A direct comparison of long- and short-acting GLP-1 receptor agonists (taspoglutide once weekly and exenatide twice daily) on postprandial metabolism after 24 weeks of treatment

AIMS

T-emerge 2 was a randomized, open-label, 24-week trial comparing subcutaneous taspoglutide 10 mg weekly (Taspo10), taspoglutide 20 mg weekly (Taspo20; titrated after 4 weeks of Taspo10), with exenatide 10 mcg BID (Exe; after 4 weeks of Exe 5 mcg) in patients inadequately controlled on metformin, a thiazolidinedione, or both. T-emerge 2 showed that once-weekly Taspo provided better glycaemic control than Exe. This report focuses on a subset of T-emerge 2 participants undergoing a standardized liquid meal comparing Taspo to Exe, which has been previously shown to lower postprandial glucose.

METHODS

Meal tolerance tests (MTT) were performed at baseline and at week 24 in a subset of Taspo10, Taspo20 and Exe patients (n = 42, 39 and 67, respectively). Blood samples for glucose, insulin, glucagon and C-peptide were obtained before and after (30, 60, 90, 120 and 180 min) ingestion of a standardized liquid meal.

RESULTS

The 2-h postprandial, mean 0-3 h and iAUC0-3 h glucose during the MTT was reduced to a similar extent in all groups and the time profile of the postprandial glucose showed a similar pattern. Taspo10 and Taspo20, but not Exe, significantly increased insulin from baseline (both mean and iAUC0-3 h). Although changes from baseline in C-peptide were not significant within any treatment group, the mean change from baseline (both mean 0-3 h and iAUC0-3 h) was significantly increased in Taspo10 vs. Exe. Mean glucagon showed significant decreases in all groups.

CONCLUSION

Taspoglutide and Exe improved postprandial glucose tolerance to a similar extent but possibly with different intimate mechanisms.

Efficacy and safety of lixisenatide once daily vs. placebo in people with Type 2 diabetes insufficiently controlled on metformin (GetGoal-F1)

AIMS

To assess the efficacy and safety of one- and two-step dose-increase regimens of lixisenatide once daily in participants with Type 2 diabetes mellitus insufficiently controlled with metformin.

METHODS

This was a randomized, double-blind, placebo-controlled, parallel-group, multi-centre study enrolling participants with Type 2 diabetes (n = 484) treated with metformin. Participants were randomized to receive either lixisenatide in a one-step dose increase or a two-step dose increase vs. placebo for 24 weeks, followed by a ≥ 52-week variable double blind period. Primary outcome was HbA1c reduction at week 24.

RESULTS

Lixisenatide one-/two-step once daily significantly improved HbA1c at week 24 compared with placebo (P < 0.0001) and allowed more participants to achieve HbA1c < 53 mmol/mol (< 7.0%) (P ≤ 0.0005). Improvements were observed in fasting plasma glucose (-0.5/-0.6 vs. +0.1 mmol/l; P < 0.001) and body weight (-2.6/-2.7 vs. -1.6 kg; P < 0.005). At week 24, adverse events were reported by 67.7/70.8/65.6% of participants treated with lixisenatide one-/two-step/placebo, respectively--nausea and vomiting being reported most frequently. Symptomatic hypoglycaemia occurred in 1.9/2.5% of participants on one-/two-step lixisenatide and 0.6% with placebo, with no severe episodes. Lixisenatide continued to be efficacious and well tolerated during the variable double-blind extension period of at least 52 weeks.

CONCLUSIONS

Lixisenatide one- or two-step dose-increase regimens significantly improved glycaemic control and decreased body weight over 24 weeks and during a long-term extension period without increasing hypoglycaemia. The study confirmed that tolerability in the one-step group was at least similar to the two-step dose increase, with nausea/vomiting and hypoglycaemia frequency being lower in the one-step regimen.

