Effect of early addition of rosiglitazone to sulphonylurea therapy in older type 2 diabetes patients (>60 years): the Rosiglitazone Early vs. SULphonylurea Titration (RESULT) study

Anti-Diabetic Potentials of Thiazolidinedione Analogues with Efficient Synthetic Procedures: A Review of Literature

Background::

Diabetes mellitus refers to one of the leading cause of diseases that affect large populations of human and is characterized by a high glucose level in the blood (also known as hyperglycemia). Thiazolidinedione (TZD) is a five-member heterocyclic compound consisting of three carbons, nitrogen and sulfur. It is also known as glitazones, can be used as potent hypoglycemic agents and is also reduce many other cardiovascular risk factors including percutaneous coronary intervention, carotid and coronary atherosclerosis. As it plays a very important role in the field of medicinal chemistry or pharmaceutical sciences, novel medicine developed and many are on underdevelopment, these derivatives have thiazolidinedione as their primary nucleus.

Objective::

This article has discussed the different synthetic procedures of thiazolidinediones that exhibited potential antidiabetic activity by the activation of PPAR-γ, by reducing the blood glucose levels and by different metabolic process incorporation.

Conclusion::

Thiazolidinediones has effective profile as the future investigational drug and can be processed in drug discovery because of its efficient anti-diabetic potential.

A Systematic Review of Patient-Reported Satisfaction with Oral Medication Therapy in Patients with Type 2 Diabetes

OBJECTIVE

To provide a comprehensive comparative evaluation of the psychometric properties of satisfaction with medication surveys used for patients with type 2 diabetes (T2D) in clinical trials.

METHODS

Instruments identified through a comprehensive literature search were evaluated based on the following criteria: disease specificity, peer-reviewed publication (administered in English in patients with T2D on oral therapy), and availability of psychometric properties.

RESULTS

Eight instruments (Diabetes Medication Satisfaction [DiabMedSat]; Diabetes Treatment Satisfaction Questionnaire, status version [DTSQs]; Diabetes Medication System Rating Questionnaire [DMSRQ]; Diabetes Medication System Rating Questionnaire-Short Form [DMSRQ-SF]; Diabetes Tablet Treatment Questionnaire [DTTQ]; Perceptions About Medications for Diabetes [PAM-D]; Satisfaction with Oral Anti-Diabetic Agent Scale [SOADAS]; Diabetes Medication Satisfaction Tool [DMSAT]) were included in the study based on the predefined inclusion criteria. Seven of the instruments (all but DTTQ) utilized patients in the survey development process. All eight instruments could be completed within 15 minutes and thus were considered practical. DiabMedSat, DMSRQ, and DMSRQ-SF encompassed broader aspects of satisfaction than the other instruments. All of the instruments reviewed showed substantial floor or ceiling effects, except for DMSAT and DiabMedSat, without complete information. The DMSRQ and DMSRQ-SF each satisfied the criteria for reliability. DiabMedSat, DTSQs, DMSRQ, DMSRQ-SF, SOADAS, and DMSAT showed favorable convergent and discriminant validity. All of the instruments except DTTQ were determined to satisfactorily meet the criteria of responsiveness.

CONCLUSION

Although it is up to researchers to decide which instrument to use according to the resources available and specific aims of their studies, DMSRQ and DSMRQ-SF were recommended based on the evaluative criteria employed in this study.

Treatment variation related to comorbidity and complications in type 2 diabetes: A real world analysis

A complex comorbidity status may cause treatment variance interfering with type 2 diabetes (T2D) guideline-confirm therapy and influence the occurrence of complications but evidence on its relationships and alternative treatments are lacking. This study aimed to identify treatment variance and common T2D drug treatment related to comorbid status and the association with comorbidity and complications.Based on Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC) databases, we conducted a retrospective, observational exploratory study including 7123 T2D patients without microvascular-, macrovascular complication. We explored patterns of comorbid status and drug treatment and its relation to the development of complications within 4-year period. Analysis was performed by two-step cluster analysis and nonlinear canonical correlation analysis.64.9% had at least one other chronic disease and 61.7% of T2D patients were treated with >1 glucose lowering drugs. 15.8% developed microvascular complications and 6.5% had ischemic heart disease or cerebrovascular complications. 82.2% of the treatment patterns were identified among T2D patients with 1 or no comorbidity while 14.4% was identified in patients with ≥2 comorbidities. Combination treatment such as, sulfonylurea or dipeptidyl peptidase-4 inhibitors combined with metformin were observed. Occurrence of microvascular- or/and macrovascular complication and its relation to comorbidity and treatment pattern was not identified.In conclusion, as number of comorbidity increased with both type of comorbidity (diabetes related-, unrelated) present, common treatment patterns were less or not identified. More treatment variance was observed in patient's groups that had developed complications.

Trends in Antihyperglycemic Medication Prescriptions and Hypoglycemia in Older Adults: 2002-2013

Background

Over the last decade, several new antihyperglycemic medications have been introduced including those associated with a lower hypoglycemia risk. We aimed to investigate how these medications are being prescribed to older adults in our region.

Methods

We conducted population-based cross-sectional analyses of older adults (mean age 75 years) with treated diabetes in Ontario, Canada from 2002 until 2013, to examine the percentage prescribed insulin, sulphonylureas, alpha-glucosidase inhibitors, metformin, thiazolidinediones, meglitinides, and dipeptidyl peptidase-4 inhibitors. Over the study period, we also examined their hospital encounters for hypoglycemia (emergency room or inpatient encounter).

Results

The mean age of treated patients increased slightly over the study quarters and the proportion that were women declined. With the exception of chronic kidney disease, cancer, dementia, and neuropathy, the percentage with a comorbidity appeared to decline. The percentage of treated patients prescribed metformin, gliclazide and dipeptidyl peptidase-4 inhibitors increased as did combination therapy. Glyburide and thiazolidinedione prescriptions declined, and insulin use remained stable. In those with newly treated diabetes, the majority were prescribed metformin, with smaller percentages prescribed insulin and other oral agents. Although the absolute number of treated patients with a hypoglycemia encounter increased until mid-2006 and then decreased, the overall percentage with an encounter declined over the study period (0.8% with an event in the first quarter, 0.4% with an event in the last quarter).

Conclusions

Antihyperglycemic medications with safer profiles are being increasingly prescribed to older adults. In this setting there has been a decrease in the percentage of treated patients with a hospital encounter for hypoglycemia.

Review of patient-reported outcome instruments measuring health-related quality of life and satisfaction in patients with type 2 diabetes treated with oral therapy

OBJECTIVE

Treatments and their mode of administration may represent a burden for patients and can therefore impact their health-related quality of life (HRQL) or treatment/health satisfaction. Patients with type 2 diabetes mellitus (T2DM) can be treated with oral hypoglycemic agents (OHAs), injectable medications (such as insulin), or a combination of agents. This review aimed to identify patient-reported outcome (PRO) instruments measuring HRQL and/or satisfaction that could differentiate between oral medications based on medication related attributes such as efficacy, tolerability, weight loss, dosing frequency and pill burden.

RESEARCH DESIGN AND METHODS

Medline, Embase, PsycINFO, Cochrane Library and the Patient-Reported Outcome and Quality of Life Questionnaires (PROQOLID) biomedical databases were searched to identify instruments and document their development methodology, content and psychometric properties (i.e. validity, reliability), responsiveness and ability to detect changes between treatments.

