Comparison of different drugs as add-on treatments to metformin in type 2 diabetes: a meta-analysis

Comparison of the efficacy of anti-diabetic medications as add-on to metformin in type 2 diabetes mellitus from a real-world database

BACKGROUND

Metformin is recommended as a first-line drug in the guidelines of the treatment for type 2 diabetes mellitus. However, high-quality evidence from clinical trials directly comparing the degree of hypoglycemic effect of combination therapy of metformin and a hypoglycemic agent with a different mechanism of action with that of monotherapy of a hypoglycemic drug is lacking. We aimed to examine whether combination therapy of hypoglycemic agents with metformin showed antagonism, addition, or synergism compared to monotherapy with hypoglycemic agents other than metformin regarding hemoglobin A1c levels.

METHODS

This retrospective cohort study used a medical information database in Japan. Non-insulin anti-hyperglycemic agents with different mechanisms of action were classified into eight drug classes. A monotherapy cohort and a combination therapy added to the metformin cohort were defined. The change in hemoglobin A1c levels was evaluated to compare the treatment effect between the cohorts.

RESULTS

A total of 13,359 patients with type 2 diabetes mellitus in the monotherapy cohort and 1,064 in the metformin combination therapy cohort were identified. A comparison of the change from baseline HbA1c level by drug class between the two cohorts showed a similar trend. Among those treated with dipeptidyl peptidase-4 inhibitor and sodium-glucose co-transporter-2 inhibitor, no clinically significant difference was observed between the two cohorts (0.00% and -0.07% for unadjusted, 0.15% and -0.03% for propensity score matching-adjusted, and 0.09% and -0.01% for inverse probability treatment weighting-adjusted analysis).

CONCLUSIONS

According to the results of this study, the effect of dipeptidyl peptidase-4 inhibitor or sodium-glucose co-transporter-2 inhibitor added to metformin seems to be additive with respect to the reduction in hemoglobin A1c.

Treatment of periodontitis for glycaemic control in people with diabetes mellitus

BACKGROUND

Glycaemic control is a key component in diabetes mellitus (diabetes) management. Periodontitis is the inflammation and destruction of the underlying supporting tissues of the teeth. Some studies have suggested a bidirectional relationship between glycaemic control and periodontitis.  Treatment for periodontitis involves subgingival instrumentation, which is the professional removal of plaque, calculus, and debris from below the gumline using hand or ultrasonic instruments. This is known variously as scaling and root planing, mechanical debridement, or non-surgical periodontal treatment. Subgingival instrumentation is sometimes accompanied by local or systemic antimicrobials, and occasionally by surgical intervention to cut away gum tissue when periodontitis is severe. This review is part one of an update of a review published in 2010 and first updated in 2015, and evaluates periodontal treatment versus no intervention or usual care.  OBJECTIVES: To investigate the effects of periodontal treatment on glycaemic control in people with diabetes mellitus and periodontitis.

SEARCH METHODS

An information specialist searched six bibliographic databases up to 7 September 2021 and additional search methods were used to identify published, unpublished, and ongoing studies.  SELECTION CRITERIA: We searched for randomised controlled trials (RCTs) of people with type 1 or type 2 diabetes mellitus and a diagnosis of periodontitis that compared subgingival instrumentation (sometimes with surgical treatment or adjunctive antimicrobial therapy or both) to no active intervention or 'usual care' (oral hygiene instruction, education or support interventions, and/or supragingival scaling (also known as PMPR, professional mechanical plaque removal)). To be included, the RCTs had to have lasted at least 3 months and have measured HbA1c (glycated haemoglobin).

DATA COLLECTION AND ANALYSIS

At least two review authors independently examined the titles and abstracts retrieved by the search, selected the included trials, extracted data from included trials, and assessed included trials for risk of bias. Where necessary and possible, we attempted to contact study authors. Our primary outcome was blood glucose levels measured as glycated (glycosylated) haemoglobin assay (HbA1c), which can be reported as a percentage of total haemoglobin or as millimoles per mole (mmol/mol). Our secondary outcomes included adverse effects, periodontal indices (bleeding on probing, clinical attachment level, gingival index, plaque index, and probing pocket depth), quality of life, cost implications, and diabetic complications.

MAIN RESULTS

We included 35 studies, which randomised 3249 participants to periodontal treatment or control. All studies used a parallel-RCT design and followed up participants for between 3 and 12 months. The studies focused on people with type 2 diabetes, other than one study that included participants with type 1 or type 2 diabetes. Most studies were mixed in terms of whether metabolic control of participants at baseline was good, fair, or poor. Most studies were carried out in secondary care.  We assessed two studies as being at low risk of bias, 14 studies at high risk of bias, and the risk of bias in 19 studies was unclear. We undertook a sensitivity analysis for our primary outcome based on studies at low risk of bias and this supported the main findings. Moderate-certainty evidence from 30 studies (2443 analysed participants) showed an absolute reduction in HbA1c of 0.43% (4.7 mmol/mol) 3 to 4 months after treatment of periodontitis (95% confidence interval (CI) -0.59% to -0.28%; -6.4 mmol/mol to -3.0 mmol/mol). Similarly, after 6 months, we found an absolute reduction in HbA1c of 0.30% (3.3 mmol/mol) (95% CI -0.52% to -0.08%; -5.7 mmol/mol to -0.9 mmol/mol; 12 studies, 1457 participants), and after 12 months, an absolute reduction of 0.50% (5.4 mmol/mol) (95% CI -0.55% to -0.45%; -6.0 mmol/mol to -4.9 mmol/mol; 1 study, 264 participants). Studies that measured adverse effects generally reported that no or only mild harms occurred, and any serious adverse events were similar in intervention and control arms. However, adverse effects of periodontal treatments were not evaluated in most studies.

AUTHORS' CONCLUSIONS

Our 2022 update of this review has doubled the number of included studies and participants, which has led to a change in our conclusions about the primary outcome of glycaemic control and in our level of certainty in this conclusion. We now have moderate-certainty evidence that periodontal treatment using subgingival instrumentation improves glycaemic control in people with both periodontitis and diabetes by a clinically significant amount when compared to no treatment or usual care. Further trials evaluating periodontal treatment versus no treatment/usual care are unlikely to change the overall conclusion reached in this review.

What Next After Metformin in Type 2 Diabetes? Selecting the Right Drug for the Right Patient

INTRODUCTION

Metformin is the recommended initial treatment in type 2 diabetes mellitus (T2DM), but when this does not give adequate glucose control the choice of which second-line drug to use is uncertain as none have been found to have a better overall glycaemic response. In this real-world study dipeptidyl peptidase 4 inhibitors (DPP4i), sulphonylureas (SU), thiazolidinediones (TZD) and sodium glucose co-transporter 2 inhibitors (SGLT2i) were compared for their effectiveness in lowering glycated haemoglobin (HbA1c) levels for a particular individual based on their clinical characteristics.

METHODS

A retrospective analysis was undertaken of electronic health records of people with T2DM prescribed metformin alongside a DPP4i, SU, TZD or SGLT2i at second-line. Regression modelling was used to model the changes in HbA1c from baseline at month 6 and month 12 for the individual therapies, adjusting for demographic and clinical characteristics.

RESULTS

There were 7170 people included in the study. Treatment at second-line with SUs, DPP4i, TZDs and SGLT2i resulted in similar percentages of people achieving the recommended HbA1c target of < 7.5% (58 mmol/mol) at both 6 and 12 months. For those receiving SGLT2i and SUs, the greatest improvement in HbA1c was observed in relatively younger and older people, respectively. Trends were detected between other baseline characteristics and HbA1c improvement by drug class, but they were not statistically significant. Non-adherence rates were low for all drug classes. People with a higher medication possession ratio (≥ 80%) also had greater improvements in HbA1c at 12 months.

CONCLUSION

This study identified patients' phenotypic characteristics that may have the potential to influence individual treatment response. Accounting for these characteristics in clinical treatment decisions may facilitate individualised prescribing by being able to select the right drug for the right patient.

Acarbose Add-on Therapy in Patients with Type 2 Diabetes Mellitus with Metformin and Sitagliptin Failure: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study

BACKGROUND

We evaluated the efficacy and safety of acarbose add-on therapy in Korean patients with type 2 diabetes mellitus (T2DM) who are inadequately controlled with metformin and sitagliptin.