Differential effects of GLP-1 receptor agonists on components of dysglycaemia in individuals with type 2 diabetes mellitus

Metabolic consequences of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are the result of enhanced glucose-stimulated insulin secretion, inhibition of glucagon release, delayed gastric emptying and increased satiety. These attributes make GLP-1 agonists a treatment option in type 2 diabetes mellitus (T2DM). To optimise treatment choice, a detailed understanding of the effects of GLP-1 RAs on glucose homeostasis in individuals with T2DM is necessary. Although the various GLP-1 RAs share the same basic mechanisms of action, differences in pharmacokinetic/pharmacodynamic characteristics translate into differential effects on parameters of glycaemia. Head-to-head comparisons between long-acting non-prandial (liraglutide once daily and exenatide once weekly) and shorter-acting prandial (exenatide twice daily and lixisenatide once daily prandial) GLP-1 RAs confirm their differential effects on fasting plasma glucose (FPG) and post-prandial glucose (PPG). Liraglutide once daily and exenatide once weekly demonstrate greater reductions in FPG but lesser impacts on PPG excursions plasma than exenatide twice daily. Prandial GLP-1 RAs have a profound effect on post-prandial glycaemia, mediated by delaying gastric emptying, which is not subject to the tachyphylaxis occurring due to the sustained elevated plasma GLP-1 concentrations after treatment with long-acting GLP-1 RAs. Lixisenatide once-daily prandial, in contrast to liraglutide, strongly suppresses post-prandial glucagon secretion, further contributing to the more pronounced PPG-lowering effect found with lixisenatide. Evidence suggests that the GLP-1 RAs that predominantly target the prandial glucose excursions, such as exenatide twice daily and lixisenatide once-daily prandial, are therefore best used as combination therapy with basal insulin and will form an important new treatment option for individuals with T2DM.

Abstract P4-13-08: Diabetes, Related Factors and Breast Cancer Risk

Diabetes and breast cancer are both extremely common conditions in women and may share common risk factors. It is natural to investigate any potential common risk factors and to seek biological clarification and improve prospects for prevention.

Therefore, in order to help clarify the potential association between diabetes, related factors and breast cancer risk, a comprehensive literature review and formal meta-analysis was carried out, planned, conducted and reported following PRISMA guidelines regarding meta-analysis of observational studies. Variables studies in relation to breast cancer risk were adiposity, physical activity, glycaemic load, glycaemic index, diabetes, IGF-1, fasting glucose, fasting insulin and C-peptide, adiponectin and metformin and glargine use among patients with diabetes. For all variables except diabetes and breast cancer, only prospective studies were included in meta-analyses. Summary Relative Risks (SRR) and corresponding 95% Confidence Intervals (CI) were calculated from random effect models.

For breast cancer at all ages, the calculated risks were as follows: diabetes (SRR = 1.27 95% CI (1.16, 1.39); physical activity (SRR = 0.88, 95% CI (0.85, 0.92)); glycaemic load (SRR = 1.06, 95% CI (1.00, 1.12)); glycaemic index (SRR = 1.04, 95% CI (0.99, 1.10)); fasting glucose (SRR = 1.12, 95% CI (1.01, 1.24)); serum insulin (SRR = 1.18, 95% CI (0.75, 1.85)); c-peptide (SRR = 1.29, 95% CI (0.91, 1.82)); adiponectin (SRR = 1.16, 95% CI (0.93, 1.46)); metformin (SRR = 1.00, 95% CI (0.69, 1.46)); and glargine (SRR = 1.11, 95% CI (1.00, 1.24)). An increase of 5 units in Body Mass Index (a weight increase if 14.5 kg in a person 1.70 metres tall) was associated in post-menopausal breast cancer (SRR = 1.12, 95% CI (1.08, 1.16)) but not at pre-menopausal ages (SRR = 0.83, 95% CI (0.72, 0.95)). Serum insulin was associated with breast cancer at post-menopausal ages but not at pre-menopausal ages whereas with c-peptide there was a significant association at pre-menopausal ages but not post-menopausal. For IGF-1, Hodge's Standardised Mean Difference (HSMD) was calculated in cohort studies and there was no significant association with breast cancer at all ages (HSMD = 0.003, 95% CI (−0.059, 0.065)), at post-menopausal ages (HSMD = −0.014, 95% CI (−0.106, 0.077)) or at pre-menopausal ages (HSMD = 0.039, 95% CI (−0.038, 0.117)).

