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

Efficacy and Safety of DPP-4 Inhibitors and Metformin Combinations in Type 2 Diabetes: A Systematic Literature Review and Network Meta-Analysis

Objective

Several oral antidiabetic regimens are available for treating type 2 diabetes mellitus (T2DM), dipeptidyl peptidase-4 inhibitors (DPP4i) being one of them. We conducted a network meta-analysis (NMA) comparing DPP4i plus metformin (Met) combination with other Met-based oral antidiabetic drug (OAD) combinations used in treating patients with T2DM.

Methods

We searched PubMed and Embase from inception until 19th April, 2022 for phase II and phase III trials in patients with T2DM on Met-based traditional OADs. The primary outcome was assessed by change in glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and 2-hour post-prandial blood glucose (2h-PPG). The secondary safety outcomes assessed were hypoglycemic events, serious adverse events (SAEs), cardiovascular (CV) events, and gastrointestinal (GI) events.

Results

Sixty-two trials were included in the analysis. The combination of DPP4i + Met revealed a comparable mean reduction in HbA1c levels to the glinides (Gli) + Met combination (mean difference [MD]: -0.03%, 95% CI: 0.69, -0.65), although the difference was not statistically significant. The mean HbA1c reduction with DPP4i + Met was greater than with sulfonylureas (SU) + Met (MD: -0.05, 95% CI: -0.29, 0.39), thiazolidinedione (TZD) + Met (MD: -0.69, 95% CI: -1.39, -0.02), and SU + TZD (MD: 0.21; 95% CI: -1.30, 1.71), with no statistical significance. DPP4i + Met demonstrated a non-significant lower incidence of CV events in comparison to TZD + Met (RR: 1.01, 95% CI: 0.46, 2.45) and SU + Met (RR: 1.06, 95% CI: 0.61, 2.06).

Conclusion

DPP4i in combination with Met was efficacious and had a well-tolerated safety profile compared with other traditional OADs. This combination can be considered as a suitable treatment option for patients with T2DM.

Does optimal HbA1c in diabetes differ according to drug treatment? An evaluation of national electronic database in Malta

BACKGROUND AND AIMS

A J-shaped relationship between HbA_1c and mortality has been reported in subjects with type 2 diabetes. The postulated mechanism linking low HbA_1c with increased mortality is increased hypoglycaemia risk. We tested this hypothesis by comparing the relationship between low HbA_1c to mortality in patients on therapies with different hypoglycaemia risk.

METHODS

We selected patients on any type of treatment for diabetes from a national electronic database (n = 25,743) and linked to other databases, including laboratory database and the national mortality register.

RESULTS

We observed a J-shaped or U-shaped association between HbA_1c and all-cause mortality in the whole type 2 diabetes patient cohort as well as in patients on metformin monotherapy and in those on metformin-sulphonylurea combination therapy, but not in subjects on sulphonylurea monotherapy or in those on insulin.

CONCLUSIONS

Our data confirm the J-shaped relationship between HbA_1c and mortality in type 2 diabetes, but suggest that a low HbA_1c is deleterious even in absence of hypoglycaemia and that subjects with type 2 diabetes might require a slightly elevated blood glucose for optimal outcome. Our data also suggest that the increased mortality associated with sulphonylureas cannot be mediated solely through increased hypoglycaemia risk.

Optimization of Metformin in the GRADE Cohort: Effect on Glycemia and Body Weight

OBJECTIVE

We evaluated the effect of optimizing metformin dosing on glycemia and body weight in type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a prespecified analysis of 6,823 participants in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE) taking metformin as the sole glucose-lowering drug who completed a 4- to 14-week (mean ± SD 7.9 ± 2.4) run-in in which metformin was adjusted to 2,000 mg/day or a maximally tolerated lower dose. Participants had type 2 diabetes for <10 years and an HbA1c ≥6.8% (51 mmol/mol) while taking ≥500 mg of metformin/day. Participants also received diet and exercise counseling. The primary outcome was the change in HbA1c during run-in.

RESULTS

Adjusted for duration of run-in, the mean ± SD change in HbA1c was -0.65 ± 0.02% (-7.1 ± 0.2 mmol/mol) when the dose was increased by ≥1,000 mg/day, -0.48 ± 0.02% (-5.2 ± 0.2 mmol/mol) when the dose was unchanged, and -0.23 ± 0.07% (-2.5 ± 0.8 mmol/mol) when the dose was decreased (n = 2,169, 3,548, and 192, respectively). Higher HbA1c at entry predicted greater reduction in HbA1c (P < 0.001) in univariate and multivariate analyses. Weight loss adjusted for duration of run-in averaged 0.91 ± 0.05 kg in participants who increased metformin by ≥1,000 mg/day (n = 1,894).

