years of diagnosis, and the prevalence increased significantly to 42.9% (P < 0.0001) among patients who had been diabetics for more than 10 years. Stepwise multiple regression analysis showed that besides the disease duration, systolic blood pressure was the most common and significant determinant for both microalbuminuria and retinopathy in both types of DM, thus implying that in order to reduce the risk of microvascular complications in diabetes mellitus, systolic and not just the diastolic blood pressure, should be effectively controlled.

The narrow therapeutic window of glycated hemoglobin and assay variability

Glycated hemoglobin is measured by a variety of assays, each of which has a unique normal level. Our purpose is to show that among the different assays available in the United States, using the same patient's blood sample, assay results may vary widely and may more or less easily achieve a glycated hemoglobin value within the normal range. The following assays were compared using the same patient's blood sample for each pair of assays: glycohemoglobin affinity assay (GHB Reader; Isolab, Akron, OH) versus gel electrophoresis assay (n = 76); Isolab versus ion capture assay (IMX; Abbott Laboratories, Irving, TX) (n = 57); monoclonal antibody assay (DCA2000; Bayer Diagnostics, Pittsburgh, PA) versus IMX (n = 100); and high-performance liquid chromatography (HPLC) assay (Bio-Rad Variant A1c; Bio-Rad Laboratories, Richmond, CA) versus IMX assay (n = 55). Our analyses indicate that a relative ranking can be established for the ease of achieving a normal glycated hemoglobin level. The ranking indicates that the most stringent or difficult assays for achieving a normal level are the Isolab and DCA2000 assays. The intermediate assays are the IMX and Bio-Rad Variant, and the easiest method for achieving a normal value is the gel electrophoresis assay. Our results indicate that various glycated hemoglobin assays vary widely and are associated with more or less difficulty for an individual patient to achieve a glycated hemoglobin level within the normal range. These results are especially significant with respect to (1) the clinically narrow therapeutic window of glycated hemoglobin values in type 1 diabetes to avoid rapidly advancing severe hypoglycemia rates and chronic microvascular complication rates, and (2) the glycated hemoglobin threshold for rapidly advancing macrovascular disease in both type 1 and type 2 patients.

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.

Defining and measuring quality of diabetes care

The literature on diabetes mellitus has increasingly focused on the quality of diabetes care and its measurement. Serious and widespread quality problems exist throughout American medicine. Current efforts to improve will not succeed unless we undertake a major, systematic effort to overhaul how we deliver health care services, educate and train clinicians, and assess and improve quality. This article defines the components of quality of diabetes care provision and discusses approaches to their measurement individually and globally.

The natural history of type 2 diabetes. Implications for clinical practice

This article reviews the natural history of type 2 diabetes and emphasizes that the disease is a continuum from impaired glucose tolerance and impaired fasting glucose to frank diabetes. Understanding this natural history aids the clinician in identifying those individuals most at risk for developing type 2 diabetes. Early intervention may significantly limit the severity of the microvascular and macrovascular complications of diabetes. Additionally, this article discusses oral antidiabetic agents and reviews their potential effectiveness at the different stages in the continuum to aid the clinician in developing a treatment strategy.

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.

Inadequate suspension of neutral protamine Hagendorn (NPH) insulin in pens

BACKGROUND

Neutral protamine Hagedorn (NPH) insulin is one of the most commonly used insulins in insulin pens. NPH in pen cartridges is in a two-phase solution with either a solvent or a short-acting insulin, and needs adequate mixing for complete resuspension. We assessed whether NPH insulin is accurately resuspended by patients and the association of suspension errors with diabetes control.

METHODS

109 patients (39 with type 1 diabetes) who had received conventional diabetic education had the NPH content of their cartridges measured by an optical system; a control cartridge was designated as 100%. A questionnaire was used to assess clinical details and insulin suspension habits. After the information about residual insulin error was known, all 109 patients were instructed to resuspend their insulin by rolling and tipping the pen 20 times. 52 patients were randomly selected to have cartridges re-analysed 3 months or 6 months later and to complete another questionnaire.