The risk of breast cancer is increased among post-menopausal women who have diabetes. Among those factors related to diabetes, key risk factors for breast cancer appear to be adiposity and lack of physical activity which are both related to the risk of developing diabetes. Action on these lifestyle factors should form the basis of a common prevention strategy. There is a need to re-evaluate potential biological mechanisms to explain the increased risk in post-menopausal women with diabetes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-13-08.

Abstract P4-13-07: Meta-analysis of epidemiological studies of Insulin Glargine and Breast Cancer Risk

After having lain dormant for a while, the association between diabetes, its risk factors and treatments, and cancer risk and death is now high on the clinical and research agenda. The microscope is currently focused on the relationships between Pioglitazone and Bladder Cancer, Exenatide and Pancreas Cancer, Liraglutide and pancreas cancer and insulin use and lung cancer. The potential association between use of insulin glargine and breast cancer risk has been the subject of recent major studies.

All data regarding cancer risk and use of insulin glargine has been assembled and meta-analyses performed using state-of-the-art statistical methodology. A random effects model was employed with tests for heterogeneity (I2) and publication bias. These meta-analyses are based on reports from 21 epidemiological studies involving over one million patients and 3 million person-years of observation.

Based on independent estimates from these studies, the Summary Relative Risk (SRR) for all forms of cancer was (SRR = 0.91, 95% CI (0.84, 0.99)), and for breast cancer SRR = 1.11 (95% CI (1.00, 1.48)). For new users of glargine, the SRR for breast cancer was SRR = 1.22 (95% CI (1.00, 1.48)). For colorectal cancer the SRR = 0.83 (95% CI (0.74, 0.94)) and for prostate cancer SRR = 1.14 (95% CI (0.93, 1.39)). Overall, the risk of developing cancer among users of insulin glargine is reduced compared to the risk of users of other insulins. Similarly, the risk of colorectal cancer is reduced among users of glargine.

While the lower bound of the 95% confidence interval is 1.00, the risk of breast cancer does not increase with increasing duration of use of glargine. In some studies the trend in risk with increasing duration of use goes in opposite directions. The development of a detectable breast cancer from the initial carcinogenic event depends on the tumour doubling time. The time for a de novo breast cancer to become detectable ranges from 12.3 years for a doubling time of 150 days; 16.4 years for a doubling time of 200 days; and 20.5 years for a doubling time of 250 days. Most published studies have a maximum of 3–4 years of glargine use.

The databases employed in these analyses were not designed for such epidemiological investigation. A major limitation is the absence of knowledge as to why a potential treatment was prescribed for an individual and why a change in therapy was indicated. Further potential limitations to this meta-analysis include that the comparison group was not the same in all studies but this could also be seen as a strength. The meta-analysis of the randomized trials had several insulin comparators and the retinopathy study had NPH as the comparator. This is not likely to invalidate the findings of this analysis nor would the fact that different adjustments were made in the individual studies.

The current evidence gives no support to the hypothesis that insulin glargine is associated with an increased risk of cancer as compared to other insulins and should give reassurance to physicians and their patients. In respect to breast cancer, there is no indication of a causal association between use of insulin glargine and increased risk of breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-13-07.

Early insulin treatment in type 2 diabetes: ORIGINal sin or valuable choice as ORIGINal treatment? An open debate on the ORIGIN study results

