Prevention of cardiovascular outcomes in type 2 diabetes mellitus: trials on the horizon

There has been an explosion of interest in CVD and diabetes mellitus because of the epidemic nature of the diseases and their tight epidemiologic link. Clinical trials over the past decade have built substantial evidence for the role of lipid management, blood pressure control, and antiplatelet therapy in managing risk for CVD in patients who have diabetes mellitus. The many clinical trials underway will not only hone existing recommendations by establishing appropriate targets and techniques for lipid and blood pressure management, but also should demonstrate the role and most appropriate techniques for management of glycemia, flow-limiting coronary lesions, and obesity.

Quality of diabetes care in U.S. academic medical centers: low rates of medical regimen change

OBJECTIVE

To assess both standard and novel diabetes quality measures in a national sample of U.S. academic medical centers.

RESEARCH DESIGN AND METHODS

This retrospective cohort study was conducted from 10 January 2000 to 10 January 2002. It involved 30 U.S. academic medical centers, which contributed data from 44 clinics (27 primary care clinics and 17 diabetes/endocrinology clinics). For 1,765 eligible adult patients with type 1 or type 2 diabetes with at least two clinic visits in the 24 months before 10 January 2002, including one visit in the 6 months before 10 January 2002, we assessed measurement and control of HbA(1c), blood pressure, and cholesterol and corresponding medical regimen changes at the most recent clinic visit.

RESULTS

In this ethnically and economically diverse cohort, annual testing rates were very high (97.4% for HbA(1c), 96.6% for blood pressure, and 87.6% for total cholesterol). Fewer patients were at HbA(1c) goal (34.0% <7.0%) or blood pressure goal (33.0% <130/80 mmHg) than lipid goals (65.1% total cholesterol <200 mg/dl, 46.1% with LDL cholesterol <100 mg/dl). Only 10.0% of the cohort met recommended goals for all three risk factors. At the most recent clinic visit, 40.4% of patients with HbA(1c) concentrations above goal underwent adjustment of their corresponding regimens. Among untreated patients, few with elevated blood pressure (10.1% with blood pressure >130/80 mmHg) or elevated LDL cholesterol (5.6% with LDL >100 mg/dl) were started on corresponding therapy. Patients with type 2 diabetes were no less likely to be intensified than patients with type 1 diabetes.

CONCLUSIONS

High rates of risk factor testing do not necessarily translate to effective metabolic control. Low rates of medication adjustment among patients with levels above goal suggest a specific and novel target for quality improvement measurement.

Effects of exenatide (exendin-4) on glycemic control over 30 weeks in sulfonylurea-treated patients with type 2 diabetes

OBJECTIVE

This study evaluated the ability of the incretin mimetic exenatide (exendin-4) to improve glycemic control in patients with type 2 diabetes failing maximally effective doses of a sulfonylurea as monotherapy.

RESEARCH DESIGN AND METHODS

This was a triple-blind, placebo-controlled, 30-week study conducted at 101 sites in the U.S. After a 4-week, single-blind, placebo lead-in period, 377 subjects were randomized (60% men, age 55 +/- 11 years, BMI 33 +/- 6 kg/m(2), HbA(1c) 8.6 +/- 1.2% [+/-SD]) and began 4 weeks at 5 microg subcutaneous exenatide twice daily (before breakfast and dinner; arms A and B) or placebo. Subsequently, subjects in arm B were escalated to 10 microg b.i.d. exenatide. All subjects continued sulfonylurea therapy.

RESULTS

At week 30, HbA(1c) changes from baseline were -0.86 +/- 0.11, -0.46 +/- 0.12, and 0.12 +/- 0.09% (+/-SE) in the 10-microg, 5-microg, and placebo arms, respectively (adjusted P < 0.001). Of evaluable subjects with baseline HbA(1c) > 7% (n = 237), 41% (10 microg), 33% (5 microg), and 9% (placebo) achieved HbA(1c) <or= 7% (P < 0.001). Fasting plasma glucose concentrations decreased in the 10-microg arm compared with placebo (P < 0.05). Subjects in the exenatide arms had dose-dependent progressive weight loss, with an end-of-study loss in the 10-microg exenatide arm of -1.6 +/- 0.3 kg from baseline (P < 0.05 vs. placebo). The most frequent adverse events were generally mild or moderate and gastrointestinal in nature. No severe hypoglycemia was observed.

