Treatment maintenance duration of dual therapy with metformin and sitagliptin in type 2 diabetes: The ODYSSEE observational study

Benefits and risks of drug combination therapy for diabetes mellitus and its complications: a comprehensive review

Diabetes is a chronic metabolic disease, and its therapeutic goals focus on the effective management of blood glucose and various complications. Drug combination therapy has emerged as a comprehensive treatment approach for diabetes. An increasing number of studies have shown that, compared with monotherapy, combination therapy can bring significant clinical benefits while controlling blood glucose, weight, and blood pressure, as well as mitigating damage from certain complications and delaying their progression in diabetes, including both type 1 diabetes (T1D), type 2 diabetes (T2D) and related complications. This evidence provides strong support for the recommendation of combination therapy for diabetes and highlights the importance of combined treatment. In this review, we first provided a brief overview of the phenotype and pathogenesis of diabetes and discussed several conventional anti-diabetic medications currently used for the treatment of diabetes. We then reviewed several clinical trials and pre-clinical animal experiments on T1D, T2D, and their common complications to evaluate the efficacy and safety of different classes of drug combinations. In general, combination therapy plays a pivotal role in the management of diabetes. Integrating the effectiveness of multiple drugs enables more comprehensive and effective control of blood glucose without increasing the risk of hypoglycemia or other serious adverse events. However, specific treatment regimens should be tailored to individual patients and implemented under the guidance of healthcare professionals.

Time to Treatment Intensification in Patients Receiving DPP4 Inhibitors Versus Sulfonylureas as the First Add-On to Metformin Monotherapy: A Retrospective Cohort Study

Background: To verify whether, in patients on metformin (MET) monotherapy for type 2 diabetes (T2D), the add-on of a dipeptidyl peptidase inhibitor (DPP4i) compared to a sulfonylurea (SU) can delay the time to the subsequent treatment intensification (TI).

Methods: Population-based administrative data banks from four Italian geographic areas were used. Patients aged ≥18 years on MET monotherapy receiving first DPP4i or SU dispensing between 2008 and 2015 (cohort entry) were followed up to the occurrence of TI (insulin dispensing or add-on of a third non-insulin hypoglicemic >180 days after cohort entry), treatment discontinuation, switch, cancer, death, TI occurrence within, end of data availability, end of study period (31 December 2016), whichever came first. Patients on MET + DPP4i were matched 1:1 with those on MET + SU by sex, age, year of cohort entry, and data bank. Hazard Ratio (HR) and 95% confidence intervals (95%CI) were estimated using multivariable Cox regression model including matching variables and potential confounders measured at baseline. Different sensitivity analyses were performed: i) matching at 180 days after cohort entry, ii) intent to treat (ITT) analysis, iii) matching by duration of MET monotherapy, iv) matching by propensity score.

Results: The matched study cohort included 10,600 patients. Overall, 763 TI were observed (4.5/100 person-years; mean follow-up = 1.6 years). The primary analysis showed no difference in time to TI between the two groups (HR = 1.02; 95% CI = 0.88–1.19). Sensitivity analyses confirmed this result, except from the ITT analysis (HR = 1.27; 1.13–1.43).

Conclusion: The use of a DPP4i rather than a SU as add-on to MET monotherapy was not associated with a delay in treatment intensification.

Cost-Utility Analysis of Saxagliptin/Dapagliflozin Versus Gliclazide and Insulin Glargine: Economic Implications of the Outcomes of the CVD-Real Studies I and II