Diabetes is ultimately the result of relative or absolute insulin deficiency; insulin should therefore represent its "natural" treatment, from the very moment of diagnosis, or even earlier, such as any other hormonal deficiency. Insulin treatment, however, has been accused of the worst crimes, including that of fostering obesity, insulin resistance, atherosclerosis, and, lately, cancer. Are these charges real? Does insulin treatment truly carry in its nature the original sin of causing such terrible consequences? This unresolvable, past and present dispute has had important effects on our clinical behavior in insulin initiation in the management of Type 2 diabetes, and we all hoped that a specifically designed trial could help us on this controversy. The ORIGIN (Outcome Reduction with an Initial Glargine Intervention) trial aimed to establish whether an initial insulin treatment with glargine, as compared with standard treatments, was able to delay the onset of cardiovascular disease. Although the trial appeared negative, several viewpoints came out, alimenting the debate on how to analyze results from the ORIGIN trial and, ultimately, on the role of early insulin treatment in type 2 diabetes. In these pages we invited two experienced scientists to freely argument their interpretation of the trial, aiming to help our understanding of the consequences of the ORIGIN trial on insulin therapy.

Comparative pharmacodynamic and pharmacokinetic characteristics of subcutaneous insulin glulisine and insulin aspart prior to a standard meal in obese subjects with type 2 diabetes

AIMS

A multinational, randomized, double-blind, two-way crossover trial to compare the pharmacokinetic and pharmacodynamic properties of bolus, subcutaneously administered insulin glulisine (glulisine) and insulin aspart (aspart) in insulin-naÏve, obese subjects with type 2 diabetes.

METHODS

Thirty subjects [9/21 females/males; mean ± SD age: 60.7 ± 7.7 years; body mass index (BMI): 33.5 ± 3.3 kg/m(2) ; duration of diabetes: 6.8 ± 4.6 years; HbA1c: 7.1 ± 0.8%] were included in the analysis. They fasted overnight and then received a 0.2 U/kg subcutaneous dose of glulisine or aspart 2 min before starting a standardized test meal, 7 days apart, according to a randomization schedule. Blood samples were taken every 15 min, starting 20 min before the meal and ending 6 h postprandially.

RESULTS

The area under the absolute glucose concentration-time curve between 0 and 1 h after insulin injection and maximal glucose concentration was significantly lower with glulisine than with aspart (p = 0.0455 and 0.0337, respectively). However, for the total study period, plasma glucose concentration was similar for glulisine and aspart. Peak insulin concentration was significantly higher for glulisine than for insulin aspart (p < 0.0001). Hypoglycaemic events (≤ 70 mg/dl with or without symptoms) occurred in 13 and 16 subjects treated with glulisine and aspart, respectively, but there were no cases of severe hypoglycaemia requiring intervention.

CONCLUSIONS

Glulisine was associated with lower glucose levels during the first hour after a standard meal; the remaining glucose profiles were otherwise equivalent, with higher insulin levels observed throughout the study period.

Lower fasting blood glucose, glucose variability and nocturnal hypoglycaemia with glargine vs NPH basal insulin in subjects with Type 1 diabetes

BACKGROUND AND AIMS

To compare switching from NPH insulin (NPH) to insulin glargine (glargine) with continuing NPH for changes in fasting blood glucose (FBG) in patients with Type 1 diabetes on basal-bolus therapy with insulin lispro as bolus insulin. Secondary objectives included self-monitoring blood glucose, mean daily blood glucose (MDBG) and mean amplitude glucose excursion (MAGE) values alongside changes in HbA(1c) and safety profiles.

METHODS AND RESULTS

This was a 30-week, parallel, open-label, multicentre study. Seven-point profiles were used to calculate MDBG and MAGE. Hypoglycaemia and adverse events were recorded by participants. FBG improved significantly with both glargine (baseline-endpoint change: -28.0 mg/dL; 95% CI: -37.3, -18.7 mg/dL; p<0.001) and NPH (-9.8 mg/dL; 95% CI: -19.1, -0.5 mg/dL; p=0.0374). The improvement was significantly greater with glargine than NPH (mean difference: -18.2 mg/dL; 95% CI: -31.3, -5.2 mg/dL; p=0.0064). MDBG (-10.1 mg/dL; 95% CI: -18.1, -2.1 mg/dL; p=0.0126) and MAGE (-20.0 mg/dL; 95% CI: -34.5, -5.9 mg/dL; p=0.0056) decreased significantly with glargine, but not NPH although endpoint values were no different with the two insulins. Baseline to endpoint change in HbA(1c) was similar (-0.56 vs -0.56%) with no differences at endpoint. Overall hypoglycaemia was no different, but glargine reduced nocturnal hypoglycaemia ("serious episodes" with BG < 42 mg/dl, p=0.006) whereas NPH did not (p=0.123), although endpoint values were no different.

