Increased mortality in Type II diabetic patients using sulphonylurea and metformin in combination: a population-based observational study

Impact of Race and Ethnicity on Severe Hypoglycemia Associated with Sulfonylurea Use for Type 2 Diabetes among Veterans

Sulfonylureas are associated with hypoglycemia. Whether a racial/ethnic disparity in this safety outcome exists is unknown. We sought to assess the impact of race/ethnicity on severe hypoglycemia associated with sulfonylurea use for type 2 diabetes (T2D). Using Veterans Affairs and Medicare data, Veterans initially receiving metformin monotherapy for T2D between 2004 and 2006 were identified. Sulfonylurea use (either alone or via the addition of a prescription for a sulfonylurea to metformin) was captured and compared to remaining on metformin alone during the follow-up period (2007-2016). Hazard ratios (HR) and 95% confidence intervals (CI) from longitudinal competing risk Cox models were used to measure the association between sulfonylurea use and severe hypoglycemia defined as hospitalization for hypoglycemia. A total of 113,668 Veterans with T2D were included. A higher risk of severe hypoglycemia was associated with the receipt of sulfonylurea prescriptions versus remaining on metformin alone across all groups. The effect was largest among Hispanic Veterans (HR: 7.59, 95%CI:4.32-13.33), followed by Veterans in the other race/ethnicity cohort (HR: 4.57, 95%CI:2.50-8.36) and Non-Hispanic Black Veterans (HR: 3.67, 95%CI:2.78-4.85). The effect was smallest among Non-Hispanic White Veterans (HR: 3.11, 95%CI:2.77-3.48). In conclusion, a higher risk of severe hypoglycemia associated with sulfonylurea prescriptions was observed across all analyses. The relationship was most pronounced for Hispanic Veterans, who had nearly 8 times the risk of severe hypoglycemia with sulfonylureas versus remaining on metformin alone.

Sulfonylureas as second line therapy for type 2 diabetes among veterans: Results from a National Longitudinal Cohort Study

AIMS

To assess if switching to or adding sulfonylureas increases major adverse cardiovascular events (MACE) or severe hypoglycemia versus remaining on metformin alone.

MATERIALS AND METHODS

This was a retrospective, longitudinal cohort utilizing United States Veterans Health Administration and Medicare data. Veterans with type 2 diabetes on metformin monotherapy between 2004 and 2006 were identified. Follow-up occurred through 2016. Those treated with either metformin plus a second-generation sulfonylurea (N = 45,305) or converted from metformin to a second-generation sulfonylurea (N = 2813) were compared to those receiving metformin monotherapy (N = 65,550). Hazard ratios (HR) and 95%CI from longitudinal competing risk Cox models were used to measure the association between sulfonylureas and outcomes.

RESULTS

Switching to or adding a sulfonylurea to metformin was associated with 3 times the risk of severe hypoglycemia versus metformin monotherapy (HR:3.44, 95% CI: 3.06,3.85 and HR: 3.08, 95% CI: 2.77,3.42, respectively). Switching to or adding a sulfonylurea to metformin was associated with a 7-19% higher risk of MACE versus metformin monotherapy (HR: 1.07, 95% CI: 1.00,1.14 and HR: 1.19, 95% CI: 1.13,1.25, respectively).

CONCLUSIONS

Switching to and adding second-generation sulfonylureas was associated an increase in severe hypoglycemia and MACE versus remaining on metformin alone. In an era where guidelines recommend diabetes therapies based on compelling indications, safety outcomes should be a key consideration when selecting therapy.

Can metformin use reduce the risk of stroke in diabetic patients? A systematic review and meta-analysis

BACKGROUND AND AIM

Stroke and cardiovascular diseases are major causes of death and disability, especially among diabetic patients. Some studies have shown that metformin has been effective in preventing cardiovascular diseases. In this study, we aim to evaluate the effect of metformin on stroke in type 2 diabetic patients.

METHODS

A comprehensive search was conducted in Medline, Embase, Scopus, and Web of Science databases from their inception till 1st July 2022. Randomized clinical trials (RCT) and cohort studies were included. Two independent researchers screened the records, extracted the data, and assessed the risk of bias and certainty of evidence. Findings were reported as risk ratio (RR) and 95% confidence interval (CI). All statistical analyses were performed using the STATA 17.0 software package.

RESULTS

Analysis of 21 included studies with 1,392,809 patients demonstrated that metformin monotherapy was effective in reducing stroke risk in both RCTs (RR = 0.66, 95% CI: 0.50, 0.87 p = 0.004) and cohort studies (RR = 0.67, 95% CI: 0.55, 0.81, p < 0.0001). However, combined administration of metformin with other antihyperglycemic agents had no significant effect on stroke risk reduction in either the RCTs (RR = 0.92, 95% CI: 0.69, 1.22 p = 0.558) or the cohort studies (RR = 0.79, 95% CI: 0.59, 1.06, p = 0.122).

CONCLUSION

Low to moderate level of evidence in RCTs showed that metformin monotherapy could reduce stroke risk in type 2 diabetic patients. However, the preventive effect of metformin in stroke was not observed in patients who received a combination of metformin plus other hypoglycemic agents.

Who benefits most in disease management programs: Improving target efficiency

Disease management programs aim to reduce cost by improving the quality of care for chronic diseases. Evidence of their effectiveness is mixed. Reducing health care spending sufficiently to cover program costs has proved particularly challenging. This study uses a difference in differences design to examine the impact of a diabetes disease management program for high risk patients on preventive tests, health outcomes, and cost of care. Heterogeneity is examined along the dimensions of severity (measured using the proxy of poor glycemic control) and preventive testing received in the baseline year. Although disease management programs tend to focus on the sickest, the impact of this program concentrates in the group of people who had not received recommended tests in the preintervention period. If confirmed, such findings are practically important to improve cost-effectiveness in disease management programs by targeting relevant subgroups defined both based on severity and on (missing) test information.

Sodium-glucose Cotransporter-2 Inhibitors: Moving Beyond the Glycemic Treatment Goal

Revelations of the multifactorial pathogenesis of type 2 diabetes mellitus (T2DM) that extend beyond the role of insulin and glucose utilization have been crucial in redefining the treatment paradigm. The focus of treatment is currently directed towards achieving wide-ranging targets encompassing the management of cardiovascular comorbidities that have been evidenced as indispensable aspects of T2DM. While most currently prescribed antihyperglycemic agents have little or no effect on reducing cardiovascular risks, some have been associated with undesirable effects on common risk factors such as weight gain and cardiovascular sequelae. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are newer additions to the array of therapeutic agents for T2DM that have demonstrated robust glycemic control as mono and add-on therapies. Their unique renal mode of action, independent of insulin modulation, confers complementary metabolic benefits. By virtue of these effects, SGLT2i may have a distinct role in the revised treatment recommendations by established working groups such as the American Diabetes Association and the American Association of Clinical Endocrinologists that advocate a more comprehensive management of T2DM, not restricting to glycemic targets. The current review gives an overview of the changing treatment needs for T2DM and discusses the nonglycemic effects of SGLT2i. It provides an updated summary on the efficacy of canagliflozin, dapagliflozin, and empagliflozin in promoting weight loss, stabilizing blood pressure, and other favorable metabolic effects.

