The switch from sulfonylurea to preprandial short- acting insulin analog substitution has an immediate and comprehensive beta-cell protective effect in patients with type 2 diabetes mellitus

Effectiveness and Safety of Insulin Glulisine When Initiating Supplementary Prandial Insulin Treatment (SIT) in Insulin-Naïve Patients with Type 2 Diabetes: The Observational IGLU-SIT Study

INTRODUCTION

The IGLU-SIT study documented the effectiveness of initiating supplementary prandial insulin treatment (SIT) with insulin glulisine after failure of oral antidiabetic drugs alone in patients with type 2 diabetes (T2DM) in a real-world setting in Germany.

METHODS

The IGLU-SIT study was an open-label, prospective, multicentre, non-interventional study with an observation period of 12 ± 1 months. The primary objective was to determine the proportion of patients reaching their pre-defined glycosylated haemoglobin (HbA1c) goal at 3, 6, 9 and 12 months. Selected secondary objectives were absolute change in HbA1c, a 7-point blood glucose profile, and rate of hypoglycaemia. Data were evaluated overall and by age group (< 65, 65-74 and ≥ 75 years).

RESULTS

Overall, 215 patients with T2DM were observed in 64 centres. Baseline HbA1c was 8.3%, and mean HbA1c target was 6.8% (baseline 8.1% and target 6.9% in patients ≥ 75 years). Individual HbA1c target attainment in patients peaked at 38.9% (95% confidence interval [CI] 32.1-46.1%) after 12 months; this was 45.9% in patients aged ≥ 75 years. The mean HbA1c reduction was 1.12 ± 1.05% (p < 0.0001) with only minor differences by age group. A 7-point blood glucose profile revealed significant reductions (p < 0.0001) at all time-points. The rate of confirmed symptomatic hypoglycaemia was 2.2% (95% CI 0.7-5.1) during the 12-month follow-up; rates were increased in patients aged ≥ 75 years (7.0%; 95% CI 1.5-19.1) as were the rates of adverse events (17.8 vs. 6.1%).

CONCLUSION

Initiating SIT with insulin glulisine is an appropriate treatment option in patients whose T2DM is insufficiently controlled. Particular attention should be paid to elderly patients in whom higher attainment rates of treatment target were associated with adverse events.

TRIAL REGISTRATION

https://awbdb.bfarm.de ; Identifier: 6819; Date of registration: 23.06.2016.

Clinical and Laboratory Evaluation of a New Specific Point-of-Care Test for Intact Proinsulin

BACKGROUND

Intact proinsulin is a biomarker for pancreatic ß-cell dysfunction. In large prospective studies in nondiabetic subjects, elevated intact proinsulin predicted development of type 2 diabetes and/or macrovascular events up to 7 years in advance. This study was performed to evaluate a new semiquantitative lateral flow-based point-of-care rapid test (POCT) for elevated intact proinsulin (cutoff: 15 pmol/L). The test requires 10 µL of capillary whole blood, with visual readout after 5 minutes. It is best applied at 2 hours after a glucose challenge or a meal.

METHODS

POCT results were obtained by health care professionals from 60 patients and healthy subject (33 female, 27 male, 28 type 2 diabetes, age: 53.6 ± 12.3 years). An additional venous blood sample was obtained from all participants for measurement of intact proinsulin by means of a quantitative ELISA reference method (TecoMedical, Sissach, Switzerland).

RESULTS

Elevated intact proinsulin levels (>15 pmol/L) were determined by the reference method in 26 participants, of whom 22 were also positive with the POCT (sensitivity: 85%). All 34 subjects with low intact proinsulin levels were tested negative by the POCT (specificity: 100%).

CONCLUSIONS

The test successfully detected elevated postprandial intact proinsulin levels in 85% of the tested subjects and no false positive test result occurred. This POCT can therefore serve as a simple screening tool for identification of patients with prevalent ß-cell dysfunction, who are at high risk for development of type 2 diabetes and/or macrovascular events within the next 5-7 years.

Reduction of Sulfonylurea with the Initiation of Basal Insulin in Patients with Inadequately Controlled Type 2 Diabetes Mellitus Undergoing Long-Term Sulfonylurea-Based Treatment

BACKGROUND

There were a limited number of studies about β-cell function after insulin initiation in patients exposed to long durations of sulfonylurea treatment. In this study, we aimed to evaluate the recovery of β-cell function and the efficacy of concurrent sulfonylurea use after the start of long-acting insulin.

