Postprandial serum C-peptide value is the optimal index to identify patients with non-obese type 2 diabetes who require multiple daily insulin injection: Analysis of C-peptide values before and after short-term intensive insulin therapy

Predictive value of postprandial C-peptide for utilizing multiple daily injection therapy in type 2 diabetes

PURPOSE

Multiple daily injection (MDI) insulin therapy is an effective method of glycemic control and appropriate assignment to MDI therapy could minimize the risks of hypoglycemia and weight gain. The aim of the present study was to identify factors associated with indication for MDI therapy in type 2 diabetes (T2DM).

METHODS

We recruited 360 participants with T2DM that were admitted to the Endocrinology Department of Peking University People's Hospital between August 2017 and July 2018. They first underwent intensive insulin therapy, then were switched to an optimized, simpler insulin treatment that aimed to maintain fasting blood glucose between 4.4 and 7.2 mmol/L, without episodes of hypoglycemia. The baseline characteristics of groups administering either MDI or basal/premix insulin were compared and multivariable logistic regression analysis was used to determine the odds ratios (ORs) for factors associated with MDI therapy. Receiver operating characteristic (ROC) curves were then used to identify independent predictors of MDI insulin regimen efficacy.

RESULTS

The mean age of the participants was 57.6 ± 12.9 years, and diabetes duration was 14.2 ± 8.2 years. Two hundred and sixty-seven participants administered basal/premix insulin and 93 underwent MDI therapy, of whom 61.8% and 46.2% were male, respectively (p = 0.01). The duration of diabetes was significantly longer in the MDI group (13.1 ± 7.7 years vs. 17.3 ± 8.7 years; p < 0.01). Fasting plasma glucose (FPG) was higher in the MDI group than in the basal/premix group (8.3 [6.7, 11.3] mmol/L vs. 7.2 [5.7, 9.3] mmol/L; p < 0.01), while the postprandial C-peptide concentration (PCP) was significantly lower in the MDI group (2.6 [1.8, 3.5] ng/mL) compared to the basal/premix group (3.6 [2.5, 6.2] ng/mL, p < 0.01. Multivariable logistic regression analysis suggested that diabetes duration and FPG were positively associated with MDI therapy: OR (95% confidence interval [CI]) 1.06 (1.02, 1.10) and 1.12 (1.02, 1.24), respectively. In addition, PCP was negatively associated with MDI therapy (0.72 [0.60, 0.86]). ROC analysis suggested that a PCP of < 3.1 ng/mL predicted MDI therapy with 59.6% sensitivity and 72.1% specificity.

CONCLUSION

The results of our study suggest that longer diabetes duration, higher FPG, and lower PCP were associated with necessity for MDI insulin regimen. These findings should assist with the personalization of insulin treatment.

C-peptide index at 2 h post-meal is a useful predictor of endogenous insulin secretory capacity and withdrawal from insulin therapy in subjects with type 2 diabetes

AIMS

To evaluate the correlation between C-peptide index (CPI) at 2 h post-meal and endogenous insulin secretory capacity and to develop clinical models to predict the possibility of withdrawal from insulin therapy in patients with type 2 diabetes.

METHOD

This was a single-centre retrospective study of patients with type 2 diabetes admitted to our hospital. Patients were divided into a withdrawal group (n = 72) and a non-withdrawal group (n = 75) based on whether they were able to withdraw from insulin therapy at discharge, and the correlation between CPI at 2 h after meal and diabetes-related parameters was evaluated. In addition, we created two clinical models to predict the possibility of withdrawal from insulin therapy using machine learning.

RESULTS

The glycated haemoglobin values of the study participants were 87.8 ± 22.6 mmol/mo. The CPI at 2 h post-meal was 1.93 ± 1.28 in the non-withdrawal group and 2.97 ± 2.07 in the withdrawal group (p < 0.001). CPI at 2 h post-meal was an independent predictor of withdrawal from insulin therapy. In addition, CPI at 2 h post-meal was a better predictor than fasting CPI. Six factors associated with insulin therapy withdrawal (age, duration of diabetes, creatinine, alanine aminotransferase, insulin therapy until hospitalization, and CPI at 2 h post-meal) were used to generate two clinical models by machine learning. The accuracy of the generated clinical models ranged from 78.3% to 82.6%.