CONCLUSION

Switching from NPH to glargine is well tolerated and results into lower FBG, and lower glucose variability while reducing nocturnal hypoglycaemia. These data provide a rationale for more aggressive titration to target with glargine in Type 1 diabetes.

Comparison of vildagliptin and pioglitazone in patients with type 2 diabetes inadequately controlled with metformin

AIM

To compare the tolerability and efficacy of vildagliptin to pioglitazone as add-on therapy in patients with type 2 diabetes inadequately controlled with metformin monotherapy over 1-year duration.

METHODS

This 52-week, multicentre, randomized, active-controlled study compared vildagliptin (50 mg b.i.d., n = 295) and pioglitazone (30 mg daily, n = 281) in patients with inadequate glycaemic control [haemoglobin A1c (HbA(1c)) 7.5-11%] receiving a stable dose of metformin (>or=1500 mg). The primary objective was to demonstrate non-inferiority of vildagliptin at 24 weeks in the change in HbA(1c) from baseline. The objective of the additional 28 weeks of the study was to assess long-term safety, while also assessing mean change from baseline to study end in HbA(1c), fasting plasma glucose and body weight.

RESULTS

When added to a stable dose of metformin (mean baseline dose approximately 2 g/day), the non-inferiority of HbA(1c) lowering of vildagliptin to pioglitazone over 24 weeks was established at the non-inferiority margin of 0.3% (between-group difference = 0.1%). During the remaining 28 weeks, comparable HbA(1c) decreases were recorded in both groups. Overall adverse event (AE) rates were similar in both groups, as was the occurrence of peripheral oedema. Hypoglycaemia occurred rarely in both groups. Serious AEs occurred more frequently with pioglitazone group. While mean body weight increased significantly in the pioglitazone group (+2.6 kg) from baseline, there was no significant weight gain with vildagliptin (+0.2 kg).

CONCLUSIONS

When added to metformin, vildagliptin demonstrates favourable safety and tolerability over 1 year. Vildagliptin provided additional HbA(1c) lowering to that achieved with metformin alone and comparable to that achieved with pioglitazone, with only pioglitazone causing weight gain.

Beyond the era of NPH insulin--long-acting insulin analogs: chemistry, comparative pharmacology, and clinical application

The new rDNA and DNA-derived "basal" insulin analogs, glargine and detemir, represent significant advancement in the treatment of diabetes compared with conventional NPH insulin. This review describes blood glucose homeostasis by insulin in people without diabetes and outlines the physiological application of exogenous insulin in patients with type 1 and type 2 diabetes. The requirements for optimal basal insulin treatment are discussed and the methods used in the evaluation of basal insulins are presented. An essential criterion in the development of an "ideal" basal insulin preparation is that the molecular modifications made to the human insulin molecule do not compromise safety. It is also necessary to obtain a clear understanding of the pharmacokinetic and pharmacodynamic characteristics of the two currently available basal insulin analogs. When comparing glargine and detemir, the different molar concentration ratios of the two insulin formulations should be considered along with the nonspecificity of assay systems used to determine insulin concentrations. However, euglycemic clamp studies in crossover study design provide a good basis for comparing the pharmacodynamic responses. When the latter is analyzed by results of intervention clinical trials, it is concluded that both glargine and detemir are superior to NPH in type 1 and type 2 diabetes. However, there is sufficient evidence to demonstrate that these two long-acting insulin analogs are different in both their pharmacokinetic and pharmacodynamic profiles. These differences should be taken into consideration when the individual analogs are introduced to provide basal insulin supplementation to optimize blood glucose control in patients with type 1 and type 2 diabetes as well. PubMed-Medline was searched for articles relating to pharmacokinetics and pharmacodynamics of glargine and detemir. Articles retrieved were reviewed and selected for inclusion if (1) the euglycemic clamp method was used with a duration >or=24 h, (2) a single subcutaneous dose of glargine/detemir was used, and (3) area under the curve for insulin concentrations or glucose infusion rates were calculated.