CONCLUSIONS

Optimizing metformin to 2,000 mg/day or a maximally tolerated lower dose combined with emphasis on medication adherence and lifestyle can improve glycemia in type 2 diabetes and HbA1c values ≥6.8% (51 mmol/mol). These findings may help guide efforts to optimize metformin therapy among persons with type 2 diabetes and suboptimal glycemic control.

Durability and tolerability of dapagliflozin over 52 weeks as add-on to metformin and sulphonylurea in type 2 diabetes

AIMS

To evaluate the safety and efficacy of dapagliflozin as add-on therapy to metformin plus sulphonylurea over 52 weeks.

METHODS

Patients with type 2 diabetes mellitus (T2DM) using sulphonylurea and metformin received dapagliflozin 10 mg/day or placebo added to therapy for 52 weeks (24-week randomized, double-blind period plus 28-week double-blind extension).

RESULTS

A total of 219 patients were randomized 1 : 1 to dapagliflozin or placebo. Over 52 weeks, glycated haemoglobin (HbA1c) and fasting plasma glucose levels showed greater improvement from baseline with dapagliflozin (-0.8% and -1.5 mmol/l) than with placebo (-0.1% and 0.6 mmol/l). More patients achieved HbA1c <7.0% with dapagliflozin (27.3%) than with placebo (11.3%) at 52 weeks. Dapagliflozin was associated with greater reductions in body weight and systolic blood pressure (-2.9 kg and -1.0 mmHg) compared with placebo (-1.0 kg and 1.1 mmHg). Greater increases in total, LDL and HDL cholesterol and decreases in triglycerides were observed with dapagliflozin (3.4, 4.8, 6.9 and -8.0%, respectively) versus placebo (1.4, 0.9, 0.6 and 2.9%, respectively). Fewer patients were rescued for failing to reach glycaemic targets with dapagliflozin (9.3%) than with placebo (44.4%). Adverse events and serious adverse events were similar between groups (dapagliflozin: 69.7 and 6.4%; placebo: 73.4 and 7.3%). More hypoglycaemic events were observed with dapagliflozin (15.6%) than with placebo (8.3%). Genital infections were reported in more patients in the dapagliflozin (10.1%) than in the placebo group (0.9%) and urinary tract infection frequency was similar in the two groups (10.1 and 11.0%).

CONCLUSION

Dapagliflozin as add-on to metformin plus a sulphonylurea was well tolerated and improvement in glycaemic control was maintained over 52 weeks.

Assessment of glycemic control in patients with type 2 diabetes mellitus treated with metformin-sulfonylurea combination: Results of a multicenter, cross-sectional, observational study in Korea

AIMS/INTRODUCTION

To assess the current status of glycemic control in patients with type 2 diabetes treated with a combination of metformin and sulfonylurea for >3 months, as measured by glycosylated hemoglobin (HbA1c).

MATERIALS AND METHODS

Data on patient demographics, diabetic complications, HbA1c, fasting plasma glucose (FPG) and type of treatment were collected in this multicenter, cross-sectional, non-interventional study.

RESULTS

From April 2008 to February 2009, 5,628 patients were recruited from 299 centers in Korea. Patients characteristics (mean ± SD) were as follows: age 58.4 ± 10.8 years, duration of diabetes 6.1 ± 4.7 years, body mass index 24.7 ± 2.9 kg/m(2), HbA1c 7.77 ± 1.22%, FBG 147.4 ± 46.5 mmol/L and FPG 164.0 ± 54.3 mmol/L. The most common diabetic complication was neuropathy (22.5%), followed by retinopathy (18.3%) and microalbuminuria (16.1%). Just 1,524 (27.1%) patients achieved HbA1c ≤7%. A higher number of patients (32.6%) treated by endocrinologists achieved HbA1c ≤7% than those treated by internists (24.4%) and primary care physicians (23.2%). In multivariate analyses, diabetic retinopathy (odds ratio 0.455, 95% confidence interval 0.341-0.606), nephropathy (odds ratio 0.639, 95% confidence interval 0.43-0.949), diabetes for ≥5 years (odds ratio 0.493, 95% confidence interval 0.4-0.606) and older age added by 1 year (odds ratio 1.019, 95% confidence interval 1.01-1.029) was significantly associated with achieving target HbA1c. In addition, treatment by endocrinologists rather than internists significantly increased chances of achieving target HbA1c (odds ratio 1.417, 95% confidence interval 1.146-1.751).

CONCLUSIONS

The majority of patients with type 2 diabetes in Korea had inadequate glycemic control, despite receiving a combination of metformin and sulfonylurea.

Association of hypoglycemic treatment regimens with cardiovascular outcomes in overweight and obese subjects with type 2 diabetes: a substudy of the SCOUT trial

OBJECTIVE

To assess the association of hypoglycemic treatment regimens with cardiovascular adverse events and mortality in a large population of type 2 diabetic patients at increased cardiovascular risk.