RESULTS

Nineteen instruments were retained based on their potential to differentiate between OHAs. Ten instruments assessed HRQL, amongst which the Audit of Diabetes Dependent Quality of Life, Diabetes 39, Diabetes Health Profile and Impact of Weight on Quality of Life displayed good psychometric properties in T2DM populations and comprehensive HRQL content. Nine instruments assessed satisfaction. Both the Oral Hypoglycemic Agent Questionnaire (OHAQ) and Diabetes Medication Satisfaction (DiabMedSat) Questionnaire have highly relevant content regarding drug attributes. The OHAQ is specific to oral treatment and the DiabMedSat includes HRQL items. The Diabetes Treatment Satisfaction Questionnaire is a standard instrument that is extensively used and provides conclusive results in studies of patients with T2DM.

CONCLUSIONS

Very few of the existing PRO instruments are specific to OHAs. Despite satisfaction instruments being recommended to differentiate between OHAs in studies of T2DM based on medication attributes, we find that none of the existing instruments appear to be useful in detecting differences between treatments, therefore limiting their use in clinical and observational research.

Pleiotropic effects of thiazolidinediones: implications for the treatment of patients with type 2 diabetes mellitus

Thiazolidinediones (TZDs) are insulin-sensitizing antidiabetes agents that act through the peroxisome proliferator-activated receptor-γ to cause a durable improvement in glycemic control in patients with type 2 diabetes mellitus. Although less well recognized, TZDs also exert a protective effect on β-cell function. In addition to their beneficial effects on glucose homeostasis, TZDs-especially pioglitazone-exert a number of other pleiotropic effects that make them ideal agents as monotherapy or in combination with other oral agents, glucagon-like peptide-1 analogs, or insulin. Pioglitazone improves endothelial dysfunction, reduces blood pressure, corrects diabetic dyslipidemia, and reduces circulating levels of inflammatory cytokines and prothrombotic factors. Pioglitazone also redistributes fat and toxic lipid metabolites in muscle, liver, β cells, and arteries, and deposits the fat in subcutaneous adipocytes where it cannot exert its lipotoxic effects. Consistent with these antiatherogenic effects, pioglitazone reduced major adverse cardiac event endpoints (ie, mortality, myocardial infarction, and stroke) in the Prospective Pioglitazone Clinical Trial in Macrovascular Events and in a meta-analysis of all other published pioglitazone trials. Pioglitazone also mobilizes fat out of the liver, improving liver function and histologic abnormalities in patients with nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Pioglitazone also reduces proteinuria, all-cause mortality, and cardiovascular events in patients with type 2 diabetes mellitus with a reduced glomerular filtration rate. These benefits must be weighed against the side effects of the drug, including weight gain, fluid retention, atypical fractures, and, possibly, bladder cancer. When low doses of pioglitazone are used (eg, 7.5-30 mg/d) with gradual titration, and physician recognition of the potential side effects are applied, the risk-to-benefit ratio is very favorable. Despite having similar effects on glycemic control, pioglitazone and rosiglitazone appear to have different effects on cardiovascular outcomes. Rosiglitazone has been associated with an increased risk of myocardial infarction, and its use in the United States is restricted because of cardiovascular safety concerns.

Rosiglitazone decreases bone mineral density and increases bone turnover in postmenopausal women with type 2 diabetes mellitus

CONTEXT

Postmenopausal status and type 2 diabetes mellitus (T2DM) are independent risk factors for fractures. An increased fracture risk has been observed with rosiglitazone (RSG), a thiazolidinedione, in patients with T2DM.

DESIGN AND SETTING

This was a randomized, double-blind study in postmenopausal women with T2DM. A 52-week double-blind phase (RSG or metformin [MET]) was followed by a 24-week open-label phase, during which time all patients received MET.

MAIN OUTCOME MEASURES

The primary endpoint was to assess the mean percentage change in bone mineral density (BMD) at the femoral neck (FN) by dual-energy x-ray absorptiometry from baseline to week 52 in the RSG treatment group. Key secondary objectives included assessment of changes in BMD at the total hip, trochanter, and lumbar spine and to evaluate RSG effects on bone turnover markers.

RESULTS

From baseline to week 52, RSG was associated with a reduction in FN BMD by dual-energy x-ray absorptiometry (-1.47%). During the open-label phase (weeks 52-76), no further loss in FN BMD was observed. A decrease in BMD occurred at the total hip during RSG or MET treatment at 52 weeks (-1.62 and -0.72%, respectively). Total hip BMD loss by RSG was attenuated after switching to MET and was similar between treatment groups at the end of the open-label phase. From baseline to week 52, bone turnover markers significantly increased with RSG compared with MET, but decreased significantly during the open-label phase.

CONCLUSIONS

RSG for 52 weeks in postmenopausal women with T2DM was associated with small reductions in FN, total hip, and lumbar spine BMD and increased bone turnover markers. These effects are attenuated after cessation of RSG treatment.

Quality of life and patient-perceived difficulties in the treatment of type 2 diabetes

BACKGROUND

Clinical evidence points to patient-perceived difficulties and compliance problems in implementing early insulin therapy. Therefore, individual treatment aims are necessary to optimize diabetes therapy, as currently acknowledged by the new ADA/EASD guidelines. Better characterization of patient-perceived difficulties in the implementation of early insulin treatment may contribute to improved compliance and optimal tailoring of treatment regimens for the individual patient.

OBJECTIVES

To assess differences in quality of life (QoL) and patient-perceived difficulties in health care with every addition of oral hypoglycemic agents (OHAs) and insulin therapy.

METHODS

The analysis was conducted on a cross-sectional sample of 714 diabetic patients treated with OHAs or with insulin once or twice daily. Differences in diabetes-specific QoL, overall QoL, and perception of difficulties associated with specific diabetes treatment attributes were evaluated using trend analysis and comparisons between groups. The contribution of each diabetes treatment attribute to QoL measures and glycemic control was also assessed.

RESULTS

No significant differences were found in QoL measures among patients treated exclusively with OHAs when these patients were assessed by the number of oral agents, irrespective of the degree of glycemic control. Better controlled patients treated with 2 OHAs, compared with poorly controlled patients treated with a single OHA, had a lower perception of difficulties associated with diabetes treatment attributes. Poorly controlled patients treated with 2 OHAs and better controlled patients treated with 3 OHAs had similar QoL and perceived difficulties with care. However, the insulin-based alternative was consistently associated with a significantly higher perception of pain and lower overall QoL when compared with the oral regimens. Multivariate models accounted for 52% and 32% of the variance in QoL measures.

CONCLUSIONS

From the patients' perspective, oral therapy is the preferred strategy for attaining the treatment goals since the addition of OHAs was not associated with lower QoL or patient-perceived difficulties with care. If early insulin treatment is considered, physicians should address specific diabetes treatment characteristics, mainly the issue of pain, to promote improved QoL and disease control.

Thiazolidinediones and risk of heart failure in patients with or at high risk of type 2 diabetes mellitus: a meta-analysis and meta-regression analysis of placebo-controlled randomized clinical trials

BACKGROUND

Recent meta-analyses of randomized clinical trials (RCTs) demonstrated a higher risk of heart failure (HF) with the use of thiazolidinediones (TZDs). However, this effect may have been diluted by including active controls. Also, it is uncertain whether the risk of HF is similar with rosiglitazone and pioglitazone.

OBJECTIVES

This study quantified the risks of HF with the use of TZDs in patients with or at high risk of developing type 2 diabetes mellitus (DM), and evaluated differential effects by type of TZD. Secondarily, we evaluated risks of peripheral edema.