CONCLUSIONS

Exenatide significantly reduced HbA(1c) in patients with type 2 diabetes failing maximally effective doses of a sulfonylurea. Exenatide was generally well tolerated and was associated with weight loss.

The effects of oral anti-hyperglycaemic medications on serum lipid profiles in patients with type 2 diabetes

AIM

Patients with type 2 diabetes often have dyslipidaemia, putting them at risk of cardiovascular disease, and are frequently treated with oral anti-hyperglycaemic medications (OAMs). This review compares the effects of OAMs on serum lipids [total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs) and free fatty acids (FFAs)] in patients with type 2 diabetes.

METHODS

medline was searched for entries indexed from January 1966 to November 2002; search terms included the names of OAMs and serum lipids, limited to English language and human subjects. We selected clinical studies in type 2 diabetes of OAM monotherapy that included serum lipid data, treated all patients in a treatment group with the same drug, used therapeutic OAM doses not higher than the maximum recommended in the USA, compared therapy with baseline or placebo and specified statistical tests used. One unblinded investigator selected studies for inclusion. Data reported include number of patients, study length, OAM dose, serum lipid data at baseline and endpoint, p-values and statistical tests.

RESULTS

Data on the serum lipid effects of sulphonylureas, repaglinide, nateglinide and miglitol were inconclusive. Acarbose increased HDL-C and decreased LDL-C and voglibose reduced TC. Metformin at higher doses reduced TC; data on its effects on other lipids were inconclusive. Rosiglitazone increased LDL-C, HDL-C and TC and reduced FFAs but had no effect on TGs. Pioglitazone increased HDL-C and reduced TGs and FFAs but did not affect LDL-C or TC.

CONCLUSIONS

Lipid changes as a result of improved glycaemic control are not uniform findings associated with anti-diabetic therapy. Only metformin, acarbose, voglibose, rosiglitazone and pioglitazone had significant effects on the lipid profile. These effects should be considered when selecting OAMs for patients with type 2 diabetes.

Impact of adjunctive thiazolidinedione therapy on blood lipid levels and glycemic control in patients with type 2 diabetes

OBJECTIVE

This study was undertaken to assess the effect of pioglitazone hydrochloride and rosiglitazone maleate on blood lipid levels and glycemic control when these drugs are used as adjunctive therapy in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes receiving metformin and/or sulfonylurea (n = 829) were evaluated in this national, multicenter, retrospective study. Medical records from 318 endocrinology practices in the USA were randomly selected and screened for study inclusion. Data related to patient demographics and laboratory data were extracted from medical records and analyzed for primary and secondary outcomes.

MAIN OUTCOME MEASURES

The primary study outcome was the mean change in plasma rosiglitazone was associated with no significant triglyceride (TG) levels. Secondary outcome measures included mean changes in total cholesterol (TChol), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) concentrations and hemoglobin A1C levels.

RESULTS

With pioglitazone, TG levels declined by a mean of 51.5 mg/dl (P < 0.001), HDL-C levels rose by 3.3mg/dl (P < 0.001), and no change was seen in LDL-C or TChol. Treatment with change in TG levels and a 1.5mg/dl mean increase in HDL-C (P < 0.001). Furthermore, rosiglitazone therapy was associated with an 8 mg/dl mean increase in TChol (P < 0.001), and a 5.8 mg/dl mean increase in LDL-C (P < 0.001). Hemoglobin A1C levels were significantly reduced by approximately 1% within thiazolidinedione (TZD) cohorts (P < 0.001), but were not significantly different between study groups (P = 0.257).

CONCLUSIONS

Results from this study suggest that pioglitazone has a more favorable effect on lipid profiles of patients with type 2 diabetes compared with rosiglitazone. In particular, differences were observed in TG and LDL-C levels. Both TZDs were equivalent at reducing hemoglobin A1C levels. These differences in lipid effects may have an impact on cardiovascular outcomes. The full clinical importance of these lipid alterations must be further assessed in prospective trials.