Efficacy and tolerability of vildagliptin vs. pioglitazone when added to metformin: a 24-week, randomized, double-blind study

AIM

The aim of this study was to compare the efficacy and tolerability of vildagliptin vs. pioglitazone as add-on therapy in patients with type 2 diabetes inadequately controlled with metformin monotherapy.

METHODS

This 24-week, multicentre, double-blind, randomized, active-controlled study compared vildagliptin (100 mg daily, given as equally divided doses, n = 295) and pioglitazone (30 mg daily, given as a single q.d. dose, n = 281) in patients with inadequate glycaemic control (A1C 7.5-11%) while receiving a stable metformin dose (> or =1500 mg daily). The adjusted mean changes from baseline to study endpoint (AMDelta) in A1C, fasting plasma glucose (FPG), fasting lipids and body weight were compared by analysis of covariance.

RESULTS

When added to a stable dose of metformin (mean dose at baseline >2000 mg/day), both vildagliptin and pioglitazone decreased A1C (AMDelta = -0.9 +/- 0.1% and -1.0 +/- 0.1%, respectively) from identical baseline values (8.4 +/- 0.1%). The between-group difference in AMDelta A1C was 0.1 +/- 0.1%, and non-inferiority of vildagliptin to pioglitazone was established at both 0.4 and 0.3% margins for upper limit of the 95% confidence intervals. Pioglitazone decreased FPG (AMDelta = -2.1 +/- 0.1 mmol/l) to a greater extent than vildagliptin (AMDelta = -1.4 +/- 0.1 mmol/l), but only pioglitazone increased body weight (AMDelta = +1.9 +/- 0.2 kg: between-group difference = -1.6 +/- 0.3 kg, p < 0.001). Adverse events (AEs) were reported by 60% of vildagliptin-treated patients and by 56.4% of pioglitazone-treated patients; serious AEs were reported by 2.0 and 4.6% of patients receiving vildagliptin and pioglitazone respectively. Mild hypoglycaemia was reported by one patient (0.3%) in the vildagliptin group and by no patients receiving pioglitazone.

CONCLUSIONS

When added to metformin, the efficacy of vildagliptin is non-inferior to that of pioglitazone. The treatments were similarly well tolerated, but only pioglitazone increased body weight.

Effect of the amino acid alanine on glucagon secretion in non-diabetic and type 1 diabetic subjects during hyperinsulinaemic euglycaemia, hypoglycaemia and post-hypoglycaemic hyperglycaemia

AIMS/HYPOTHESIS

The aim of our study was to establish whether the well-known defective or absent secretion of glucagon in type 1 diabetes in response to hypoglycaemia is selective or includes lack of responses to other stimuli, such as amino acids.

MATERIALS AND METHODS

Responses of glucagon to hypoglycaemia were measured in eight patients with type 1 diabetes and six non-diabetic subjects during hyperinsulinaemic (insulin infusion 0.5 mU kg(-1) min(-1)) and eu-, hypo- and hyperglycaemic clamp studies (sequential steps of plasma glucose 5.0, 2.9, 5.0, 10 mmol/l). Subjects were studied on three randomised occasions with infusion of low- or high-dose alanine, or saline.

RESULTS

With saline, glucagon increased in hypoglycaemia in non-diabetic subjects but not in diabetic subjects. Glucagon increased further with low-dose (181 +/- 16 ng l(-1) min(-1)) and high-dose alanine (238 +/- 20 ng l(-1) min(-1)) in non-diabetic subjects, but only with high-dose alanine in diabetic subjects (area under curve 112 +/- 5 ng l(-1) min(-1)). The alanine-induced glucagon increase in diabetic subjects paralleled the spontaneous glucagon response to hypoglycaemia in non-diabetic subjects not receiving alanine. The greater responses of glucagon to hypoglycaemia with alanine infusion were offset by recovery of eu- or hyperglycaemia.