METHODS

A total of 165 subjects were randomized to metformin and sitagliptin (Met+Sita, n=65), metformin, sitagliptin, and acarbose (Met+Sita+Acarb, n=66) and sitagliptin and acarbose (Sita+Acarb, exploratory assessment, n=34) therapy in five institutions in Korea. After 16 weeks of acarbose add-on or metformin-switch therapy, a triple combination therapy was maintained from week 16 to 24.

RESULTS

The add-on of acarbose (Met+Sita+Acarb group) demonstrated a 0.44%±0.08% (P<0.001 vs. baseline) decrease in glycosylated hemoglobin (HbA1c) at week 16, while changes in HbA1c were insignificant in the Met+Sita group (-0.09%±0.10%, P=0.113). After 8 weeks of triple combination therapy, HbA1c levels were comparable between Met+Sita and Met+Sita+Acarb group (7.66%±0.13% vs. 7.47%±0.12%, P=0.321). Acarbose add-on therapy demonstrated suppressed glucagon secretion (area under the curve of glucagon, 4,726.17±415.80 ng·min/L vs. 3,314.38±191.63 ng·min/L, P=0.004) in the absence of excess insulin secretion during the meal tolerance tests at week 16 versus baseline. The incidence of adverse or serious adverse events was similar between two groups.

CONCLUSION

In conclusion, a 16-week acarbose add-on therapy to metformin and sitagliptin, effectively lowered HbA1c without significant adverse events. Acarbose might be a good choice as a third-line therapy in addition to metformin and sitagliptin in Korean subjects with T2DM who have predominant postprandial hyperglycemia and a high carbohydrate intake.

Metformin and second- or third-generation sulphonylurea combination therapy for adults with type 2 diabetes mellitus

BACKGROUND

The number of people with type 2 diabetes mellitus (T2DM) is increasing worldwide. The combination of metformin and sulphonylurea (M+S) is a widely used treatment. Whether M+S shows better or worse effects in comparison with other antidiabetic medications for people with T2DM is still controversial.

OBJECTIVES

To assess the effects of metformin and sulphonylurea (second- or third-generation) combination therapy for adults with type 2 diabetes mellitus.

SEARCH METHODS

We updated the search of a recent systematic review from the Agency for Healthcare Research and Quality (AHRQ). The updated search included CENTRAL, MEDLINE, Embase, ClinicalTrials.gov and WHO ICTRP. The date of the last search was March 2018. We searched manufacturers' websites and reference lists of included trials, systematic reviews, meta-analyses and health technology assessment reports. We asked investigators of the included trials for information about additional trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) randomising participants 18 years old or more with T2DM to M+S compared with metformin plus another glucose-lowering intervention or metformin monotherapy with a treatment duration of 52 weeks or more.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles and records, assessed risk of bias and extracted outcome data independently. We used a random-effects model to perform meta-analysis, and calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the certainty of the evidence using the GRADE instrument.

MAIN RESULTS

We included 32 RCTs randomising 28,746 people. Treatment duration ranged between one to four years. We judged none of these trials as low risk of bias for all 'Risk of bias' domains. Most important events per person were all-cause and cardiovascular mortality, serious adverse events (SAE), non-fatal stroke (NFS), non-fatal myocardial infarction (MI) and microvascular complications. Most important comparisons were as follows:Five trials compared M+S (N = 1194) with metformin plus a glucagon-like peptide 1 analogue (N = 1675): all-cause mortality was 11/1057 (1%) versus 11/1537 (0.7%), risk ratio (RR) 1.15 (95% confidence interval (CI) 0.49 to 2.67); 3 trials; 2594 participants; low-certainty evidence; cardiovascular mortality 1/307 (0.3%) versus 1/302 (0.3%), low-certainty evidence; serious adverse events (SAE) 128/1057 (12.1%) versus 194/1537 (12.6%), RR 0.90 (95% CI 0.73 to 1.11); 3 trials; 2594 participants; very low-certainty evidence; non-fatal myocardial infarction (MI) 2/549 (0.4%) versus 6/1026 (0.6%), RR 0.57 (95% CI 0.12 to 2.82); 2 trials; 1575 participants; very low-certainty evidence.Nine trials compared M+S (N = 5414) with metformin plus a dipeptidyl-peptidase 4 inhibitor (N = 6346): all-cause mortality was 33/5387 (0.6%) versus 26/6307 (0.4%), RR 1.32 (95% CI 0.76 to 2.28); 9 trials; 11,694 participants; low-certainty evidence; cardiovascular mortality 11/2989 (0.4%) versus 9/3885 (0.2%), RR 1.54 (95% CI 0.63 to 3.79); 6 trials; 6874 participants; low-certainty evidence; SAE 735/5387 (13.6%) versus 779/6307 (12.4%), RR 1.07 (95% CI 0.97 to 1.18); 9 trials; 11,694 participants; very low-certainty evidence; NFS 14/2098 (0.7%) versus 8/2995 (0.3%), RR 2.21 (95% CI 0.74 to 6.58); 4 trials; 5093 participants; very low-certainty evidence; non-fatal MI 15/2989 (0.5%) versus 13/3885 (0.3%), RR 1.45 (95% CI 0.69 to 3.07); 6 trials; 6874 participants; very low-certainty evidence; one trial in 64 participants reported no microvascular complications were observed (very low-certainty evidence).Eleven trials compared M+S (N = 3626) with metformin plus a thiazolidinedione (N = 3685): all-cause mortality was 123/3300 (3.7%) versus 114/3354 (3.4%), RR 1.09 (95% CI 0.85 to 1.40); 6 trials; 6654 participants; low-certainty evidence; cardiovascular mortality 37/2946 (1.3%) versus 41/2994 (1.4%), RR 0.78 (95% CI 0.36 to 1.67); 4 trials; 5940 participants; low-certainty evidence; SAE 666/3300 (20.2%) versus 671/3354 (20%), RR 1.01 (95% CI 0.93 to 1.11); 6 trials; 6654 participants; very low-certainty evidence; NFS 20/1540 (1.3%) versus 16/1583 (1%), RR 1.29 (95% CI 0.67 to 2.47); P = 0.45; 2 trials; 3123 participants; very low-certainty evidence; non-fatal MI 25/1841 (1.4%) versus 21/1877 (1.1%), RR 1.21 (95% CI 0.68 to 2.14); P = 0.51; 3 trials; 3718 participants; very low-certainty evidence; three trials (3123 participants) reported no microvascular complications (very low-certainty evidence).Three trials compared M+S (N = 462) with metformin plus a glinide (N = 476): one person died in each intervention group (3 trials; 874 participants; low-certainty evidence); no cardiovascular mortality (2 trials; 446 participants; low-certainty evidence); SAE 34/424 (8%) versus 27/450 (6%), RR 1.68 (95% CI 0.54 to 5.21); P = 0.37; 3 trials; 874 participants; low-certainty evidence; no NFS (1 trial; 233 participants; very low-certainty evidence); non-fatal MI 2/215 (0.9%) participants in the M+S group; 2 trials; 446 participants; low-certainty evidence; no microvascular complications (1 trial; 233 participants; low-certainty evidence).Four trials compared M+S (N = 2109) with metformin plus a sodium-glucose co-transporter 2 inhibitor (N = 3032): all-cause mortality was 13/2107 (0.6%) versus 19/3027 (0.6%), RR 0.96 (95% CI 0.44 to 2.09); 4 trials; 5134 participants; very low-certainty evidence; cardiovascular mortality 4/1327 (0.3%) versus 6/2262 (0.3%), RR 1.22 (95% CI 0.33 to 4.41); 3 trials; 3589 participants; very low-certainty evidence; SAE 315/2107 (15.5%) versus 375/3027 (12.4%), RR 1.02 (95% CI 0.76 to 1.37); 4 trials; 5134 participants; very low-certainty evidence; NFS 3/919 (0.3%) versus 7/1856 (0.4%), RR 0.87 (95% CI 0.22 to 3.34); 2 trials; 2775 participants; very low-certainty evidence; non-fatal MI 7/890 (0.8%) versus 8/1374 (0.6%), RR 1.43 (95% CI 0.49 to 4.18; 2 trials); 2264 participants; very low-certainty evidence; amputation of lower extremity 1/437 (0.2%) versus 1/888 (0.1%); very low-certainty evidence.Trials reported more hypoglycaemic episodes with M+S combination compared to all other metformin-antidiabetic agent combinations. Results for M+S versus metformin monotherapy were inconclusive. There were no RCTs comparing M+S with metformin plus insulin. We identified nine ongoing trials and two trials are awaiting assessment. Together these trials will include approximately 16,631 participants.