Synthetic exendin-4 (exenatide) significantly reduces postprandial and fasting plasma glucose in subjects with type 2 diabetes

Despite the advent of new treatments, glucose control in the type 2 diabetes population is unsatisfactory. AC2993 (synthetic exendin-4; exenatide), a novel glucose-dependent insulinotropic agent, exhibited notable antidiabetic potential in two clinical studies in patients with type 2 diabetes. In study A, 24 subjects received sc injections of study medication (0.1 micro g/kg AC2993 or placebo) twice daily with meals for 5 d. Statistically significant reductions in mean postprandial circulating concentrations of glucose, insulin, and glucagon occurred following treatment with AC2993. In study B, 13 subjects receiving a single dose of study medication (0.05, 0.1, or 0.2 micro g/kg AC2993 or placebo) following an overnight fast had reduced fasting plasma glucose concentrations during the subsequent 8-h period. The relative glucose and insulin concentration profiles were consistent with glucose-dependent insulinotropism. AC2993 was well tolerated. Mild transient headache, nausea, and vomiting were the main adverse events. In conclusion, AC2993 acutely and markedly reduces fasting and postprandial glucose concentrations in patients with type 2 diabetes. During fasting, glucose-dependent enhancement of insulin secretion and suppression of glucagon secretion are the predominant mechanisms, and postprandially, slowing of gastric emptying is additionally operative. This robust antidiabetic effect warrants further evaluation of AC2993.

The insulin resistance syndrome and coronary artery disease

Insulin resistance is an increasingly common metabolic abnormality characterized by an impaired physiological response to insulin. The constellation of insulin resistance and several other metabolic and vascular disorders is known as the insulin resistance syndrome. The characteristic features of the insulin resistance syndrome include central obesity, hypertension, dyslipidemia, glucose intolerance and specific abnormalities of both endothelial cell and vascular function. Although insulin resistance can arise in response to aging, obesity and inactivity, there is a clear genetic component. Insulin resistance is not generally attributable to a single genetic defect. Indeed, it is very likely to be a polygenic disorder in most individuals. A genetic predisposition is suggested to be the demonstration of increased insulin resistance in first-degree relatives of patients with diabetes and by a high incidence of insulin resistance in specific populations. Epidemiological data have demonstrated a strong association between a clustering of specific factors and the risk of cardiovascular disease. The diagnosis of the insulin resistance syndrome remains a significant clinical challenge. At present, clinicians are faced with establishing a clinical diagnosis despite varying definitions of the disorder and controversy regarding how many components presage clinical events. A proposed approach to the management of patients with the insulin resistance syndrome is discussed.

A retrospective cohort study of diabetes mellitus and antipsychotic treatment in the United States

Treatment-emergent diabetes mellitus (DM) has been described for conventional and atypical antipsychotics. In our study, antipsychotic prescription claims from AdvancePCS's database were used to identify patients starting antipsychotic monotherapy. The relative risk of developing DM was determined using prescription claims for antidiabetic agents in the following cohorts: AdvancePCS general patient population, combined conventional antipsychotics, and combined atypical antipsychotics. Cox proportional hazards regression was used to adjust for differences in age, gender, and duration of antipsychotic exposure between cohorts in the estimation of risk of developing diabetes. Hazard ratios for developing DM in the combined conventional, combined atypical, and individual conventional and atypical antipsychotic treatment cohorts were greater than the AdvancePCS general patient population cohort. An increased risk of developing diabetes compared with the AdvancePCS general patient population was observed during treatment with conventional or atypical antipsychotics.

Serum 1,5-anhydroglucitol (GlycoMark ): a short-term glycemic marker

1,5-Anhydroglucitol (1,5-AG), the 1-deoxy form of glucose, has been measured and used clinically in Japan for over a decade to monitor short-term glycemic control. Evaluation of glucose control otherwise requires measuring plasma glucose or glycated proteins whose levels reflect average glucose concentration over the half-life of the protein analyzed. Hemoglobin A1c measurements reflect blood glucose levels over that past 2-3 months, while fructosamine can be used to evaluate glycemic control over 10-14 days. In contrast, 1,5-AG levels in blood respond within 24 h as a result of glucose's competitive inhibition of 1,5-AG reabsorption in the kidney tubule. When glucose levels rise, even transiently, urinary loss of 1,5-AG occurs, and circulating levels fall. Because of changes in renal hemodynamics in normal pregnancies, 1,5-AG appears of limited usefulness in evaluation of gestational diabetes. However, the characteristics of 1,5-AG levels in patients with moderate to near-normal glycemic control suggest that it may be a valuable complement to frequent self-monitoring or continuous monitoring of plasma glucose to confirm stable glycemic control. Measurements performed daily or weekly in a given patient would suggest that overall glycemic control has been stable or improved if 1,5-AG levels are stable or increasing. If 1,5-AG levels fall, greater attention to glucose monitoring and both lifestyle and medical management could be prescribed to correct the glycemic excursions that would underlie such changes. The behavior of this analyte is different from all others used in the management of diabetes, creating potential opportunities for its use in clinical practice.