Diabetes treatment cost represents an ever-growing problem. The adoption of new drugs in therapy, although they can guarantee an improvement in patient’s quality of life, can meet obstacles when it involves an increase in costs. We decided to compare the costs and benefits of the new saxagliptin and dapagliflozin combination versus traditional therapies. Bodyweight loss and the sharp reduction in hypoglycemic episodes were the 2 main clinical outcomes that emerged from registered studies of saxagliptin and dapagliflozin compared with the sulfonylureas. These results, combined with the good cardiovascular risk profile, led to develop a cost-utility analysis. We aimed to show the economic value of this new association therapy. We carried out a cost-utility analysis from the Italian National Healthcare System (NHS) perspective, focused on direct costs related to the treatment and management of main diabetes complications. Utility scores adopted have been measured based on the patient’s perception of weight changes. In light of the better durability profile of saxagliptin/dapagliflozin compared with gliclazide, we also considered a simulation scenario to assess the impact on costs of switching to basal insulin, starting from gliclazide and the fixed combination, respectively, and based on the related probabilities to switch. To assess the robustness of the results, a 1-way sensitivity analysis was performed by changing the main parameters by ±20%. Furthermore, the sensitivity of the results was tested considering the addition of a percent discount, because the purchase costs of drugs are usually subject to hidden discounts. We calculated the total direct annual cost per patient of saxagliptin/dapagliflozin versus gliclazide and insulin glargine for patients with type 2 diabetes mellitus not achieving glycemic control on metformin plus saxagliptin alone, dapagliflozin alone, or gliclazide at a lower dosage. Total treatment costs have been obtained adding the direct cost of the drug, needles, glycemic self-monitoring, hypoglycemic events, cardiovascular complications, and effect on consumption of other drugs. The total direct cost of saxagliptin/dapagliflozin fixed dose combination was €414.62 higher than gliclazide (€1.067.72 vs €653.10), and greater than basal insulin, with a difference of €166.99 (€1067.72 vs €900.72). Despite the higher annual direct total cost, the additional cost per quality-adjusted life year (QALY) gained, compared with gliclazide, has been €11 517, and €4639, when compared with insulin glargine in the base-case scenario, and the robustness of the results has been shown in the sensitivity analysis. The results of our cost-utility analysis, expressed as incremental cost-effectiveness ratios, were fully compliant with the threshold adopted for Italy. Then, saxagliptin/dapagliflozin can be considered a cost-effective oral hypoglycemic agent. The positive effect of this drug on the quality of life, induced by the bodyweight loss, has allowed this outcome, despite the higher annual cost per patient, mainly determined by the drug purchase cost.

Cost of Managing Type 2 Diabetes Before and After Initiating Dipeptidyl Peptidase 4 Inhibitor Treatment: A Longitudinal Study Using a French Public Health Insurance Database

INTRODUCTION

Diabetes is a growing epidemic that imposes a substantial economic burden on healthcare systems. This study aimed to evaluate the cost of managing type 2 diabetes (T2D) with dipeptidyl peptidase 4 inhibitors (DPP4Is) using real-world data.

METHOD

This longitudinal study used data from the French EGB (Echantillon Généraliste des Bénéficiaires) database. The annual average direct healthcare cost of treating patients with T2D was calculated 3 years prior and 3 years after initiation of DPP4I therapy. Actual total ambulatory and hospital care expenditure for the 3 years after DPP4I initiation was compared to projected costs. The distribution of costs across all care modalities was assessed over the 6-year period.

RESULTS

Ambulatory and hospital care expenditure data for 919 patients with T2D starting DPP4I therapy alone or in combination in 2013 were analyzed. A total of 526 patients (57.2%) were still being treated with DPP4I 3 years after DPP4I initiation. Regardless of the treatment regimen, the ambulatory and hospital care costs increased above projected costs in the first year following DPP4I initiation, and then declined during the second and third years to levels in line with or below projected values for patients using DPP4Is as an add-on therapy. The increase in total expenditure in the first year following DPP4I initiation and the subsequent decline in costs in the second and third years were both associated with general trends in consumption across all aspects of patient care.

CONCLUSION

Despite an initial increase in healthcare expenditure, concomitant with reevaluation of patient care, this study showed that initiation of DPP4Is as an add-on therapy in French patients with T2D was associated with care expenditure that was in line or below predicted values within the 3 years following treatment initiation. Additional studies are required to evaluate the economic impact of the long-term treatment benefits.