AUTHORS' CONCLUSIONS

There is inconclusive evidence whether M+S combination therapy compared with metformin plus another glucose-lowering intervention results in benefit or harm for most patient-important outcomes (mortality, SAEs, macrovascular and microvascular complications) with the exception of hypoglycaemia (more harm for M+S combination). No RCT reported on health-related quality of life.

Systemic effects of periodontitis treatment in patients with type 2 diabetes: a 12 month, single-centre, investigator-masked, randomised trial

BACKGROUND

Chronic inflammation is believed to be a major mechanism underlying the pathophysiology of type 2 diabetes. Periodontitis is a cause of systemic inflammation. We aimed to assess the effects of periodontal treatment on glycaemic control in people with type 2 diabetes.

METHODS

In this 12 month, single-centre, parallel-group, investigator-masked, randomised trial, we recruited patients with type 2 diabetes, moderate-to-severe periodontitis, and at least 15 teeth from four local hospitals and 15 medical or dental practices in the UK. We randomly assigned patients (1:1) using a computer-generated table to receive intensive periodontal treatment (IPT; whole mouth subgingival scaling, surgical periodontal therapy [if the participants showed good oral hygiene practice; otherwise dental cleaning again], and supportive periodontal therapy every 3 months until completion of the study) or control periodontal treatment (CPT; supra-gingival scaling and polishing at the same timepoints as in the IPT group). Treatment allocation included a process of minimisation in terms of diabetes onset, smoking status, sex, and periodontitis severity. Allocation to treatment was concealed in an opaque envelope and revealed to the clinician on the day of first treatment. With the exception of dental staff who performed the treatment and clinical examinations, all study investigators were masked to group allocation. The primary outcome was between-group difference in HbA_1c at 12 months in the intention-to-treat population. This study is registered with the ISRCTN registry, number ISRCTN83229304.

FINDINGS

Between Oct 1, 2008, and Oct 31, 2012, we randomly assigned 264 patients to IPT (n=133) or CPT (n=131), all of whom were included in the intention-to-treat population. At baseline, mean HbA_1c was 8·1% (SD 1·7) in both groups. After 12 months, unadjusted mean HbA_1c was 8·3% (SE 0·2) in the CPT group and 7·8% (0·2) in the IPT group; with adjustment for baseline HbA_1c, age, sex, ethnicity, smoking status, duration of diabetes, and BMI, HbA_1c was 0·6% (95% CI 0·3-0·9; p<0·0001) lower in the IPT group than in the CPT group. At least one adverse event was reported in 30 (23%) of 133 patients in the IPT group and 23 (18%) of 131 patients in the CPT group. Serious adverse events were reported in 11 (8%) patients in the IPT group, including one (1%) death, and 11 (8%) patients in the CPT group, including three (2%) deaths.

INTERPRETATION

Compared with CPT, IPT reduced HbA_1c in patients with type 2 diabetes and moderate-to-severe periodontitis after 12 months. These results suggest that routine oral health assessment and treatment of periodontitis could be important for effective management of type 2 diabetes.

FUNDING

Diabetes UK and UK National Institute for Health Research.

Exploring the Dual Inhibitory Activity of Novel Anthranilic Acid Derivatives towards α-Glucosidase and Glycogen Phosphorylase Antidiabetic Targets: Design, In Vitro Enzyme Assay, and Docking Studies

A few new anthranilate diamide derivatives, 3a–e, 5a–c and 7a–d, were designed, synthesized, and evaluated for their inhibitory activity against two interesting antidiabetic targets, α-glucosidase and glycogen phosphorylase enzymes. Different instrumental analytical tools were applied in identification and conformation of their structures like; ¹³C NMR, ¹H NMR and elemental analysis. The screening of the novel compounds showed potent inhibitory activity with nanomolar concentration values. The most active compounds (5c) and (7b) showed the highest inhibitory activity against α-glucosidase and glycogen phosphorylase enzymes IC₅₀ = 0.01247 ± 0.01 µM and IC₅₀ = 0.01372 ± 0.03 µM, respectively. In addition, in vivo testing of the highly potent α-glucosidase inhibitor (7b) on rats with DTZ-induced diabetes was done and showed significant reduction of blood glucose levels compared to the reference drug. Furthermore, a molecular docking study was performed to help understand the binding interactions of the most active analogs with these two enzymes. The data obtained from the molecular modeling were correlated with those obtained from the biological screening. These data showed considerable antidiabetic activity for these newly synthesized compounds.

Predictors of response to glucagon-like peptide-1 receptor agonists: a meta-analysis and systematic review of randomized controlled trials

AIMS

The aim of the present meta-analysis is the identification of the characteristics of patients, which predict the efficacy on HbA1c of glucagon-like peptide-1 receptor agonists (GLP-1 RA).

METHODS

A Medline and Embase search for "exenatide" OR "liraglutide" OR "albiglutide" OR "dulaglutide" OR "lixisenatide" was performed, collecting randomized clinical trials (duration > 12 weeks) up to September 2016, comparing GLP-1 RA at the maximal approved dose with placebo or active drugs. Furthermore, unpublished studies were searched in the www.clinicaltrials.gov register. For meta-analyses, the outcome considered were 24- and 52-week HbA1c. Separate analyses were performed, whenever possible, for subgroups of trials based on several inclusion criteria. In addition, meta-regression analyses were performed for comparisons for which 10 or more trails were available.

RESULTS

A total of 92 trials fulfilling the inclusion criteria were identified. In placebo-controlled trials (n = 41), the 24-week mean reduction of HbA1c with GLP-1 RA was - 0.75 [- 0.87; - 0.63]%. Shorter-acting molecules appear to be more effective in patients with lower fasting glucose, whereas longer-acting agents in patients with higher fasting hyperglycaemia. Obesity and duration of diabetes do not seem to moderate the efficacy of GLP-1 RA, whereas in non-Caucasians and older patients liraglutide could be less effective. At 52 weeks, only 9 placebo-controlled trials were available for preventing any reliable analyses.

CONCLUSIONS

Using a variety of approaches (meta-analyses of subgroup of trials, meta-regression, systematic review of subgroup analyses in individual trials, and meta-analyses of subgroups of patients), we identified some putative predictors of efficacy of GLP-1 RA, which deserve further investigation.

Estimating the effects of second-line therapy for type 2 diabetes mellitus: retrospective cohort study

OBJECTIVE

Metformin is the recommended initial drug treatment in type 2 diabetes mellitus, but there is no clearly preferred choice for an additional drug when indicated. We compare the counterfactual drug effectiveness in lowering glycated hemoglobin (HbA1c) levels and effect on body mass index (BMI) of four diabetes second-line drug classes using electronic health records.

STUDY DESIGN AND SETTING

Retrospective analysis of electronic health records of US-based patients in the Explorys database using causal inference methodology to adjust for patient censoring and confounders.

PARTICIPANTS AND EXPOSURES

Our cohort consisted of more than 40 000 patients with type 2 diabetes, prescribed metformin along with a drug out of four second-line drug classes-sulfonylureas, thiazolidinediones, dipeptidyl peptidase 4 (DPP-4) inhibitors and glucagon-like peptide-1 agonists-during the years 2000-2015. Roughly, 17 000 of these patients were followed for 12 months after being prescribed a second-line drug.

MAIN OUTCOME MEASURES

HbA1c and BMI of these patients after 6 and 12 months following treatment.

RESULTS

We demonstrate that all four drug classes reduce HbA1c levels, but the effect of sulfonylureas after 6 and 12 months of treatment is less pronounced compared with other classes. We also estimate that DPP-4 inhibitors decrease body weight significantly more than sulfonylureas and thiazolidinediones.

CONCLUSION

Our results are in line with current knowledge on second-line drug effectiveness and effect on BMI. They demonstrate that causal inference from electronic health records is an effective way for conducting multitreatment causal inference studies.

Metformin: From Research to Clinical Practice

Metformin is the recommended first-line oral glucose-lowering drug initiated to control hyperglycemia in type 2 diabetes mellitus. It acts in the liver, small intestines, and skeletal muscles with its major effect on decreasing hepatic gluconeogenesis. It is safe, inexpensive, and weight neutral and can be associated with weight loss. It can reduce microvascular complication risk and its use is associated with a lower cardiovascular mortality compared with sulfonylurea therapy. It is also used to delay the onset of type 2 diabetes mellitus, in treating gestational diabetes, and in women with polycystic ovary syndrome.