METHODS

In this randomized controlled study, patients with type 2 diabetes mellitus (T2DM), receiving sulfonylurea for at least 2 years with glycosylated hemoglobin (HbA1c) >7%, were randomly assigned to two groups: sulfonylurea maintenance (SM) and sulfonylurea reduction (SR). Following a 75-g oral glucose tolerance test (OGTT), we administered long-acting basal insulin to the two groups. After a 6-month follow-up, we repeated the OGTT.

RESULTS

Among 69 enrolled patients, 57 completed the study and were analyzed: 31 in the SM and 26 in the SR group. At baseline, there was no significant difference except for the longer duration of diabetes and lower triglycerides in the SR group. After 6 months, the HbA1c was similarly reduced in both groups, but there was little difference in the insulin dose. In addition, insulin secretion during OGTT was significantly increased by 20% to 30% in both groups. A significant weight gain was observed in the SM group only. The insulinogenic index was more significantly improved in the SR group.

CONCLUSION

Long-acting basal insulin replacement could improve the glycemic status and restore β-cell function in the T2DM patients undergoing sulfonylurea-based treatment, irrespective of the sulfonylurea dose reduction. The dose reduction of the concurrent sulfonylurea might be beneficial with regard to weight grain.

Elevated Intact Proinsulin Levels During an Oral Glucose Challenge Indicate Progressive ß-Cell Dysfunction and May Be Predictive for Development of Type 2 Diabetes

BACKGROUND

Elevated fasting intact proinsulin is a biomarker of late-stage ß-cell-dysfunction associated with clinically relevant insulin resistance. In this pilot investigation, we explored the potential value of measuring intact proinsulin as a functional predictor of ß-cell exhaustion during an oral glucose tolerance test (OGTT).

METHODS

The study was performed with 31 participants, 11 of whom were healthy subjects (7 female, age: 59 ± 20 years), 10 had impaired glucose tolerance (IGT, 6 female, 62 ± 10 years), and 10 had known type 2 diabetes (T2DM, 5 female, 53 ± 11 years, HbA1c: 7.0 ± 0.6%, disease duration: 8 ± 5 years). During OGTT, blood was drawn after 0 hours, 1 hour, and 2 hours for determination of glucose and intact proinsulin. Five years later, patients were again contacted to assess their diabetes status and the association to the previous OGTT results was analyzed.

RESULTS

The OGTT (0 hours/1 hour/2 hours) results were as follows: healthy subjects: glucose: 94 ± 8 mg/dL/140 ± 29 mg/dL/90 ± 24 mg/dL, intact proinsulin: 3 ± 2 pmol/L/10 ± 7 pmol/L/10 ± 5 pmol/L); IGT: glucose: 102 ± 9 mg/dL/158 ± 57 mg/dL/149 ± 34 mg/dL, intact proinsulin: 7 ± 4 pmol/L/23 ± 8 pmol/L/28 ± 6 pmol/L; T2DM: glucose: 121 ± 20 mg/dL/230 ± 51 mg/dL/213 ± 34 mg/dL; intact proinsulin: 7 ± 7 pmol/L/26 ± 9 pmol/L/27 ± 10 pmol/L). Five years later, all of the IGT and 2 of the healthy subjects had developed T2DM and one had devloped IGT. All of them had elevated 2-hour proinsulin values in the initial OGTT, while patients with normal intact proinsulin results did not develop diabetes.

CONCLUSIONS

Elevated 2-hour intact proinsulin levels during OGTT were predictive for later type 2 diabetes development. Further studies need to confirm our findings in larger populations.

Factors associated with beta-cell dysfunction in type 2 diabetes: the BETADECLINE study

Aims

Beta-cell dysfunction is an early event in the natural history of type 2 diabetes. However, its progression is variable and potentially influenced by several clinical factors. We report the baseline data of the BetaDecline study, an Italian prospective multicenter study on clinical predictors of beta-cell dysfunction in type 2 diabetes.