Cost-consequence analysis of sitagliptin versus sulfonylureas as add-on therapy for the treatment of diabetic patients in Italy

Objective

Diabetes mellitus is a chronic disease related to a significant impact in both epidemiologic and economic terms. In Italy, around 3.6 million people are affected by diabetes and this number is expected to increase significantly in the next few years. As recommended by current national and international guidelines, metformin (Met) is prescribed as first-line pharmacological treatment, and many pharmacological alternatives are available for patients uncontrolled with Met monotherapy. Despite the availability of many innovative oral antidiabetic drugs (OADs), such as dipeptidyl peptidase 4 inhibitors (DPP4-i) and its first-in-class sitagliptin (SITA), which entered the Italian market in the last 10 years, their usage is consistently lower than traditional drugs such as sulfonylureas (SUs). In fact, due to higher acquisition costs, the prescription of innovative OADs in Italy is restricted to specialist, resulting in a prominent usage of traditional OAD that can be prescribed also by general practitioners (GPs). A cost consequence analysis (CCA) was performed in order to compare SITA with SU, as second-line therapy in add-on to Met, in terms of costs and related clinical events over 36 months.

Methods

A CCA was conducted on a hypothetical cohort of 100,000 type 2 diabetes mellitus (T2DM) patients uncontrolled with Met monotherapy, from both the Italian National Health Service (INHS) and societal perspective. Therefore, both direct (drugs, self-monitoring, hypoglycemia, major cardiovascular events [MACEs], and switch to insulin) and indirect costs (expressed in terms of productivity losses) were evaluated. Clinical and economic data were collected through Italian national tariffs, literature, and experts' opinions. Three expert clinicians finally validated data inputs. To assess robustness of base case results, a one-way sensitivity analysis (OWSA) and a conservative scenario analysis - excluding MACEs - were carried out.

Results

In the base case analysis, the higher drug costs related to SITA were offset by other management costs (ie, lower use of devices for glycemia self-monitoring, lower incidence of hypoglycemia and MACE, and delay to insulin switch). As a result, the economic evaluation showed that, compared to SU, SITA was cost saving from both societal (-€61,217,723) and INHS (-€51,846,442) perspectives over 3 years as add-on to Met. The base case results were also confirmed by the scenario analysis and by the OWSA performed on the key parameters. The adoption of SITA, in a cohort of 100,000 diabetes patients, would avoid 26,882 non-severe hypoglycemic events, 6,528 severe hypoglycemic events, and 1,562 MACEs.

Conclusion

This analysis suggests that, compared to SU, SITA could be a sustainable and cost-saving alternative for the management of T2DM patients uncontrolled with Met monotherapy from both clinical and economic perspectives.

Effectiveness of sitagliptin compared to sulfonylureas for type 2 diabetes mellitus inadequately controlled on metformin: a systematic review and meta-analysis

OBJECTIVE

To assess the effectiveness of sitagliptin compared to sulfonylureas as add-on to metformin in adults with type 2 diabetes mellitus from both randomised controlled trials (RCTs) and 'real-world' non-randomised studies.

METHODS AND ANALYSES

We conducted a systematic review of EMBASE, MEDLINE, CENTRAL and grey literature for RCTs and non-randomised studies. We reported outcomes relating to change in HbA1c, fasting glucose, weight, blood pressure and lipids from baseline and need for treatment change. No study investigating macrovascular and microvascular diabetes complications was found. Meta-analysis was used where studies were sufficiently homogenous.

RESULTS

Seven RCTs and five non-randomised studies were eligible for inclusion from 1335 articles retrieved. Meta-analysis of three homogenous RCTs revealed a statistically significant decrease in weight with sitagliptin when compared to sulfonylureas (weighted mean difference (WMD) -2.05 kg; 95% CI -2.38 to -1.71); however, a similar change from baseline in HbA1c (WMD 0.05; 95% CI -0.03 to 0.12), fasting glucose (WMD 0.11; 95% CI -0.08 to -0.29), blood pressure, lipids and the proportion achieving HbA1c <7% by study end (OR 0.98; 95% CI 0.85 to 1.13) was observed.Non-randomised studies identified consisted of four prospective and one retrospective cohort study. Three of these five studies were of moderate/high quality, and results though less precise suggested similar real-world comparative glycaemic and weight effectiveness for both treatments. Data from two cohort studies suggested that treatment change (HR 0.65; 95% CI 0.57 to 0.73) and insulin initiation (HR 0.76; 95% CI 0.65 to 0.90) were less likely among those prescribed sitagliptin; however, inadequate reporting of HbA1c at time of treatment change made interpreting results challenging.