Sulfonylureas and the Risks of Cardiovascular Events and Death: A Methodological Meta-Regression Analysis of the Observational Studies

Recent randomized trials have compared the newer antidiabetic agents to treatments involving sulfonylureas, drugs associated with increased cardiovascular risks and mortality in some observational studies with conflicting results. We reviewed the methodology of these observational studies by searching MEDLINE from inception to December 2015 for all studies of the association between sulfonylureas and cardiovascular events or mortality. Each study was appraised with respect to the comparator, the outcome, and study design-related sources of bias. A meta-regression analysis was used to evaluate heterogeneity. A total of 19 studies were identified, of which six had no major design-related biases. Sulfonylureas were associated with an increased risk of cardiovascular events and mortality in five of these studies (relative risks 1.16-1.55). Overall, the 19 studies resulted in 36 relative risks as some studies assessed multiple outcomes or comparators. Of the 36 analyses, metformin was the comparator in 27 (75%) and death was the outcome in 24 (67%). The relative risk was higher by 13% when the comparator was metformin, by 20% when death was the outcome, and by 7% when the studies had design-related biases. The lowest predicted relative risk was for studies with no major bias, comparator other than metformin, and cardiovascular outcome (1.06 [95% CI 0.92-1.23]), whereas the highest was for studies with bias, metformin comparator, and mortality outcome (1.53 [95% CI 1.43-1.65]). In summary, sulfonylureas were associated with an increased risk of cardiovascular events and mortality in the majority of studies with no major design-related biases. Among studies with important biases, the association varied significantly with respect to the comparator, the outcome, and the type of bias. With the introduction of new antidiabetic drugs, the use of appropriate design and analytical tools will provide their more accurate cardiovascular safety assessment in the real-world setting.

Is gliclazide a sulfonylurea with difference? A review in 2016

Sulfonylureas (SUs) remain the most commonly prescribed drug after metformin in the treatment of type 2 diabetes (T2DM), despite the availability of several newer agents. The primary reason of SUs being most popular is their quick glycemic response, time-tested experience and least cost. Although SUs are one amongst the several other second line agents after metformin in all major guidelines, the new Dutch type 2 guidelines specifically advise gliclazide as the preferred second line drug instead of SUs as a class. The World Health Organization (WHO) has also included gliclazide in their Model List of Essential Medicines 2013 motivated by its safety data in elderly patients. Specifically advising gliclazide may have been based on emerging evidence suggesting cardiovascular neutrality of gliclazide over other SUs. This prompted us to do a literature review of gliclazide efficacy and safety data compared to other SUs as well as oral anti-diabetic drugs.

Antidiabetic treatment with gliptins: focus on cardiovascular effects and outcomes

The traditional oral pharmacological therapy for type 2 diabetes mellitus (T2DM) has been based on the prescription of metformin, a biguanide, as first line antihyperglycemic agent world over. It has been demonstrated that after 3 years of treatment, approximately 50 % of diabetic patients could achieve acceptable glucose levels with monotherapy; but by 9 years this had declined to only 25 %. Therefore, the implementation of a combined pharmacological therapy acting via different pathways becomes necessary, and its combination with a compound of the sulfonylurea group was along decades the most frequently employed prescription in routine clinical practice. Meglitinides, glitazones and alpha-glucosidase inhibitors were subsequently developed, but the five mentioned groups of oral antihyperglycemic agents are associated with variable degrees of undesirable or even severe cardiovascular events. The gliptins—also called dipeptidyl peptidase 4 (DPP4) inhibitors—are an additional group of antidiabetic compounds with increasing clinical use. We review the status of the gliptins with emphasis on their capabilities to positively or negatively affect the cardiovascular system, and their potential involvement in major adverse cardiovascular events (MACE). Alogliptin, anagliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin and vildagliptin are the compounds currently in clinical use. Regardless differences in chemical structure and metabolic pathways, gliptins as a group exert favorable changes in experimental models. These changes, as an almost general rule, include improved endothelial function, reduction of inflammatory markers, oxidative stress ischemia/reperfusion injury and atherogenesis. In addition, increased adiponectin levels and modest decreases in lipidemia and blood pressure were reported. In clinical settings, several trials—notably the longer one, employing sitagliptin, with a mean follow-up period of 3 years—did not show an increased risk for ischemic events. Anyway, it should be emphasized that the encouraging results from basic science were not yet translated into clinical evidence, probably due the multiple and pleiotropic enzymatic effects of DPP4 inhibition. Moreover, when employing saxagliptin, while the drug was not associated with an augmented risk for ischemic events, it should be pinpointed that the rate of hospitalization for heart failure was significantly increased. Gliptins as a group constitute a widely accepted therapy for the management of T2DM, usually as a second-line medication. Nonetheless, for the time being, a definite relationship between gliptins treatment and improved cardiovascular outcomes remains uncertain and needs yet to be proven.

Incretins and selective renal sodium-glucose co-transporter 2 inhibitors in hypertension and coronary heart disease

Hyperglycemia is associated with an increased risk of cardiovascular disease, and the consequences of intensive therapy may depend on the mechanism of the anti-diabetic agent(s) used to achieve a tight control. In animal models, stable analogues of glucagon-like peptide-1 (GLP-1) were able to reduce body weight and blood pressure and also had favorable effects on ischemia following coronary reperfusion. In a similar way, dipeptidyl peptidase IV (DPP-IV) showed to have favorable effects in animal models of ischemia/reperfusion. This could be due to the fact that DPP-IV inhibitors were able to prevent the breakdown of GLP-1 and glucose-dependent insulinotropic polypeptide, but they also decreased the degradation of several vasoactive peptides. Preclinical data for GLP-1, its derivatives and inhibitors of the DPP-IV enzyme degradation suggests that these agents may be able to, besides controlling glycaemia, induce cardio-protective and vasodilator effects. Notwithstanding the many favorable cardiovascular effects of GLP-1/incretins reported in different studies, many questions remain unanswered due the limited number of studies in human beings that aim to examine the effects of GLP-1 on cardiovascular endpoints. For this reason, long-term trials searching for positive cardiovascular effects are now in process, such as the CAROLINA and CARMELINA trials, which are supported by small pilot studies performed in humans (and many more animal studies) with incretin-based therapies. On the other hand, selective renal sodium-glucose co-transporter 2 inhibitors were also evaluated in the prevention of cardiovascular outcomes in type 2 diabetes. However, it is quite early to draw conclusions, since data on cardiovascular outcomes and cardiovascular death are limited and long-term studies are still ongoing. In this review, we will analyze the mechanisms underlying the cardiovascular effects of incretins and, at the same time, we will present a critical position about the real value of these compounds in the cardiovascular system and its protection.

Observational studies of the association between glucose-lowering medications and cardiovascular outcomes: addressing methodological limitations

BACKGROUND

Recent years have witnessed a growing body of observational literature on the association between glucose-lowering treatments and cardiovascular disease. However, many of the studies are based on designs or analyses that inadequately address the methodological challenges involved.