FINDINGS

Only 10 (9%) of 109 patients tipped and rolled their pen more than ten times. NPH insulin content ranged from 5% to 214% and varied by more than 20% in 71 (65%) of 109 cartridges. There was no relation between inadequate suspension and the frequency of hypoglycaemic episodes (r=0.2, p=0.08). For all patients, there was a correlation between the absolute error of NPH suspension and cycles of rolling and tipping the pen (r=-0.23, p<0.05). After education on resuspending the pen's contents, data were available from 44 of 52 patients; suspension errors decreased in 35 (80%), were unchanged in three (7%), and increased in six (13%). The 35 patients with improved NPH insulin suspension had fewer mean hypoglycaemic episodes per month compared with the previous period (0.4 [SD 0.1] vs 1.0 [0.3], p<0.05). Mean HbA1c values in patients with improved suspension quality did not differ from baseline (8.4% [0.3] vs 8.9% [0.4], p=0.07). Mixing of NPH insulin by a mechanical device showed that at least 20 cycles were necessary before complete resuspension was obtained.

INTERPRETATION

Inadequate NPH insulin suspension is common. We recommended that patients tip pens that contain NPH insulin at least 20 times, since inadequate mixing may impair diabetes control.

The effects of tolbutamide on lipoproteins, lipoprotein lipase and hormone-sensitive lipase

Type 2 diabetic patients are at increased risk to develop atherosclerotic vascular disease. These patients are often treated with sulphonylurea derivatives, and it has been suggested that this treatment might contribute to the increased atherosclerotic process. The aim of the present study was therefore to investigate whether tolbutamide influences lipid metabolism in such a way that the atherosclerotic process may be promoted. Addition of tolbutamide (5-500 mg/l) to isolated rat fat adipocytes inhibited the lipoprotein lipase (LPL) activity in a dose-dependent manner to levels about 50% of those registered in the absence of tolbutamide. This effect was due to inhibition of the activation of the enzyme in the tissue and not to interference with the interaction of enzyme with its substrate. Addition of tolbutamide (500 mg/l) also inhibited noradrenaline (100 nM) and isoprenaline (40 nM)-induced lipolysis by 48.1 +/- 7.4% (mean +/- S.E.M.) and 47.3 +/- 5.5%, respectively. The decreased lipolysis in tolbutamide preincubated adipocytes was shown to be the result of an inhibition of the phosphorylation of hormone sensitive lipase (HSL). Three months of tolbutamide treatment (0.5 g t.i.d.) in diet treated type 2 diabetic patients did not influence the plasma concentrations of cholesterol, triglycerides, LDL cholesterol, HDL cholesterol as well as HDL triglycerides and HDL phospholipids, and there were no differences compared to placebo treated patients. There was a tendency towards a decrement in the elimination rate of exogenous triglycerides in the tolbutamide group (P = 0.0801). No differences between the groups and no treatment effects were seen on LPL and hepatic lipase activities. In conclusion, our in vitro data show that tolbutamide has dual effects on lipid transport, with impairment of the LPL system, which would tend to decrease plasma lipoproteins by reducing hepatic production of lipoproteins. In vivo, these two effects seem to balance each other and plasma lipoprotein levels remain unaffected.

Clinical management of diabetic nephropathy

From the viewpoint of nephrologists dealing with diabetic patients with ESRD and the associated complications and devastating prognosis, the need to reduce the incidence, and delay the rate of progression of diabetic nephropathy is obvious. Studies published within the last year have provided support for views that seem intuitively obvious; that improved glycaemic control and reduced blood pressure are associated with delayed onset and delayed progression of diabetic nephropathy. These reports have also demonstrated the difficulty of achieving ideal blood pressure targets and glycaemic control in diabetic patients. Thus, even with available therapy it is likely that improved compliance and achieving targets will have a major impact on disease outcome. There is evidence in several subgroups that ACEi are beneficial over other agents and the favourable side-effect and efficacy profile of these agents makes it reasonable to suggest that they should be used 'first line' in all patients with diabetes unless specifically contra-indicated. However, the failure to readily achieve blood pressure targets and the need for polypharmacy suggest that novel agents are required. We believe that statin therapy will have a major impact on CVD in diabetic patients and is also likely to delay progression; studies assessing the combined affect of anti-hypertensive and statin therapy specifically on the development and progression of diabetic nephropathy will be necessary before evidence-based recommendations can be made. The role for newer agents and targeting high risk groups using genetic markers remains uncertain but we await there development with interest. The future can only get better for patients with DN.