Hypoglycaemia when adding sulphonylurea to metformin: a systematic review and network meta-analysis

AIMS

The risk of hypoglycaemia may differ among sulphonylureas (SUs), but evidence from head-to-head comparisons is sparse. Performing a network meta-analysis to use indirect evidence from randomized controlled trials (RCTs), we compared the relative risk of hypoglycaemia with newer generation SUs when added to metformin.

METHODS

A systematic review identified RCTs lasting 12-52 weeks and evaluating SUs added to inadequate metformin monotherapy (≥1000 mg/day) in type 2 diabetes. Adding RCTs investigating the active comparators from the identified SU trials, we established a coherent network. Hypoglycaemia of any severity was the primary end point.

RESULTS

Thirteen trials of SUs and 14 of oral non-SU antihyperglycaemic agents (16 260 patients) were included. All reported hypoglycaemia only as adverse events. Producing comparable reductions in HbA_1C of -0.66 to -0.84% (-7 to -9 mmol/mol), the risk of hypoglycaemia was lowest with gliclazide compared to glipizide (OR 0.22, CrI: 0.05 to 0.96), glimepiride (OR 0.40, CrI: 0.13 to 1.27), and glibenclamide (OR 0.21, CrI: 0.03 to 1.48). A major limitation is varying definitions of hypoglycaemia across studies.

CONCLUSIONS

When added to metformin, gliclazide was associated with the lowest risk of hypoglycaemia between the newer generation SUs. Clinicians should consider the risk of hypoglycaemia agent-specific when selecting an SU agent.

Shared decision making in endocrinology: present and future directions

In medicine and endocrinology, there are few clinical circumstances in which clinicians can accurately predict what is best for their patients. As a result, patients and clinicians frequently have to make decisions about which there is uncertainty. Uncertainty results from limitations in the research evidence, unclear patient preferences, or an inability to predict how treatments will fit into patients' daily lives. The work that patients and clinicians do together to address the patient's situation and engage in a deliberative dialogue about reasonable treatment options is often called shared decision making. Decision aids are evidence-based tools that facilitate this process. Shared decision making is a patient-centred approach in which clinicians share information about the benefits, harms, and burden of different reasonable diagnostic and treatment options, and patients explain what matters to them in view of their particular values, preferences, and personal context. Beyond the ethical argument in support of this approach, decision aids have been shown to improve patients' knowledge about the available options, accuracy of risk estimates, and decisional comfort. Decision aids also promote patient participation in the decision-making process. Despite accumulating evidence from clinical trials, policy support, and expert recommendations in endocrinology practice guidelines, shared decision making is still not routinely implemented in endocrine practice. Additional work is needed to enrich the number of available tools and to implement them in practice workflows. Also, although the evidence from randomised controlled trials favours the use of this shared decision making in other settings, populations, and illnesses, the effect of this approach has been studied in a few endocrine disorders. Future pragmatic trials are needed to explore the effect and feasibility of shared decision making implementation into routine endocrinology and primary care practice. With the available evidence, however, endocrinologists can now start to practice shared decision making, partner with their patients, and use their expertise to formulate treatment plans that reflect patient preferences and are more likely to fit into the context of patients' lives. In this Personal View, we describe shared decision making, the evidence behind the approach, and why and how both endocrinologists and their patients could benefit from this approach.

Shared decision-making in the care of individuals with diabetes

People with diabetes often live with other chronic conditions and lead complicated lives. Determining what is the best management decision for a patient requires consideration of each individual's personal, social and biomedical context, what he or she values, the reasons he or she has to value the available options, and the relative contribution of each option in terms of benefits, harms, costs and inconveniences. Empathic conversations between patients and clinicians to diagnose the patient situation that necessitates action and the range of evidence-based actions that best address the situation, so-called shared decision-making, are essential to the personalized care of people with diabetes. The aim of the present review was to present key elements of shared decision-making and propose three different approaches for its application. The first approach focuses on transferring information to patients so that they can make decisions. The second approach, choice, focuses on cultivating the individual's ability to give voice to which choice is best for them. The third approach, conversation, establishes an empathic conversational environment through which the individual with diabetes and their clinician think and talk through how to address the problems of living with diabetes and related illnesses. These approaches are manifest in the design of evidence-based decision aids created to support shared decision-making. In randomized trials, decision aids can efficiently improve patient's knowledge, satisfaction, risk awareness, decisional conflict and involvement. Further research, however, is needed to better understand when and how to promote the empathic conversations, patient, clinician and service and policy contexts necessary to routinely implement shared decision-making in different at scale healthcare systems. In the interim, sufficient evidence and tools exist for persons with diabetes and their clinicians to gain expertise in making decisions together.

Evidence that periodontal treatment improves diabetes outcomes: a systematic review and meta-analysis

CONTEXT

The effect of periodontal therapy on diabetes outcomes has not been established.

OBJECTIVE

This update examines the effect of periodontal treatment on diabetes outcomes.

DATA SOURCES

Literature since October 2009 using MEDLINE.

STUDY ELIGIBILITY CRITERIA

Published RCTs including periodontal therapy for diabetic subjects, a metabolic outcome, an untreated control group, and follow-up of 3 months.

DATA EXTRACTION

Pre-defined data fields, including study quality indicators were used.

DATA SYNTHESIS

A search revealed 56 publications of which 9 met inclusion criteria. Mean change of HbA1c from baseline was compared across treatment groups. Pooled analysis was based on random effects models.

RESULTS

A meta-analysis indicated a mean treatment effect of -0.36% HbA1c (CI -0.54, -0.19) compared to no treatment after periodontal therapy (p < 0.0001). Heterogeneity tests revealed only minimal evidence of publication bias (I(2 ) = 9%).

LIMITATIONS

Small sample size and high risk of bias remain problematic for studies of this type. Periodontal therapy varied considerably.

CONCLUSION

The modest reduction in HbA1c observed as a result of periodontal therapy in subjects with type 2 diabetes is consistent with previous systematic reviews. Despite this finding, there is limited confidence in the conclusion due to a lack of multi-centre trials of sufficient sample size are lacking.

Evidence that periodontal treatment improves diabetes outcomes: a systematic review and meta-analysis

CONTEXT

The effect of periodontal therapy on diabetes outcomes has not been established.

OBJECTIVE

This update examines the effect of periodontal treatment on diabetes outcomes.

DATA SOURCES

Literature since October 2009 using MEDLINE.

STUDY ELIGIBILITY CRITERIA

Published RCTs including periodontal therapy for diabetic subjects, a metabolic outcome, an untreated control group, and follow-up of 3 months.

DATA EXTRACTION

Pre-defined data fields, including study quality indicators were used.

DATA SYNTHESIS

A search revealed 56 publications of which 9 met inclusion criteria. Mean change of HbA1c from baseline was compared across treatment groups. Pooled analysis was based on random effects models.

RESULTS

A meta-analysis indicated a mean treatment effect of _0.36% HbA1c (CI _0.54, _0.19) compared to no treatment after periodontal therapy (p < 0.0001). Heterogeneity tests revealed only minimal evidence of publication bias (I2 = 9%).

LIMITATIONS

Small sample size and high risk of bias remain problematic for studies of this type. Periodontal therapy varied considerably.

CONCLUSION

The modest reduction in HbA1c observed as a result of periodontal therapy in subjects with type 2 diabetes is consistent with previous systematic reviews. Despite this finding, there is limited confidence in the conclusion due to a lack of multi-centre trials of sufficient sample size are lacking.

The Effectiveness of Myo-Inositol and D-Chiro Inositol Treatment in Type 2 Diabetes

Inositol has been used as a supplement in treating several pathologies such as PCOS, metabolic syndrome, and gestational diabetes. Both myo-inositol and its isomer d-chiro-inositol showed insulin mimetic effects in conditions of insulin resistance. Type 2 diabetes (T2DM) is a condition typically caused by insulin resistance. There is a lack of evidence of inositol use in T2DM. We evaluated the effectiveness and safety of myo-inositol and d-chiro-inositol treatment in T2DM. This was a pilot study involving a consecutive sample of patients with T2DM with suboptimal glycemic control (HbA1c 7.0-10.0%) already treated with glucose-lowering agents. Patients (23.1% males, mean age of 60.8 ± 11.7 years) took for three months a combination of myo-inositol (550 mg) and d-chiro-inositol (13.8 mg) orally twice a day as add-on supplement to their glucose-lowering drugs. Possible occurrence of side effects was investigated. After three months of treatment fasting blood glucose (192.6 ± 60.2 versus 160.9 ± 36.4; p = 0.02) and HbA1c levels (8.6 ± 0.9 versus 7.7 ± 0.9; p = 0.02) significantly decreased compared to baseline. There was no significant difference in blood pressure, lipid profile, and BMI levels. None of the participants reported side effects. In conclusion, a supplementation with a combination of myo- and d-chiro-inositol is an effective and safe strategy for improving glycemic control in T2DM.