Physician attitudes and practices and patient awareness of the cardiovascular complications of diabetes

OBJECTIVES

Studies were conducted to: 1) assess physicians' attitudes and practices in managing cardiovascular disease (CVD) risks in diabetes; and 2) determine the awareness of CVD risks among diabetic patients.

BACKGROUND

Cardiovascular disease is the leading cause of premature death among diabetic patients. As diabetes is often seen as a "glucose-centric" disease, it is unclear whether diabetic patients are talking with their doctors about CVD and other key clinical parameters of diabetes care such as blood pressure and cholesterol.

METHODS

An online survey was completed by a nationally representative sample of 900 physicians. The 95% confidence interval is approximately +/-2.5%. Before this study, a telephone survey of 2,008 people with diabetes was conducted using random, direct-dial screenings of U.S. households.

RESULTS

Ninety-one percent of physicians believe that their patients with diabetes are "very" or "extremely" likely to have a cardiovascular event. Although physicians report discussing CVD risk factors with 88% of their diabetic patients, they perceive their diabetic patients as being only moderately knowledgeable about their increased CVD risks. Sixty-eight percent of the people with diabetes do not consider CVD to be a serious complication of diabetes; they are more likely to be aware of complications such as blindness (65%) or amputation (36%) rather than heart disease (17%), heart attack (14%), or stroke (5%). Physicians perceive "poor compliance" with behavioral modifications and medication regimens as the greatest barriers to the management of CVD risks in diabetic patients.

CONCLUSION

Materials should be made available to help facilitate communication about CVD risks, and strategies for improving compliance with life-style modifications and multiple drug therapies should be explored. Efforts should continue to promote a comprehensive approach to the management of diabetes to include aggressive control of blood glucose and other CVD risk factors.

Efficacy, safety, and tolerability of once-daily niacin for the treatment of dyslipidemia associated with type 2 diabetes: results of the assessment of diabetes control and evaluation of the efficacy of niaspan trial

BACKGROUND

Diabetic dyslipidemia is characterized by high triglyceride levels; low high-density lipoprotein cholesterol levels; small, dense low-density lipoprotein particles; and high free fatty acid levels. Niacin reduces concentrations of triglyceride-rich and small low-density lipoprotein particles while increasing high-density lipoprotein cholesterol levels. It also lowers levels of free fatty acids and lipoprotein(a). However, the use of niacin in patients with diabetes has been discouraged because high doses can worsen glycemic control. We evaluated the efficacy and safety of once-daily extended-release (ER) niacin in patients with diabetic dyslipidemia.

METHODS

During a 16-week, double-blind, placebo-controlled trial, 148 patients were randomized to placebo (n = 49) or 1000 (n = 45) or 1500 mg/d (n = 52) of ER niacin. Sixty-nine patients (47%) were also receiving concomitant therapy with statins.

RESULTS

Dose-dependent increases in high-density lipoprotein cholesterol levels (+19% to +24% [P<.05] vs placebo for both niacin dosages) and reductions in triglyceride levels (-13% to -28% [P<.05] vs placebo for the 1500-mg ER niacin) were observed. Baseline and week 16 values for glycosylated hemoglobin levels were 7.13% and 7.11%, respectively, in the placebo group; 7.28% and 7.35%, respectively, in the 1000-mg ER niacin group (P=.16 vs placebo); and 7.2% and 7.5%, respectively, in the 1500-mg ER niacin group (P=.048 vs placebo). Four patients discontinued participation because of inadequate glucose control. Rates of adverse event rates other than flushing were similar for the niacin and placebo groups. Four patients discontinued participation owing to flushing (including 1 receiving placebo). No hepatotoxic effects or myopathy were observed.