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.

Long term effect of a structured inpatient diabetes teaching and treatment programme in type 2 diabetic patients: influence of mode of follow-up

Structured diabetes teaching and treatment programmes (STTP) are increasingly offered for patients with diabetes to improve metabolic control. We prospectively studied the long term-effect of STTP on metabolic control and knowledge of diabetes in patients with type 2 diabetes. In addition, differences in the mode of follow-up by a university diabetes centre (UDC) versus general practitioner (GP) were assessed. Of the 64 patients with type 2 diabetes (61 +/- 10 years old, diabetes duration 11 +/- 7 years) included in the study 52 could be reevaluated after 2 years. Of those, 31 were followed up by the UDC and 21 by their GPs who received detailed follow-up instructions from the UDC. In all patients, HbA1c decreased from 9.1 +/- 0.3% before the programme to 8.3 +/- 0.3% 2 years after the programme (P = 0.004), whereas body mass index increased from 28.8 +/- 0.8 to 30.3 +/- 0.9 kg/m2 (P < 0.001). Patients had a significantly better knowledge of diabetes and diet 2 years after the programme. For all parameters tested, none of the changes differed between patients managed by the UDC versus those managed by their GP. However, patients who chose follow-up by the UDC were more obese and had a better knowledge of diabetes. In conclusion, the STTP for patients with type 2 diabetes was effective in improving the long-term glycaemic control and knowledge of diabetes. Moreover, with precise therapeutic goals and follow-up instructions given to patient and GP this improvement was independent of the mode of outpatient follow-up.

Anti-oxidant therapy for the treatment of coronary artery disease

Coronary artery disease is the most common cause of death in developed countries. It may present in many different ways, but most frequently as a myocardial infarction, sudden death, angina or heart failure. Preventive measures in relation to coronary artery disease are particularly important because of its high incidence, high mortality and because most patients die outside hospital. Since the oxidation of low density lipoprotein cholesterol (LDL-C) is a critical early step in the process of atheroma formation, taking anti-oxidants to prevent LDL-C oxidation may prove a very effective means of reducing coronary artery disease mortality. However, the role of anti-oxidants in coronary artery disease prevention needs to be evaluated as part of an overall strategy that includes pharmacological and non-pharmacological measures, which are described in this review. In addition, a more structured and scientific approach to anti-oxidant therapy needs to be adopted. This requires that evidence for oxidative stress in a particular condition is obtained, the nature and severity determined and an appropriate anti-oxidant is administered, in an effective dose, which can be shown to correct the oxidative stress. When this is achieved, meaningful clinical trials should be possible, which will determine the place of anti-oxidant therapy for the specified condition.

A five-year evaluation of intervention in diabetes care in Trinidad and Tobago

AIMS

To evaluate an intervention to improve diabetes care in government-run heath centres in Trinidad and Tobago over 5 years.

METHODS

A cross-sectional survey of 690 subjects with clinical diabetes attending nine health centres was carried out in 1993. The intervention was: reports to the Ministry of Health, dissemination of management guidelines and annual training workshops for healthcare staff. Re-evaluation was through a survey of 1579 subjects with diabetes, attending 23 health centres in 1998.

RESULTS

Comparing 1993 with 1998, foot examinations in the previous year increased from 38 (6%) to 346 (22%) and fundoscopy from 6 (1%) to 139 (9%). For subjects attending for 1 year or less, 34/96 (35%) had dietary advice recorded in 1993 compared with 77/143 (54%) in 1998. Exercise advice was recorded for 3/96 (3%) in 1993 and 48/143 (34%) in 1998. In 1993, 329 (48%) were taking chlorpropamide but this fell to 57 (4%) in 1998. Glibenclamide use increased from 214 (31%) to 856 (54%) and gliclazide from four (1%) to 205 (13%). In 1993, 198/338 (56%) of hypertensive subjects were taking Brinerdin, this fell to 56/829 (7%) in 1998 while use of thiazide diuretics, methyldopa and angiotensin-converting enzyme (ACE) inhibitors increased. There were no changes in indicators of metabolic control, blood pressure control or body weight.