Important differences in the durability of glycaemic response among second-line treatment options when added to metformin in type 2 diabetes: a retrospective cohort study

IMPORTANCE

There is limited information about the durability of glycaemic control when different oral glucose-lowering therapies (GLTs) are used as add-on treatments to metformin (MET) in patients with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To compare time to treatment failure between different classes of oral GLT when used as second line (add-on) treatments to MET monotherapy at HbA1c ≥ 7.5%.

DESIGN, SETTING AND PARTICIPANTS

A retrospective cohort study on 20,070 patients who were newly treated with a sulphonylurea (SU), dipeptidyl-peptidase-4 (DPP-4) inhibitor or thiazolidinedione (TZD) following MET therapy failure (2007-2014). Patients' data was sourced from UK General Practices via The Health Improvement Network (THIN) database. The risk of dual therapy failure was compared between three treatment groups: MET + SU (reference group, n = 15,508), MET + DPP-4 inhibitor (n = 3,080) and MET + TZD (n = 1,482). Follow-up was until treatment substitution or intensification with a 3rd GLT, or for up to 5 years (totalling 46,430 person-years). Propensity score weighting and Cox proportional hazard regression analyses were employed.

MAIN OUTCOMES AND MEASURES

Risk of dual therapy failure was compared between treatment groups while adjusting for baseline covariates.

RESULTS

Unadjusted survival analysis showed the incidence of dual therapy failure at 1 year was 15% with SU, 23% with DPP-4 inhibitor and 8% with TZD. Corresponding failure rates at 2 years were 26, 38 and 12%, respectively. Adjusted multivariate models showed that, compared to the SU group, adding a DPP-4 inhibitor was associated with an increased risk of treatment failure (adjusted hazard ratio, aHR, 1.58; 95% CI: 1.48-1.68), while adding a TZD was associated with a reduced hazard (aHR, 0.45; 95% CI: 0.41-0.50). Baseline parameters associated with an increased hazard of intensification included HbA1c, diabetes duration, gender, smoking status and the use of statins.

CONCLUSIONS AND RELEVANCE

In routine clinical practice, adding a DPP-4 inhibitor to MET is associated with an increased, earlier requirement for treatment intensification compared to adding an SU or TZD. Adding a TZD to MET resulted in the most durable glycaemic response. Key messages The Agency for Healthcare Research and Quality has suggested that the durability of glycaemic response after treatment intensification is best investigated using well-designed long-term observational studies. In routine clinical practice, among patients with T2DM receiving a second line glucose lowering treatment as add-on to MET, the addition of a Thiazolidinediones is associated with the most durable glycaemic response, followed by a Sulfonylurea and then a DPP-4 inhibitor. Factors associated with earlier dual therapy failure included concomitant use of statin therapy, being female, a smoker, those with longer diabetes duration and higher baseline HbA1c levels. The addition of a Thiazolidinediones was associated with significant weight gain (1.8 kg, p < 0.001), while add-on DPP-4 inhibitor produced a significant weight reduction (-1.8 kg, p < 0.001). A very small reduction in body weight was observed with the SU (-0.2 kg, p < 0.001).

Shared Decision-Making in Diabetes Care

Shared decision-making (SDM) is a collaborative process by which patients and clinicians work together in a deliberative dialogue. The purpose of this dialogue is to identify reasonable management options that best fit and addresses the unique situation of the patient. SDM supports the patient-centered translation of research into practice. SDM also helps implement a core principle of evidence-based medicine: evidence is necessary but never sufficient to make a clinical decision, as consideration of patient values and context is also required. SDM conversations build on a partnership between the patient and the clinician, draw on the body of evidence with regard to the different treatment options, and consider options in light of the values, preferences, and context of the patient. SDM is appropriate for diabetes care because diabetes care often requires consideration of management options that differ in ways that matter to patients, such as the way in which they place significant demands on patient's life and living. In the last decade, SDM has proven feasible and useful for sharing evidence with patients and for involving patients in making decisions with their clinicians. Health care and clinical policies advocate SDM, but these policies have yet to impact diabetes care. In this paper, we describe what SDM is, its known impact on diabetes care, and needed work to implement this patient-centered approach in the care of the millions of patients with diabetes.

Comparative efficacy and safety of antidiabetic drug regimens added to metformin monotherapy in patients with type 2 diabetes: a network meta-analysis

Introduction

When first line therapy with metformin is insufficient for patients with type 2 diabetes (T2D), the optimal adjunctive therapy is unclear. We assessed the efficacy and safety of adjunctive antidiabetic agents in patients with inadequately controlled T2D on metformin alone.

Materials and Methods

A search of MEDLINE and CENTRAL, clinicaltrials.gov, regulatory websites was performed. We included randomized controlled trials of 3–12 months duration, evaluating Food and Drug Administration or European Union approved agents (noninsulin and long acting, once daily basal insulins) in patients experiencing inadequate glycemic control with metformin monotherapy (≥1500 mg daily or maximally tolerated dose for ≥4 weeks). Random-effects network meta-analyses were used to compare the weighted mean difference for changes from baseline in HbA1c, body weight (BW) and systolic blood pressure (SBP), and the risk of developing hypoglycemia, urinary (UTI) and genital tract infection (GTI).

Results

Sixty-two trials evaluating 25 agents were included. All agents significantly reduced HbA1c vs. placebo; albeit not to the same extent (range, 0.43% for miglitol to 1.29% for glibenclamide). Glargine, sulfonylureas (SUs) and nateglinide were associated with increased hypoglycemia risk vs. placebo (range, 4.00–11.67). Sodium glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 analogs, miglitol and empagliflozin/linagliptin significantly reduced BW (range, 1.15–2.26kg) whereas SUs, thiazolindinediones, glargine and alogliptin/pioglitazone caused weight gain (range, 1.19–2.44kg). SGLT2 inhibitors, empagliflozin/linagliptin, liraglutide and sitagliptin decreased SBP (range, 1.88–5.43mmHg). No therapy increased UTI risk vs. placebo; however, SGLT2 inhibitors were associated with an increased risk of GTI (range, 2.16–8.03).

Conclusions

Adding different AHAs to metformin was associated with varying effects on HbA1c, BW, SBP, hypoglycemia, UTI and GTI which should impact clinician choice when selecting adjunctive therapy.

Resource utilization and costs associated with using insulin therapy within a newly diagnosed type 2 diabetes mellitus population

BACKGROUND

Although oral antidiabetic medications are the mainstay for managing type 2 diabetes mellitus (T2DM), patients often require insulin therapy to achieve optimal glycemic control. Given the prevalence of insulin use among patients with T2DM, this study evaluated the economic impact of this treatment modality in patients treated in a managed care setting.

OBJECTIVE

To estimate costs and resource utilization associated with using insulin therapy among patients with newly diagnosed T2DM who were initially treated with other noninsulin antidiabetic (NIAD) medications.

METHODS

An observational, retrospective study design was implemented using integrated medical and pharmacy claims data. Adults with a diagnosis of T2DM from July 1, 2003, through March 31, 2008, were identified. The date of first diagnosis was deemed the index date. The 24-month period after the index date was used to assess treatment patterns. Based on the treatment patterns, the following 2 cohorts were selected: NIAD-only cohort, users who received greater than 1 NIAD class medication but never received insulin, and insulin-use cohort, NIAD users who switched to/added on insulin therapy (duration ≥ 60 days). Patients were matched in a 1:3 (insulin-use:NIAD-only) ratio based on propensity scores and other key covariates of interest. Hypoglycemia rates, monthly costs, and resource use during the outcome assessment period were compared between cohorts.