METHODS

We reviewed recent observational literature on the association between glucose-lowering medications and cardiovascular outcomes and assessed the design and analysis methods used, with a focus on their ability to address specific methodological challenges. We describe and illustrate these methodological issues and their impact on observed associations, providing examples from the reviewed literature. We suggest approaches that may be employed to manage these methodological challenges.

RESULTS

From the evaluation of 81 publications of observational investigations assessing the association between glucose-lowering treatments and cardiovascular outcomes, we identified the following methodological challenges: 1) handling of temporality in administrative databases; 2) handling of risks that vary with time and treatment duration; 3) definitions of the exposure risk window; 4) handling of exposures that change over time; and 5) handling of confounding by indication. Most of these methodological challenges may be suitably addressed through application of appropriate methods.

CONCLUSIONS/INTERPRETATION

Observational research plays an increasingly important role in the evaluation of the clinical effects of diabetes treatment. Implementation of appropriate research methods holds the promise of reducing the potential for spurious findings and the risk that the spurious findings will mislead the medical community about risks and benefits of diabetes medications.

Sulfonylurea use and incident cardiovascular disease among patients with type 2 diabetes: prospective cohort study among women

OBJECTIVE

Evidence is inconsistent for the association between sulfonylurea use and risk of cardiovascular disease among patients with diabetes. We aimed to prospectively evaluate this association using the Nurses' Health Study (NHS), a well-established cohort of U.S. women with long-term follow-up.

RESEARCH DESIGN AND METHODS

We followed 4,902 women (mean age 68 years) with diabetes (mean duration 11 years), but without cardiovascular disease at baseline. The use of sulfonylureas and other medications was self-reported at baseline and during the follow-up period of up to 10 years. Cox proportional hazards regression models were used to estimate the relative risk (RR) and 95% CI for the association between the sulfonylurea use and incident cardiovascular disease while accounting for potential confounders, including age, diabetes duration, diabetes-related complications, other antihyperglycemic medications, BMI, lifestyle factors, family history of cardiovascular diseases, and present chronic conditions. We also applied the propensity score stratification method to address the possibility of residual confounding.

RESULTS

We identified 339 incident cases of cardiovascular disease, including 191 cases of coronary heart disease (CHD) and 148 cases of stroke. A longer duration of sulfonylurea use was significantly associated with a higher risk of CHD (P for trend = 0.002); the RRs for CHD were 1.24 (95% CI 0.85-1.81) for patients who used sulfonylurea therapy for 1-5 years, 1.51 (0.94-2.42) for 6-10 years, and 2.15 (1.31-3.54) for >10 years, compared with nonusers. Compared with users of metformin monotherapy, the RR for CHD was 3.27 (1.31-8.17) for those who were treated with the combination of metformin and sulfonylurea. The analysis using propensity score stratification yielded similar results. We did not observe a significant association between sulfonylurea therapy and stroke risk.

CONCLUSIONS

Long-term use of sulfonylureas was associated with a significantly higher risk of developing CHD among women with diabetes.

Hypoglycemia requiring ambulance services in patients with type 2 diabetes is associated with increased long-term mortality

OBJECTIVE

To report population burden of hypoglycemia requiring ambulance services and long term outcomes thereafter, among people with type 2 diabetes (T2D).

METHODS

We retrieved all ambulance calls made by T2D for hypoglycemia in Olmsted County, Minnesota, between January 1, 2003, and December 31, 2009.

RESULTS

Seven hundred eighteen calls were made by 503 T2D (age 69 ± 12 years, 51% male), of which 328 (65%) were on insulin (INS), 54 (11%) on insulin + noninsulin agents (NIAI), 95 (19%) on sulphonylurea alone or in combination with other noninsulin agents (SFU), 21 (4%) on nonsulphonylurea noninsulin agents (NSFU), and 5 (1%) on no therapy (excluded from further analysis). NSFU had lower repeated calls (INS 25%, NIAI 26%, SFU 12%, NSFU 5%; P = .02), emergency room transportation (ERT) (INS 62%, NIAI 67%, SFU 68%, NSFU 38%; P = .06), and hospitalizations (INS 31%, NIAI 46%, SFU 38%, NSFU 19%; P = .02) compared to other groups. In multivariable mortality model, increased age (P<.001) was associated with an increased risk of death, whereas hypoglycemia predisposing comorbidities (chronic liver disease, end stage renal disease, adrenal insufficiency) (P = .06) were associated with a borderline increased risk, but no association was found with treatment group, repeated calls, ERT, hospitalization and baseline diabetic end organ complications.

CONCLUSION

To our knowledge, we report the first estimate of hypoglycemia requiring ambulance services among T2D, in contemporary clinical practice. NSFU cohort was associated with lower repeated calls, ERT, and hospitalizations compared to other therapeutic programs. Predictors of mortality post-hypoglycemia were age and hypoglycemia predisposing comorbidities.

Mortality in type 2 diabetes mellitus: magnitude of the evidence from a systematic review and meta-analysis

Background:

Type 2 diabetes is associated with an increase in age-related mortality. A systematic review and meta-analysis were performed to define the relative risks (RR) of all-cause or cause-specific mortality in type 2 diabetes and to determine gaps in current research.

Methods:

A comprehensive literature search was undertaken for studies (published 1990–2010) on mortality in type 2 diabetes. The study reports on the measure of mortality as defined by RR for all-cause and cause-specific mortality, heterogeneity, sensitivity analyses and biases.

Results:

In total 35 studies (220,689 patients; mean follow-up of 10.7 years) were eligible for inclusion: 33 studies reported increased mortality risks; 24 had full data on 95% confidence intervals (CIs), one study reported no excess mortality in men diagnosed after 65 years whereas three reported increased mortality in similar age groups in both sexes. Meta-analysis showed RR = 1.85 (95% CI 1.79–1.92) for all-cause mortality [men RR=1.57 (95% CI 1.46–1.68); women RR=2.0 (95% CI 1.89–2.12)], RR=1.76 (95% CI 1.66–1.88) for cardiovascular mortality and RR=2.26 (95% CI: 1.7-3.02) for stroke. There was no statistically significant evidence of publication bias.

Conclusion:

Type 2 diabetes increases mortality approximately two-fold increase and macrovascular disease is the principal cause of death.

Mortality outcomes of different sulphonylurea drugs: the results of a 14-year cohort study of type 2 diabetic patients

OBJECTIVE

Available data about mortality of type 2 diabetic patients treated with different sulphonylureas are scarce and contradictory.

DESIGN

We evaluated the associations between all-cause and cause-specific mortality and treatments with different sulphonylureas in a retrospective cohort of type 2 diabetic patients from a diabetes clinic.

METHODS

All 1277 patients treated with sulphonylureas during 19961997 were enrolled: 159 patients were treated with tolbutamide, 977 glibenclamide and 141 gliclazide. The baseline data (centralised laboratory parameters, anthropometric data and presence of chronic complications) were abstracted from the clinical records. Information on vital status was collected from demographic files after 14-year follow-up. Adjusted hazard ratios (HR) were estimated with Cox (all-cause mortality) or Fine and Gray models (cause-specific mortality), including several potential confounders.