CONCLUSIONS

Use of audit data to inform health policy and practice, linked with educational interventions, may modify patterns of care in government-run primary care health centres in a middle-income country with a high prevalence of diabetes.

End-stage renal failure in type 2 diabetes: A medical catastrophe of worldwide dimensions

The incidence of patients with end-stage renal failure and diabetes mellitus type 2 as a comorbid condition has increased progressively in the past decades, first in the United States and Japan, but subsequently in all countries with a western lifestyle. Although there are explanations for this increase, the major factor is presumably diminishing mortality from hypertension and cardiovascular causes, so that patients survive long enough to develop nephropathy and end-stage renal failure. This review summarizes the striking differences between countries against the background of a similar tendency of an increasing incidence in all countries. Survival on renal replacement therapy continues to be substantially worse for patients with type 2 diabetes. A major reason for this observation is that patients enter renal replacement programs with cardiovascular morbidity acquired in the preterminal phase of renal failure. It is argued that the challenge for the future will be better patient management in earlier phases of diabetic nephropathy to attenuate or prevent progression, as well as cardiovascular complications.

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.

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.

Insulin delivery using pen devices. Simple-to-use tools may help young and old alike

Results of landmark studies such as the Diabetes Control and Complications Trial and the United Kingdom Prospective Diabetes Study are encouraging patients with diabetes and health professionals alike to strive to achieve and maintain the best possible glucose control. Insulin pens have the potential to become a major asset for improving compliance among diabetic patients. These devices offer substantial improvements in convenience, freedom, and flexibility for all insulin-using patients. Furthermore, more accurate dosing associated with use of the pen may hold the key to better longterm outcomes.

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.

Metformin as secondary therapy in a defined population with type 2 diabetes

This study was undertaken to assess the effect of metformin as a second-line oral antihyperglycemic agent in a defined population with type 2 diabetes mellitus. We measured the extent and circumstances of metformin use in the 15,000-person diabetes registry of a large, group-model health maintenance organization (HMO). Among subsets of patients in whom adequate glycemic control could not be maintained with sulfonylurea (SU) therapy, we compared glycemic control before and after metformin use to glycemic control during a similar interval before metformin was introduced. Metformin users were significantly more likely than nonusers to have had poor glycemic control at baseline. Nearly two thirds (63.8%) of patients with a glycosylated hemoglobin (Hb A1c) level >10% switched to metformin, as did 46.3% of those with an Hb A1c level of 8% to 10%. In all patients (metformin users and nonusers) in whom SU therapy failed to maintain glycemic control, Hb A1c levels decreased 0.9% after metformin was introduced, compared with a decrease of 0.4% during the control period. In a group-model HMO that promoted the use of metformin as second-line therapy in patients unable to maintain glycemic control with SU therapy, metformin reduced hyperglycemic levels.

The lipoprotein profile differs during insulin treatment alone and combination therapy with insulin and sulphonylureas in patients with Type 2 diabetes mellitus

AIMS

To study whether changes in endogenous insulin secretion at the same glycaemic control affect the plasma concentrations of lipoproteins in patients with Type 2 diabetes mellitus.

METHODS

Fifteen patients, age 59+/-2 years (mean +/- SEM), body weight 86.3+/-3.0kg, body mass index 29.6+/-0.9 kg/m2 were treated with sulphonylurea and insulin in combination or with insulin alone in a randomized, double-blind, crossover study. All patients were treated with a multiple daily injection regimen with the addition of glibenclamide 10.5 mg daily or placebo tablets.

