C-peptide response to glucagon challenge is correlated with improvement of early insulin secretion by liraglutide treatment

Efficacy and safety of oral semaglutide in older patients with type 2 diabetes: a retrospective observational study (the OTARU-SEMA study)

BACKGROUND

Oral semaglutide in older subjects with type 2 diabetes was as effective as in younger subjects, according to phase 3 clinical trials. However, its efficacy can be limited in very aged population, due to the presence of impaired cognitive function and the complex instructions for its use. Here, we investigated its efficacy and safety by further age bracket in older subjects in real-world.

METHODS

We retrospectively studied subjects > 65 years of age with type 2 diabetes who started oral semaglutide treatment. The primary outcome was the change in glycated hemoglobin (HbA1c) over 6 months. Adverse events and cognitive function were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) and the Hasegawa Dementia Rating Scale-revised (HDS-R). The achievement rate of glycemic targets was evaluated based on the age, health status of subjects and their use of anti-diabetic agents which can cause hypoglycemia, with additional analysis between two subgroups; early (65-74) versus late (≥ 75) older. Furthermore, we evaluated the relationships between their improvements in HbA1c and the baseline characteristics of the subjects, including their cognitive function and insulin secretory capacity.

RESULTS

We studied the efficacy of the drug in 24 subjects. Their HbA1c and body weight significantly decreased (- 13.1 ± 7.5 mmol/mol and - 3.0 ± 2.4 kg, respectively; P < 0.01). Although cognitive function was lower in the late older group (r = -0.57, P < 0.01), changes in HbA1c showed no difference between the two subgroups (P = 0.66) and it correlated with the insulin secretory capacity rather than cognitive function (r = -0.49, P < 0.05). Glycemic targets were more likely to be achieved (P < 0.01), but HbA1c excessively decreased in late older subjects who were also using insulin or an insulin secretagogue. The frequency of adverse events was similar to that in the clinical trial, whereas discontinuation of medication were more frequent among the late older subjects (Early; n = 2, Late; n = 4).

CONCLUSIONS

Oral semaglutide improves the glycemic control of older subjects, but it might be a risk for potential hypoglycemia and discontinuation because of adverse events in subjects of ≥ 75 years. Attention should be paid to insulin secretory capacity and concomitant medications rather than concern about adherence.

Distinct hypoglycemic effect of different formulations of a fixed ratio of basal insulin plus glucagon-like peptide-1 receptor agonist in a patient with pancreatic diabetes

Fixed-ratio combination injection therapy (FRC) is a fixed-ratio mixture containing basal insulin and glucagon-like peptide-1 receptor agonist (GLP-1 RA) in a single injection for the treatment of patients with type 2 diabetes. The two types of FRC products contain different concentrations and mixing ratios of basal insulin and GLP-1 RA. Both products demonstrated satisfactory blood glucose control throughout the day, with less hypoglycemia and weight gain. However, few studies have examined the differences in the actions of the two formulations. Herein, we present a case of a 71-year-old man with pancreatic diabetes and significantly impaired intrinsic insulin secretion capacity, who demonstrated a marked difference in glycemic control following treatment with two different FRC formulations. Treatment with IDegLira, an FRC product, demonstrated suboptimal glucose control in the patient. However, after a change in therapy to another FRC product, IGlarLixi, his glucose control markedly improved, even with a decrease in the injection dose. This difference could have been due to lixisenatide, a short-acting GLP-1RA contained in IGlarLixi, which exerts a postprandial hypoglycemic effect irrespective of intrinsic insulin secretion capacity. In conclusion, IGlarLixi has the potential to achieve good fasting and postprandial glucose control with a once-daily injection, even in patients with type 2 diabetes who have a reduced intrinsic insulin secretion capacity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-023-00621-5.