CONCLUSION

Sitagliptin users experienced modest weight loss compared to gain with sulfonylureas; however, this difference was around 2 kg, which may not be of major clinical significance for most individuals. Similar change was observed across most other effectiveness outcomes reported. Further studies are needed to address longer-term effectiveness outcomes for sitagliptin compared to sulfonylureas as add-on to metformin.

PROSPERO REGISTRATION NUMBER

CRD42016033983.

The Use of Saxagliptin in People with Type 2 Diabetes in France: The Diapazon Epidemiological Study

INTRODUCTION

Saxagliptin is a potent, reversible inhibitor of dipeptidyl peptidase-4 that is indicated for the treatment of type 2 diabetes. The DIAPAZON study was a multicenter observational study intended to document the effectiveness, safety and patterns of saxagliptin use in France, including the saxagliptin retention rate, over 2 years of follow-up.

METHODS

A geographically representative sample of 304 French physicians (general practitioners and specialist endocrinologists or diabetologists) recruited 1131 adults with type 2 diabetes into an ambispective cohort; 1033 fulfilled the inclusion criteria. All had started saxagliptin during the previous 6 months or at study inclusion, and follow-up was for 24 ± 3 months after starting saxagliptin.

RESULTS

The mean age of the study population when starting saxagliptin was 61 years, and the mean HbA1c level was 8.0%; 79% had an HbA1c level ≥7%. Prior to starting saxagliptin treatment, most participants (91%) were receiving treatment with oral glucose-lowering drugs alone. The most commonly prescribed regimen at starting saxagliptin (53% of participants) was a combination of saxagliptin and metformin. The overall saxagliptin retention rate at 2 years was 79%, as estimated by the Kaplan-Meier method. The most common reasons for discontinuation were inadequate glycemic control (52%) and intolerance (22%). During the course of the study, the mean HbA1c level decreased to 7.0%, and the percentage of people with HbA1c <7% increased from 21% to 49%. The mean change in body weight was -1.8 kg. A total of 294 hypoglycemic episodes were reported in 70 participants (6.8%) during the follow-up period. Of these, 143 episodes in 41 participants (4.0%) occurred when saxagliptin was used in combination with agents associated with hypoglycemia, such as insulin, sulfonylureas or glinides.

CONCLUSION

Saxagliptin is efficacious and well tolerated in a real-world practice setting, with almost 80% of participants remaining on treatment after 2 years.

FUNDING

AstraZeneca, France.

Safety, Efficacy, and Bioavailability of Fixed-Dose Combinations in Type 2 Diabetes Mellitus: A Systematic Updated Review

Purpose

Type 2 diabetes mellitus (T2DM) is a multifactorial disease characterized by insulin resistance. As time progresses, monotherapy often does not provide effective glycemic control, generating the need for an add-on therapy. Hence, multiple oral hypoglycemic agents formulated as a single-dose form called fixed-dose combinations (FDCs) play an essential role in glycemic control. The purpose of this systematic review is to appraise the recently published evidence on the safety, efficacy, and bioavailability of FDCs.

Methods

A comprehensive literature search of PUBMED, Scopus, ScienceDirect.com, ProQuest, SpringerLink, clintrials.gov, Embase, and EBSCO using the key words FDCs, combination therapy, T2DM management, and add-on therapy was conducted. Studies on the safety profile/tolerability, efficacy, and bioavailability of various FDCs of oral hypoglycemic agents were preferred.

Findings

The systematic review of all the publications suggests that FDCs of oral hypoglycemic agents (OHAs) significantly reduce HbA_1c and fasting plasma glucose values, thereby efficiently reducing hyperglycemia in patients in whom monotherapy fails. FDCs are the bioequivalent of the concomitant drugs administered as individual components. Improved adherence to FDCs and the absence of serious adverse drug reactions compared with dual therapy play an important role in decreasing the incidence of hyperglycemia in patients with T2DM.

Implications

From this updated review, it was found that metformin was the most widely used component of FDCs with other OHAs. Studies on the safety and efficacy of newly approved OHAs such as sodium glucose cotransporter inhibitors were limited. An increasing number of randomized trials on the safety and efficacy of newly emerging FDCs suggests that they would be better treatment options for T2DM patients.