CONCLUSIONS/INTERPRETATION

In type 1 diabetes, the usually deficient responses of glucagon to hypoglycaemia may improve after increasing the concentration of plasma amino acids. Amino acid-enhanced secretion of glucagon in response to hypoglycaemia remains under physiological control since it is regulated primarily by the ambient plasma glucose concentration. These findings might be relevant to improving counter-regulatory defences against insulin-induced hypoglycaemia in type 1 diabetes.

Evaluation of the accuracy of a microdialysis-based glucose sensor during insulin-induced hypoglycemia, its recovery, and post-hypoglycemic hyperglycemia in humans

BACKGROUND

These studies were designed to evaluate the accuracy of a microdialysis-based subcutaneous glucose sensor (GlucoDay, A. Menarini Diagnostics, Firenze, Italy) compared with a standard reference method of plasma glucose measurement during insulin-induced hypoglycemia.

RESEARCH DESIGN AND METHODS

Nine subjects without diabetes were studied in eu-, hypo-, and hyperglycemia (clamp technique). The GlucoDay was calibrated against one arterialized plasma glucose measurement (Glucose Analyzer, Beckman, Brea, CA), and plasma glucose estimates every 3 min were compared with paired plasma glucose values.

RESULTS

Accuracy of glucose estimates was not homogeneously distributed among subjects and depended on stability of the sensor's current signal during spontaneous euglycemia (R +/- -0.68). Linear regression analysis showed a good correlation between the two methods of measurement (R = 0.9), Deming regression showed the inclusion of the unit in the confidence interval of the slope (slope 0.95, 95% confidence interval 0.87-1.02), and the accuracy of the GlucoDay reached 40 +/- 15% (American Diabetes Association criteria). The mean relative difference was 6 +/- 8% in euglycemia, 13 +/- 14% during plasma glucose fall, 5 +/- 22% in the hypoglycemic plateau, and -14 +/- 16% during recovery from hypoglycemia. The Bland-Altman analysis indicated a bias of -1.9 +/- 16.6 mg/dL, whereas the Error Grid Analysis showed 94% of the Gluco- Day measurements in the acceptable zones of the grid. The time to reach the glycemic nadir was longer when measured with the GlucoDay (90 +/- 5 vs. 72.5 +/- 9 min, P < 0.05). However, absolute values of glycemic nadir, time spent in hypoglycemia, and the rate of fall of glycemia and the rate of recovery from the hypoglycemia were not statistically different.

CONCLUSIONS

GlucoDay closely monitors changes in plasma glucose before, during, and after hypoglycemia. However, these results can be achieved only if calibration of the GlucoDay is performed under conditions of sensor signal stability. Similar studies have to be performed in subjects with diabetes to validate the GlucoDay system.

Glucagon: the effects of its excess and deficiency on insulin action

AIM

To review the role that glucagon plays in physiology, physiopathology and clinical medicine.

DATA SYNTHESIS

Glucagon assays employing specific radioimmunoassay (RIA) techniques are now widely used to characterize pathologic conditions where the effect of the excess or deficiency of glucagon on insulin actions might play a role. Glucagon excess counteracts the action of insulin on glucose metabolism by stimulating glycogenolysis and gluconeogenesis. Aside from glucagon excess in association with glucagonoma, glucagon excess is found in several metabolic disturbances. In diabetes mellitus, hyperglycaemia is the consequence of the glycogenolytic and gluconeogenic effects of glucagon excess occurring in the setting of a relative insulin deficiency (i.e. Type 2 diabetes), whereas excess of glucagon and absent insulin levels are typical features of diabetic ketoacidosis. Although plasma glucagon levels of patients with diabetes are usually increased relative to the prevailing plasma glucose concentrations, it is a paradox that in those patients glucagon levels fail to rise when hypoglycaemia develops. Since glucagon release is considered the primary defence against insulin-induced hypoglycaemia, the defective response of glucagon to hypoglycaemia may favour the development of severe hypoglycaemia. Such defective response to hypoglycaemia in diabetes can be regarded as a condition of selective glucagon deficiency the mechanisms of which remain to be elucidated.