RESULTS

During combination therapy, the dose of insulin was 25% less (P < 0.002) and there was a 29% increase in plasma C-peptide concentration (P = 0.01). Plasma levels of free insulin were not changed. Plasma levels of sex hormone-binding globulin (SHBG) and insulin-like growth factor-binding protein (IGFBP)-1 were lowered. There were no differences in the 24-h blood glucose profiles or HbA1c (6.0+/-0.2 vs. 6.3+/-0.2%; P = 0.16). Body weight was similar. There was a significant decrease in plasma LDL cholesterol (3.04+/-0.24 vs. 3.41+/-0.21 mmol/l; P = 0.04), apolipoprotein A1 and of lipoprotein(a) but an increase in VLDL-triglycerides (1.36+/-0.31 vs. 0.96+/-0.16 mmol/l; P = 0.02) during combination therapy. The ratio between LDL cholesterol and apolipoprotein B concentrations was significantly lower during combination therapy (P < 0.01).

CONCLUSIONS

Combination therapy with insulin and sulphonylureas increases portal insulin supply and thereby alters liver lipoprotein metabolism when compared with insulin therapy alone.

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.

Insulin lispro in the treatment of patients with type 2 diabetes mellitus after oral agent failure

This study assessed the safety profile and efficacy of a new combination therapy (insulin lispro plus sulfonylurea) in patients with type 2 diabetes mellitus experiencing secondary oral agent failure. A total of 423 patients were randomly assigned to 3 treatment groups: preprandial insulin lispro plus sulfonylurea (L + S), bedtime neutral protamine Hagedorn (NPH) insulin plus sulfonylurea (N + S), and preprandial insulin lispro plus bedtime NPH insulin (L + N). Mean decreases in glycosylated hemoglobin from baseline were 1.60%+/-1.27% for patients receiving L + S, 1.21%+/-1.21% for those receiving N + S, and 1.40%+/-1.46% for those receiving L + N (within treatment, P<0.001; for L + S vs. N + S, P = 0.003). Fasting blood glucose level was higher in patients receiving L + S (171+/-46.5 mg/dL) or L + N (166+/-52.5 mg/dL) than in those receiving N + S (144+/-48.2 mg/dL) (P<0.001, for both comparisons). Conversely, postprandial blood glucose level was lower in patients receiving L + S (165+/-41.6 mg/dL) or L + N (165+/-46.3 mg/dL) than in those receiving N + S (213+/-58.3 mg/dL) (P<0.001, for both comparisons). The overall rate of hypoglycemia (episodes per 30 days) was not statistically significant when the L + S, N + S, and L + N therapies were compared (0.99+/-1.74 vs. 0.87+/-2.31 vs. 1.16+/-2.38, respectively). The rate of nocturnal hypoglycemia was lowest in the L + S group (0.00+/-0.00 vs. 0.10+/-0.37 for the N + S group vs. 0.15+/-0.54 for the L + N group; P = 0.004). L + S, which has a safety profile equal to those of N + S and L + N, is an effective treatment for patients with type 2 diabetes who experience oral sulfonylurea agent failure. L + S offers an alternative to these established combination therapies in patients whose type 2 diabetes cannot be controlled with a sulfonylurea alone.

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.

Treatment of severe proliferative retinopathy and diabetic maculopathy

Strict blood glucose control, early detection and surveillance of diabetic retinopathy by means of validated screening programmes, and judicious use of laser photocoagulation can greatly reduce the risk of visual loss in diabetes. Some patients however, have aggressive neovascular disease resistant to laser treatment, or present at a late stage with advanced fibroproliferative disease, and may progress rapidly to blindness. In the elderly with Type 2 disease, diabetic maculopathy is more common and requires a different therapeutic approach. The present article describes two diabetic patients and discusses the management of patients with severe proliferative retinopathy or diabetic maculopathy.

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.

Effects of long-term treatment with alpha-glucosidase inhibitor on the peripheral nerve function and structure in Goto-Kakizaki rats: a genetic model for type 2 diabetes

BACKGROUND

Continuous hyperglycemia is implicated in the pathogenesis of chronic diabetic complications. It is not well known, however, how and to what extent the development of neuropathy is inhibited by blood glucose control in subjects with Type 2 diabetes. We investigated therefore the effects of an alpha-glucosidase inhibitor (voglibose; Vg) on neuropathic changes in diabetic Goto-Kakizaki (GK) rats, a genetic model for Type 2 diabetes.

