Effect of obesity on declining beta cell function after diagnosis of type 2 diabetes: a possible link suggested by cross-sectional analysis

Analysis glycemic variability in pregnant women with various type of hyperglycemia

OBJECTIVE

The study primarily aims to compare alterations in the daily patterns of glucose fluctuations across individuals with different kinds of diabetes in pregnancy and secondly investigate influencing factors that may react with glucose variations.

METHODS

We conducted a retrospective cohort study of 776 pregnant women in Shanghai General Hospital. We grouped participants who were exposed to gestational hyperglycemia into 5 sub-groups [Type 1 diabetes (T1DM), Type 2 diabetes (T2DM), Overt diabetes, Gestational diabetes (GDMA1 and GDMA2). Demographic variables and GV parameters were compared among 5 groups through ANOVA-test and Chi-square test. We estimated odd ratios (ORs) for the association between glucose coefficient of variation (CV) and possible influencing variables.

RESULTS

A final total of 776 pregnant women were analyzed. The proportion of pregnant women with pre-gestational diabetes was 31.83% (T1DM: 3.35%,T2DM: 28.48%), ODM 26.68%, and GDM was 41.49% (GDMA1:18.04%, GDMA2: 23.45%). T1DM group performed greatest glucose fluctuations with a CV value 35.02% whereas the number in all the other groups was no more than 22.82% (ODM group). In terms of achieving glycemic control target, only 57.70% participants hit the goal while all the other groups achieved the standard with at least a percentage of 94.20% (ODM group). Other parameters (GMI < 6.0%, GA < 15.70% and HbA1c < 6.0%) showed similar trends in each group. On multivariate logistic regression analysis of possible factors influencing CV, only body mass index (BMI) (OR: 0.754, 95% CI: 0.585-0.971; P = 0.029), HOMA- β (OR:0.969, 95%CI: 0.959-0.976; P = 0.037) and fasting plasma glucose (FPG) (OR: 1.832, 95% CI: 1.170-2.870; P = 0.008) reached statistical significance.

CONCLUSIONS

Pregnant women with type 1 or type 2 diabetes exhibit significantly greater glycemic variability compared to those with gestational diabetes, with the ODM group showing intermediate variability, and BMI, HOMA-β, and FPG identified as independent risk factors for unstable glucose variability.

Higher Genetic Risk for Type 2 Diabetes Is Associated With a Faster Decline of β-Cell Function in an East Asian Population

OBJECTIVE

While most genetic variants of type 2 diabetes (T2D) are suggested to be associated with β-cell dysfunction cross sectionally, their association with the longitudinal change of β-cell function remains largely unknown.

RESEARCH DESIGN AND METHODS

We analyzed data from 6,311 participants without T2D at baseline (mean [SD] age 51.6 [8.7] years) from a community-based prospective cohort in Korea. Participants underwent biennial 2-h 75-g oral glucose tolerance tests (OGTTs) during 14 years of follow-up, and the OGTT-derived disposition index (DI) was used as a marker for β-cell function. Genetic risk was quantified using the genome-wide polygenic risk score (PRS) and was stratified into low (1st quintile), intermediate (2nd-4th quintiles), and high (5th quintile) genetic risk. Lifestyle was assessed according to Life's Essential 8.

RESULTS

During a mean follow-up of 10.9 years, 374 (29.6%), 851 (22.5%), and 188 (14.9%) participants developed T2D in the high, intermediate, and low genetic risk groups, respectively. Compared with the low genetic risk group, participants in the high genetic risk group had a 25% lower DI at baseline. Furthermore, in longitudinal analysis, we observed a 1.83-fold faster decline in log2-transformed DI per year (-0.034 vs. -0.019, P = 2.1 × 10-3; per 1-SD increase in T2D PRS, P = 1.2 × 10-4). Healthy lifestyle attenuated the rate of decline in DI across all genetic risk groups.

CONCLUSIONS

Individuals with a higher genetic risk for T2D exhibited not only a lower OGTT-derived β-cell function at baseline but also a notably more rapid decline during follow-up. This information could be used to enable a focused precision prevention with lifestyle intervention.