METHODS

We performed a systematic review and meta-analysis of placebo-controlled RCTs evaluating the effect of rosiglitazone or pioglitazone on investigator-reported HF and edema. Articles published before 31 December 2009 were searched in MEDLINE, The Web of Science, and Scopus, and the data were extracted by three investigators. RCTs with ≥100 patients and ≥3 months of follow-up were included. We quantified the effect of TZDs as odds ratios (ORs) by using the Mantel-Haenzel and alternative models. We further evaluated the risk of serious/severe HF, and the effect of several trial characteristics on HF risk by subgroup analysis and meta-regression analysis.

RESULTS

29 trials (n = 20 254) were evaluated. TZDs were significantly associated with HF (TZD 360/6807 [5.3%] vs placebo 234/6328 [3.7%], OR 1.59; 95% CI 1.34, 1.89; p < 0.00001). The risk of HF was higher with rosiglitazone than with pioglitazone (2.73 [95% CI 1.46, 5.10] vs 1.51 [1.26, 1.81]; p = 0.06). TZDs were associated with a similar risk of serious/severe HF (OR 1.47; 95% CI 1.16, 1.87; p = 0.002). Use of TZDs was also associated with edema (OR 2.04; 95% CI 1.85, 2.26; p < 0.00001). HF and edema risks were consistent using Peto and random effects models. Risks of HF were significantly high for the subgroups of trials including patients with or at high risk for type 2 DM, and for the subgroup of trials with ≥12 months of follow-up. Meta-regression analysis showed that trials with lower overall baseline risk had higher HF risks.

CONCLUSION

In placebo-controlled trials of adult patients with or at high risk for type 2 DM, TZD therapy is significantly and consistently associated with a higher risk of HF. The risk of serious/severe HF is also increased with the use of TZDs. HF risks are similar to those of meta-analyses combining active- and placebo-controlled trials. The benefit/risk profile of TZDs should be considered when treating diabetic patients with or without prior HF.

Management of patients with type 2 diabetes

BACKGROUND

The number of treatment options in the diabetes arena has grown dramatically in a short period of time, with a corresponding increase in the breadth and depth of literature from which physicians and diabetes organizations make evidence-based decisions. Thus, the purpose of this article is to provide an up-to-date review of the literature describing current treatment options and guidelines available for the management of type 2 diabetes and prevention of its complications.

METHODS

Pubmed searches were conducted for recent literature pertaining to the prevention of complications in type 2 diabetes. Comprehensive search terms were devised to identify articles describing micro- and macrovascular complications including nephropathy, neuropathy, retinopathy, and cardiovascular disease associated with type 2 diabetes.

CONCLUSIONS

The current body of literature demonstrates that a significant reduction in the incidence of diabetic complications is achievable with early initiation and long-term maintenance of controlled blood glucose and cardiovascular risk factors. Screening for diabetic complications should be initiated early and continued at regular intervals to ensure early pharmacological intervention.

Drug-induced hypoglycaemia: an update

Drugs are the most frequent cause of hypoglycaemia in adults. Although hypoglycaemia is a well known adverse effect of antidiabetic agents, it may occasionally develop in the course of treatment with drugs used in everyday clinical practice, including NSAIDs, analgesics, antibacterials, antimalarials, antiarrhythmics, antidepressants and other miscellaneous agents. They induce hypoglycaemia by stimulating insulin release, reducing insulin clearance or interfering with glucose metabolism. Several drugs may also potentiate the hypoglycaemic effect of antidiabetic agents. Administration of these agents to individuals with diabetes mellitus is of most concern. Many of these drugs, and depending on clinical setting, may also induce hyperglycaemia. Drug-induced hepatotoxicity and nephrotoxicity may lead in certain circumstances to hypoglycaemia. Some drugs may also induce hypoglycaemia by causing pancreatitis. Drug-induced hypoglycaemia is usually mild but may be severe. Effective clinical management can be handled through awareness of this drug-induced adverse effect on blood glucose levels. Herein, we review pertinent clinical information on the incidence of drug-induced hypoglycaemia and discuss the underlying pathophysiological mechanisms, and prevention and management.

Weight-related quality of life, health utility, psychological well-being, and satisfaction with exenatide once weekly compared with sitagliptin or pioglitazone after 26 weeks of treatment

OBJECTIVE

To assess change in patient-reported outcomes in subjects with type 2 diabetes treated with exenatide once weekly compared with those treated with sitagliptin or pioglitazone.

RESEARCH DESIGN AND METHODS

In this 26-week randomized, multicenter, double-dummy study, 491 subjects received 2 mg of exenatide once weekly or maximum daily doses of sitagliptin (100 mg) or pioglitazone (45 mg) on a background of metformin. Weight-related quality of life, health utility, psychological well-being, and diabetes treatment satisfaction were assessed at baseline and week 26. Mean group changes from baseline to week 26 were estimated by ANCOVA.

RESULTS

Weight-related quality of life total scores improved significantly in the exenatide once weekly and sitagliptin arms only; the exenatide once weekly group experienced significantly greater improvement than the pioglitazone group in weight-related quality of life total scores and in several domain scores. Health utility scores improved significantly for exenatide once weekly and sitagliptin groups (P < 0.05) with no significant difference between the exenatide once weekly group and either comparison group. All groups experienced significant improvements on the psychological well-being global scale and all six domain scores, with no significant difference between the exenatide once weekly group and either comparator. All groups experienced significant improvements in total diabetes treatment satisfaction scores. The exenatide once weekly group experienced greater improvement than the sitagliptin group in treatment satisfaction total scores.

CONCLUSIONS

In combination with clinical outcomes from this study, these results indicate it is possible for patients treated with metformin to initiate exenatide therapy with potential benefits in both clinical and patient-reported outcomes.

Pioglitazone and alogliptin combination therapy in type 2 diabetes: a pathophysiologically sound treatment

Insulin resistance and islet (beta and alpha) cell dysfunction are major pathophysiologic abnormalities in type 2 diabetes mellitus (T2DM). Pioglitazone is a potent insulin sensitizer, improves pancreatic beta cell function and has been shown in several outcome trials to lower the risk of atherosclerotic and cardiovascular events. Glucagon-like peptide-1 deficiency/resistance contributes to islet cell dysfunction by impairing insulin secretion and increasing glucagon secretion. Dipeptidyl peptidase-4 (DPP-4) inhibitors improve pancreatic islet function by augmenting glucose-dependent insulin secretion and decreasing elevated plasma glucagon levels. Alogliptin is a new DPP-4 inhibitor that reduces glycosylated hemoglobin (HbA_1c), is weight neutral, has an excellent safety profile, and can be used in combination with oral agents and insulin. Alogliptin has a low risk of hypoglycemia, and serious adverse events are uncommon. An alogliptin–pioglitazone combination is advantageous because it addresses both insulin resistance and islet dysfunction in T2DM. HbA_1c reductions are significantly greater than with either monotherapy. This once-daily oral combination medication does not increase the risk of hypoglycemia, and tolerability and discontinuation rates do not differ significantly from either monotherapy. Importantly, measures of beta cell function and health are improved beyond that observed with either monotherapy, potentially improving durability of HbA_1c reduction. The alogliptin–pioglitazone combination represents a pathophysiologically sound treatment of T2DM.