CONCLUSION

The CPI at 2 h post-meal is a clinically useful measure of endogenous insulin secretory capacity under non-fasting conditions.

Leveraging the future of diagnosis and management of diabetes: From old indexes to new technologies

BACKGROUND

Diabetes is a heterogeneous and multifactorial disease. However, glycemia and glycated hemoglobin have been the focus of diabetes diagnosis and management for the last decades. As diabetes management goes far beyond glucose control, it has become clear that assessment of other biochemical parameters gives a much wider view of the metabolic state of each individual, enabling a precision medicine approach.

METHODS

In this review, we summarize and discuss indexes that have been used in epidemiological studies and in the clinical practice.

RESULTS

Indexes of insulin secretion, sensitivity/resistance and metabolism have been developed and validated over the years to account also with insulin, C-peptide, triglycerides or even anthropometric measures. Nevertheless, each one has their own objective and consequently, advantages and disadvantages for specific cases. Thus, we discuss how new technologies, namely new sensors but also new softwares/applications, can improve the diagnosis and management of diabetes, both for healthcare professionals but also for caretakers and, importantly, to promote the empowerment of people living with diabetes.

CONCLUSIONS

In long-term, the solution for a better diabetes management would be a platform that allows to integrate all sorts of relevant information for the person with diabetes and for the healthcare practitioners, namely glucose, insulin and C-peptide or, in case of need, other parameters/indexes at home, sometimes more than once a day. This solution would allow a better and simpler disease management, more adequate therapeutics thereby improving patients' quality of life and reducing associated costs.

Search for clinical predictors of good glycemic control in patients starting or intensifying oral hypoglycemic pharmacological therapy: A multicenter prospective cohort study

AIMS

Our aim was to search for clinical predictors of good glycemic control in patients starting or intensifying oral hypoglycemic pharmacological therapy.

METHODS

A multicenter, prospective cohort of 499 diabetic subjects was enrolled in this study: patients with newly diagnosed diabetes (NDM group) or poor glycemic control with oral antidiabetic drugs (OADs) (PDM group). All subjects then started or intensified OADs therapy and followed up for 91 days. Glycemic control was determined according to HbA1c at day 91 with HbA1c <7% considered good.

RESULTS

The proportions of patients with good glycemic control after follow up for 91 days were 66.9% and 34.8% in NDM group and PDM group respectively. Logistic regression analysis showed that the change in GA at 28 days was the only predictor of good glycemic control in NDM patients (OR = 1.630, 95% CI 1.300-2.044, P < 0.001). In PDM patients, changes in GA at 28 days, CPI, baseline HbA1c, diabetic duration, and BMI were all independent predictors of good glycemic control (All P < 0.05).

CONCLUSIONS

GA decline is a good predictor of future success in newly diagnosed patients. In patients intensifying therapy, beside GA decline, other individualized clinical characteristics should also be considered.

Clinical Utility of the Meal Tolerance Test in the Care of Patients with Type 2 Diabetes Mellitus