•

Comprehensive analysis of current fixed-dose combinations used in the treatment of type 2 diabetes mellitus

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Most widely used component of fixed-dose combinations is metformin with other oral hypoglycemic agents (eg, like glimepiride, pioglitazone, rosiglitazone, acarbose, and sitagliptin.

•

Fixed-dose combinations help to reduce hyperglycemia efficiently; the long-term complication of diabetes could be minimized in these patients, thereby improving the quality of life of patients.

Incidence and correlated factors of beta cell failure in a 4-year follow-up of patients with type 2 diabetes: a longitudinal analysis of the BETADECLINE study

AIMS

Type 2 diabetes is associated with progressive deterioration of beta cell function and loss of glycemic control, with increased morbidity and mortality from microvascular and macrovascular complications. Factors predictive of beta cell decline are needed.

METHODS

We have conducted a prospective evaluation of baseline predictors of beta cell dysfunction and insulin initiation in a cohort of outpatients with type 2 diabetes receiving stable treatment with oral hypoglycemic agents or dietary intervention, over a 4-year follow-up period.

RESULTS

Of 507 patients enrolled, 56 (10.8 %) experienced the study endpoint of initiation of insulin therapy. Univariate and multivariate Cox proportional hazard regression analyses revealed that the likelihood of initiating insulin therapy during follow-up increased with longer diabetes duration and with higher baseline values for hemoglobin A1c, fasting plasma glucose, triglycerides, proinsulin, interleukin-6, Homeostatic Model Assessment-IR and lower values for Homeostatic Model Assessment-B. The likelihood of initiating insulin therapy increased by 46 % for each 1 % increase (10.9 mmol/mol) in baseline hemoglobin A1c and by 6 % for each unit increase (1 ng/l) in baseline IL-6 level. The risk was fourfold higher in the lowest versus highest Homeostatic Model Assessment-B quartile. Treatment with metformin plus a secretagogue increased the risk by fourfold.

CONCLUSIONS

Our results show that commonly measured parameters may predict treatment failure in type 2 diabetes and suggest that early treatment with metformin plus secretagogues may foretell this failure.

Risk factors associated with treatment discontinuation and down-titration in type 2 diabetes patients treated with sulfonylureas

OBJECTIVES

Sulfonylurea therapy among patients with type 2 diabetes mellitus (T2DM) can be disrupted due to adverse events, including hypoglycemia. A retrospective study using the MarketScan claims database quantified the frequency of sulfonylurea discontinuation or down-titration and identified associated risk factors.

RESEARCH DESIGN AND METHODS

Adult patients with an index sulfonylurea prescription between 2008 and 2012 and 1 year continuous enrollment pre- and post-index were included. Therapy changes assessed over 1 year post-index included discontinuation and down-titration. Discontinuation occurred if the date of a fill was >90 days from the end date of the preceding fill. Down-titration occurred when a fill had a lower equivalent dose than the fill on the index date. Kaplan-Meier methods estimated the probability of either discontinuation or down-titration over 12 months, and Cox regression models identified associated risk factors.

RESULTS

A total of 104,082 sulfonylurea users were included in the study and the probability of either discontinuation or down-titration at 3, 6 and 12 months was 23.2%, 38.9%, and 52.3%, respectively. Major risk factors associated with therapy changes included post-index hypoglycemia (discontinuation hazard ratio [HR] = 1.78 [1.68, 1.89]; down-titration HR =2.79 [2.40, 3.23]) and concomitant use of insulin (discontinuation HR =1.48 [1.40, 1.57]; down-titration HR =1.82 [1.56, 2.11]). Other risk factors included younger age, female gender, use of second generation sulfonylureas, prior cardiovascular comorbidity and liver disease.

LIMITATIONS

The study was not able to assess unreported, potentially mild cases of hypoglycemia, nor was it able to evaluate the association between changes in therapy and HbA1c levels or body weight.

CONCLUSIONS

More than half of T2DM patients who initiated sulfonylurea therapy discontinued or down-titrated within 1 year. Insulin use and hypoglycemia were associated with sulfonylurea therapy change.