RESULTS

Five hundred and fifty-six patients died during the follow-up: 262 from cardiovascular causes, 158 from cancer and 136 from other causes. When compared with the glibenclamide users, the gliclazide and tolbutamide users showed a significantly lower cancer mortality (HR=0.30; 95% CI 0.16-0.55, and HR=0.48; 95% CI 0.29-0.79 respectively). These results were strongly confirmed in the 555 patients on sulphonylurea monotherapy. None of the patients who were treated with gliclazide monotherapy died from cancer during the follow-up, and the patients on tolbutamide treatment exhibited a lower cancer mortality than the glibenclamide users (HR=0.40; 95% CI 0.22-0.71). Data did not change after stratification for the duration of sulphonylurea treatment from diabetes diagnosis to the study enrollment.

CONCLUSIONS

Cancer mortality was markedly reduced in the patients on gliclazide and tolbutamide treatment. These results suggest additional benefits for these drugs beyond their blood glucose-lowering effect and strongly advocate for further investigation.

The risk of overall mortality in patients with Type 2 diabetes receiving different combinations of sulfonylureas and metformin: a retrospective analysis

AIMS

Sulfonylureas have been shown to increase mortality when used in combination with metformin. This may not be a class effect of sulfonylureas, but rather secondary to differences in properties inherent to the individual sulfonylureas (hypoglycaemic risk, sulfonylurea receptor selectivity and effects on myocardial ischemic preconditioning). The purpose of this study was to assess the risk of overall mortality in patients with Type 2 diabetes treated with different combinations of sulfonylureas and metformin.

METHODS

A retrospective cohort study was conducted using an academic health center enterprise-wide electronic health record system to identify 7320 patients with Type 2 diabetes (3768 initiators of glyburide (glibenclamide) and metformin, 2277 initiators of glipizide and metformin and 1275 initiators of glimepiride and metformin), ≥ 18 years of age and not on insulin or a non-insulin injectable at baseline. The patients were followed for mortality by documentation in the electronic health record and Social Security Death Index. Multivariable Cox models with propensity analysis were used to compare cohorts.

RESULTS

No statistically significant difference in overall mortality risk was observed among the different combinations of sulfonylureas and metformin: glimepiride and metformin vs. glipizide and metformin (HR 1.03; 95% CI 0.89-1.20), glimepiride and metformin vs. glyburide (glibenclamide) and metformin (HR 1.08; 95% CI 0.90-1.30), or with glipizide and metformin vs. glyburide (glibenclamide) and metformin (HR 1.05; 95% CI 0.95-1.15).

CONCLUSIONS

Our results did not identify an increased mortality risk among the different combinations of sulfonylureas and metformin, suggesting that overall mortality is not substantially influenced by the choice of sulfonylurea.

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.

Multiple outcomes associated with the use of metformin and sulphonylureas in type 2 diabetes: a population-based cohort study in Italy

OBJECTIVE

To compare the effect of metformin and sulphonylureas on the risks of switching to insulin therapy, hospitalisation for macrovascular disease and all-cause mortality.

METHODS

The 70,437 residents of the Italian Region of Lombardy aged 40 to 90 years who started diabetes treatment with metformin or sulphonylureas during 2001-2003 entered the study and were followed until July 2007. We estimated the effects of the first-line agent, early compliance, and persistence with first-line therapy on the risks of switching to insulin, hospitalisation for macrovascular disease and all-cause mortality, by fitting a multistate model and adjusting for age, gender and selected clinical factors.

RESULTS

Compared with patients who started on metformin, those who started on sulphonylureas were at a higher risk of switching to insulin (adjusted hazard ratio and 95% CI, 1.55; 1.43, 1.68), hospitalisation (1.15; 1.08, 1.21), and death (1.37; 1.26, 1.49). Compared with patients who stayed on sulphonylureas for 3 months or less, those on sulphonylureas for more than 9 months had an adjusted hazard ratio of 1.24 (1.13, 1.35) for switching to insulin and 1.14 (1.05, 1.23) for hospitalisation. The risks of switching to insulin and hospitalisation were both increased among patients who switched from metformin to another oral hypoglycaemic agent or combined initial monotherapy with another agent.

CONCLUSIONS

Our study provides evidence that the risks of switching to insulin, hospitalisation because of macrovascular events and death changes according to the first prescribed oral hypoglycaemic agent, as well as to the early compliance and persistence with such agent.

Sulphonylurea-metformin combination therapy, cardiovascular disease and all-cause mortality: the Fremantle Diabetes Study

AIM

To determine whether combination of metformin-sulphonylurea is associated with an increased risk of cardiovascular disease (CVD) and mortality in an urban community-based cohort of type 2 patients.

METHODS

We studied 1271 (98.2%) of 1294 type 2 participants in the observational Fremantle Diabetes Study (mean age 64.2 years, 48.8% males) who had detailed diabetes-specific therapy recorded at baseline and complete follow-up data. Mortality and hospital discharge data were collected over 13 174 patient-years (mean +/- SD: 10.4 +/- 3.9 years). Cox proportional hazards modelling was used to determine whether baseline diabetes treatments were independently associated with cardiovascular mortality, hospitalization for/death from CVD or all-cause mortality after adjustment for other explanatory variables.

RESULTS

During follow-up, 523 deaths occurred (41.1%) of which 269 (51.4%) were attributed to CVD. Hospitalization for CVD as principal diagnosis occurred at least once for 481 (37.8%) participants. In Kaplan-Meier analyses, there were significant differences in cardiovascular mortality, hospitalization for/death from CVD and all-cause mortality between diabetes therapy groups (p < 0.001). Compared with diet and metformin monotherapy, those treated with metformin-sulphonylurea had higher cardiovascular and all-cause mortality (p < or = 0.024). Insulin users had significantly higher cardiovascular mortality, hospitalization for/death from CVD and all-cause mortality than those on combination therapy (p < or = 0.016). After adjustment for significant variables in the most parsimonious models, diabetes treatment was not independently associated with any of the three study endpoints (p > or = 0.49).

CONCLUSIONS

Combination metformin-sulphonylurea appears as safe as other blood glucose-lowering therapies used for type 2 diabetes.

Randomized clinical trial of quick-release bromocriptine among patients with type 2 diabetes on overall safety and cardiovascular outcomes

OBJECTIVE

Quick-release bromocriptine (bromocriptine-QR), a D2 dopamine receptor agonist, is indicated as a treatment for type 2 diabetes. The Cycloset Safety Trial, a 52-week, randomized, double-blind, multicenter trial, evaluated the overall safety and cardiovascular safety of this novel therapy for type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 3,095 patients with type 2 diabetes were randomized 2:1 to bromocriptine-QR or placebo in conjunction with the patient's usual diabetes therapy (diet controlled only or up to two antidiabetes medications, including insulin). The all-cause-safety end point was the occurrence of any serious adverse event (SAE), with a hazard ratio (HR) noninferiority margin of 1.5. In a prespecified analysis, the frequency of cardiovascular disease (CVD) events defined as a composite of myocardial infarction, stroke, coronary revascularization, and hospitalization for angina or congestive heart failure was evaluated using modified intent-to-treat analysis (clinicaltrials.gov, NCT00377676).