Objective The measurement of C-peptide immunoreactivity (CPR) is essential for evaluating the pancreatic β-cell function and selecting appropriate therapeutic agents in patients with diabetes mellitus. The meal tolerance test (MTT) is simple to administer physiological insulin-stimulating test. Previous studies have reported that several CPR-related indices are useful markers for predicting insulin requirement in type 2 diabetes. In the present study, we investigated the serum CPR response during the MTT in hospitalized patients with type 2 diabetes mellitus in order to clarify the clinical utility of the MTT. Methods We performed the MTT using a test meal with timed measurements of the serum CPR level based on the oral glucose tolerance test over 180 minutes and tested the correlation of various CPR-related indices and clinical factors in patients with type 2 diabetes mellitus. Patients The subjects were patients with type 2 diabetes mellitus who had been admitted to our hospital for diabetes management and education. The final study population consisted of 68 patients. Results The fasting CPR level was correlated with the 24-hour urinary CPR excretion and body mass index. The serum CPR level at 120 minutes in the MTT was strongly correlated with the area under the curve of CPR during the MTT. The patients who needed insulin therapy at 6 months after hospitalization showed a significant lower incremental CPR value from 0 to 120 minutes in the MTT than those who did not need insulin therapy. Conclusion The plasma C-peptide levels at 0 and 120 minutes in the MTT provide essential information for the clinical management of patients with type 2 diabetes mellitus.

Differential role of insulin resistance and β-cell function in the development of prediabetes and diabetes in middle-aged and elderly Chinese population

BACKGROUND

The prevalence of diabetes and prediabetes were estimated to be 10.9% and 35.7% in the Chinese adult population, respectively, and the middle-aged and elderly Chinese are at even higher risk of diabetes and prediabetes than younger population. With the increasing trend of aging in China, the burden of diabetes and related complications will be aggravated.

OBJECTIVES

Through comparing the indices of insulin resistance and β-cell function between subjects with different glucose metabolic status, to analyze the differential role of insulin resistance and β-cell function in the development of prediabetes and type 2 diabetes (T2DM) in the middle-aged and elderly Chinese population.

METHODS

In this cross-sectional study, we enrolled 512 participants aged 50 and over. The indices of insulin resistance (homoeostasis model assessment of insulin resistance (HOMA-IR) and adipose tissue insulin resistance (Adipo-IR), and indices of β-cell function [HOMA-β), fasting C-peptide to glucose ratio (FCPRI) and postprandial C-peptide to glucose ratio (PCPRI)] were calculated. Association of insulin resistance and β-cell function with prediabetes or T2DM were evaluated by multivariate logistic regression analysis, in which potential confounding factors were adjusted.

RESULTS

Of the 509 participants with complete information, 263 (51.7%) had normal glucose tolerance (NGT), 161 (31.6%) were in prediabetic status and 85 (16.7%) were overt T2DM. With the advancing of unfavorable glucose metabolism, the insulin resistance (HOMA-IR and Adipo-IR) and β-cell function (FCPRI, PCPRI) deteriorated (P _trend < 0.05 for all indices). We found that increase in insulin resistance expressed by Adipo-IR and HOMA-IR is associated with increased risk of prediabetes, whereas decrease in β-cell function expressed by HOMA-β and PCPRI is associated with increased risk of T2DM. We also demonstrated that Adipo-IR was more closely associated with developing prediabetes than HOMA-IR, and PCPRI was most closely related with developing T2DM among the indices of β-cell function used in this study.

CONCLUSIONS

Insulin resistance is the main determinant of developing prediabetes, whereas β-cell function is the main determinant of developing T2DM.

Pathophysiology-based phenotyping in type 2 diabetes: A clinical classification tool

BACKGROUND

Type 2 diabetes may be a more heterogeneous disease than previously thought. Better understanding of pathophysiological subphenotypes could lead to more individualized diabetes treatment. We examined the characteristics of different phenotypes among 5813 Danish patients with new clinically diagnosed type 2 diabetes.

METHODS

We first identified all patients with rare subtypes of diabetes, latent autoimmune diabetes of adults (LADA), secondary diabetes, or glucocorticoid-associated diabetes. We then used the homeostatic assessment model to subphenotype all remaining patients into insulinopenic (high insulin sensitivity and low beta cell function), classical (low insulin sensitivity and low beta cell function), or hyperinsulinemic (low insulin sensitivity and high beta cell function) type 2 diabetes.