Materials and Methods

Clinical, lifestyle, and laboratory data, including circulating levels of inflammatory markers and non-esterified fatty acids, were collected in 507 type 2 diabetic outpatients on stable treatment with oral hypoglycemic drugs or diet for more than 1 year. Beta-cell dysfunction was evaluated by calculating the proinsulin/insulin ratio (P/I).

Results

At baseline, the subjects in the upper PI/I ratio quartile were more likely to be men and receiving secretagogue drugs; they also showed a borderline longer diabetes duration (P = 0.06) and higher serum levels of glycated hemoglobin (HbA_1c), fasting blood glucose, and triglycerides. An inverse trend across all PI/I quartiles was noted for BMI and serum levels of total cholesterol (T-C), LDL-C, HDL-C and C reactive protein (CRP), and with homeostatic model assessment (HOMA-B) and HOMA of insulin resistance (HOMA-IR) values (P<0.05 for all). At multivariate analysis, the risk of having a P/I ratio in the upper quartile was higher in the subjects on secretagogue drugs (odds ratio [OR] 4.2; 95% confidence interval [CI], 2.6–6.9) and in the males (OR 1.8; 95% CI, 1.1–2.9).

Conclusions

In the BetaDecline study population, baseline higher PI/I values, a marker of beta-cell dysfunction, were more frequent in men and in patients on secretagogues drugs. Follow-up of this cohort will allow the identification of clinical predictors of beta-cell failure in type 2 diabetic outpatients.

In type 2 diabetes patients, insulin glargine is associated with lower postprandial release of intact proinsulin compared with sulfonylurea treatment

OBJECTIVE

Our objective was to investigate how postprandial processing of intact proinsulin is influenced by different pharmacological strategies in type 2 diabetes mellitus (T2DM).

MATERIALS/METHODS

This exploratory, nonrandomized, cross-sectional study recruited T2DM patients and healthy subjects. Upon recruitment, eligible T2DM patients had been treated for ≥6 months with insulin glargine (GLA) plus metformin (MET), sulfonylureas (SU) plus MET, or dipeptidyl-peptidase-4 inhibitors (DPP-4-I) plus MET. Blood samples were drawn from study participants after an 8 h fast and at regular intervals for up to 5 h after consumption of a standardized meal. Study endpoints included postprandial intact proinsulin and insulin levels and the insulin/proinsulin ratio.

RESULTS

As expected, postprandial secretion of proinsulin was greater in all T2DM treatment groups than in healthy subjects (p < .01 for all comparisons). Postprandial release of proinsulin was significantly greater in T2DM patients treated with SU plus MET than in those treated with GLA plus MET (p = .003). Treatment with DPP-4-I plus MET was associated with reduced proinsulin secretion versus SU plus MET and an increased insulin/proinsulin ratio versus the other T2DM groups.

CONCLUSIONS

Treatment of T2DM with GLA plus MET or DPP-4-I plus MET was associated with a more physiological postprandial secretion pattern of the β cell compared with those treated with SU plus MET.

Insulin detemir attenuates food intake, body weight gain and fat mass gain in diet-induced obese Sprague-Dawley rats

OBJECTIVE

Initiation and intensification of insulin therapy commonly causes weight gain, a barrier to therapy. A contrasting body of evidence indicates that insulin functions as an adiposity negative feedback signal and reduces food intake, weight gain and adiposity via action in the central nervous system. Basal insulin analogs, detemir (Det) and glargine (Glar), have been associated with less hypoglycemia compared with neutral protamine hagedorn insulin, and Det with less weight gain, especially in patients with higher body mass index (BMI). We sought to determine whether insulin therapy per se causes body weight and fat mass gain when delivered via a clinically relevant subcutaneous (SC) route in the absence of hypoglycemia and glycosuria in non-diabetic lean and diet-induced obese rats.

MATERIALS AND METHODS

Rats were exposed to either a low-fat diet (LFD; 13.5% fat) or high-fat diet (HFD; 60% fat), and received Det (0.5 U kg(-1)), Glar (0.2 U kg(-1)) or vehicle (Veh) SC once daily for 4 weeks. These dosages of insulin were equipotent in rats with respect to blood-glucose concentration and did not induce hypoglycemia.