Comparative review of dipeptidyl peptidase-4 inhibitors and sulphonylureas

Type 2 diabetes (T2DM) is a progressive disease, and pharmacotherapy with a single agent does not generally provide durable glycaemic control over the long term. Sulphonylurea (SU) drugs have a history stretching back over 60 years, and have traditionally been the mainstay choice as second-line agents to be added to metformin once glycaemic control with metformin monotherapy deteriorates; however, they are associated with undesirable side effects, including increased hypoglycaemia risk and weight gain. Dipeptidyl peptidase (DPP)-4 inhibitors are, by comparison, more recent, with the first compound being launched in 2006, but the class now globally encompasses at least 11 different compounds. DPP-4 inhibitors improve glycaemic control with similar efficacy to SUs, but do not usually provoke hypoglycaemia or weight gain, are relatively free from adverse side effects, and have recently been shown not to increase cardiovascular risk in large prospective safety trials. Because of these factors, DPP-4 inhibitors have become an established therapy for T2DM and are increasingly being positioned earlier in treatment algorithms. The present article reviews these two classes of oral antidiabetic drugs (DPP-4 inhibitors and SUs), highlighting differences and similarities between members of the same class, as well as discussing the potential advantages and disadvantages of the two drug classes. While both classes have their merits, the choice of which to use depends on the characteristics of each individual patient; however, for the majority of patients, DPP-4 inhibitors are now the preferred choice.

Four-Year Durability of Initial Combination Therapy with Sitagliptin and Metformin in Patients with Type 2 Diabetes in Clinical Practice; COSMIC Study

OBJECTIVES

We investigated the efficacy of initial combination therapy with sitagliptin and metformin in patients with type 2 diabetes for 4 years in clinical practice.

METHODS

Between 2009 and 2010, we reviewed 1,178 patients with type 2 diabetes (HbA1c ≥7.5% or 58 mmol/mol) prescribed initial combination therapy with sitagliptin and metformin. After excluding 288 patients without a second follow-up, 890 individuals (age, 58.0 ± 12.5 years; BMI, 25.4 ± 3.5 kg/m2; HbA1c, 8.6 ± 1.1%) were followed up with every 3-6 months for 4 years. Homeostasis model assessments for insulin resistance and β-cell function (HOMA-β) were recorded at baseline. The response criterion was HbA1c reduction by ≥0.8% from baseline or attainment of the target HbA1c (≤7.0% or 53 mmol/mol). At the end of every year of treatment, changes in HbA1c from the baseline were assessed.

RESULTS

After 1 year, 72.2% of patients with initial combination therapy had responded, defined as HbA1c reduction ≥0.8% or attainment of the target HbA1c ≤7.0%. After 4 years, 35.4% of the patients still showed a response, with an HbA1c level of 7.0 ± 0.9%. A high HbA1c level at baseline was the most significant independent predictor of the long-term response (P<0.001). In addition, low HOMA-β was a significant predictor of a greater reduction in HbA1c. This treatment was generally well tolerated over the 4-year follow-up period, without any serious adverse events.

CONCLUSIONS

This real-world follow-up study shows a persistent glucose-reducing effect of initial combination therapy with sitagliptin and metformin for up to 4 years.

Clinical use of GLP-1 agonists and DPP4 inhibitors

Type 2 diabetes is a growing problem, with 387 million people currently affected, and 592 million by 2035. Whilst diet and exercise are the corner stones of treatment, oral hypoglycaemic agents are often needed to achieve glycaemic control, thereby reducing the chance of long term diabetic complications. Biguanides and sulfonylureas have been the standard tablets used for this disorder, until 2005-7 when glucagon-like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP4) inhibitors became available. Their major advantage over sulfonylureas is that they are weight lowering or weight neutral, and have a very low incidence of hypoglycaemia. GLP-1 agonists are injectables, whereas the DPP4 inhibitors are administered orally. Both agents are best used in combination with other hypoglycaemic medication, especially metformin and sodium glucose co-transporter 2 (SGLT2) inhibtors. Usage is increasing, being roughly equal to that of sulfonylureas, but less than that of metformin. Side effects appear to be minimal.