RESULTS

Among 5813 patients diagnosed with incident type 2 diabetes in the community clinical setting, 0.4% had rare subtypes of diabetes, 2.8% had LADA, 0.7% had secondary diabetes, 2.4% had glucocorticoid-associated diabetes, and 93.7% had WHO-defined type 2 diabetes. In the latter group, 9.7% had insulinopenic, 63.1% had classical, and 27.2% had hyperinsulinemic type 2 diabetes. Classical patients were obese (median waist 105 cm), and 20.5% had cardiovascular disease (CVD) at diagnosis, while insulinopenic patients were fairly lean (waist 92 cm) and 17.5% had CVD (P = 0.14 vs classical diabetes). Hyperinsulinemic patients were severely obese (waist 112 cm), and 25.5% had CVD (P < 0.0001 vs classical diabetes).

CONCLUSIONS

Patients clinically diagnosed with type 2 diabetes are a heterogeneous group. In the future, targeted treatment based on pathophysiological characteristics rather than the current "one size fits all" approach may improve patient prognosis.

The Postprandial-to-Fasting Serum C-Peptide Ratio is a Predictor of Response to Basal Insulin-Supported Oral Antidiabetic Drug(s) Therapy: A Retrospective Analysis

INTRODUCTION

Basal insulin is widely recommended for the treatment of type 2 diabetes mellitus (T2DM) patients who are unable to achieve glycemic control with oral antidiabetic drug(s) (OADs). However, some patients are still unable to control their blood glucose levels even when on basal insulin-supported OAD(s) therapy (BOT). The aim of this study was to investigate the factor(s) predicting patient response to BOT.

METHODS

A total of 212 patients with T2DM, ranging in age from 18 to 65 years, admitted to the university hospital of Sun Yat-sen University, Guangzhou, China, were enrolled in the study between January 2013 and July 2016. All patients had fasting blood glucose levels of ≥ 10.0 mmol/L despite receiving OAD(s) treatment. According to study design, these patients first received intensive insulin therapy for 2 weeks to attain and maintain their glycemic goals and then were switched to BOT. Responders were defined as subjects who maintained their glycemic targets with BOT for at least 3 months; all others were considered to be non-responders. The characteristics between responders and non-responders were compared.

RESULTS

Compared with non-responders, responders had a shorter duration of diabetes (5.1 ± 5.0 vs. and 10.1 ± 3.2 years; P  < 0.001) and a higher 2-h postprandial C-peptide-to-fasting C-peptide ratio (2 h-PCP/FCP: 1.95 ± 0.51 vs. 1.67 ± 0.32; P  < 0.01). Responders showed a lower proportion of previous treatment with insulin (69/100 vs 40/3; P  < 0.001) and sulfonlureas or glinides (116/50 vs 40/0; P <0.001) than non-responders. Multivariate logistic regression analysis showed that previous insulin treatment (odds ratio [OR] 17.677, 95% confidence interval [CI] 5.205-60.027; P  < 0.001) and the 2 h-PCP/FCP ratio (OR 0.241, 95% CI 0.058-0.679; P  = 0.007) had predictive value.

CONCLUSIONS

A higher 2 h-PCP/FCP ratio and a lack of previous insulin treatment increase the likelihood of BOT success.

Efficacy of lixisenatide in patients with type 2 diabetes: A post hoc analysis of patients with diverse β-cell function in the GetGoal-M and GetGoal-S trials

AIMS

To evaluate the impact of β-cell function on the efficacy of lixisenatide, a once-daily prandial glucagon-like peptide-1 receptor agonist, in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this post hoc analysis, patients from the Phase 3 GetGoal-M and GetGoal-S clinical trials randomized to lixisenatide 20μg once daily were stratified into quartiles by baseline β-cell function, as measured by the secretory units of islet in transplantation (SUIT) index.