RESULTS

In the bromocriptine-QR group, 176 (8.6%) people reported SAEs compared with 98 (9.6%) in the placebo group (HR 1.02 [96% one-sided CI 1.27]). Fewer people reported a CVD end point in the bromocriptine-QR group versus the placebo group (37 [1.8%] vs. 32 [3.2%], respecively) (HR 0.60 [95% two-sided CI 0.35-0.96]). Nausea was the most commonly reported adverse event in the bromocriptine-QR group.

CONCLUSIONS

The frequency of SAEs was comparable between the treatment arms. Compared with patients in the placebo arm, fewer patients taking bromocriptine-QR experienced a cardiovascular end point.

Future perspectives for insulinotropic agents in the treatment of type 2 diabetes-DPP-4 inhibitors and sulphonylureas

The introduction of dipeptidyl-peptidase IV inhibitors (DPP-4 inhibitors) brought a novel class of insulinotropic agents into the treatment options for type 2 diabetes. This paper compares the actions, clinical efficacy and safety of sulphonylureas with those of the DPP-4 inhibitors. First, the mode of action of both classes of antidiabetic agents is described. Then clinical studies for both substances in monotherapy and combination therapies are compared concerning their effects on glycaemic parameters and long-term duration of action. Hypoglycaemia incidence and other adverse effects are compared and data on cardiovascular parameters and endpoints are summarized. The effects of sulphonylureas and DPP-4 inhibitors on beta-cell function and beta-cell mass are highlighted. The present and future indications for both sulphonylureas and DPP-4 inhibitors are discussed.

Cardiovascular prevention in type 2 diabetes mellitus patients: the role of oral glucose-lowering agents

Diabetes mellitus (DM) is a metabolic disorder that requires medical diagnosis and treatment. Type 2 DM is due to a combination of defective secretion of and responsiveness to insulin. In early stages, the predominant abnormality is reduced insulin sensitivity, and hyperglycemia can be reversed by a variety of measures and medications. In this stage, the cornerstone of glucose-lowering therapy is lifestyle modification, but when counseling does not adequately achieve the recommended glycemic targets, at least five classes of oral drugs are available. In general, alpha-glucosidase inhibitors delay carbohydrate absorption, metiglinides and sulfonylureas increase insulin supply, and biguanides and thiazolidinediones enhance insulin action. Given the high cardiovascular morbidity and mortality in type 2 DM patients, the attempt to reduce cardiovascular complications, beyond the glucose lowering itself, is an extremely relevant task. Indeed, the role of oral glucose-lowering agents concerning hyperglycemia reduction is defined; however, they have not clearly demonstrated to reduce micro- and macrovascular disease, and hitherto, no firm evidence favors one pharmacological treatment over another. The aim of this update is to describe the existing experiences with oral glucose-lowering agents for type 2 DM treatment with respect to cardiovascular prevention.

A cardiologic approach to non-insulin antidiabetic pharmacotherapy in patients with heart disease

Classical non-insulin antihyperglycemic drugs currently approved for the treatment of type 2 diabetes mellitus (T2DM) comprise five groups: biguanides, sulfonylureas, meglitinides, glitazones and alpha-glucosidase inhibitors. Novel compounds are represented by the incretin mimetic drugs like glucagon like peptide-1 (GLP-1), the dipeptidyl peptidase 4 (DPP-4) inhibitors, dual peroxisome proliferator-activated receptors (PPAR) agonists (glitazars) and amylin mimetic drugs. We review the cardiovascular effects of these drugs in an attempt to improve knowledge regarding their potential risks when treating T2DM in cardiac patients. Metformin may lead to lethal lactic acidosis, especially in patients with clinical conditions that predispose to this complication, such as recent myocardial infarction, heart or renal failure. Sulfonylureas exert their effect by closing the ATP-dependent potassium channels. This prevents the opening of these channels during myocardial ischemia, impeding the necessary hyperpolarization that protects the cell. The combined sulfonylurea/metformin therapy reveals additive effects on mortality in patients with coronary artery disease (CAD). Meglitinides effects are similar to those of sulfonylureas, due to their almost analogous mechanism of action. Glitazones lower leptin levels, leading to weight gain and are unsafe in NYHA class III or IV. The long-term effects of alpha-glucosidase inhibitors on morbidity and mortality rates is yet unknown. The incretin GLP-1 is associated with reductions in body weight and appears to present positive inotropic effects. DPP-4 inhibitors influences on the cardiovascular system seem to be neutral and patients do not gain weight. The future of glitazars is presently uncertain following concerns about their safety. The amylin mimetic drug paramlintide, while a satisfactory adjuvant medication in insulin-dependent diabetes, is unlikely to play a major role in the management of T2DM. Summarizing the present information it can be stated that 1. Four out the five classical oral antidiabetic drug groups present proven or potential cardiac hazards; 2. These hazards are not mere 'side effects', but biochemical phenomena which are deeply rooted in the drugs' mechanism of action; 3. Current data indicate that the combined glibenclamide/metformin therapy seems to present special risk and should be avoided in the long-term management of T2DM with proven CAD; 4. Glitazones should be avoided in patients with overt heart failure; 5, The novel incretin mimetic drugs and DPP-4 inhibitors--while usually inadequate as monotherapy--appear to be satisfactory adjuvant drugs due to the lack of known undesirable cardiovascular effects; 6. Customized antihyperglycemic pharmacological approaches should be implemented for the achievement of optimal treatment of T2DM patients with heart disease. In this context, it should be carefully taken into consideration whether the leading clinical status is CAD or heart failure.

Effect of metformin-containing antidiabetic regimens on all-cause mortality in veterans with type 2 diabetes mellitus

OBJECTIVE

There are conflicting reports concerning metformin use and mortality rates in patients with type 2 diabetes (T2DM). The aim of this study was to examine the relationship between metformin use and all-cause mortality in veterans with T2DM.

RESEARCH DESIGN AND METHODS

An observational cohort study involving 2206 patients with T2DM was performed using computerized database from the Veterans Affairs Medical Center, Memphis, TN. All-cause mortality was compared among cohorts of metformin and nonmetformin users. Univariate and multivariate Cox regression models were used to estimate hazard ratios (HR) for all-cause mortality after adjusting for age, race, baseline estimated glomerular filtration rate, glycosylated hemoglobin, use of insulin, use of ACE inhibitors or angiotensin II receptor blockers or statins.

RESULTS

The average length of follow-up in metformin and nonmetformin users was 62 +/- 17 and 61 +/- 18 months, respectively. The mean age was 63 +/- 11 years. Crude mortality rates were similar in both groups: 266 (22%) metformin users and 253 (25.3%) nonmetformin users died. There was a trend for improved survival with metformin use (unadjusted HR 0.85, P = 0.07). After multivariate adjustment, metformin users had significantly decreased HR for time to all-cause mortality compared with nonmetformin users (adjusted HR 0.77, P < 0.01). Insulin use was an independent predictor of worsened survival in both univariate and multivariate analyses. In subgroup analysis of patients exposed to insulin, all-cause mortality remained decreased in metformin users (adjusted HR 0.62, P < 0.04).