C-peptide determination in the diagnosis of type of diabetes and its management: A clinical perspective

Impaired beta-cell function is a recognized cornerstone of diabetes pathophysiology. Estimates of insulin secretory capacity are useful to inform clinical practice, helping to classify types of diabetes, complication risk stratification and to guide treatment decisions. Because C-peptide secretion mirrors beta-cell function, it has emerged as a valuable clinical biomarker, mainly in autoimmune diabetes and especially in adult-onset diabetes. Nonetheless, the lack of robust evidence about the clinical utility of C-peptide measurement in type 2 diabetes, where insulin resistance is a major confounder, limits its use in such cases. Furthermore, problems remain in the standardization of the assay for C-peptide, raising concerns about comparability of measurements between different laboratories. To approach the heterogeneity and complexity of diabetes, reliable, simple and inexpensive clinical markers are required that can inform clinicians about probable pathophysiology and disease progression, and so enable personalization of management and therapy. This review summarizes the current evidence base about the potential value of C-peptide in the management of the two most prevalent forms of diabetes (type 2 diabetes and autoimmune diabetes) to address how its measurement may assist daily clinical practice and to highlight current limitations and areas of uncertainties to be covered by future research.

Successful Resolution of Glucose Toxicity With the Use of Fixed-Ratio Combination Injection of Basal Insulin and Short-Acting Glucagon-Like Peptide 1 (GLP-1) Receptor Agonist

Chronic hyperglycemia leads to a decrease in glucose-stimulated insulin secretion and an increase in insulin resistance. Resolving these glucose toxicities is pivotal in type 2 diabetes therapy because the decline in insulin secretion and insulin sensitivity causes further hyperglycemia. Conventionally, multiple daily insulin injection therapy was applied in such a situation. However, it could not be easily introduced, especially in outpatients. We present a case involving the successful resolution of glucose toxicity easily, immediately, and safely by using a fixed-ratio combination (FRC) injection of basal insulin and short-acting glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1 RA). Additionally, we discuss the advantages of this new injection therapy.

Effect of liraglutide on markers of insulin production in persons with type 2 diabetes treated with multiple daily insulin injections

In this post-hoc analysis of data from a randomised clinical trial, we compared the effect of liraglutide to placebo on markers of insulin secretion in persons with type 2 diabetes treated with multiple daily insulin injections. Liraglutide increased insulin secretion, measured by C-peptide, by 19% after 24 weeks of treatment. CLINICAL TRIAL REGISTRATION: EudraCT 2012-001941-42.

Predictive factors of efficacy of combination therapy with basal insulin and liraglutide in type 2 diabetes when switched from longstanding basal-bolus insulin: Association between the responses of β- and α-cells to GLP-1 stimulation and the glycaemic control at 6 months after switching therapy

AIMS

To evaluate the glycaemic control of combination therapy with basal insulin and liraglutide, and to explore the factors predictive of efficacy in patients with type 2 diabetes when switched from longstanding basal-bolus insulin therapy.

METHODS

We studied 41 patients who switched from basal-bolus insulin therapy of more than 3 years to basal insulin/liraglutide combination therapy. Glycaemic control was evaluated at 6 months after switching therapy and used to subdivide the patients into good-responders (HbA1c <7.0% or 1.0% decrease) and poor-responders (the rest of participants). To evaluate the glucose-dependent insulin/glucagon responses without/with liraglutide, a 75-g oral glucose tolerance test (OGTT) was performed twice, before (1st-OGTT) and 2-days after (2nd-OGTT) liraglutide administration.

RESULTS

Twenty-eight patients (68.3%) were identified as good-responders. No differences were found in baseline characteristics including insulin/glucagon responses during 1st-OGTT between the groups. 2nd-OGTT revealed that paradoxical hyperglucagonemia were significantly improved in both groups, but significant increases in insulin secretory response were observed only in good-responders. Logistic regression analyses revealed that the improvement of the insulin-response during 2nd-OGTT compared to that during 1st-OGTT is associated with the good-responder.

CONCLUSIONS

Enhancement of glucose-dependent insulin-response under liraglutide administration is a potential predictor of long-term glycaemic control after switching the therapies.