RESULTS

Patients (N=437) were distributed evenly among SUIT index quartiles 1 to 4 (lowest to highest β-cell function). Clinical outcomes improved from baseline across all SUIT quartiles; mean changes at week 24 were: glycated hemoglobin (HbA1c; % [mmol/mol]), -0.99 (-10.8), -0.87 (-9.5), -0.86 (-9.4), -0.83 (-9.1); and postprandial plasma glucose (PPG; mmol/L), -7.9, -5.6, -5.5, -4.3 (overall effect P<0.0001). Furthermore, postprandial glucagon was reduced in all SUIT quartiles, while insulinogenic index improved only in patients with higher baseline SUIT (overall effect P=0.0286). No severe symptomatic hypoglycemic events were reported.

CONCLUSIONS

Lixisenatide treatment resulted in reductions in HbA1c and PPG levels across all SUIT quartiles. This suggests that non-insulin-related actions of lixisenatide contribute to improved glycemic control in T2D.

Clinical characteristics of patients aged 65 and older with newly developed type 1 diabetes: An analysis of elderly patients at our hospital

AIM

We herein investigated the clinical features of elderly patients with newly developed type 1 diabetes with respect to onset age, frequency of islet-associated antibodies, and other clinical markers.

METHODS

One hundred and ninety-nine patients aged 65 and older with new-onset diabetes, who were admitted to our hospital between July 2000 and June 2013, were classified into 4 types of diabetes. In addition, 85 patients with newly diagnosed type 1A diabetes among all age ranges admitted during the same period were divided into two groups: a younger group (less than 65 years, n=71) and an elderly group (65 years and older, n=14). Clinical features including mode of onset, frequency of islet-associated antibodies, and serum C-peptide (CPR) levels were compared between these groups. The elderly group was further divided into two age groups (less than 75 years, n=7; 75 years and older, n=7), and the frequency of autoantibodies was compared.

RESULTS

The patients (n=199) were classified into type 1 (n=16, 8%), type 2 (n=155, 78%), pancreatic (n=22, 11%), and other type (n=6, 3%) diabetes. Between the younger and elderly groups with type 1 diabetes, no significant difference in the CPR levels, frequency of autoantibodies, or other clinical features were observed. Positivity for IA-2 antibody was higher in the younger group (53.5%) than in the elderly group (35.7%), however, it was also considerably high (57.1%) in the oldest age group (75 years and older).

CONCLUSIONS

Type 1 diabetes may develop in the elderly, and an IA-2 antibody test may be useful for diagnosing type 1 diabetes in older patients.

Postprandial C-Peptide to Glucose Ratio as a Marker of β Cell Function: Implication for the Management of Type 2 Diabetes

C-peptide is secreted from pancreatic β cells at an equimolar ratio to insulin. Since, in contrast to insulin, C-peptide is not extracted by the liver and other organs, C-peptide reflects endogenous insulin secretion more accurately than insulin. C-peptide is therefore used as a marker of β cell function. C-peptide has been mainly used to assess the presence of an insulin-dependent state for the diagnosis of type 1 diabetes. However, recent studies have revealed that β cell dysfunction is also a core deficit of type 2 diabetes, and residual β cell function is a key factor in achieving optimal glycemic control in patients with type 2 diabetes. This review summarizes the role of C-peptide, especially the postprandial C-peptide to glucose ratio which likely better reflects maximum β cell secretory capacity compared with the fasting ratio in assessing β cell function, and discusses perspectives on its clinical utility for managing glycemic control in patients with type 2 diabetes.

Liraglutide in people treated for type 2 diabetes with multiple daily insulin injections: randomised clinical trial (MDI Liraglutide trial)

STUDY QUESTION

What are the effects of liraglutide, an incretin based treatment, on glycaemic control in people with type 2 diabetes treated with multiple daily insulin injections?

METHODS

The study was a randomised, double blind, placebo controlled trial with a parallel group design carried out at 13 hospital based outpatient clinics and one primary care unit in Sweden. Patients were considered eligible for inclusion if they had type 2 diabetes and inadequate glycaemic control (HbA1c concentrations ≥ 58 mmol/mol (7.5%) and ≤ 102 mmol/mol (11.5%)), a body mass index of 27.5-45 kg/m(2), and required multiple daily insulin injections. Overall, 124 participants were randomised 1:1 to subcutaneous liraglutide or placebo by minimisation allocation. The main outcome measure was change in HbA1c level from baseline to week 24.