Diabesity: therapeutic options

A pathogenic relationship exists between type 2 diabetes and obesity. Over the last decade, the escalation in diabetes cases has paralleled the rapid increase in obesity rates, constituting a global health crisis. Environmental risk factors attributed to the global increase in obesity include the consumption of high-calorie, high-fat foods and inadequate physical activity. Obese individuals may also have a genetic predisposition for obesity. Both diabetes and obesity confer an elevated risk of developing a range of complications and comorbidities, including cardiovascular disease, hypertension and stroke, which can complicate disease management. This review examines the aetiology of the linkages between diabetes and obesity and the range of available therapies. Recent clinical evidence substantiating the efficacy and safety of incretin-based antidiabetic therapies is analysed, in addition to data on antiobesity therapeutic strategies, such as antiobesity agents, behaviour modification and bariatric surgery. Glucose control is often accompanied by weight-neutral or modest weight reduction effects with DPP-4 inhibitor treatment (sitagliptin, vildagliptin, saxagliptin) and weight loss with GLP-1 receptor agonist therapy (exenatide, liraglutide). Studies of antiobesity agents including orlistat, sibutramine and rimonabant have shown attrition rates of 30-40%, and the long-term effects of these agents remain unknown. Bariatric surgical procedures commonly performed are laparoscopic adjustable banding of the stomach and the Roux-en-Y gastric bypass, and have produced type 2 diabetes remission rates of up to 73%. Therapeutic strategies that integrate glycaemic control and weight loss will assume greater importance as the prevalence of diabetes and obesity increase.

Improving cardiovascular risk--applying evidence-based medicine to glucose-lowering therapy with thiazolidinediones in patients with type 2 diabetes

BACKGROUND

The management of patients with type 2 diabetes aims to reduce the elevated risk of cardiovascular disease (CVD) by addressing established risk factors including hyperglycaemia, dyslipidaemia and hypertension. The thiazolidinediones are equally effective in improving glycaemic control when used in combination regimens in patients with type 2 diabetes, but have differing effects on the diabetic dyslipidaemia.

AIMS

To compare the effects of rosiglitazone and pioglitazone on inflammatory mediators associated with atherosclerosis and CVD, surrogate cardiovascular endpoints, and hard cardiovascular outcomes in patients with type 2 diabetes.

MATERIALS AND METHODS

A search of the PubMed database plus manual search of referenced papers for other relevant citations.

RESULTS

Both glitazones reduce inflammatory markers and other circulating markers of CV disease. Available data suggest that pioglitazone can delay progression of atherosclerosis in patients with type 2 diabetes, as shown by the PERISCOPE and CHICAGO studies, and that it can reduce the rate of clinical CV events as shown by PROactive. Clinical end-point data for rosiglitazone are inconclusive, providing no evidence of benefit and a possible increase in myocardial infarction.

DISCUSSION

There is a consistency of benefit with pioglitazone on markers, surrogate cardiovascular outcomes and clinical end-point trials.

CONCLUSION

Pioglitazone is the preferred thiazolidinedione to reduce cardiovascular risk in people with type 2 diabetes.

Cardiovascular outcomes in trials of oral diabetes medications: a systematic review

BACKGROUND

A wide variety of oral diabetes medications are currently available for the treatment of type 2 diabetes mellitus, but it is unclear how these agents compare with respect to long-term cardiovascular risk. Our objective was to systematically examine the peer-reviewed literature on the cardiovascular risk associated with oral agents (second-generation sulfonylureas, biguanides, thiazolidinediones, and meglitinides) for treating adults with type 2 diabetes.

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, from inception through January 19, 2006. Forty publications of controlled trials that reported information on cardiovascular events (primarily myocardial infarction and stroke) met our inclusion criteria. Using standardized protocols, 2 reviewers serially abstracted data from each article. Trials were first described qualitatively. For comparisons with 4 or more independent trials, results were pooled quantitatively using the Mantel-Haenszel method. Results are presented as odds ratios (ORs) and corresponding 95% confidence intervals (CIs).

RESULTS

Treatment with metformin hydrochloride was associated with a decreased risk of cardiovascular mortality (pooled OR, 0.74; 95% CI, 0.62-0.89) compared with any other oral diabetes agent or placebo; the results for cardiovascular morbidity and all-cause mortality were similar but not statistically significant. No other significant associations of oral diabetes agents with fatal or nonfatal cardiovascular disease or all-cause mortality were observed. When compared with any other agent or placebo, rosiglitazone was the only diabetes agent associated with an increased risk of cardiovascular morbidity or mortality, but this result was not statistically significant (OR, 1.68; 95% CI, 0.92-3.06).

CONCLUSIONS

Meta-analysis suggested that, compared with other oral diabetes agents and placebo, metformin was moderately protective and rosiglitazone possibly harmful, but lack of power prohibited firmer conclusions. Larger, long-term studies taken to hard end points and better reporting of cardiovascular events in short-term studies will be required to draw firm conclusions about major clinical benefits and risks related to oral diabetes agents.

A retrospective evaluation of congestive heart failure and myocardial ischemia events in 14,237 patients with type 2 diabetes mellitus enrolled in 42 short-term, double-blind, randomized clinical studies with rosiglitazone

PURPOSE

Retrospectively investigate potential associations between rosiglitazone and congestive heart failure (CHF) and, separately, events of myocardial ischemia.

METHODS

Data from 14 237 individuals in 42 short-term, double-blind, randomized studies of rosiglitazone versus placebo or active diabetes medications were analyzed across seven treatment comparisons using an exact logistic regression model, adjusted for number of major cardiovascular risk factors and duration of exposure.

RESULTS

CHF incidence ranged 0-1.27% (SAEs) and 0.12-2.42% (all AEs) with rosiglitazone versus 0.07-0.75% (SAEs) and 0.25-1.36% (all AEs) with control. Higher odds ratios (95%CI) were observed for CHF SAEs with sulfonylurea- and insulin-containing combinations: rosiglitazone monotherapy versus placebo, 0.25 (<0.01-4.75); rosiglitazone monotherapy versus sulfonylurea/metformin monotherapy, 0.23 (<0.01-2.14); sulfonylurea + rosiglitazone versus sulfonylurea monotherapy, 0.95 (0.01-75.20); metformin + rosiglitazone versus metformin monotherapy, 0.60 (0.00-8.28); metformin + rosiglitazone versus metformin + sulfonylurea, 1.04 (0.39-2.86); sulfonylurea + metformin + rosiglitazone versus sulfonylurea + metformin, 3.15 (0.35-150.52); insulin + rosiglitazone versus insulin monotherapy, 1.63 (0.52-6.01). Myocardial ischemia incidence ranged 0.75-1.40% (SAEs) and 1.49-2.77% (all AEs) with rosiglitazone versus 0.21-2.04% (SAEs) and 0.56-2.38% (all AEs) with control. Each comparison had an OR >1, with wide confidence intervals generally including unity. With data pooling, more events of myocardial ischemia were observed with rosiglitazone (2.00%) versus control (1.53%) (HR 1.30, 95%CI 1.004-1.69).

CONCLUSIONS

CHF incidence may be greater when rosiglitazone is combined with sulfonylureas or insulin. When data were pooled, more events of myocardial ischemia were observed with rosiglitazone versus control. Final results from RECORD will allow a more rigorous evaluation of the cardiovascular safety profile.

Potential benefits of early addition of rosiglitazone in combination with glimepiride in the treatment of type 2 diabetes

AIM

To assess the efficacy and tolerability of early combination therapy with rosiglitazone (RSG) and glimepiride (GLIM) vs. GLIM monotherapy in patients with type 2 diabetes mellitus (T2DM).

METHODS

Strategies for the addition of RSG in combination with GLIM were evaluated with data from two randomized, double-blind, placebo (PBO)-controlled studies. Study A - addition of RSG (4 or 8 mg) or PBO to continued GLIM 3 mg once daily; study B - addition of low-dose RSG (4 mg) prior to uptitration of GLIM (from 2 to 4 mg) vs. continued uptitration of GLIM (from 2 to 8 mg).