Comparison of liraglutide plus basal insulin and basal-bolus insulin therapy (BBIT) for glycemic control, body weight stability, and treatment satisfaction in patients treated using BBIT for type 2 diabetes without severe insulin deficiency: A randomized prospective pilot study

AIMS

We examined whether 0.9 mg/day liraglutide plus basal insulin (Lira-basal) is superior to basal-bolus insulin therapy (BBIT) for type 2 diabetes (T2DM) without severe insulin deficiency as determined by glucagon stimulation.

METHODS

Fifty patients receiving BBIT were enrolled in this 24-week, prospective, randomized, open-labeled study. After excluding subjects with fasting C-peptide immunoreactivity (CPR) < 1.0 ng/mL and CPR increase < 1.0 ng/mL at 6 min post glucagon injection, 25 were randomly allocated to receive Lira-basal (n = 12) or continued BBIT (n = 13). Primary endpoint was change in HbA1c. Secondary endpoints were changes in body weight (BW), 7-point self-monitored blood glucose (SMBG), and Diabetes Treatment Satisfaction Questionnaire status (DTSQs) scores.

RESULT

The Lira-basal group demonstrated reduced HbA1c, whereas the BBIT group showed no change. BW was reduced in the Lira-basal group but increased in the BBIT group. The Lira-basal group also exhibited significantly reduced pre-breakfast and pre-lunch SMBG. DTSQs scores improved in the Lira-basal group but not the BBIT group. Plasma lipids, liver function, and kidney function were not significantly changed in either group.

CONCLUSIONS

Lira-basal therapy is superior to BBIT for T2DM without severe insulin deficiency. This study was registered with UMIN Clinical Trials Registry (UMIN000028313).

Insulin tolerance test predicts non response vs. sustained efficacy of Liraglutide on glycemic control in type 2 diabetes patients: A prospective real-world setting study

AIMS

Less than half of type 2 diabetes patients treated with Glucagon-Like Peptide 1 (GLP-1) analogs displays good glycemic control, according to real life studies. Predictive markers of inefficacy/efficacy are therefore needed. The effectiveness of Liraglutide in terms of glycemic control and weight loss was then evaluated according to putative predictive parameters.

METHODS

80 type 2 diabetes patients treated with Liraglutide were included in this prospective study. An Insulin Tolerance test (ITT) was performed at baseline to calculate velocity of C-Peptide decrease (C-peptide T½). Several clinical and biological parameters including HbA_1c and weight were assessed at baseline and after 12, 24, 52 and 104 weeks of treatment.

RESULTS

HbA_1c decrease over the follow-up period was highly associated with C-peptide T½. A mean fall of 0.7% of HbA1c (7.7 mmol/mol) was predicted with 82% sensitivity and 80% specificity by C-peptide T½. In patients with rapid response during ITT (C-peptide T½ < 120 min), a HbA1c decrease of 1.5% (16.5 mmol/mol) was constantly found (p = .002) all over the follow-up. HbA1c remained unmodified for the rest of the patients (p = .34) compared to baseline. HbA_1c evolution was not predicted by diabetes duration. Weight loss was predicted only by low baseline C-peptide plasma level.

CONCLUSIONS

This study suggests ITT as an efficient test to discriminate non-response from long-term efficacy before initiating Liraglutide. ITT could therefore help avoiding "try and see" prescription pattern by using a more precise and patient-centered strategy in order to reduce inertia in adapting treatment and so reduce subsequent complications.

A Practical Review of C-Peptide Testing in Diabetes

C-peptide is a widely used measure of pancreatic beta cell function. It is produced in equimolar amounts to endogenous insulin but is excreted at a more constant rate over a longer time. Methods of estimation include urinary and unstimulated and stimulated serum sampling. Modern assays detect levels of c-peptide which can be used to guide diabetes diagnosis and management. We explore the evidence behind the various tests available. We recommend the glucagon stimulation c-peptide testing owing to its balance of sensitivity and practicality. C-peptide levels are associated with diabetes type and duration of disease. Specifically a c-peptide level of less than 0.2 nmol/l is associated with a diagnosis of type 1 diabetes mellitus (T1DM). C-peptide level may correlate with microvascular and macrovascular complications and future use of insulin therapy, as well as likely response to other individual therapies. We explore the potential uses of c-peptide measurement in clinical practice.