STUDY ANSWER AND LIMITATIONS

Liraglutide was associated with a significant reduction of 16.9 mmol/mol (1.5%) in HbA1c versus 4.6 mmol/mol (0.4%) for placebo, difference -12.3 mmol/mol (95% confidence interval -15.8 to -8.8 mmol/mol; -1.13%, -1.45 to -0.81 mmol/mol). Body weight was significantly reduced in participants in the liraglutide compared with placebo group (3.8 v 0.0 kg, difference -3.8, -4.9 to -2.8 kg), and total daily insulin doses were significantly reduced, by 18.1 units and 2.3 units (difference -15.8, -23.1 to -8.5 units). Reductions in mean and standard deviation of glucose levels estimated by masked continuous glucose monitoring were significantly greater in the liraglutide group than placebo group (-1.9 and -0.5 mmol/L). Neither group experienced severe hypoglycaemic events nor were there any significant differences in symptomatic or asymptomatic non-severe hypoglycaemia (<4.0 or <3.0 mmol/L). The mean number of non-severe symptomatic hypoglycaemic events (<4.0 mmol/L) during follow-up was 1.29 in the liraglutide group and 1.24 in the placebo group (P=0.96). One of the study's limitations was its relatively short duration. Sustained effects of liraglutide have, however, been found over lengthier periods in connection with other treatment regimens. Cardiovascular safety and potential adverse events during longer exposure to liraglutide need to be evaluated. Nausea was experienced by 21 (32.8%) participants in the liraglutide group and 5 (7.8%) in the placebo group and 3 (5%) and 4 (7%) participants in these groups, respectively, had any serious adverse event.

WHAT THIS STUDY ADDS

Adding liraglutide to multiple daily insulin injections in people with type 2 diabetes improves glycaemic control without an increased risk of hypoglycaemia, reduces body weight, and enables patients to lower their insulin doses.

FUNDING, COMPETING INTERESTS, DATA SHARING

This study was an investigator initiated trial, supported in part by Novo Nordisk and InfuCare. Potential competing interests have been reported and are available on the bmj.com.

STUDY REGISTRATION

EudraCT 2012-001941-42.

A reliable serum C-peptide index for the selection of an insulin regimen to achieve good glycemic control in obese patients with type 2 diabetes: an analysis from a short-term study with intensive insulin therapy

Insulin regimens achieving favorable glycemic control in patients with type 2 diabetes are expected to closely relate to residual insulin secretory ability. We herein attempted to identify a reliable C-peptide immunoreactivity (CPR) index as an insulin secretory marker that would contribute to the selection of an appropriate insulin regimen for patients with type 2 diabetes. We near-normalized blood glucose in 246 obese patients with type 2 diabetes using our protocol (which included short-term intensive insulin therapy, IIT), and administered an oral hypoglycemic agent (OHA). Based on responsiveness to OHA, patients were classified into three therapy groups: non-insulin therapy (n = 78), basal-insulin supported oral therapy (BOT) (n = 109), and multiple daily insulin injection (MDI) therapy (n = 59). Glucagon-loading CPR increment (ΔCPR), fasting CPR (FCPR), CPR2h after breakfast (CPR2h), ratio of FCPR to fasting plasma glucose (CPI), CPI2h after breakfast (CPI2h), and secretory unit of islets in transplantation (SUIT) were assessed with receiver operating characteristic (ROC) and multiple logistic analyses to discriminate the MDI group from the other therapy groups. ROC analysis revealed that CPR2h had the greatest area under the curve and specificity. Multiple logistic analysis identified CPR2h and CPI2h as the most significant explanatory variables for identifying patients assigned to the MDI group. A postprandial serum CPR marker such as CPR2h or CPI2h was shown to be the best index for predicting an appropriate insulin regimen to achieve good glycemic control in obese patients with type 2 diabetes.