CONCLUSION

Treatment of T2DM with regimens containing metformin alone or in combination with other hypoglycemic agents was associated with reduced all-cause mortality compared with regimens without metformin.

Is the combination of sulfonylureas and metformin associated with an increased risk of cardiovascular disease or all-cause mortality?: a meta-analysis of observational studies

OBJECTIVE

Observational studies assessing the association of combination therapy of metformin and sulfonylurea on all-cause and/or cardiovascular mortality in type 2 diabetes have shown conflicting results. We therefore evaluated the effects of combination therapy of sulfonylureas and metformin on the risk of all-cause mortality and cardiovascular disease (CVD) among people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A MEDLINE search (January 1966-July 2007) was conducted to identify observational studies that examined the association between combination therapy of sulfonylureas and metformin on risk of CVD or all-cause mortality. From 299 relevant reports, 9 were included in the meta-analysis. In these studies, combination therapy of metformin and sulfonylurea was assessed, the risk of CVD and/or mortality was reported, and adjusted relative risk (RR) or equivalent (hazard ratio and odds ratio) and corresponding variance or equivalent was reported.

RESULTS

The pooled RRs (95% CIs) of outcomes for individuals with type 2 diabetes prescribed combination therapy of sulfonylureas and metformin were 1.19 (0.88-1.62) for all-cause mortality, 1.29 (0.73-2.27) for CVD mortality, and 1.43 (1.10-1.85) for a composite end point of CVD hospitalizations or mortality (fatal or nonfatal events).

CONCLUSIONS

The combination therapy of metformin and sulfonylurea significantly increased the RR of the composite end point of cardiovascular hospitalization or mortality (fatal and nonfatal events) irrespective of the reference group (diet therapy, metformin monotherapy, or sulfonylurea monotherapy); however, there were no significant effects of this combination therapy on either CVD mortality or all-cause mortality alone.

Effect of combined secretagogue/biguanide treatment on mortality in type 2 diabetic patients with and without ischemic heart disease

BACKGROUND

The aim of this investigation was the assessment of the association of combined secretagogue/biguanide treatment with mortality in type 2 diabetic patients with and without ischemic heart disease (IHD).

METHODS

A retrospective observational cohort study was performed on a consecutive series of 1108 non insulin-treated diabetic outpatients, with a mean follow-up of 28.0+/-6.5 months. Information on all-cause mortality was obtained by the City of Florence Registry Office.

RESULTS

Patients treated with combinations of insulin secretagogues and biguanides at enrolment showed a significantly higher yearly mortality rate when compared with the rest of the sample (3.6% vs. 6.2% yearly; p<0.05); this was confirmed at multivariate analysis (OR [95% CI] 1.618[1.044;2.512]). When patients with IHD were analyzed separately, combined therapy was associated with a significantly higher mortality (hazard ratio 2.262[1.005;5.102]). Conversely, among patients without a previous diagnosis of IHD, a non significant trend toward an increase of mortality was observed in those on combined therapy.

CONCLUSIONS

The present study shows that the increase of mortality associated with combinations of biguanides and insulin secretagogues is evident only in patients with IHD. It can be speculated that biguanides could enhance the well-known effects of sulphonylureas on ischemic preconditioning in patients with IHD, aggravating the damage determined by ischemia.

Defining the role of repaglinide in the management of type 2 diabetes mellitus: a review

Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia due to a combination of insulin resistance and impaired insulin secretion. The hyperglycemia is associated with an increased risk for micro- and macrovascular complications, and lowering fasting and postprandial hyperglycemia may be protective against these complications. Repaglinide is an insulin secretagogue that lowers blood glucose levels in patients with T2DM. We review the effects of repaglinide in patients with T2DM, its impact on glycemia and its non-glycemic effects, and its effects when used in special situations or patient populations. Results from randomized controlled trials, observational studies, and safety reports involving humans and published in the English-language through 1 May 2007 identified by a search in PubMed/MEDLINE were evaluated. Present knowledge indicates that repaglinide reduces fasting and postprandial hyperglycemia and the level of glycosylated hemoglobin (HbA1c) in patients with T2DM. It is at least as effective in reducing HbA1c and fasting plasma glucose as sulphonylureas, metformin, or the glitazones and in combination therapy with other drugs, repaglinide is as effective as any other combination. Some studies show a better effect of repaglinide on postprandial glycemia than the comparators. Its propensity to induce hypoglycemia is similar to or a little less than that of sulphonylureas. Repaglinide is associated with less weight gain than sulphonylureas and the glitazones. Repaglinide has primarily a role in the treatment of T2DM when metformin cannot be used due to adverse effects, when metformin fails to adequately control blood glucose levels, when there is a need for flexible dosing (i.e. the elderly or during Ramadan fasting), or when there is a specific wish to lower postprandial glucose. Repaglinide may also have an advantage when an oral agent is needed in diabetic patients with renal impairment. Because of its short duration of action, repaglinide should be taken before each meal, usually at least three times a day. Although no study has investigated whether repaglinide lowers total mortality or cardiovascular endpoints, several studies indicate beneficial effects on cardiovascular surrogate endpoints, such as carotid intima-media thickening, markers of inflammation, platelet activation, lipid parameters, endothelial function, adiponectin, and oxidative stress. In conclusion, repaglinide is a compound that can be used in both mono- and combination therapy for the treatment of both fasting and postprandial hyperglycemia in patients with T2DM. It can be used in patients at different stages of the disease, from uncomplicated to severe renal impairment. Although the drug has been tested in a large number of clinical trials and observational studies, its world-wide use is far less than, for example, sulphonylureas. Repaglinide may offer an additional potential for lowering blood glucose levels in T2DM that until now has not been fully realized by many clinicians.

Thiazolidinedione insulin sensitizers and the heart: a tale of two organs?

Thiazolidinediones (TZDs) are relatively new agents for the treatment of type 2 diabetes. They act as agonists at the PPAR-gamma nuclear receptor and their therapeutic effects include decreased insulin resistance and hyperglycaemia, an improved plasma lipid, inflammation and pro-coagulant profile, and amelioration of hypertension, microalbuminuria and hepatic steatosis. The most common side effects of TZDs include weight gain and oedema, with occasional reports of congestive heart failure (CHF). This review discusses the benefit-risk profile of TZDs in treating patients with type 2 diabetes, with particular reference to the heart. To provide context, we explore briefly the epidemiology and pathophysiology of heart failure in patients with type 2 diabetes, touch on the association of heart disease and cardiovascular mortality with antihyperglycaemic treatment modalities other than TZDs, and then focus on the effects of TZDs on the heart, cardiovascular risk factors and outcomes. We describe the cluster of host factors, which seems to predispose patients with type 2 diabetes to TZD-induced or TZD-exacerbated oedema and CHF and then provide an overview of the putative mechanisms of these TZD-related side effects. We also propose that certain diuretics (amiloride and spironolactone), by targeting the distal nephron that expresses PPARgamma in collecting duct cells, might be of benefit in ameliorating the fluid retention and oedema associated with TZDs.