A higher body mass index attenuates the long-term HbA1c-lowering effects of liraglutide in type 2 diabetes patients treated using sulfonylurea-based therapy

Objective

To identify the attenuating factor of glycated hemoglobin (HbA1c)-lowering effects of liraglutide in type 2 diabetes (T2D) patients over the long term.

Methods

Forty-six T2D patients received liraglutide-glimepiride combination therapy. Clinical characteristics were compared between the following two subgroups: the relapse group (≥0.4 % increase in HbA1c in 48 weeks compared to 12 weeks) and non-relapse group (remaining patients). A glucagon-loading test was performed to evaluate baseline endogenous insulin secretion.

Results

In the relapse group, significantly reduced HbA1c, as observed at 12 weeks, tended to increase at 24 and 48 weeks. In the non-relapse group, reduced HbA1c was maintained for 48 weeks. Body weight was decreased at 12 weeks and then recovered at 48 weeks in both groups. Baseline BMI was significantly higher in the relapse group than in the non-relapse group. Age, HbA1c, duration of diabetes, fasting C-peptide, daily glimepiride dose and the duration of glimepiride treatment were comparable between both groups. Multiple logistic regression analysis revealed that baseline BMI was independently associated with the relapse group.

Conclusion

A higher BMI is the leading factor for attenuating long-term glycemic control by liraglutide in T2D patients undergoing sulfonylurea-based therapy.

Markers of β-Cell Failure Predict Poor Glycemic Response to GLP-1 Receptor Agonist Therapy in Type 2 Diabetes

OBJECTIVE

To assess whether clinical characteristics and simple biomarkers of β-cell failure are associated with individual variation in glycemic response to GLP-1 receptor agonist (GLP-1RA) therapy in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We prospectively studied 620 participants with type 2 diabetes and HbA1c ≥58 mmol/mol (7.5%) commencing GLP-1RA therapy as part of their usual diabetes care and assessed response to therapy over 6 months. We assessed the association between baseline clinical measurements associated with β-cell failure and glycemic response (primary outcome HbA1c change 0-6 months) with change in weight (0-6 months) as a secondary outcome using linear regression and ANOVA with adjustment for baseline HbA1c and cotreatment change.

RESULTS

Reduced glycemic response to GLP-1RAs was associated with longer duration of diabetes, insulin cotreatment, lower fasting C-peptide, lower postmeal urine C-peptide-to-creatinine ratio, and positive GAD or IA2 islet autoantibodies (P ≤ 0.01 for all). Participants with positive autoantibodies or severe insulin deficiency (fasting C-peptide ≤0.25 nmol/L) had markedly reduced glycemic response to GLP-1RA therapy (autoantibodies, mean HbA1c change -5.2 vs. -15.2 mmol/mol [-0.5 vs. -1.4%], P = 0.005; C-peptide <0.25 nmol/L, mean change -2.1 vs. -15.3 mmol/mol [-0.2 vs. -1.4%], P = 0.002). These markers were predominantly present in insulin-treated participants and were not associated with weight change.

CONCLUSIONS

Clinical markers of low β-cell function are associated with reduced glycemic response to GLP-1RA therapy. C-peptide and islet autoantibodies represent potential biomarkers for the stratification of GLP-1RA therapy in insulin-treated diabetes.

C-peptide immunoreactivity index is associated with improvement of HbA1c: 2-Year follow-up of sitagliptin use in patients with type 2 diabetes

AIMS

This retrospective study aimed to determine the hypoglycaemic effect of 2 years of sitagliptin administration in terms of changes in HbA1c and C-peptide immunoreactivity (CPR) index (plasma CPR [ng/mL]/glucose [mg/dL]×100).