RESULTS

After matching, 1,400 patients (350 insulin users and 1,050 NIAD-only users) were included in the analysis (42% women; mean age, 56 years). After controlling for covariates, the insulin-use cohort incurred $71 per patient per month higher total T2DM-specific costs than the NIAD-only cohort ($241/month vs. $170/month, P = 0.0003). Pharmacy costs and utilization of physician visits were drivers of cost differences between cohorts. The rate of hypoglycemic events was 10.2 per 100 person-years for the insulin-use cohort versus 2.9 per 100 person-years in the NIAD-only cohort (P  less than  0.0001).

CONCLUSIONS

Use of insulin therapy is associated with increased hypoglycemic events, increased pharmacy and medical costs, and greater utilization of T2DM-specific health care services.

Effectiveness and safety of fixed dose combination of acarbose/metformin in Indian Type 2 diabetes patients: Results from observational GLOBE Study

Primary objective - evaluate effectiveness and safety of acarbose/metformin fixed dose FDC on glycemic control in Indian T2DM patients in real life clinical setting. Secondary objective - evaluate safety and satisfaction of treatment.

MATERIALS AND METHODS

Open-label, prospective, multicentre, single-arm, non-interventional study. Patients included were aged ≥18 years with T2DM on Acarbose (25/50 mg) and Metformin (500 mg) FDC. Glycemic parameters were recorded during observation.

RESULTS

Total 9364 patients were enrolled in the study (mean age, 50.7 years and 60.1% were male). Mean (SD) FBG and PPG was significantly reduced by 42.4 (32.6) mg/dl (P < 0.0001) and 80.2 (49.7) mg/dl (P < 0.0001) respectively at the end of observation. Mean (SD) HbA1c reduced by -1.0% (0.8) to 7.3% (0.7) at the last follow-up visit (P <0.0001). Majority of patients (97.5%) and physicians (98.42%) were satisfied with acarbose/metformin FDC treatment. Also, significant reduction in body weight by -1.7 (2.2) kg was observed (P < 0.0001). Patients with known T2DM and newly diagnosed showed a similar glycemic control (P < 0.0001). Drug-related adverse events were reported by only 1.4% patients mostly gastrointestinal.

CONCLUSIONS

Acarbose/metformin FDC was efficacious, safe well accepted in routine clinical practice. It was well-tolerated without significant risk of hypoglycemia and can be used in early T2DM management.

Observational and clinical trial findings on the comparative effectiveness of diabetes drugs showed agreement

OBJECTIVES

This study compares an observational study of diabetes treatment effectiveness to randomized controlled trials to assess their convergent validity.

STUDY DESIGN AND SETTING

Multivariate models were developed using observational data to describe change in hemoglobin A1c (HbA1c; % unit) and weight (kilograms) after addition of a second-line oral diabetes drug to metformin monotherapy. Randomized trials of these scenarios were systematically identified. The models were used to simulate each trial, and simulated and actual results were compared by linear regression and meta-analysis.

RESULTS

Thirty-two randomized trials of second-line diabetes oral therapy were identified. For all outcomes and drugs studied, simulation and actual results correlated (P < 0.001). There were no statistically significant differences between meta-analyzed randomized and simulated results for effect on HbA1c. For effect on weight, results were qualitatively comparable, but for sulfonylureas, the simulated weight gain was nominally greater than seen in the randomized controlled trials.

CONCLUSION

An observational study of diabetes drug effectiveness showed convergent validity with randomized data. This supports cautious use of the observational research to draw conclusions about drug effectiveness in populations not studied in clinical trials. This approach may be useful in other situations where observational and randomized data need integration.

Combine and conquer: advantages and disadvantages of fixed-dose combination therapy

The majority of patients with type 2 diabetes mellitus (T2DM) do not achieve the glycaemic goals recommended by leading diabetes organizations using monotherapy alone, and often require multiple antihyperglycaemic agents to achieve glycaemic control. Fixed-dose combination (FDC) therapies offer a means to simplify complex treatment regimens, and have several advantages that help patients reach their glycaemic goals. In this review, four key benefits are identified and discussed in support of FDCs for treatment of patients with T2DM: (i) Greater efficacy compared with higher dose monotherapy, (ii) Reduced risk of adverse reactions relative to higher dose monotherapy, (iii) Lower overall costs and (iv) Improved medication concordance. Given these advantages, the place of fixed combination therapy in the course of treatment is discussed. Establishing a therapeutic strategy that incorporates fixed combination therapy (including combinations with insulin) will simplify the treatment of diabetes, ideally resulting in improved medication concordance, clinical outcomes and quality of life for patients with T2DM.

Effects on lipid profile of dipeptidyl peptidase 4 inhibitors, pioglitazone, acarbose, and sulfonylureas: meta-analysis of placebo-controlled trials

INTRODUCTION

Lipid profile is an important determinant of cardiovascular risk in type 2 diabetes. It is well known that patients with type 2 diabetes are more likely to be dyslipidemic than the general population. Given the observed connection between glucose and lipid metabolism in patients with type 2 diabetes, it is conceivable that different glucose-lowering agents can have a varying impact on the lipid profile. When metformin monotherapy fails, other drugs can be added to achieve sufficient glycemic control. Available oral agents include pioglitazone, acarbose, dipeptidyl peptidase 4 (DPP-4) inhibitors, and insulin secretagogs. The present meta-analysis was designed to assess the effect of DPP-4 inhibitors, pioglitazone, insulin secretagogs, and acarbose on blood lipids when compared to placebo.

METHODS

An extensive search (any date up to November 1, 2011) was performed for all trials performed on the following classes of drugs: gliptin, insulin secretagogs, pioglitazone, and acarbose. The following endpoints were considered: endpoint total, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) and triglycerides.

RESULTS

The difference in mean total cholesterol values at endpoint versus baseline was significantly higher in patients on pioglitazone, sulfonylureas, and DPP-4 inhibitor treatment (but not on acarbose) than those on placebo, demonstrating that treatment with these drugs (except acarbose) is associated with a significant reduction in total cholesterol. With respect to triglycerides, a significant reduction could be observed with acarbose, pioglitazone, and DPP-4 inhibitors, but not with sulfonylureas. HDL-C appeared to be increased by treatment with acarbose and pioglitazone, and decreased by sulfonylureas.

CONCLUSION

The present meta-analysis shows that available glucose-lowering drugs may have varying effects on the lipid profile. DPP-4 inhibitors, acarbose, and pioglitazone seem to have a more favorable effect on the lipid profile than sulfonylureas.

Syzygium cumini ameliorates insulin resistance and β-cell dysfunction via modulation of PPAR, dyslipidemia, oxidative stress, and TNF-α in type 2 diabetic rats

Syzygium cumini (SC) is well known for its anti-diabetic potential, but the mechanism underlying its amelioration of type 2 diabetes is still elusive. Therefore, for the first time, we investigated whether SC aqueous seed extract (100, 200, or 400 mg/kg) exerts any beneficial effects on insulin resistance (IR), serum lipid profile, antioxidant status, and/or pancreatic β-cell damage in high-fat diet / streptozotocin-induced (HFD-STZ) diabetic rats. Wistar albino rats were fed with HFD (55% of calories as fat) during the experiment to induce IR and on the 10th day were injected with STZ (40 mg/kg, i.p.) to develop type 2 diabetes. Subsequently, after confirmation of hyperglycemia on the 14th day (fasting glucose level > 13.89 mM), diabetic rats were treated with SC for the next 21 days. Diabetic rats showed increased serum glucose, insulin, IR, TNF-α, dyslipidemia, and pancreatic thiobarbituric acid-reactive substances with a concomitant decrease in β-cell function and pancreatic superoxide dismutase, catalase, and glutathione peroxidase antioxidant enzyme activities. Microscopic examination of their pancreas revealed pathological changes in islets and β-cells. These alterations reverted to near-normal levels after treatment with SC at 400 mg/kg. Moreover, hepatic tissue demonstrated increased PPARγ and PPARα protein expressions. Thus, our study demonstrated the beneficial effect of SC seed extract on IR and β-cell dysfunction in HFD-STZ-induced type 2 diabetic rats.