RESULTS

Study A reported significant reductions in fasting plasma glucose (FPG) from baseline to week 26 with the addition of both 4 and 8 mg RSG to GLIM 3 mg [-21 mg/dl (-1.2 mmol/l), p = 0.0019 and -43 mg/dl (-2.4 mmol/l), p < 0.0001, respectively] and in haemoglobin A(1c) (HbA(1c)) (-0.63%, p = 0.00015 and -1.17%, p < 0.0001, respectively) from a baseline of 8.2 and 8.1%, respectively. At the end of the study, target HbA(1c) <7.0% was achieved in 43 and 68% of patients in the RSG 4 mg + GLIM and RSG 8 mg + GLIM groups, respectively, compared with 32% in the PBO + GLIM (GLIM alone) group. In study B, addition of RSG to GLIM reduced mean FPG and HbA(1c) levels at week 24 from baseline [-28 mg/dl (-1.5 mmol/l), p < 0.0001, and -0.68%, p < 0.0001, respectively]. There were no significant changes with GLIM monotherapy in either study. Favourable effects of RSG + GLIM on insulin sensitivity, beta-cell function and cardiovascular disease biomarkers were also observed. All treatments were similarly well tolerated.

CONCLUSIONS

Early addition of RSG to GLIM is an effective and well-tolerated treatment option to improve glycaemic control in sulphonylurea-treated patients with T2DM.

Initial treatment with fixed-dose combination rosiglitazone/glimepiride in patients with previously untreated type 2 diabetes

AIM

This study assessed the efficacy and safety of two different dosing regimens of fixed-dose combination (FDC) rosiglitazone (RSG) plus glimepiride (GLIM) compared with RSG or GLIM monotherapy in drug-naive subjects with type 2 diabetes mellitus (T2DM).

METHODS

Drug-naive subjects (n = 901) were enrolled into this 28-week, double-blind, parallel-group study if their glycosylated haemoglobin A(1c) (HbA(1c)) was >7.5% but <or=12%. Subjects were randomized to receive either GLIM [4 mg once daily (OD) maximal], RSG (8 mg OD maximal) or RSG/GLIM FDC regimen A (4 mg/4 mg OD maximal) or RSG/GLIM FDC regimen B (8 mg/4 mg OD maximal). Patients were assessed for efficacy and safety every 4 weeks for the first 12 weeks of the study, and at weeks 20 and 28. The primary efficacy endpoint was change in HbA(1c) from baseline. Key secondary endpoints included the proportion of patients achieving recommended HbA(1c) and fasting plasma glucose (FPG) targets; change from baseline in FPG, insulin, C-reactive protein (CRP), adiponectin, free fatty acids and lipids; and percentage change in homeostasis model assessment-estimated insulin sensitivity and beta-cell function. Safety evaluations included adverse-event (AE) monitoring and clinical laboratory evaluations.

RESULTS

At week 28, both RSG/GLIM FDC regimens significantly reduced HbA(1c) (mean +/- s.d.: -2.4 +/- 1.4% FDC regimen A; -2.5 +/- 1.4% FDC regimen B) to a greater extent than RSG (-1.8 +/- 1.5%) or GLIM (-1.7 +/- 1.4%) monotherapy (model-adjusted mean treatment difference, p < 0.0001 vs. both RSG and GLIM). Significantly more subjects achieved HbA(1c) target levels of <or=6.5 and <7% with either RSG/GLIM FDC regimen compared with RSG or GLIM alone (model-adjusted odds ratio, p < 0.0001 for both comparisons). Similarly, a significantly greater reduction in FPG levels was observed in subjects treated with the RSG/GLIM FDC [mean +/- s.d. (mg/dl): -69.5 +/- 57.5 FDC regimen A; -79.9 +/- 56.8 FDC regimen B) compared with RSG (-56.6 +/- 58.1) or GLIM (-42.2 +/- 66.1) monotherapy (model-adjusted mean treatment difference, p < 0.0001 for both comparisons). Improvement in CRP was also observed in subjects who were treated with a RSG/GLIM FDC or RSG monotherapy compared with GLIM monotherapy. RSG/GLIM FDC was generally well tolerated, with no new safety or tolerability issues identified from its monotherapy components, and a similar AE profile was observed across FDC regimens. The most commonly reported AE was hypoglycaemia, and the incidence of confirmed symptomatic hypoglycaemia (3.6-5.5%) was comparable among subjects treated with an RSG/GLIM FDC and GLIM monotherapy.

CONCLUSIONS

Compared with RSG or GLIM monotherapy, the RSG/GLIM FDC improved glycaemic control with no significant increased risk of hypoglycaemia. RSG/GLIM FDC provides an effective and well-tolerated treatment option for drug-naive individuals with T2DM.

Impact of therapeutic advances on hypoglycaemia in type 2 diabetes

Patients with type 2 diabetes experience hypoglycaemia less frequently than those with type 1 diabetes. Some protection against hypoglycaemia is afforded by the relatively intact glucose counter-regulatory pathways that characterize the pathophysiology of early type 2 diabetes. To some extent, this protection explains why hypoglycaemic episodes in intensively treated individuals with type 2 diabetes, when they occur, are rarely severe. As diabetes progresses and therapy intensifies to achieve recommended glycaemic goals, hypoglycaemia frequency and severity increase. Thus, when it comes to instituting intensive therapy, fear of hypoglycaemia may contribute to health-care providers' 'clinical inertia'. Because maintaining glycaemic control is so important to both public and individual health, many new therapies and technologies have been developed. This manuscript reviews and considers whether these advancements in therapy make glycaemic goals easier to achieve by minimizing hypoglycaemia. Putting the hypoglycaemia experienced by type 2 diabetes patients into appropriate clinical perspective, the impact of recent progress made in pharmacotherapy, drug delivery systems, and BG monitoring on hypoglycaemia incidence is largely positive. The extent to which this progress can effect improvement over traditional therapies will, however, depend upon patient (and provider) education, motivation and behaviour change.

Protection of pancreatic beta-cells: is it feasible?

Hyperglycemia, which is the biochemical hallmark of type 2 diabetes, mainly results from insulin resistance and beta-cell dysfunction. However, the latter is crucial in the development of the disease because diabetes cannot occur without an impairment of insulin secretion. Beta-cell failure is also responsible for progressive loss of metabolic control in type 2 diabetic patients and the eventual need for insulin treatment. An impairment of beta-cell function can be detected in several ways and can be observed already in pre-diabetic individuals. Histopathology studies documented that beta-cell volume is reduced in pre-diabetes and, to a greater extent, in type 2 diabetes mainly because the apoptotic rate of beta-cells is increased whereas neogenesis is intact. All anti-diabetic agents can improve, directly or indirectly, beta-cell function. However, only PPAR-gamma agonists and incretin-mimetic agents seem to have favorable effects on beta-cell morphology and volume. Many trials showed that type 2 diabetes can be prevented but few of them directly addressed the issue of beta-cell protection by the intervention used in the study. It is reasonable to conclude that in these trials diabetes prevention, which was based on the use of lifestyle changes (diet and/or exercise) or different drugs (tolbutamide, acarbose, metformin, glitazones, bezafibrate, orlistat, angiotensin converting enzyme inhibitors, angiotensin II receptor blockers or pravastatin), depended also, or mainly, on a protection of the beta-cells but in most studies data on insulin secretion are not available or are insufficient to draw firm conclusions. The mechanisms of beta-cell protection in these trials, if any, remain unknown. They could be various and likely included reduced glucotoxicity, lipotoxicity, insulin resistance, inflammation, oxidant stress and/or apoptosis, an amelioration of islet blood flow and/or favorable changes in cation balance within the islets. Contrasting the decline and the eventual failure of beta-cells is crucial in preventing type 2 diabetes as well as in changing the natural history of the disease, when it occurs. The protection can be achieved in several ways but any strategy should include a change in lifestyle in order to generate a healthier islet milieu. Among anti-diabetic drugs, PPAR-gamma agonists and incretin-mimetic agents are the most promising in the protection. Among other drugs, inhibitors of the renin-angiotensin system might play a significant role. The increased worldwide diffusion of type 2 diabetes and the progressive loss of metabolic control in affected patients are clear demonstrations that the strategies to protect the beta-cells implemented so far, if any, were largely inadequate. Anti-diabetic agents targeting the intimate mechanisms of beta-cell damage might change the scenario in the near future.