METHODS

Twelve week-old male GK rats were given a diet containing Vg (50 ppm) for 24 weeks and monitored for blood glucose, glycated hemoglobin, motor nerve conduction velocity (MNCV). At the end of the administration period (Na(+), K(+))-ATPase activity and the structure of the peripheral nerves were examined. Age- and sex-matched normal Wistar rats were treated similarly and served as controls.

RESULTS

GK rats showed fasting hyperglycemia after 8 weeks of age, and Vg treatment significantly lowered levels of blood glucose and glycated hemoglobin. Slowing of MNCV to 80% of normal control levels was detected in GK rats. Vg treatment inhibited this delay by 24% at 24 weeks and 57% at 36 weeks of age. Nerve (Na(+), K(+))-ATPase activity was reduced to 80% of normal control levels in GK rats and was restored by Vg treatment. Teased fiber studies revealed a higher incidence of fibers with paranodal, segmental demyelination and axonal degeneration in GK rats. Vg treatment significantly inhibited the development of these nerve-fiber abnormalities.

CONCLUSIONS

Lowering of high blood glucose levels achieved by the use of Vg in GK rats improved MNCV and demyelinative nerve changes with restoration of (Na(+), K(+))-ATPase activity.

The effects of intensive glycemic control on neuropathy in the VA cooperative study on type II diabetes mellitus (VA CSDM)

To determine whether a difference in HbA(1c) could be safely sustained between a standard therapy (STD) arm and an intensive therapy (INT) arm, while maintaining HbA(1c) levels in both arms within a range acceptable in community practice. The effects of intensive treatment on various parameters were studied in this feasibility trial. We report here the results of 24 months of INT on peripheral and autonomic neuropathy.A prospective trial was conducted in five medical centers in 153 men of 60 +/- 6 years of age who had a known diagnosis of diabetes for 7.8 +/- 4 years. They were randomly assigned to a standard insulin treatment group (one morning injection per day) or to an intensive therapy group designed to attain near-normal glycemia and a clinically significant separation of glycohemoglobin from the standard arm. A four-step plan was used in the intensive therapy group along with daily self-monitoring of glucose: (1) an evening insulin injection, (2) the same injection adding daytime glipizide, (3) two injections of insulin alone, and (4) multiple daily injections. Peripheral neuropathy was diagnosed clinically by a history and physical examination, and by abnormal autonomic neuropathy Valsalva ratio (VR < 1.2) and RR variation (RRV < 10). An average HbA(1c) separation of 2.07% was achieved with INT, having HbA(1c) at or below 7.3% (p = 0. 001 versus STD). Baseline prevalence of peripheral neuropathy was 53% in STD, and 48% in INT. By 24 months, the prevalence increased to 69% in STD (p = 0.005 versus baseline), and to 64% in INT (p = 0. 008 versus baseline, but no different than STD). Though INT did not reverse all elements of peripheral neuropathy, there was a decreased prevalence of cranial neuropathy (p = 0.053 versus STD) and more frequent preservation of touch sensation in the upper extremities (p = 0.03 versus STD) in INT. At baseline, an abnormal Valsalva ratio and/or RR variation was seen in 38% of STD and 31% of INT. By 24 months in STD, the prevalence rose to 55% (p = 0.0067 versus baseline), and in INT, to 48% (p = 0.012 versus baseline and no different from STD). The prevalence of erectile dysfunction increased from 53% at baseline to 73% at 2 years, p = 0.002 in STD, and from 51% to 73% at 2 years (p = 0.003 versus baseline) and no different from STD. There was no change in the frequency of abnormal gastrointestinal or sweating symptoms. Our conclusion was that 2 years of meticulous glycemic control did not decrease overall prevalence of peripheral or autonomic neuropathy. In fact, the prevalence rose equivalently and significantly in both treatment arms. There was some benefit, however, in decreased frequency of cranial neuropathy and better preservation of touch sensation in INT.