Effects of dulaglutide and trelagliptin on beta-cell function in patients with type 2 diabetes: a randomized controlled study: DUET-beta study

Aims

This randomized, open-label, parallel-group, controlled trial compared the effects of dulaglutide and trelagliptin on beta-cell function in patients with type 2 diabetes.

Materials and methods

For 24 weeks, participants received dulaglutide (0.75 mg/week) or trelagliptin (100 mg/week), after which beta-cell function was evaluated using a glucagon stimulation test-based disposition index. The primary endpoint was the change in disposition index over the 24-week treatment period.

Results

Fifty patients with type 2 diabetes who received metformin with or without basal insulin were randomized to receive dulaglutide or trelagliptin. Forty-eight patients completed the 24-week dulaglutide (n = 23) or trelagliptin (n = 25) treatment. The dulaglutide group reduced HbA1c levels more than the trelagliptin group (dulaglutide: - 0.77% ± 0.07% vs. trelagliptin: - 0.57% ± 0.07%; p = 0.04). Change in disposition index during the 24 weeks did not differ between the groups (dulaglutide: - 0.07 ± 1.08 vs. trelagliptin: + 0.59 ± 1.04; p = 0.66), but the dulaglutide group increased HOMA2-%β levels more than the trelagliptin group (dulaglutide: + 26.2 ± 4.3% vs. trelagliptin: + 5.4 ± 4.1%; p = 0.001). The dulaglutide group showed greater body fat mass reduction than the trelagliptin group (dulaglutide: - 1.2 ± 0.3 kg vs. trelagliptin: - 0.3 ± 0.2 kg; p = 0.02) without skeletal muscle mass loss.

Conclusion

Dulaglutide and trelagliptin had similar effects on beta-cell function according to the glucagon stimulation test-based disposition index. However, dulaglutide promoted improved HOMA2-%β levels compared to trelagliptin and body fat mass was reduced without loss of skeletal muscle mass (UMIN-CTR 000024164).

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-024-00717-6.

Factors that determine glucose variability, defined by the coefficient of variation in continuous glucose monitoring values, in a Chinese population with type 2 diabetes

AIMS

To elucidate the clinical determinants of the coefficient of variation (CV) of glucose by analysing the pancreatic β-cell function of subjects with type 2 diabetes mellitus (T2DM).

METHODS

A total of 716 Chinese subjects with T2DM were included. Continuous glucose monitoring (CGM) was used to assess blood glucose, and the CV was calculated. C-peptide concentration at 0, 0.5, 1, 2 and 3 hours (Cp0h, Cp0.5h, Cp1h, Cp2h and Cp3h, respectively) was measured after a standard 100-g steamed bun meal test to assess pancreatic β-cell function. The determinants of glucose variability defined by the CV of CGM values were explored from two perspectives: the CV of qualitative variables and the CV of quantitative variables.

RESULTS

Our data revealed that C-peptide concentration (Cp0h, Cp0.5h, Cp1h, Cp2h, Cp3h), area under the curve for C-peptide concentration at 0.5 and 3 hours (AUC-Cp0.5h and AUC-Cp3h) decreased with increasing CV quartile (P < 0.05). The CV was negatively correlated with homeostatic model assessment of β-cell function index, C-peptide concentration at all timepoints, and AUC-Cp0.5h and AUC-Cp3h (P < 0.001). Quantile regression analysis showed that AUC-Cp0.5h had an overall negative effect on the CV in the 0.05 to 0.95 quartiles, and AUC-Cp3h tended to have a negative effect on the CV in the 0.2 to 0.65 quartiles. After adjusting for confounders, multinomial logistic regression showed that each 1-unit increase in AUC-Cp0.5h was associated with a 31.7% reduction in the risk of unstable glucose homeostasis (CV > 36%; P = 0.036; odds ratio 0.683; 95% confidence interval 0.478-0.976). We also identified the AUC-Cp0.5h (0.735 ng/mL) and AUC-Cp3h (13.355 ng/mL) cut-off values for predicting unstable glucose homeostasis (CV >36%) in T2DM subjects.

CONCLUSION

Our study suggests that impaired pancreatic β-cell function may be a clinical determining factor of CV of glucose in people with T2DM.

Factors affecting glycemic control in diabetes mellitus complicated by autoimmune pancreatitis

AIMS/INTRODUCTION

To investigate factors influencing glycemic control in diabetes mellitus complicated by autoimmune pancreatitis.