RESULTS

As predicted by current models of energy homeostasis, neither insulin Det nor Glar therapy affected food intake and weight gain in LFD rats. Det treatment significantly attenuated food intake, body weight gain and fat mass gain relative to the Glar and Veh in high-fat fed animals, mirroring observations in humans.

CONCLUSIONS

That neither insulin group gained excess weight, suggests weight gain with SC basal insulin therapy may not be inevitable. Our data further suggest that Det possesses a unique property to attenuate the development of obesity associated with a HFD.

Elevated intact proinsulin levels are indicative of Beta-cell dysfunction, insulin resistance, and cardiovascular risk: impact of the antidiabetic agent pioglitazone

BACKGROUND

Insulin resistance (IR) and deterioration of beta-cell secretion are main features in the development of type 2 diabetes, which is reflected in increasing serum intact proinsulin levels in later disease stage. Introduction of stable assays that are able to distinguish between intact proinsulin and its specific and unspecific cleavage products has resulted in the finding that serum intact proinsulin values can serve as a direct marker for beta-cell dysfunction, are a highly specific indicator of IR, and can predict cardiovascular risk.

METHOD

Determination of fasting intact proinsulin may be used to monitor and optimize antidiabetic therapeutic approaches. Our study group has been involved in a variety of clinical studies investigating drug effects on beta-cell secretory capacity, IR, and intact proinsulin levels. One focus was on the impact of insulin-sensitizing therapy with pioglitazone on the pancreatic beta-cell load.

RESULTS

Treatment with pioglitazone resulted in significant decreases in elevated proinsulin levels in type 2 diabetes patients. This effect was independent from glycemic control.

CONCLUSIONS

Measurement of fasting intact proinsulin values allows a staging of beta-cell dysfunction and evaluation of IR, thus providing an interesting diagnostic tool for both selection of appropriate therapy and monitoring of treatment success.

Decreasing postprandial C-peptide levels over time are not associated with long-term use of sulphonylurea: an observational study

AIM

The present study aimed to describe changes over 10 years in HbA(1c) and beta-cell function, as assessed by postprandial C-peptide (PP-CPT) and C-peptide/glucose (PP-CPT/glucose) ratio, and to investigate whether treatment with sulphonylurea (SU) exerts a deleterious effect on beta-cell function.

METHODS

During 1997-1998, HbA(1c), PP-CPT and PP glucose were measured in 462 patients. Ten years later, 171 of the 341 patients who were still alive were followed-up.

RESULTS

HbA(1c) decreased from 7.41 to 6.96% (P=0.002) as treatments were intensified. There was a decrease in both PP-CPT (P<0.001) and PP-CPT/glucose ratio (P=0.063). A multivariable-regression model was used to evaluate the effects on beta-cell function changes, using the following variables as effect modifiers: gender; age; BMI; diabetes duration; baseline PP-CPT/glucose ratio; HbA(1c); GAD-antibody class; and SU treatment (continuously, periodically, never). Baseline PP-CPT/glucose ratio was the most important variable (R(2)=45%; P<0.001) for explaining variations in beta-cell function. An increase in HbA(1c) was associated with a decrease in beta-cell function, and beta-cell function remained unchanged if glycaemic control was improved. Long-term treatment with SU had no effect on long-term changes in beta-cell function (R(2)=0.1%; P=0.894).

CONCLUSION

Both HbA(1c) and beta-cell function decreased over 10 years with SU treatment, but such treatment was not associated with a pronounced decline in beta-cell function. These results, however, need to be interpreted with caution, as this was an observational study. Nevertheless, the present study findings do not support the notion that SU, as used in clinical practice, is harmful to beta-cell function.

Adding insulin glargine vs. NPH insulin to metformin results in a more efficient postprandial beta-cell protection in individuals with type 2 diabetes

AIM

Postprandial release of intact proinsulin (IP) is an independent marker for beta-cell dysfunction in patients with type 2 diabetes. This open-label, parallel-group, two-arm, pilot study compared the beta-cell protective effect of adding insulin glargine (GLA) vs. NPH insulin to ongoing metformin.