Rosiglitazone and glimeperide: review of clinical results supporting a fixed dose combination

Type 2 diabetes has become a major burden to the health care systems worldwide. Among the drugs approved for this indication, glimepiride and rosiglitazone have gained substantial importance in routine use. While glimepiride stimulates β-cell secretion and leads to reduction of blood glucose values, rosiglitazone activates PPARγ and improves insulin resistance, at the vascular and metabolically active cells. Therefore, the combination of the two drugs may be an interesting approach to improve glycemic control and lower cardiovascular risk. A fixed combination of both drugs has been approved for clinical use in the US and EU. The combination of glimepiride and rosiglitazone is generally well tolerated and the use of a fixed combination may lead to improved adherence of the patients to their therapy. The purpose of this review is to evaluate the clinical data that have been published on this combination, appearing to represent a convenient way to obtain therapeutic targets in patients with type 2 diabetes mellitus.

Rosiglitazone for type 2 diabetes mellitus

BACKGROUND

Diabetes has long been recognised as a strong, independent risk factor for cardiovascular disease, a problem which accounts for approximately 70% of all mortality in people with diabetes. Prospective studies show that compared to their non-diabetic counterparts, the relative risk of cardiovascular mortality for men with diabetes is two to three and for women with diabetes is three to four. The two biggest trials in type 2 diabetes, the United Kingdom Prospective Diabetes Study (UKPDS) and the University Group Diabetes Program (UGDP) study did not reveal a reduction of cardiovascular endpoints through improved metabolic control. Theoretical benefits of the peroxisome proliferator activated receptor gamma (PPAR-gamma) activator rosiglitazone on endothelial function and cardiovascular risk factors might result in fewer macrovascular disease events in people with type 2 diabetes mellitus.

OBJECTIVES

To assess the effects of rosiglitazone in the treatment of type 2 diabetes.

SEARCH STRATEGY

Studies were obtained from computerised searches of MEDLINE, EMBASE and The Cochrane Library.

SELECTION CRITERIA

Studies were included if they were randomised controlled trials in adult people with type 2 diabetes mellitus and had a trial duration of at least 24 weeks.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Pooling of studies by means of fixed-effects meta-analysis could be performed for adverse events only.

MAIN RESULTS

Eighteen trials which randomised 3888 people to rosiglitazone treatment were identified. Longest duration of therapy was four years with a median of 26 weeks. Published studies of at least 24 weeks rosiglitazone treatment in people with type 2 diabetes mellitus did not provide evidence that patient-oriented outcomes like mortality, morbidity, adverse effects, costs and health-related quality of life are positively influenced by this compound. Metabolic control measured by glycosylated haemoglobin A1c (HbA1c) as a surrogate endpoint did not demonstrate clinically relevant differences to other oral antidiabetic drugs. Occurrence of oedema was significantly raised (OR 2.27, 95% confidence interval (CI) 1.83 to 2.81). The single large RCT (ADOPT - A Diabetes Outcomes Progression Trial) indicated increased cardiovascular risk. New data on raised fracture rates in women reveal extensive action of rosiglitazone in various body tissues.

AUTHORS' CONCLUSIONS

New studies should focus on patient-oriented outcomes to clarify the benefit-risk ratio of rosiglitazone therapy. Safety data and adverse events of all investigations (published and unpublished) should be made available to the public.

Comparison of extended-release metformin in combination with a sulfonylurea (glyburide) to sulfonylurea monotherapy in adult patients with type 2 diabetes: a multicenter, double-blind, randomized, controlled, phase III study

BACKGROUND

Metformin is widely used in the management of type 2 diabetes, either as monotherapy or in combination with other oral antihyperglycemic agents such as sulfonylureas and thiazolidinediones. Combination treatment with metformin and sulfonylurea in patients who failed monotherapy has been reported to be effective in maintaining glycemic control.

OBJECTIVE

The purpose for this study was to compare the efficacy and tolerability of extended-release metformin (MER) administered with a sulfonylurea (glyburide) to sulfonylurea monotherapy in patients with type 2 diabetes.

METHODS

This multicenter, double-blind, randomized, controlled study enrolled adult patients with type 2 diabetes who were either drug naive or previously treated with oral diabetic medications and who had not achieved glycemic control. Patients were stabilized on sulfonylurea (10 mg/d for 2 weeks, then 15 mg/d for 4 weeks) then randomly assigned at base line to receive MER (1500 mg QD, 1000 mg BID, or 2000 mg QD) plus sulfonylurea (MER+S) or sulfonylurea monotherapy for 24 weeks. Patients were evaluated every 1 to 2 weeks during sulfonylurea stabilization and initial metformin treatment, and then every 4 weeks until study end. The primary efficacy end point was glycemic control as determined by changes in glycosylated hemoglobin (HbA(1c)) from baseline to study end between those receiving combination MER+S treatment and those receiving sulfonylurea monotherapy. Adverse events (AEs) were recorded throughout the study by direct questioning, self-reporting by patients, and from the results of physical examinations and clinical laboratory tests.

RESULTS

A total of 741 patients were enrolled. Of these, 134 patients were stabilization failures, 607 patients were randomized, 575 patients received treatment and were included in the intent-to-treat population, and 417 patients completed the study per protocol. There were no significant differences between treatment groups for any demographic or baseline characteristics (all patients: mean [SD] age, 53.0 [10.6] years; male sex, 54.6% [314/575]; race, white, 58.8% [338/575], Hispanic, 28.5% [164/575]; mean [SD] weight, 97.0 [22.2] kg; obese [body mass index > or =30 kg/m(2)], 69.4% [399/575] ). There were significant decreases from baseline in mean fasting plasma glucose (FPG) levels by the end of week 1 and in mean HbA(1c) levels by week 8 in each MER+S group (both, P < 0.001). The mean (95% CI) changes from baseline to study end in the combined MER+S groups (HbA(1c), -0.74% [-0.85% to -0.64%]; FPG, -12.9 [-17.1 to -8.7] mg/dL) were significantly different from the sulfonylurea monotherapy group (HbA(1c), 0.08% [-0.08% to 0.25%]; FPG, 15.5 [8.2 to 22.8] mg/dL; P < 0.001). Among patients treated with MER+S, the mean (SEM) change in HbA(1c) was -1.26% (-1.44% to -1.07%) for drugnaive patients and -0.59% (-0.46% to 0.71%) for patients previously treated with metformin. There was a significant difference between treatment groups with regard to the prevalence of hypoglycemia (MER+S groups, 11.6% vs sulfonylurea monotherapy group, 4.2%; P = 0.007), but no significant difference was observed for gastrointestinal events. The most common gastrointestinal AEs were diarrhea and nausea (8.6% and 3.9%, respectively, in the combined MER+S groups; 2.8% and 1.4%, respectively, in the sulfonylurea monotherapy group).

CONCLUSIONS

The combination of QD or BID treatment with MER+S was significantly more effective in lowering HbA(1c) and glucose levels than sulfonylurea monotherapy in these adult patients with type 2 diabetes. However, a significant increase in the prevalence of hypoglycemia was observed in the MER+S treatment groups compared with the sulfonylurea monotherapy group.