MATERIALS AND METHODS

This retrospective cohort study investigated 33 patients with diabetes mellitus complicated by autoimmune pancreatitis who had received steroid therapy at Toranomon Hospital between January 1, 2011, and December 31, 2020. The course of glycemic control at 12 months after starting steroids was classified into three groups: Improved, Unchanged, or Worsened. Factors affecting these groups were investigated. Furthermore, we created two scores: (1) time of diabetes mellitus onset and baseline body mass index; (2) time of diabetes mellitus onset and baseline C-peptide index. Diabetes mellitus occurring at the same time as autoimmune pancreatitis, body mass index ≥22 kg/m2 , and C-peptide index ≥1.1 were each worth 1 point. Scores were summed and totals of 0-2 were compared between groups.

RESULTS

Ten patients were in the Improved group, 10 were in the Unchanged group, and 13 were in the Worsened group. The baseline body mass index and baseline C-peptide index were lower in the Worsened group than in the Improved group (P < 0.05 each). In addition, the scores were lower in the Worsened group than in the other groups (P < 0.05).

CONCLUSIONS

Patients with a lower baseline body mass index and a decreased baseline C-peptide index may experience worse glycemic control on steroid therapy.

Beta-Cell Mass in Obesity and Type 2 Diabetes, and Its Relation to Pancreas Fat: A Mini-Review

Type 2 diabetes (T2DM) is characterized by insulin resistance and beta-cell dysfunction. Although insulin resistance is assumed to be a main pathophysiological feature of the development of T2DM, recent studies have revealed that a deficit of functional beta-cell mass is an essential factor for the pathophysiology of T2DM. Pancreatic fat contents increase with obesity and are suggested to cause beta-cell dysfunction. Since the beta-cell dysfunction induced by obesity or progressive decline with disease duration results in a worsening glycemic control, and treatment failure, preserving beta-cell mass is an important treatment strategy for T2DM. In this mini-review, we summarize the current knowledge on beta-cell mass, beta-cell function, and pancreas fat in obesity and T2DM, and we discuss treatment strategies for T2DM in relation to beta-cell preservation.

Clinical Significance of the Maximum Body Mass Index Before Onset of Type 2 Diabetes for Predicting Beta-Cell Function

Objective

This study aimed to clarify the clinical significance of the maximum body mass index (BMI) before the onset of type 2 diabetes (MBBO) for predicting pancreatic beta-cell function.

Methods

This was a cross-sectional observational study. Of 1304 consecutively admitted patients with type 2 diabetes, we enrolled 410 patients satisfying the criteria in this study. The correlations between the C-peptide index (CPI), which is one of the parameters that reflects beta-cell function, and various clinical parameters, including MBBO and duration of diabetes, were analyzed in multiple linear regression analyses.

Results

The analyses revealed that MBBO was correlated with CPI independently after adjustment for age, sex, HbA1c, and duration of diabetes. When we divided the subjects into three subgroups by MBBO (MBBO < 25 kg/m²; 25 kg/m² ≤ MBBO < 30 kg/m²; MBBO ≥ 30 kg/m²), CPI was negatively correlated with duration of diabetes in each subgroup, while the rates of CPI based on the duration of diabetes were not different among the three MBBO subgroups. In contrast, the declining rates of CPI were higher in the BMI ≥ 25 kg/m² group on admission than in the BMI < 25 kg/m² group on admission.

Conclusions

MBBO may be an independent factor correlating with beta-cell function and may predict insulin secretion capacity at diagnosis, but it does not seem to affect the rate of decline in insulin secretion capacity after diagnosis. It is important to preserve beta-cell function by decreasing a patient’s BMI during treatment after diagnosis regardless of MBBO.

Impact of patient and treatment characteristics on glycemic control and hypoglycemia in patients with type 2 diabetes initiated to insulin glargine or NPH: A post hoc, pooled, patient-level analysis of 6 randomized controlled trials

BACKGROUND

The goal of this post hoc analysis was to determine key patient and treatment-related factors impacting glycosylated hemoglobin (A1C) and hypoglycemia in patients with uncontrolled type 2 diabetes who were initiated to basal insulin (neutral protamine Hagedorn [NPH] or glargine).