METHODS

The inclusion criteria for DPP-4 inhibitor-naive outpatients with type 2 diabetes (n=285) were: continuation of sitagliptin for ≥700 days from initial administration and measurement of HbA1c, serum CPR, and plasma glucose levels at 0, 3, 6, 12, 18, and 24 months after sitagliptin initiation. Logistic regression analyses determined the factors contributing to the response to sitagliptin, based on responder (ΔHbA1c ≤-0.4% [≤-4 mmol/mol]) and non-responder (ΔHbA1c >-0.4% [>-4 mmol/mol]) groups.

RESULTS

The HbA1c level decreased and CPR index increased from baseline to 3, 6, 12, 18, and 24 months after the start of sitagliptin administration (HbA1c: 7.4 ± 0.8% [57 ± 9 mmol/mol], 7.3 ± 0.9% [57 ± 9 mmol/mol], 7.4 ± 0.9% [58 ± 10 mmol/mol], 7.1 ± 0.8% [55 ± 9 mmol/mol], and 7.3 ± 0.9% [57 ± 10 mmol/mol], respectively, all P<0.001 vs. baseline [8.0 ± 1.0%, 64 ± 11 mmol/mol] and CPR index: 1.69 ± 0.96, 1.71 ± 1.10, 1.62 ± 0.96, 1.64 ± 0.92, and 1.66 ± 0.96, respectively, all P<0.05 vs. baseline [1.47 ± 0.81]). Higher baseline HbA1c level, shorter diabetes duration, and greater CPR index increase after sitagliptin administration were associated with the response to sitagliptin.

CONCLUSIONS

Our results suggest that sitagliptin improves glycaemic control via an improved intrinsic insulin response.

Prediction of response to GLP-1 receptor agonist therapy in Japanese patients with type 2 diabetes

BACKGROUND

Glucagon-like peptide-1 (GLP-1) receptor agonists can maintain good glycemic control in some diabetic. Here we compared the clinical characteristics and parameters reflecting glucose metabolism at the time of the initiation of GLP-1 receptor agonist therapy between patients who responded well to therapy and those who did not.

METHODS

The records of 43 patients with type 2 diabetes who started receiving GLP-1 receptor agonist therapy during hospitalization were retrospectively reviewed. Glucagon stimulation tests were performed, and patients were started on liraglutide or exenatide therapy. Preprandial blood glucose levels were measured on days 2 and 3 of GLP-1 receptor agonist therapy. We used the Cox proportional hazard model to compare clinical parameters between responders (HbA1c level <8% at more than 3 months after the initiation of treatment) and non-responders (HbA1c level ≥8% at more than 3 months after the initiation of treatment or a switch to insulin therapy at any time).

RESULTS

Twenty-six of the 43 patients were classified as non-responders. At baseline, mean HbA1c levels were 9.9% among responders and 9.7% among non-responders. Compared with treatment with only diet or metformin, the hazard ratio [HR] for non-response was 5.3 (95% confidence interval [CI]: 1.16-24.6, P = 0.03) for insulin therapy and 5.0 (95% CI: 1.13-22.16, P = 0.03) for sulfonylurea therapy. Compared with the lowest tertile, the HRs for non-response in the highest tertile were 3.1 (95% CI: 1.04-8.97, P = 0.04) for the mean preprandial blood glucose level on days 2 and 3 and 3.4 (95% CI: 1.05-11.01, P = 0.04) for the body mass index. The response was not significantly associated with the duration of diabetes or the glucagon stimulation test results. A receiver operating curve analysis showed that the mean preprandial blood glucose level had the highest area under the curve value (=0.72) for the prediction of non-responders.

CONCLUSIONS

In patients with poorly controlled diabetes, the response to GLP-1 receptor agonist therapy was significantly associated with the treatment used before the initiation of therapy, the body mass index, and the mean preprandial blood glucose level during the 2 days after the initiation of therapy.