RESEARCH DESIGN AND METHODS

This analysis included 8,192 overweight patients with type 2 diabetes from the Sibutramine Cardiovascular Outcomes (SCOUT) trial randomized to lifestyle intervention with or without sibutramine for up to 6 years. Patients were grouped according to hypoglycemic treatment at baseline. The primary end point was the time from randomization to the first occurrence of a primary outcome event (POE), nonfatal myocardial infarction, nonfatal stroke, resuscitation after cardiac arrest, or cardiovascular death. Multivariable Cox proportional hazards regression models were used to assess the impact of antiglycemic treatment on POE and all-cause mortality.

RESULTS

Treatments for type 2 diabetes were as follows: diet alone (n = 1,394 subjects), metformin monotherapy (n = 1,631), insulin monotherapy (n = 1,116), sulfonylurea monotherapy (n = 1,083), metformin plus sulfonylurea (n = 1,565), and metformin plus insulin (n = 1,000); 905 subjects experienced a POE and 708 died. Metformin monotherapy was associated with lower risk of POE than insulin (hazard ratio [HR], 0.74; 95% CI, 0.57-0.95; P = 0.02). Diet alone also was associated with lower risk of POE (HR, 0.65; 95% CI, 0.48-0.87; P = 0.004). Metformin monotherapy also was associated with lower mortality (HR, 0.73; 95% CI, 0.54-0.99; P < 0.05), whereas no other monotherapies or combination therapies were significantly associated with POE or all-cause mortality compared with insulin as monotherapy.

CONCLUSIONS

In obese patients with type 2 diabetes and high risk of cardiovascular disease, monotherapy with metformin or diet-only treatment was associated with lower risk of cardiovascular events than treatment with insulin.

Linagliptin as add-on therapy to insulin for patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a highly prevalent, progressive disease that often is poorly controlled. The combination of an incretin-based therapy and insulin is a promising approach to optimize the management of glycemic control without hypoglycemia and weight gain. Linagliptin, a recently approved oral dipeptidyl peptidase-4 inhibitor, has a unique pharmacological profile. The convenient, once-daily dosing does not need adjustment in patients with hepatic and/or renal impairment. In clinical studies linagliptin shows an important reduction of blood glucose with an overall safety profile similar to that of placebo. So far, the combination of linagliptin and insulin has been tested in three major clinical studies in different populations. It has been shown that linagliptin is an effective and safe add-on therapy to insulin in patients with T2DM. The efficacy and safety of this combination was also shown in vulnerable, elderly T2DM patients and in patients with T2DM and renal impairment. Favorable effects regarding the counteraction of hypoglycemia make linagliptin especially interesting as an add-on therapy to insulin. This review aims to present the existing clinical studies on the efficacy and safety of linagliptin as add-on therapy to insulin in patients with T2DM in the context of current literature. Additionally, the possible advantages of linagliptin as an add-on therapy to insulin in relation to cardiovascular safety, patient-centered therapy and the prevention of hypoglycemia, are discussed.

Safety and tolerability of linagliptin: a pooled analysis of data from randomized controlled trials in 3572 patients with type 2 diabetes mellitus

AIMS

To assess the safety and tolerability of the dipeptidyl peptidase-4 inhibitor linagliptin in patients with type 2 diabetes.

METHODS

Data were pooled from eight randomized, double-blind, placebo-controlled Phase III clinical trials lasting ≤24 weeks. Incidences were calculated with descriptive statistics for the overall population and for subgroups of elderly and renally impaired patients.

RESULTS

A total of 2523 patients received linagliptin 5 mg once daily and 1049 patients received placebo. The overall incidence of adverse events (AEs) or serious AEs with linagliptin was similar to placebo (AEs 55.8% vs. 55.0%; serious AEs 2.8% vs. 2.7%). Overall aggregated infection incidence was 19.5% for linagliptin and 21.4% for placebo. Similar or reduced incidence of AEs versus placebo were seen with linagliptin for upper respiratory tract infection (3.3% vs. 4.9%), headache (2.9% vs. 3.1%), urinary tract infection (2.2% vs. 2.7%), blood and lymphatic disorders (1.0% vs. 1.2%), hypersensitivity (0.1% vs. 0.1%), hepatic enzyme increase (0.1% and 0.1%) and serum creatinine increase (0.0% and 0.1%). There was a slight increased frequency of nasopharyngitis (5.9% vs. 5.1%) and cough (1.7% vs. 1.0%) with linagliptin. Hypoglycaemia incidence was 8.2% for linagliptin and 5.1% for placebo; incidence was higher in patients with a background of sulphonylurea therapy (20.7% and 13.3%, respectively). In patients not receiving concomitant sulphonylurea, the hypoglycaemic incidence with linagliptin was very low in both the total population (<1%), and elderly and renally impaired patients (both <1%).