Are sulphonylureas all the same? A cohort study on cardiovascular and cancer-related mortality

BACKGROUND

Aim of the present study is the comparison of all-cause, cardiovascular and non-cardiovascular mortality, and cardiac morbidity, between patients treated with glibenclamide and gliclazide.

METHODS

A retrospective observational cohort study was performed on a consecutive series of 568 outpatients (282 women, 286 men) with type 2 diabetes treated with either glibenclamide (n = 378) or gliclazide (n = 190). Information on all-cause mortality and on causes of death up to 31 December 2004 was obtained by the City of Florence Registry Office. Non-fatal cases requiring hospitalization were identified through the regional hospital discharge system using International Classification of Diseases.

RESULTS

Mean follow-up was 5.0 +/- 1.6 and 4.4 +/- 2.0 years for death and cardiac events, respectively; during follow-up, 33 and 11 deaths were observed in the glibenclamide and gliclazide groups, with a yearly mortality rate of 4.3 and 2.2%, respectively (p < 0.05). At Cox regression, after adjustment for potential confounders, including comorbidity, glibenclamide treatment was associated with a significant increase in all-cause mortality [OR 2.1(1.2;2.7), p < 0.05], while the difference in cardiovascular mortality was not statistically significant after adjustment for age and sex. Mortality for malignancies was significantly higher in patients treated with glibenclamide after adjustment for age, sex, BMI, and insulin and metformin treatment, [OR 3.6(1.1;11.9); p < 0.05]. A higher incidence of cardiac events was associated with glibenclamide treatment only in patients with previously known ischaemic heart disease.

CONCLUSIONS

Treatment with glibenclamide could be associated with higher mortality for cardiovascular diseases and malignancies, in comparison with gliclazide.

Impact of oral antihyperglycemic therapy on all-cause mortality among patients with diabetes in the Veterans Health Administration

OBJECTIVE

The objective of this analysis was to evaluate the impact of several classes of oral antihyperglycemic therapy relative to sulfonylurea monotherapy on all-cause mortality among a cohort of patients with diabetes from the Veterans Health Administration (VHA).

RESEARCH DESIGN AND METHODS

A retrospective cohort study using data obtained from the VHA Diabetes Epidemiology Cohort was used. Users of oral antihyperglycemic therapy were classified into the following cohorts: sulfonylurea monotherapy, metformin monotherapy, metformin plus sulfonylurea, thiazolidinedione (TZD) use alone or in combination with other oral agents (TZD users), and no drug therapy. All-cause mortality was the outcome of interest. Multivariate mixed models incorporating a propensity score to account for imbalance among cohorts were used to estimate drug effects on mortality with associated 95% CIs.

RESULTS

A total of 39,721 patients with diabetes were included in the study. Adjusted odds ratios and 95% CIs for all-cause mortality were 0.87 (0.68-1.10) for metformin monotherapy users, 0.92 (0.82-1.05) for metformin plus sulfonylurea users, and 1.04 (0.75-1.46) for TZD users, relative to sulfonylurea monotherapy users.

CONCLUSIONS

We did not find any significant drug effect on all-cause mortality for any oral treatment cohorts relative to sulfonylurea oral monotherapy.

Medikamentöse Therapie des Diabetes mellitus Typ 2

The sequelae and complications associated with type 2 diabetes mellitus can be reduced or inhibited by optimal therapy. Currently, a variety of medications are available for differentiated therapy, which should be used according to the German Diabetes Association Guidelines. Changes in lifestyle represent the basic therapeutic principle, and it is mandatory to continuously maintain these measures throughout life. If this is not adequately effective (HBA(1c) <6.5%), treatment with oral antidiabetic drugs (OAD) is necessary. Over time OAD monotherapy frequently fails, so that a combination of several oral antidiabetics is needed. The choice of oral antidiabetics is particularly dependent on the patient's body mass index and associated diseases. If combination therapy with OAD is not successful in achieving HbA1c values <6.5%, insulin therapy is required either in combination with OADs as a bedtime regimen or as intensive insulin therapy using both basal and short-term acting insulins.

Three-year mortality in diabetic patients treated with different combinations of insulin secretagogues and metformin

BACKGROUND

Several studies have shown an increase of mortality in diabetic patients treated with combinations of sulphonylureas and biguanides. Comparisons between different insulin secretagogues in combination with metformin with respect to all-cause mortality have not been reported so far.

METHODS

An observational cohort study was performed on a consecutive series of 2002 outpatients with type 2 diabetes mellitus. Of these patients, 696 (34.8%) were receiving combinations of insulin secretagogues and biguanides at enrollment. Three-year mortality was assessed through research in the City of Florence Registry Office.

RESULTS

During follow-up, 295 deaths were recorded. Among patients on combined secretagogue and biguanide treatment, glibenclamide was associated with a significantly higher yearly mortality (8.7%) than repaglinide (3.1%; p = 0.002), gliclazide (2.1%; p = 0.001), and glimepiride (0.4%; p < 0.0001). After adjusting for potential confounders (including age; duration of diabetes; Body Mass Index (BMI); lipid profile; HbA(1c); insulin treatment; metformin doses; Charlson co-morbidity score; CCS), mortality remained significantly higher in patients treated with combinations of glibenclamide and metformin when compared to those treated with different insulin secretagogues (OR with 95% CI: 2.09 [1.07;4.11]).

CONCLUSIONS

In the present study, sulphonylureas with greater selectivity for beta-cell receptors, such as glimepiride and gliclazide, were associated with a lower mortality when used in combination with metformin in comparison with glibenclamide. Safety of such combinations deserves further investigation.

Drug interactions of clinical importance with antihyperglycaemic agents: an update