METHODS

Using individual patient-level data pooled from 6 treat-to-target trials, 2600 patients with type 2 diabetes on oral antidiabetic agents initiated to insulin glargine or NPH and treated for 24 to 36 weeks were analyzed.

RESULTS

Both treatments led to significant reduction in A1C levels compared with baseline, with no differences between treatment groups (mean ± standard deviation; glargine: -1.32 ± 1.2% vs NPH: -1.26 ± 1.2%; P = 0.15), with greater reduction in the BMI ≥30 kg/m group than in the BMI <30 kg/m group. Glargine reduced A1C significantly more than NPH in the BMI <30 kg/m group (-1.30 ± 1.18% vs -1.14 ± 1.22, respectively; P = 0.008), but not in the BMI ≥ 30 kg/m group (-1.37 ± 1.19 vs -1.48 ± 1.22, respectively; P = 0.18). Similar proportions of patients achieved A1C target of <7% (glargine 30.6%, NPH 29.1%; P = 0.39). Incidence of severe and severe nocturnal hypoglycemia was significantly lower in glargine versus NPH-treated patients (2.0% vs 3.9%; P = 0.04, and 0.7% vs 2.1%; P = 0.002, respectively), and occurred primarily in the BMI <30 kg/m group.

CONCLUSIONS

Initiation of basal insulin is highly effective in lowering A1C after oral antidiabetic agent failure. Glargine decreases A1C more than NPH in nonobese patients, and reduces the risk for severe and severe nocturnal hypoglycemia versus NPH both in obese and nonobese patients, but more so in nonobese patients. Thus, it is the nonobese patients who may benefit more from initiation of basal insulin as glargine than NPH.

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.

Alogliptin benzoate for management of type 2 diabetes

Dipeptidyl peptidase-4 (DPP-4) inhibitors, a new class of oral hypoglycemic agents, augment glucose-dependent insulin secretion and suppress glucagon levels through enhancement of the action of endogenous incretin by inhibiting DPP-4, an incretin-degrading enzyme. DPP-4 inhibitors are generally well tolerated because of their low risk of hypoglycemia and other adverse events. Moreover, with their potential to improve beta cell function, a core defect of type 2 diabetes, DPP-4 inhibitors are becoming a major component of treatment of type 2 diabetes. Alogliptin benzoate is a newly developed, highly selective DPP-4 inhibitor which has been approved in many countries throughout the world. Once-daily administration of alogliptin as either monotherapy or combination therapy with other oral antidiabetic drugs or insulin has a potent glucose-lowering effect which is similar to that of other DPP-4 inhibitors, with a low risk of hypoglycemia and weight gain. The cardiovascular safety of this drug has been confirmed in a recent randomized controlled trial. This review summarizes the efficacy and safety of alogliptin, and discusses the role of DPP-4 inhibitors in the treatment of type 2 diabetes.

Reversal of Type 2 diabetes after bariatric surgery is determined by the degree of achieved weight loss in both short- and long-duration diabetes

AIM

To define the impact of duration of diabetes and extent of weight loss on the reversibility of Type 2 diabetes after bariatric surgery.

METHODS

Complete data were collated from 89 individuals with Type 2 diabetes mellitus undergoing any bariatric surgical procedure in a specialist bariatric centre. People with a preoperative HbA1c < 43 mmol/mol (6.1%) were excluded. Diabetes duration was defined as: short, < 4 years; medium, 4-8 years; and long, > 8 years.

RESULTS

An HbA1c of <43 mmol/mol (6.1%) was achieved by 62% of patients in the short-duration group and 26% of patients in the long-duration group. Normoglycaemia was rarely achieved in the long-duration group if weight loss was < 25 kg. In the whole cohort there was a clear relationship of greater weight loss with lower HbA1c levels (Rs = -0.53; P < 0.0001).

CONCLUSIONS

The study shows that the degree of achieved weight loss is the major determinant of return to normal blood glucose levels after bariatric surgery. Normoglycaemia can be achieved in long-duration Type 2 diabetes, but a greater degree of weight loss is required than for short-duration diabetes.

Glycemic variability and oxidative stress: a link between diabetes and cardiovascular disease?