Dual PPAR α/γ Agonists: Promises and Pitfalls in Type 2 Diabetes

Type 2 diabetes mellitus is a disease of complex pathogenesis and pleiotropic clinical manifestations. The greatest clinical challenge in this disease is the prevention of the long-term complications, many of which involve cardiovascular outcomes. The peroxisome proliferator-activated receptor (PPAR) alpha and gamma isoforms of the family of nuclear transcription factors are pharmaceutical targets for therapeutic intervention because they can potentially ameliorate not only the hyperglycemia of diabetes, but also the dyslipidemia that is characteristic of this disorder (low high-density lipoprotein cholesterol, high triglycerides, small, dense low-density lipoprotein particles). Novel drugs with dual PPAR alpha and gamma activity have been under clinical development for type 2 diabetes, and they have shown promise in early studies with regard to glucose lowering and improved lipid profile when compared with the PPAR-gamma-specific thiazolidinediones. Unfortunately, the dual PPARs available to date have some of the PPAR-gamma-associated side effect profile, including fluid retention and weight gain, which have limited the further clinical development of higher doses that show improved efficacy. This review will briefly summarize our understanding of the pathogenesis of type 2 diabetes, the role of the PPAR family of receptors, and the potential for clinical use of this novel emerging class of agents that serve as dual activators of both PPAR-alpha and PPAR-gamma.

Improvement in glycaemic control with rosiglitazone/metformin fixed-dose combination therapy in patients with type 2 diabetes with very poor glycaemic control

OBJECTIVE

Traditional first-line intervention in patients with type 2 diabetes and very poor glycaemic control is insulin therapy or high doses of sulfonylureas if there is no evidence of volume depletion. This study explored the safety and efficacy of open-label treatment with rosiglitazone and metformin (RSG/MET) fixed-dose combination therapy (AVANDAMET) in patients with type 2 diabetes with very poor glycaemic control, to better characterize the magnitude of glycated haemoglobin (A1c) reduction after 24 weeks of therapy.

METHODS

In this multicentre, open-label trial, 190 patients with an A1c greater than 11% or fasting plasma glucose (FPG) greater than 15 mmol/l were included after failing to meet glycaemic entry criteria for a primary double-blind, controlled, randomized study. Unless tolerability issues arose, eligible patients initiated RSG/MET 4 mg/1000 mg fixed-dose combination therapy and were up-titrated in increments of 2 mg/500 mg at 4-week intervals to a daily dose of 8 mg/2000 mg or the maximum tolerated dose. Patients were assessed for efficacy and safety at five visits over a 24-week period. The primary efficacy end point was change from baseline in A1c at week 24. Secondary efficacy end points included the proportion of patients achieving defined A1c targets, change from baseline to week 24 in FPG and insulin sensitivity.

RESULTS

The majority of patients (78%) completed 24 weeks of open-label treatment. At week 24, clinically significant mean reduction in A1c from 11.8 to 7.8% (mean reduction, 4.0 +/- 2.2%; p < 0.0001) and mean FPG reduction from 16.9 to 9.2 mmol/l (mean reduction, 7.7 +/- 4.4 mmol/l; p < 0.0001) were observed. A clinically significant reduction in FPG (5.2 mmol/l) was observed after 4 weeks of treatment with RSG/MET fixed-dose combination therapy. Despite a high mean baseline A1c of 11.8%, 33% of patients achieved treatment goal of A1c less than or equal to 6.5% at week 24, and 44% achieved an A1c less than 7% at week 24. RSG/MET fixed-dose combination was well tolerated, with a low incidence of hypoglycaemia (2%) and mean increase in weight from baseline of 2.6 +/- 5.2 kg, and few patients withdrew (2.6%) because of an adverse event.

CONCLUSIONS

RSG/MET fixed-dose combination therapy was effective as initial therapy in patients with type 2 diabetes and very high levels of A1c and/or FPG, as demonstrated by robust and relatively rapid improvements in glycaemic control. RSG/MET fixed-dose combination was well tolerated as first-line therapy with no new tolerability issues identified.

Initial treatment with rosiglitazone/metformin fixed-dose combination therapy compared with monotherapy with either rosiglitazone or metformin in patients with uncontrolled type 2 diabetes

AIM

This study assessed the efficacy and safety of rosiglitazone and metformin (RSG/MET) fixed-dose combination (AVANDAMET) as initial therapy in patients with uncontrolled type 2 diabetes compared with monotherapy with either RSG or MET after 32 weeks of treatment.

METHODS

A total of 468 drug-naive patients with uncontrolled type 2 diabetes were recruited for this multicentre, double-blind trial if their glycated haemoglobin (A1c) was greater than 7.5%, but less than or equal to 11%, and their fasting plasma glucose (FPG) was less than or equal to 15 mmol/l. Patients were randomized to 32 weeks of blinded treatment with either RSG/MET fixed-dose combination (n = 155), MET (n = 154) or RSG (n = 159). The groups were comparable at baseline, with mean A1c of 8.8% and FPG of 11 mmol/l. RSG/MET was initiated with a total daily dose of 2 mg/500 mg and could be increased up to 8 mg/2000 mg; MET therapy began with a total daily dose of 500 mg and could be increased up to 2000 mg; and RSG treatment began with a total daily dose of 4 mg and could be increased up to 8 mg. Medication was uptitrated during on-therapy visits based on failure to attain glycaemic target of mean daily glucose less than or equal to 6.1 mmol/l (unless at maximum tolerated dose). Patients were assessed for efficacy and safety at nine visits over a 32-week treatment period. This was a trial designed to show greater efficacy of RSG/MET combination therapy compared with MET or RSG monotherapy. The primary end point was change in A1c from baseline to week 32. Secondary end points included the proportion of patients achieving recommended A1c and FPG targets for glycaemic control and change from baseline in FPG, free fatty acid, lipids, insulin, insulin sensitivity, C-reactive protein and adiponectin. Safety evaluations included adverse-event (AE) monitoring, changes in weight and clinical laboratory evaluations.

RESULTS

At week 32, RSG/MET showed significant improvements in A1c from a baseline of 8.9 +/- 1.1% to 6.6 +/- 1.0% at study end, and this 2.3% reduction was significantly greater than the reductions achieved individually with MET (-1.8%; p = 0.0008) and RSG (-1.6%; p < 0.0001). The greatest mean decrease in FPG was seen with RSG/MET (-4.1 mmol/l) and was significant compared with MET (-2.8 mmol/l; p < 0.0001) and RSG (-2.6 mmol/l; p < 0.0001). Target A1c of less than or equal to 6.5% and less than 7% were achieved in more patients in the RSG/MET group (60% and 77%) than with MET (39% and 57%) or RSG (35% and 58%) respectively. Treatment was well tolerated, with nausea, vomiting and diarrhoea as the most commonly reported AEs. Oedema was comparable between RSG/MET (6%) and RSG (7%) and lower in the MET group (3%). No new safety and tolerability issues were observed in the RSG/MET group.

CONCLUSIONS

As first-line therapy in patients with uncontrolled type 2 diabetes, RSG/MET fixed-dose combination therapy achieved significant reductions in A1c and FPG compared with either RSG or MET monotherapy. RSG/MET was generally well tolerated as initial therapy, with no new tolerability issues identified with the fixed-dose combination.