Because management of type 2 diabetes mellitus usually involves combined pharmacological therapy to obtain adequate glucose control and treatment of concurrent pathologies (especially dyslipidaemia and arterial hypertension), drug-drug interactions must be carefully considered with antihyperglycaemic drugs. Additive glucose-lowering effects have been extensively reported when combining sulphonylureas (or the new insulin secretagogues, meglitinide derivatives, i.e. nateglinide and repaglinide) with metformin, sulphonylureas (or meglitinide derivatives) with thiazolidinediones (also called glitazones) and the biguanide compound metformin with thiazolidinediones. Interest in combining alpha-glucosidase inhibitors with either sulphonylureas (or meglitinide derivatives), metformin or thiazolidinediones has also been demonstrated. These combinations result in lower glycosylated haemoglobin (HbA(1c)), fasting glucose and postprandial glucose levels than with either monotherapy. Even if modest pharmacokinetic interferences have been reported with some combinations, they do not appear to have important clinical consequences. No significant adverse effects, except a higher risk of hypoglycaemic episodes that may be attributed to better glycaemic control, occur with any combination. Challenging the classical dual therapy with sulphonylurea plus metformin, there is a recent trend to use alternative dual combinations (sulphonylurea plus thiazolidinedione or metformin plus thiazolidinedione). In addition, triple therapy with the addition of a thiazolidinedione to the metformin-sulphonylurea combination has been recently evaluated and allows glucose targets to be reached before insulin therapy is considered. This triple therapy appears to be safe, with no deleterious drug-drug interactions being reported so far.Potential interferences may also occur between glucose-lowering agents and other drugs, and such drug-drug interactions may have important clinical implications. Relevant pharmacological agents are those that are widely coadministered in diabetic patients (e.g. lipid-lowering agents, antihypertensive agents); those that have a narrow efficacy/toxicity ratio (e.g. digoxin, warfarin); or those that are known to induce (rifampicin [rifampin]) or inhibit (fluconazole) the cytochrome P450 (CYP) system. Metformin is currently a key compound in the pharmacological management of type 2 diabetes, used either alone or in combination with other antihyperglycaemics. There are no clinically relevant metabolic interactions with metformin, because this compound is not metabolised and does not inhibit the metabolism of other drugs. In contrast, sulphonylureas, meglitinide derivatives and thiazolidinediones are extensively metabolised in the liver via the CYP system and thus, may be subject to drug-drug metabolic interactions. Many HMG-CoA reductase inhibitors (statins) are also metabolised via the CYP system. Even if modest pharmacokinetic interactions may occur, it is not clear whether drug-drug interactions between oral antihyperglycaemic agents and statins may have clinical consequences regarding both efficacy and safety. In contrast, a marked pharmacokinetic interference has been reported between gemfibrozil and repaglinide and, to a lesser extent, between gemfibrozil and rosiglitazone. This leads to a drastic increase in plasma concentrations of each antihyperglycaemic agent when they are coadministered with the fibric acid derivative, and an increased risk of adverse effects. Some antihypertensive agents may favour hypoglycaemic episodes when co-prescribed with sulphonylureas or meglitinide derivatives, especially ACE inhibitors, but this effect seems to result from a pharmacodynamic drug-drug interaction rather than from a pharmacokinetic drug-drug interaction. No, or only modest, interferences have been described with glucose-lowering agents and other pharmacological compounds such as digoxin or warfarin. The effects of inducers or inhibitors of CYP isoenzymes on the metabolism and pharmacokinetics of the glucose-lowering agents of each pharmacological class has been tested. Significantly increased (with CYP inhibitors) or decreased (with CYP inducers) plasma levels of sulphonylureas, meglitinide derivatives and thiazolidinediones have been reported in healthy volunteers, and these pharmacokinetic changes may lead to enhanced or reduced glucose-lowering action, and thus hypoglycaemia or worsening of metabolic control, respectively. In addition, some case reports have evidenced potential drug-drug interactions with various antihyperglycaemic agents that are usually associated with a higher risk of hypoglycaemia.

Risk of mortality and adverse cardiovascular outcomes in type 2 diabetes: a comparison of patients treated with sulfonylureas and metformin

AIMS/HYPOTHESIS

The aim of this study was to evaluate the risk of adverse cardiovascular outcomes in patients with type 2 diabetes newly treated with sulfonylureas and metformin.

SUBJECTS AND METHODS

The Diabetes Audit and Research in Tayside Scotland (DARTS) diabetes information system and the Medicines Monitoring Unit (MEMO) dispensed prescribing database for the population of Tayside, Scotland (400,000 people) were employed. Patients newly prescribed with oral hypoglycaemic agents between 1994 and 2001 were classified into five study cohorts according to the treatment received: metformin only, sulfonylureas only, sulfonylureas added to metformin, metformin added to sulfonylureas, and both drugs simultaneously. In Cox regression analyses, we estimated relative risks for all-cause mortality, cardiovascular mortality and cardiovascular hospital admission for patients in the five study cohorts, with metformin monotherapy as the reference group.

RESULTS

Of the 5,730 study patients, 1,000 died during a maximum of 8 years follow-up. Patients in the sulfonylureas only cohort had increased risks of mortality and cardiovascular mortality, with unadjusted relative risks of 3.12 (95% CI 2.54-3.84) and 3.71 (95% CI 2.64-5.22), respectively. After adjusting for differences between groups (age, sex, duration of diabetes, blood pressure, cholesterol, HbA(1c), smoking, previous hospital admission, treatment with cardiovascular medication), these relative risks were 1.43 (95% CI 1.15-1.77) and 1.70 (95% CI 1.18-2.45), respectively. Patients in the combination cohorts had significantly increased risks of cardiovascular hospital admission, as well as increased risks of mortality and cardiovascular mortality.

CONCLUSIONS/INTERPRETATION

In this cohort study of patients newly treated with oral hypoglycaemic agents, those treated with sulfonylureas only, or combinations of sulfonylureas and metformin, were at higher risk of adverse cardiovascular outcomes than those treated with metformin alone.

Reduced cardiovascular morbidity and mortality associated with metformin use in subjects with Type 2 diabetes

AIM

Metformin therapy reduces microvascular complications in Type 2 diabetes; questions remain, however, regarding its impact on macrovascular events. This study examined metformin use in relation to risk of cardiovascular-related hospitalization and mortality.

METHODS

We conducted a retrospective cohort analysis, using Saskatchewan Health administrative databases to identify new users of oral antidiabetic drugs. Subject groups were defined by medication use during 1991-1999: sulphonylurea monotherapy, metformin monotherapy, or combination therapy. Deaths and non-fatal hospitalizations recorded during the study period were identified as cardiovascular-related from ICD-9 codes. The main outcome was a composite of first non-fatal hospitalization or death. Standard multivariate techniques, including propensity scores, were used to adjust for potential confounding. Multivariate Cox proportional hazard models were used to examine the relationship between metformin use and the composite endpoint.

RESULTS

Metformin monotherapy was associated with a lower risk of the composite endpoint (adjusted hazard ratio 0.81; 95% confidence interval 0.68, 0.97) compared with sulphonylurea monotherapy. Combination therapy with meformin and a sulphonylurea was associated with lower mortality, but had similar hospitalization rates, to sulphonylurea monotherapy.

CONCLUSIONS

Metformin monotherapy was associated with a lower risk of cardiovascular-related morbidity and mortality, and combination metformin and sulphonylurea therapy was associated with a reduced risk of fatal cardiovascular events, when compared with sulphonylurea monotherapy.

[Management of diabetes mellitus in patients with angiopathies]

Nowadays, about 6-8% of the German population suffers from diabetes mellitus mostly type 2 but in patients with angiopathies about 30% have known diabetes and a further 30% have newly diagnosed diabetes or impaired glucose tolerance. Therefore diagnosis and therapy of glucose impairment play a central role for management of these patients. The antidiabetic therapy for secondary prevention of cardiovascular disease has to be embedded in a multifactorial concept with management of hypertension, hyperlipidemia and hypercoagulability. The management of diabetes following guidelines is a stepwise therapy with lifestyle interventions (diet, exercise) and oral drugs or insulin. Metformin has shown favorable outcome in overweight patients if aware of side effects; insulin is a safe drug in multimorbid patients and with planned interventions or operations. We are awaiting the results of multiple endpoint studies with newer antidiabetic drugs which may change our current concept of management of diabetes mellitus in these patients in the near future.