Diabetes is associated with a two to three-fold increase in risk of cardiovascular disease. However, intensive glucose-lowering therapy aiming at reducing HbA1c to a near-normal level failed to suppress cardiovascular events in recent randomized controlled trials. HbA1c reflects average glucose level rather than glycemic variability. In in vivo and in vitro studies, glycemic variability has been shown to be associated with greater reactive oxygen species production and vascular damage, compared to chronic hyperglycemia. These findings suggest that management of glycemic variability may reduce cardiovascular disease in patients with diabetes; however, clinical studies have shown conflicting results. This review summarizes the current knowledge on glycemic variability and oxidative stress, and discusses the clinical implications.

Importance of Beta Cell Function for the Treatment of Type 2 Diabetes

Type 2 diabetes (T2DM) is characterized by insulin resistance and beta cell dysfunction. Recent evidence has emerged that beta cell dysfunction is a common pathogenetic feature of both type 1 and type 2 diabetes, and T2DM never develops without beta cell dysfunction. Therefore, treatment of T2DM should aim to restore beta cell function. Although the treatment of T2DM has greatly improved over the past few decades, remaining issues in the current treatment of T2DM include (1) hypoglycemia; (2) body weight gain; (3) peripheral hyperinsulinemia and (4) postprandial hyperglycemia, which are all associated with inappropriate insulin supplementation, again underpinning the important role of endogenous and physiological insulin secretion in the management of T2DM. This review summarizes the current knowledge on beta cell function in T2DM and discusses the treatment strategy for T2DM in relation to beta cell dysfunction.

Lower beta cell function relates to sustained higher glycated albumin to glycated hemoglobin ratio in Japanese patients with type 2 diabetes

The aim of this study was to clarify the relationship between baseline beta cell function and future glycated albumin (GA) to glycated hemoglobin ratio (GA/HbA1c) in patients with type 2 diabetes. In our retrospective cohort, 210 type 2 diabetic patients who had been admitted to our hospital and in whom HbA1c and GA had been measured at baseline and 2 years after admission were included in this study. Baseline beta cell function was assessed by postprandial C-peptide immunoreactivity index (PCPRI) during admission. With intensification of treatment during admission, HbA1c and GA were significantly decreased 1 year and 2 years after admission. While baseline HbA1c was not significantly correlated with HbA1c after 2 years, baseline GA/HbA1c was strongly correlated with GA/HbA1c after 2 years (r = 0.575, P <0.001). When the patients were divided into two groups according to median PCPRI, patients with low PCPRI showed higher GA/HbA1c both at baseline and after 2 years compared to those with high PCPRI. There was a significant negative correlation between PCPRI and GA/HbA1c after 2 years (r = -0.379, P <0.001). Multiple regression analysis revealed that PCPRI was an independent predictor of GA/HbA1c after 2 years. In conclusion, our findings suggest that lower beta cell function is associated with sustained higher GA/HbA1c ratio in patients with type 2 diabetes.

Choice of early treatment regimen and impact on β-cell preservation in type 2 diabetes

The progressive deterioration of glycaemic control in individuals with type 2 diabetes mellitus (T2DM) results from insulin resistance combined with the ongoing loss of β-cell function. Although it had been suggested that most β-cell dysfunction occurs after the development of T2DM, studies have documented a substantial early loss of β-cell function, particularly during the prediabetic state. In patients diagnosed with T2DM, β-cell function continues to decline despite treatment with commonly prescribed antihyperglycaemic medications, and ultimately exogenous insulin administration is required to maintain optimal glycaemic control. Thus, interventions to address the early decline in β-cell function could potentially alter the course of T2DM, preventing or delaying its onset and decreasing the incidence of complications. Original research and review articles on this topic were identified in a PubMed search from January 2000 through August 2012. Data from prospective studies and clinical trials suggest that lifestyle modifications and certain antihyperglycaemic medications, including thiazolidinediones (TZDs), glucagon-like peptide-1 (GLP-1) agonists, dipeptidyl peptidase-4 (DPP-4) inhibitors and insulin, may preserve or enhance β-cell function. The implication of current data is that early initiation of lifestyle modifications and antihyperglycaemic agents that preserve β-cell function might reverse or delay progression to T2DM in those with prediabetes. Moreover, improved β-cell function may confer more durable glucose control and perhaps reduce/delay the incidence of diabetic complications. Long-term studies are needed to validate this hypothesis.