Efficacy of various antidiabetic agents as add-on treatments to metformin in type 2 diabetes mellitus: systematic review and meta-analysis

Background and Aim. Diabetes mellitus is a chronic disease that has a great impact on patients and society. Metformin monotherapy is capable of maintaining a target glycemic control only for a short term. The aim of this study was to determine the efficacy of combination therapy of metformin with any antidiabetic agents in type 2 diabetes mellitus (T2DM) patients. Methods. Reports of randomized controlled trials (RCTs) of combination therapy of metformin with various antidiabetic agents in T2DM failing metformin alone were identified. Results. Eight studies were identified in our paper. Thiazolidinediones (TZDs) were as effective as dipeptidyl peptidase IV inhibitors (DPP IV inhs) in reducing HbA1c value (pooled mean difference −0.03%; 95% CI −0.16 to 0.10%). In comparison between TZDs and sulphonylureas (SUs), TZDs reduced fasting plasma insulin (FPI) more effectively than SUs (pool mean difference −5.72 μU/mL; 95% CI −8.21 to −3.22 μU/mL, P < 0.00001), but no significant differences were detected in the effects on HbA1c and fasting plasma glucose (FPG) (pooled mean difference −2.19 mg/dL; 95% CI −11.32 to 6.94 mg/dL, P = 0.64). Conclusions. Our study showed that TZDs reduced FPG better than did DPP IV inhs and decreased FPI more than did SUs.

Comparative effectiveness and safety of medications for type 2 diabetes: an update including new drugs and 2-drug combinations

BACKGROUND

Given the increase in medications for type 2 diabetes mellitus, clinicians and patients need information about their effectiveness and safety to make informed choices.

PURPOSE

To summarize the benefits and harms of metformin, second-generation sulfonylureas, thiazolidinediones, meglitinides, dipeptidyl peptidase-4 (DPP-4) inhibitors, and glucagon-like peptide-1 receptor agonists, as monotherapy and in combination, to treat adults with type 2 diabetes.

DATA SOURCES

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched from inception through April 2010 for English-language observational studies and trials. The MEDLINE search was updated to December 2010 for long-term clinical outcomes.

STUDY SELECTION

Two reviewers independently screened reports and identified 140 trials and 26 observational studies of head-to-head comparisons of monotherapy or combination therapy that reported intermediate or long-term clinical outcomes or harms.

DATA EXTRACTION

Two reviewers following standardized protocols serially extracted data, assessed applicability, and independently evaluated study quality.

DATA SYNTHESIS

Evidence on long-term clinical outcomes (all-cause mortality, cardiovascular disease, nephropathy, and neuropathy) was of low strength or insufficient. Most medications decreased the hemoglobin A(1c) level by about 1 percentage point and most 2-drug combinations produced similar reductions. Metformin was more efficacious than the DPP-4 inhibitors, and compared with thiazolidinediones or sulfonylureas, the mean differences in body weight were about -2.5 kg. Metformin decreased low-density lipoprotein cholesterol levels compared with pioglitazone, sulfonylureas, and DPP-4 inhibitors. Sulfonylureas had a 4-fold higher risk for mild or moderate hypoglycemia than metformin alone and, in combination with metformin, had more than a 5-fold increased risk compared with metformin plus thiazolidinediones. Thiazolidinediones increased risk for congestive heart failure compared with sulfonylureas and increased risk for bone fractures compared with metformin. Diarrhea occurred more often with metformin than with thiazolidinediones.

LIMITATIONS

Only English-language publications were reviewed. Some studies may have selectively reported outcomes. Many studies were small, were of short duration, and had limited ability to assess clinically important harms and benefits.

CONCLUSION

Evidence supports metformin as a first-line agent to treat type 2 diabetes. Most 2-drug combinations similarly reduce hemoglobin A(1c) levels, but some increased risk for hypoglycemia and other adverse events.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Predictors of response to dipeptidyl peptidase-4 inhibitors: evidence from randomized clinical trials

AIM

Dipeptidyl peptidase-4 (DPP-4) inhibitors are used in the treatment of type 2 diabetes. Available sub-group analysis of clinical trials does not allow a clear identification of predictors of therapeutic response to these drugs. The aim of this study is the assessment of predictors of response to DPP-4 inhibitors.

MATERIALS AND METHODS

A meta-analysis was performed, exploring correlation between 24-week effects on HbA(1c) of maximal doses of DPP-4 inhibitors, compared either with placebo or with other active drugs, matches to baseline characteristics of patients enrolled in 63 randomized clinical trials, either published or unpublished but disclosed on different websites were studied.

RESULTS

DPP-4 inhibitors significantly reduce HbA(1c) at 24 weeks [by 0.6 (0.5-0.7)%] when compared with placebo; no difference in HbA(1c) was observed in comparisons with thiazolidinediones and α-glucosidase inhibitors, whereas sulfonylureas and metformin produced a greater reduction of HbA(1c) , at least in the short term. DPP-4 inhibitors produced a smaller weight gain than thiazolidinediones, and showed a lower hypoglycaemia risk than sulfonylureas. The placebo-subtracted effect of DPP-4 inhibitors on HbA(1c) was greater in older patients and in those with lower fasting plasma glucose at baseline. Similar results were obtained in comparisons with thiazolidinediones and metformin.

CONCLUSIONS

Although drugs for type 2 diabetes are studied in heterogeneous samples of patients, their efficacy can be predicted by some clinical parameters. DPP-4 inhibitors appear to be more effective in older patients with mild/moderate fasting hyperglycaemia. These data could be useful for a better definition of the profile of patients who are likely to benefit most from these drugs.

Second-line therapy in patients with type 2 diabetes inadequately controlled with metformin monotherapy: a systematic review and mixed-treatment comparison meta-analysis

BACKGROUND

Although there is general agreement that metformin should be used as first-line pharmacotherapy in patients with type 2 diabetes, uncertainty remains regarding the choice of second-line therapy once metformin is no longer effective. We conducted a systematic review and meta-analysis to assess the comparative safety and efficacy of all available classes of antihyperglycemic therapies in patients with type 2 diabetes inadequately controlled on metformin monotherapy.

METHODS

MEDLINE, EMBASE, BIOSIS Previews, PubMed and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials published in English from 1980 to October 2009. Additional citations were obtained from grey literature and conference proceedings and through stakeholder feedback. Two reviewers independently selected studies, extracted data and assessed risk of bias. Key outcomes of interest were hemoglobin A1c, body weight, hypoglycemia, quality of life, long-term diabetes-related complications, serious adverse drug events and mortality. Mixed-treatment comparison and pairwise meta-analyses were conducted to pool trial results, when appropriate.

RESULTS

We identified 49 active and non-active controlled randomized trials that compared 2 or more of the following classes of antihyperglycemic agents and weight-loss agents: sulfonylureas, meglitinides, thiazolidinediones (TZDs), dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) analogues, insulins, alpha-glucosidase inhibitors, sibutramine and orlistat. All classes of second-line antihyperglycemic therapies achieved clinically meaningful reductions in hemoglobin A1c (0.6% to 1.0%). No significant differences were found between classes. Insulins and insulin secretagogues were associated with significantly more events of overall hypoglycemia than the other agents, but severe hypoglycemia was rarely observed. An increase in body weight was observed with the majority of second-line therapies (1.8 to 3.0 kg), the exceptions being DPP-4 inhibitors, alpha-glucosidase inhibitors and GLP-1 analogues (0.6 to -1.8 kg). There were insufficient data available for diabetes complications, mortality or quality of life.

INTERPRETATION

DPP-4 inhibitors and GLP-1 analogues achieved improvements in glycemic control similar to those of other second-line therapies, although they may have modest benefits in terms of weight gain and overall hypoglycemia. Further long-term trials of adequate power are required to determine whether newer drug classes differ from older agents in terms of clinically meaningful outcomes.

Effect of linagliptin monotherapy on glycaemic control and markers of β-cell function in patients with inadequately controlled type 2 diabetes: a randomized controlled trial

AIM

To assess the safety and efficacy of the potent and selective dipeptidyl peptidase-4 inhibitor linagliptin 5 mg when given for 24 weeks to patients with type 2 diabetes who were either treatment-naive or who had received one oral antidiabetes drug (OAD).

METHODS

This multicentre, randomized, parallel group, phase III study compared linagliptin treatment (5 mg once daily, n = 336) with placebo (n = 167) for 24 weeks in type 2 diabetes patients. Before randomization, patients pretreated with one OAD underwent a washout period of 6 weeks, which included a placebo run-in period during the last 2 weeks. Patients previously untreated with an OAD underwent a 2-week placebo run-in period. The primary endpoint was the change in HbA1c from baseline after 24 weeks of treatment.