CONCLUSION

Low doses of ER niacin (1000 or 1500 mg/d) are a treatment option for dyslipidemia in patients with type 2 diabetes.

Metabolic side effects of antipsychotics: focus on hyperglycemia and diabetes

Approximately 16 million people in the United States have diabetes, and the World Health Organization has estimated that the worldwide prevalence of diabetes will more than double from 1995 to 2025. Type 2 diabetes, the most common form of diabetes, may be 2 to 4 times more prevalent in patients with severe mental disorders. Within the psychiatric community, there is a great deal of concern about diabetes as a potential side effect of antipsychotic agents. An important population to remember in the context of treatment-emergent hyperglycemia is the 20 million people with impaired glucose tolerance (IGT) (fasting plasma glucose > 110 mg/dL and < 126 mg/dL or 2-hour postload glucose > 140 mg/dL and < 200 mg/dL according to the American Diabetes Association). This prediabetic condition has a 5% to 10% annual risk of converting to diabetes. One hypothesis for antipsychotic treatment-emergent diabetes during double-blind, randomized, controlled trials is that people who develop diabetes soon after the initiation of drug therapy for schizophrenia may have had undiagnosed IGT or diabetes before they started treatment. The emergence of diabetes in clinical practice may be due to an observation effect, but because the incidence of diabetes is greater in people with severe mental illnesses, it is crucial for psychiatrists to be aware of national guidelines for the diagnosis and treatment of type 2 diabetes.

Panel discussion on achieving glycemic control

This discussion contains excerpts from the satellite symposium, "Achieving Better Glycemic Control Through Management of Mealtime Glucose," presented at the American Association of Clinical Endocrinologists Tenth Annual Meeting and Clinical Congress in San Antonio, Texas, May 2, 2001.

Treatment of postprandial hyperglycemia in type 2 diabetes

Healthcare providers usually assess glycemic control in diabetic patients by measuring fasting plasma glucose and preprandial glucose levels, as well as hemoglobin A1c (HbA1c). Evidence now suggests that elevated postprandial glucose concentrations may contribute to suboptimal glycemic control. Several medications and insulins are available that have proved valuable for obtaining better control of blood glucose levels after meals. These agents may be particularly useful for managing patients with newly diagnosed type 2 diabetes and those who have near normal preprandial blood glucose levels but elevated HbA1c values. This article discusses the efficacy of some of these agents as monotherapy and in combination with other drugs.

Management of glycemia in type 2 diabetes

The management of type 2 diabetes has been revolutionized over the last 3 to 5 years as a result of dramatic changes in our health care system, new clinical trial data, novel pharmacologic agents, and a better understanding of appropriate methods for patient education regarding lifestyle issues. As a result, diabetes management has become much more heterogeneous, with dramatic differences in style and approach used by practitioners, whether diabetes specialists, primary care providers, or allied health professionals. Diabetes care has also become much more rewarding: The vast majority of patients can now achieve excellent glycemic control while leading full and unrestricted lives. In this article, a construct is reviewed by which comprehensive diabetes care may be approached in a primary care setting. The overall goal of diabetes management should be to provide an opportunity for patients to live out their normal life expectancies with minimal complications. In other articles, screening and treatment suggestions for diabetes complications are provided. Prospective interventional and epidemiologic studies demonstrate that glycemic control is critical to avoidance of complications; the methods to achieve glycemic control are the major focus of this chapter.

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

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

The case for a role for postprandial glucose monitoring in diabetes management

Strategies for the management of diabetes have evolved considerably over the last few years. We have moved from an era where glycemic control was aimed primarily at avoiding the symptoms associated with hyperglycemia (polyuria, polydipsia, weight loss, and fatigue) to an era where the primary objective is to attain near normal glycemic control in an effort to prevent or delay the microvascular and macrovascular complications of diabetes. This switch in emphasis--and the parallel developments in pharmacologic agents and lifestyle intervention techniques--translates into greater attention to glycemic control in the postprandial state. An important role for postprandial glucose monitoring with therapy aimed at achieving postprandial glucose targets is suggested by teleologic argument, biochemical information, epidemiologic study, and limited clinical trial data.