CONCLUSIONS

This pooled analysis shows that linagliptin is well tolerated, with a low risk of hypoglycaemia.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators.

SELECTION CRITERIA

Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy.

DATA COLLECTION AND ANALYSIS

The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data.

MAIN RESULTS

Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies.

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators.

SELECTION CRITERIA

Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy.

DATA COLLECTION AND ANALYSIS

The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data.

MAIN RESULTS

Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies.

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.

Safety and tolerability of sitagliptin in patients with type 2 diabetes: a pooled analysis

BACKGROUND

Sitagliptin, a highly selective dipeptidyl peptidase-4 inhibitor, is the first in a new class of oral antihyperglycemic agents (AHAs) for the treatment of patients with type 2 diabetes. Type 2 diabetes is a life-long disease requiring chronic treatment and management. Therefore, robust assessment of the long-term safety and tolerability of newer therapeutic agents is of importance. The purpose of this analysis was to assess the safety and tolerability of sitagliptin by pooling 12 large, double-blind, Phase IIb and III studies up to 2 years in duration.

METHODS

This analysis included 6139 patients with type 2 diabetes receiving either sitagliptin 100 mg/day (N = 3415) or a comparator agent (placebo or an active comparator) (N = 2724; non-exposed group). The 12 studies from which this pooled population was drawn represent the double-blind, randomized, Phase IIB and III studies that included patients treated with the clinical dose of sitagliptin (100 mg/day) for at least 18 weeks up to 2 years and that were available in a single safety database as of November 2007. These 12 studies assessed sitagliptin as monotherapy, initial combination therapy with metformin, or add-on combination therapy with other oral AHAs (metformin, pioglitazone, sulfonylurea, sulfonylurea + metformin, or metformin + rosiglitazone). Patients in the non-exposed group were taking placebo, pioglitazone, metformin, sulfonylurea, sulfonylurea + metformin, or metformin + rosiglitazone. This safety analysis used patient-level data from each study to evaluate clinical and laboratory adverse experiences.

RESULTS

For clinical adverse experiences, the incidence rates of adverse experiences overall, serious adverse experiences, and discontinuations due to adverse experiences were similar in the sitagliptin and non-exposed groups. The incidence rates of specific adverse experiences were also generally similar in the two groups, with the exception of an increased incidence rate of hypoglycemia observed in the non-exposed group. The incidence rates of drug-related adverse experiences overall and discontinuations due to drug-related adverse experiences were higher in the non-exposed group, primarily due to the increased incidence rate of hypoglycemia in this group. For cardiac- and ischemia-related adverse experiences (including serious events), there were no meaningful between-group differences. No meaningful differences between groups in laboratory adverse experiences, either summary measures or specific adverse experiences, were observed.

CONCLUSION

In patients with type 2 diabetes, sitagliptin 100 mg/day was well tolerated in clinical trials up to 2 years in duration.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent used in the treatment of type 2 diabetes mellitus. The results of the UK Prospective Diabetes Study indicate that metformin treatment is associated with a reduction in total mortality compared to other anti-hyperglycemic treatments. Metformin, however, is thought to increase the risk of lactic acidosis, and is considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis with metformin use compared to placebo and other glucose-lowering treatments in patients with type 2 diabetes mellitus. A secondary objective was to evaluate the blood lactate levels for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A search was performed of The Cochrane Library (up to 8/2005), MEDLINE (up to 8/2005), EMBASE (up to 11/2000), OLD MEDLINE, and REACTIONS (up to 8/2005), in order to identify all studies of metformin treatment from 1966 to August 2005. The Cumulated Index Medicus was used to search relevant articles from 1959 to 1965. The search was augmented by scanning references of identified articles, and by contacting principal investigators. Date of latest search: August 2005.

SELECTION CRITERIA

Prospective trials in patients with type 2 diabetes that lasted longer than one month were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. Observational cohort studies of metformin treatment lasting greater than one month were also included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials to be included, assessed study quality and extracted data. The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for placebo or other treatments. The upper limit for the true incidence of cases in the metformin and non-metformin groups were calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed effect model for continuous data.

MAIN RESULTS

Pooled data from 206 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 47,846 patient-years of metformin use or in 38,221 patients-years in the non-metformin group. Using Poisson statistics with 95% confidence intervals the upper limit for the true incidence of metformin-associated lactic acidosis was 6.3 cases per 100,000 patient-years, and the upper limit for the true incidence of lactic acidosis in the non-metformin group was 7.8 cases per 100,000 patient-years. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to placebo or other non-biguanide therapies. The mean lactate levels were slightly lower for metformin treatment compared to phenformin (WMD -0.75 mmol/L, 95% CI -0.86 to -0.15).

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments if prescribed under the study conditions.