RESULTS

Linagliptin treatment resulted in a placebo-corrected change in HbA1c from baseline of -0.69% (p < 0.0001) at 24 weeks. In patients with baseline HbA1c ≥ 9.0%, the adjusted reduction in HbA1c was 1.01% (p < 0.0001). Patients treated with linagliptin were more likely to achieve a reduction in HbA1c of ≥0.5% at 24 weeks than those in the placebo arm (47.1 and 19.0%, respectively; odds ratio, OR = 4.2, p < 0.0001). Fasting plasma glucose improved by -1.3 mmol/l (p < 0.0001) with linagliptin vs. placebo, and linagliptin produced an adjusted mean reduction from baseline after 24 weeks in 2-h postprandial glucose of -3.2 mmol/l (p < 0.0001). Statistically significant and relevant treatment differences were observed for proinsulin/insulin ratio (p = 0.025), Homeostasis Model Assessment-%B (p = 0.049) and disposition index (p = 0.0005). There was no excess of hypoglycaemic episodes with linagliptin vs. placebo and no patient required third-party intervention. Mild or moderate renal impairment did not influence the trough plasma levels of linagliptin.

CONCLUSIONS

Monotherapy with linagliptin produced a significant, clinically meaningful and sustained improvement in glycaemic control, accompanied by enhanced parameters of β-cell function. The safety profile of linagliptin was comparable with that of placebo.

Safety and efficacy of linagliptin as add-on therapy to metformin in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled study

AIM

To evaluate the efficacy and safety of the potent and selective dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin administered as add-on therapy to metformin in patients with type 2 diabetes with inadequate glycaemic control.

METHODS

This 24-week, randomized, placebo-controlled, double-blind, parallel-group study was carried out in 82 centres in 10 countries. Patients with HbA1c levels of 7.0-10.0% on metformin and a maximum of one additional antidiabetes medication, which was discontinued at screening, continued on metformin ≥1500 mg/day for 6 weeks, including a placebo run-in period of 2 weeks, before being randomized to linagliptin 5 mg once daily (n = 524) or placebo (n = 177) add-on. The primary outcome was the change from baseline in HbA1c after 24 weeks of treatment, evaluated with an analysis of covariance (ANCOVA).

RESULTS

Mean baseline HbA1c and fasting plasma glucose (FPG) were 8.1% and 9.4 mmol/l, respectively. Linagliptin showed significant reductions vs. placebo in adjusted mean changes from baseline of HbA1c (-0.49 vs. 0.15%), FPG (-0.59 vs. 0.58 mmol/l) and 2hPPG (-2.7 vs. 1.0 mmol/l); all p < 0.0001. Hypoglycaemia was rare, occurring in three patients (0.6%) treated with linagliptin and five patients (2.8%) in the placebo group. Body weight did not change significantly from baseline in both groups (-0.5 kg placebo, -0.4 kg linagliptin).

CONCLUSIONS

The addition of linagliptin 5 mg once daily in patients with type 2 diabetes inadequately controlled on metformin resulted in a significant and clinically meaningful improvement in glycaemic control without weight gain or increased risk of hypoglycaemia.

Dipeptydil peptidase-4 inhibitors in type 2 diabetes: a meta-analysis of randomized clinical trials

BACKGROUND AND AIM

The role of Dipeptidyl Peptidase-4 (DPP-4) inhibitors in the treatment of type 2 diabetes is debated; many recent trials, which were not included in previous meta-analyses, could add relevant information.

METHODS AND RESULTS

All available randomized controlled trials (RCTs), either published or unpublished, performed in type 2 diabetic patients with DPP-4 inhibitors, with a duration >12 weeks were meta-analyzed for HbA1c, BMI, hypoglycemia, and other adverse events. A total of 41 RCTs (9 of which are unpublished) was retrieved and included in the analysis. Gliptins determine a significant improvement of HbA1c in comparison with a placebo (-0.7 [-0.8:-0.6]), with a low risk of hypoglycemia. DPP-4 inhibitors show a similar efficacy in monotherapy and in combination with other agents. The risk of cardiovascular events and all-cause death with DPP-4 inhibitors is 0.76 [0.46-1.28] and 0.78 [0.40-1.51], respectively.

CONCLUSIONS

DPP-4 inhibitors reduce HbA1c, although to a lesser extent than sulphonylureas, with no weight gain and no hypoglycemic risk; further data are needed to assess their long-term safety.

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.

The potential of cinnamon to reduce blood glucose levels in patients with type 2 diabetes and insulin resistance

AIM

Cinnamon has a long history as an antidiabetic spice, but trials involving cinnamon supplementation have produced contrasting results. The aim of this review was to examine the results of randomized controlled clinical trials of cinnamon and evaluate the therapeutic potential amongst patients with diabetes and insulin-resistant patients, particularly the ability to reduce blood glucose levels and inhibit protein glycation.

METHODS

A systematic electronic literature search using the medical subject headings 'cinnamon' and 'blood glucose' was carried out to include randomized, placebo-controlled in vivo clinical trials using Cinnamomum verum or Cinnamomum cassia conducted between January 2003 and July 2008.

RESULTS

Five type 2 diabetic and three non-diabetic studies (total N = 311) were eligible. Two of the diabetic studies illustrated significant fasting blood glucose (FBG) reductions of 18-29% and 10.3% (p < 0.05), supported by one non-diabetic trial reporting an 8.4% FBG reduction (p < 0.01) vs. placebo, and another illustrating significant reductions in glucose response using oral glucose tolerance tests (p < 0.05). Three diabetic studies reported no significant results.

CONCLUSIONS

Whilst definitive conclusions cannot be drawn regarding the use of cinnamon as an antidiabetic therapy, it does possess antihyperglycaemic properties and potential to reduce postprandial blood glucose levels. Further research is required to confirm a possible correlation between baseline FBG and blood glucose reduction and to assess the potential to reduce pathogenic diabetic complications with cinnamon supplementation.

Medical management of hyperglycaemia in type 2 diabetes mellitus: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes

The consensus algorithm for the medical management of type 2 diabetes was published in August 2006 with the expectation that it would be updated, based on the availability of new interventions and new evidence to establish their clinical role. The authors continue to endorse the principles used to develop the algorithm and its major features. We are sensitive to the risks of changing the algorithm cavalierly or too frequently, without compelling new information. An update to the consensus algorithm published in January 2008 specifically addressed safety issues surrounding the thiazolidinediones. In this revision, we focus on the new classes of medications that now have more clinical data and experience.

Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes

The consensus algorithm for the medical management of type 2 diabetes was published in August 2006 with the expectation that it would be updated, based on the availability of new interventions and new evidence to establish their clinical role. The authors continue to endorse the principles used to develop the algorithm and its major features. We are sensitive to the risks of changing the algorithm cavalierly or too frequently, without compelling new information. An update to the consensus algorithm published in January 2008 specifically addressed safety issues surrounding the thiazolidinediones. In this revision, we focus on the new classes of medications that now have more clinical data and experience.

Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes

The consensus algorithm for the medical management of type 2 diabetes was published in August 2006 with the expectation that it would be updated, based on the availability of new interventions and new evidence to establish their clinical role. The authors continue to endorse the principles used to develop the algorithm and its major features. We are sensitive to the risks of changing the algorithm cavalierly or too frequently, without compelling new information. An update to the consensus algorithm published in January 2008 specifically addressed safety issues surrounding the thiazolidinediones. In this revision, we focus on the new classes of medications that now have more clinical data and experience.

The effect of sulphonylureas on the microvascular and macrovascular complications of diabetes

INTRODUCTION

Type 2 diabetes mellitus is a chronic progressive disease that is characterised by hyperglycaemia and is associated with an increased risk of the development of microvascular complications, such as retinopathy, nephropathy and neuropathy, and cardiovascular disease. With the introduction of newer oral hypoglycaemic agents, there is a need to re-evaluate critically the effectiveness and safety of the older agents, including sulphonylureas, to assess their place in the modern management of type 2 diabetes.

BACKGROUND

Though no clear benefit of sulphonylureas has been shown with respect to large vessel disease, long term studies have, however, shown benefits in patients with microvascular complications. Studies such as the University Group Diabetes Project raised concerns about the safety profile of sulphonylureas, but large prospective studies such as the UK Prospective Diabetes Study have helped to assuage such concerns to a large degree. Their utility in the peri-infarct period continues to be debatable because of the potential effect on cardiac pre-conditioning.

CONCLUSION

Though sulphonylureas continue to be a mainstay of treatment in type 2 diabetes, future clinical trials addressing clinically relevant outcomes are indicated with the newer generation of sulphonylureas that are more beta cell-specific to address the concerns raised about sulphonylureas and cardiac myocytes.