Thiazolidinediones, insulin resistance and obesity: Finding a balance

The clinical efficacy of currently available thiazolidinediones (TZDs) in improving glycaemic control and ameliorating several risk factors for cardiovascular disease (linked to their insulin-sensitising actions as well as direct vascular effects) is well established. Treatment-associated weight gain, however, which has been identified as a class effect of the TZDs, is seen in a number of patients. The magnitude of weight gain correlates in part with improved metabolic control, i.e. better responders are more prone to increases in body weight. The cardiovascular risk associated with obesity appears to be depot specific; while peripheral obesity is associated with a low risk of cardiovascular complications, central obesity confers a greater degree of risk. Evidence is reviewed that increases in body weight associated with TZD treatment are associated with neutral effects (or even, decreases) in visceral fat, the adipose depot that is associated with central obesity.

Efficacy and safety of the dipeptidyl peptidase-4 inhibitor sitagliptin added to ongoing pioglitazone therapy in patients with type 2 diabetes: A 24-week, multicenter, randomized, double-blind, placebo-controlled, parallel-group study

OBJECTIVE

The efficacy and tolerability of the dipeptidyl peptidase-4 inhibitor sitagliptin added to ongoing pioglitazone therapy were assessed in patients with type 2 diabetes and inadequate glycemic control (glycosylated hemoglobin [HbA(1c)] > or =7% and < or =10%) while receiving a stable dose of pioglitazone.

METHODS

This was a 24-week, multicenter, randomized, double-blind, placebo-controlled, parallel group study in patients aged > or =18 years (ClinicalTrials. gov NCT00086502). At screening, all patients began a diet/exercise program that continued throughout the study period. Patients taking antihyperglycemic therapy other than pioglitazone underwent a washout of this therapy and entered an 8- to 14-week open-label pioglitazone dose-titration/stabilization period. Patients with an HbA(1c) > or =7% and < or =10% at the end of this period entered a 2-week, single-blind, placebo run-in period (total duration of run-in period, up to 21 weeks). Patients who had been receiving pioglitazone monotherapy (30 or 45 mg/d) and had an HbA(1c) > or =7% and < or =10% entered the 2-week, single-blind, placebo run-in period directly. Thus, at the time of randomization, all patients were receiving ongoing pioglitazone (30 or 45 mg/d). Patients were randomized in a 1:1 ratio to receive sitagliptin 100 mg once daily or placebo for 24 weeks. The primary efficacy end point was the change from baseline in HbA(1c) at week 24. Secondary efficacy end points included the change from baseline in fasting plasma glucose (FPG), insulin, and proinsulin; the Homeostasis Model Assessment beta-cell function and insulin-resistance indexes; the proinsulin/ insulin ratio; the Quantitative Insulin Sensitivity Check Index; the percent changes from baseline in selected lipid parameters; the proportion of patients meeting the American Diabetes Association HbA(1c), goal of <7.0%; the proportion of patients requiring metformin rescue therapy; and the time to the initiation of rescue therapy.

RESULTS

One hundred seventy-five patients were randomized to receive sitagliptin, and 178 were randomized to receive placebo. The mean (SD) baseline HbAlc value was 8.1% (0.8) in the sitagliptin group and 8.0% (0.8) in the placebo group. After 24 weeks, sitagliptin added to pioglitazone therapy was associated with significant reductions compared with placebo in HbA(1c) (between-treatment difference in least squares [LS] mean change from baseline. -0.70 %; 95 % CI, -0.85 to -0.54; P < 0.001) and FPG (-17.7 mg/dL; 95% CI, -24.3 to -11.0; P < 0.001). Mean HbA(1c) values at end point were 7.2% (0.9) and 7.8% (1.1) in the respective treatment groups, and the proportions of patients reaching a target HbA(1c) of <7.0% were 45.4% and 23.0% (P < 0.001). Significant reductions in fasting serum proinsulin levels and the proinsulin/insulin ratio were seen with sitagliptin treatment compared with placebo (both, P < 0.01). Sitagliptin was generally well tolerated, with no increased risk of hypoglycemia compared with placebo (2 vs 0 patients, respectively).

Rosiglitazone reduces microalbuminuria and blood pressure independently of glycemia in type 2 diabetes patients with microalbuminuria

OBJECTIVE

To test the hypothesis that rosiglitazone combined with metformin provides a greater reduction in microalbuminuria and blood pressure than metformin and glyburide at comparable levels of glycemic control.

METHODS

In a double-blind, parallel-group design 389 participants with type 2 diabetes were followed for 32 weeks.

RESULTS

Urinary albumin: creatinine ratio was significantly reduced at 32 weeks compared with baseline in the rosiglitazone plus metformin group (-22.7%; P < 0.01) but not in the glyburide plus metformin comparator group (-7.1%; P = 0.32). Patients who completed the study (81.5%) demonstrated a treatment difference of -19.5% (P = 0.03), favoring the rosiglitazone group. Rosiglitazone plus metformin reduced both mean 24-h systolic (-3.4 mmHg; P = 0.01) and diastolic (-2.5 mmHg; P < 0.01) ambulatory blood pressure compared with glyburide plus metformin. Addition of rosiglitazone to metformin also reduced levels of plasminogen activator inhibitor-1 antigen and activity, C-reactive protein, von Willebrand factor and fibrinogen compared with addition of glyburide.

CONCLUSIONS

Rosiglitazone added to background therapy with metformin provides greater reductions in microalbuminuria and blood pressure as compared with glyburide. These additional improvements in microalbuminuria, blood pressure and cardiovascular biomarkers were observed despite comparable improvements in glycemic control in both groups and may be related to the anti-inflammatory properties of rosiglitazone.

Rosiglitazone is effective and well-tolerated in a range of therapeutic regimens during daily practice in patients with type 2 diabetes

Subjects (N = 22,808) with inadequately controlled type 2 diabetes mellitus (T2DM) were included in a large 6-month observational study in Germany. Rosiglitazone (RSG) was added to existing therapy in line with daily practice, with 19,962 subjects evaluated for efficacy by treatment group: RSG monotherapy (n = 1017), RSG plus metformin (MET) (n = 7160), RSG plus sulphonylurea (n = 5033), triple oral therapy (n = 4247), and the remaining subject population (n = 2505). Overall, RSG significantly reduced median HbA(1c) and fasting blood glucose by 1.3% and 50 mg/dl over 6 months (p < 0.001 for both). The proportion of subjects achieving glycaemic goals of <or= 6.5% and <or= 7.0% increased from 5.7% to 33.8%, and from 13.9% to 55.5%, respectively (p < 0.001 for both). Mean systolic and diastolic blood pressures were reduced in the total subject population by 6 mmHg and 2 mmHg, respectively (p < 0.001 for both). RSG had a neutral or reductive effect on mean weight of most (69%) subjects. Consistent with clinical trial data, RSG mono- or combination therapy improved glycaemic control when used in daily clinical practice and is generally well-tolerated.

Closing the gap between clinical research and clinical practice: can outcome studies with thiazolidinediones improve our understanding of type 2 diabetes?

Recent clinical research has provided a wealth of information to support optimal management strategies in type 2 diabetes mellitus (T2DM). In particular, outcome studies appropriately have had an increasingly important impact on clinical decision-making. Additional, new data are required, however, to close the current gaps in clinical knowledge and improve patient outcomes in T2DM. These outcome studies are particularly important in assessing the long-term benefit of newer agents for which data are available for short-term glycaemic control, effects on lipids and some data on non-traditional cardiovascular risk markers, but outcome data for harder end points relevant to the natural history of T2DM, particularly beta-cell function, are lacking. Outcome studies such as ADOPT and DREAM are investigating the impact of thiazolidinediones (TZDs) on beta-cell function and disease progression in T2DM and impaired glucose tolerance, respectively, the results of which are eagerly anticipated. The primary focus of this article is on TZD outcome studies evaluating beta-cell function and disease progression.