MATERIAL AND METHODS

Overall, 28 insulin-naive type 2 diabetes subjects (mean +/- SD age, 61.5 +/- 6.7 years; diabetes duration, 9.8 +/- 6.5 years; HbA1c, 7.1 +/- 0.5%; BMI, 30.7 +/- 4.3 kg/m(2)) treated with metformin and sulfonylurea were randomized to add once-daily GLA or NPH at bedtime. At baseline and after 3 months, subjects received a standardized breakfast, lunch and dinner, with pre- and postprandial blood sampling to measure plasma IP, total insulin and blood glucose (BG).

RESULTS

Insulin dose after 3 months was comparable in both groups (GLA vs. NPH: 23.6 +/- 13.4 vs. 23.3 +/- 12.7; p = NS ). Both treatments significantly reduced fasting BG levels (GLA: 158 +/- 19 to 121 +/- 23 mg/dl; NPH: 156 +/- 34 to 119 +/- 29 mg/dl; both p < 0.01 vs. baseline). Fasting and postprandial BG levels did not differ between groups. IP levels decreased in both groups (p < 0.05 at all timepoints). Although IP release after breakfast did not differ between treatments, GLA induced a greater reduction in IP release after lunch (p = 0.08) and dinner (p = 0.04). Total plasma insulin levels did not differ between groups.

CONCLUSIONS

Adding basal insulin to metformin reduces postprandial beta-cell load. While GLA and NPH had comparable effects at breakfast, GLA reduces beta-cell stress more effectively at dinner, and with a trend at lunch, most probably because of its longer lasting pharmacodynamic profile.

Hyperinsulinism and diabetes: genetic dissection of beta cell metabolism-excitation coupling in mice

The role of metabolism-excitation coupling in insulin secretion has long been apparent, but in recent years, in parallel with studies of human hyperinsulinism and diabetes, genetic manipulation of proteins involved in glucose transport, metabolism, and excitability in mice has brought the central importance of this pathway into sharp relief. We focus on these animal studies and how they provide important insights into not only metabolic and electrical regulation of insulin secretion, but also downstream consequences of alterations in this pathway and the etiology and treatment of insulin-secretion diseases in humans.

Benefits of complementary therapy with insulin aspart versus human regular insulin in persons with type 2 diabetes mellitus

BACKGROUND

Absorption rates of the phosphate-buffered insulin analogs aspart, lispro, and glulisine prevail over that of regular human insulin. The aim of this prospective observational open-label controlled study was to compare the effects of aspart and human regular insulin resulting from their sequential long-lasting routine administration in small preprandial boluses to individuals with type 2 diabetes according to identical algorithms.

METHODS

Fifty-seven individuals with type 2 diabetes 64.0 +/- 1.29 (mean +/- SE) years old with diabetes' duration of 12.4 +/- 1.06 years, treated with human regular insulin for 5.2 +/- 0.44 years, and a serum C-peptide level of 1.1 +/- 0.10 nmol/L were enrolled into the study. Following two checkups performed in the course of the 364 +/- 17.9-day baseline period, human regular insulin was replaced with aspart in equivalent boluses, and two checkups in the course of 330 +/- 11.1-day sequential period were performed. The control group consisted of 17 individuals with type 2 diabetes 68.4 +/- 2.36 years old with diabetes' duration of 9.9 +/- 1.57 years, treated with insulin for 4.2 +/- 0.57 years, and a C-peptide level of 1.1 +/- 0.11 nmol/L. Data were analyzed using the statistical program SPSS version 10.1. (SPSS, Inc., Chicago, IL).

RESULTS

Following the switch from human regular insulin to aspart, hemoglobin A1c (HbA1c) decreased from 8.4 +/- 0.23% at baseline to 7.9 +/- 0.17% (P = 0.031), and thereafter to 7.5 +/- 0.20% (P < 0.001), while plasma glucose concentrations in 10-point profiles, daily insulin dose (37.1 +/- 1.39 IU/day), body mass index (BMI) (30.5 +/- 0.82 kg/m(2)), and frequency of hypo- and hyperglycemic episodes did not change (P > 0.05). Patients quote satisfaction was good. No adverse events were recorded. In the control group, no significant change of baseline HbA1c (8.4 +/- 0.54%), insulin dose (33.1 +/- 3.17 IU/day), and BMI (32.1 +/- 1.12 kg/m(2)) was found.

CONCLUSION

Aspart appears to be more effective than human regular insulin for complementary insulin treatment in individuals with type 2 diabetes.