CONCLUSION

The most common condition associated with glucagon excess or deficiency is diabetes mellitus. Glucagon excess contributes to hyperglycaemia whereas reduced glucagon response to insulin-induced hypoglycaemia promotes severe hypoglycaemia. It is expected that drugs that are able to reduce glucagon secretion in concert with strategies directed to recover glucagon secretion to hypoglycaemia might contribute to improve the overall glycaemic control in diabetes.

Comparison of the effects of continuous subcutaneous insulin infusion (CSII) and NPH-based multiple daily insulin injections (MDI) on glycaemic control and quality of life: results of the 5-nations trial

AIMS

The goal of the study was to determine whether continuous subcutaneous insulin infusion (CSII) differs from a multiple daily injection (MDI) regimen based on neutral protamine hagedorn (NPH) as basal insulin with respect to glycaemic control and quality of life in people with Type 1 diabetes.

METHODS

The 5-Nations trial was a randomized, controlled, crossover trial conducted in 11 European centres. Two hundred and seventy-two patients were treated with CSII or MDI during a 2-month run-in period followed by a 6-month treatment period, respectively. The quality of glycaemic control was assessed by HbA(1c), blood glucose values, and the frequency of hypoglycaemic events. For the evaluation of the quality of life, three different self-report questionnaires have been assessed.

RESULTS

CSII treatment resulted in lower HbA(1c) (7.45 vs. 7.67%, P < 0.001), mean blood glucose level (8.6 vs. 9.4 mmol/l, P < 0.001) and less fluctuation in blood glucose levels than MDI (+/- 3.9 vs. +/- 4.3 mmol/l, P < 0.001). There was a marked reduction in the frequency of hypoglycaemic events using CSII compared with MDI, with an incidence ratio of 1.12 [95% confidence interval (CI): 1.08-1.17] and 2.61 (95% CI: 1.59-4.29) for mild and severe hypoglycaemia, respectively. The overall score of the diabetes quality of life questionnaire was higher for CSII (P < 0.001), and an improvement in pump users' perception of mental health was detected when using the SF-12 questionnaire (P < 0.05).

CONCLUSION

CSII usage offers significant benefits over NPH-based MDI for individuals with Type 1 diabetes, with improvement in all significant metabolic parameters as well as in patients' quality of life. Additional studies are needed to compare CSII with glargine- and detemir-based MDI.

Better long-term glycaemic control with the basal insulin glargine as compared with NPH in patients with Type 1 diabetes mellitus given meal-time lispro insulin

BACKGROUND

Glargine is a long-acting insulin analogue potentially more suitable than NPH insulin in intensive treatment of Type 1 diabetes mellitus (T1 DM), but no study has proven superiority. The aim of this study was to test superiority of glargine on long-term blood glucose (BG) as well as on responses to hypoglycaemia vs. NPH.

METHODS

One hundred and twenty-one patients with T1 DM on intensive therapy on four times/day NPH and lispro insulin at each meal, were randomized to either continuation of NPH four times/day (n = 60), or once daily glargine at dinner-time (n = 61) for 1 year. Lispro insulin at meal-time was continued in both groups. In 11 patients from each group, responses to stepped hyperinsulinaemic-hypoglycaemia were measured before and after 1 year's treatment.

RESULTS

Mean daily BG was lower with glargine [7.6 +/- 0.11 mmol/l (137 +/- 2 mg/dl)] vs. NPH [8.1 +/- 0.22 mmol/l (146 +/- 4 mg/dl)] (P < 0.05). HbA(1c) at 4 months did not change with NPH, but decreased with glargine (from 7.1 +/- 0.1 to 6.7 +/- 0.1%), and remained lower than NPH at 12 months (6.6 +/- 0.1%, P < 0.05 vs. NPH). Frequency of mild hypoglycaemia [self-assisted episodes, blood glucose < or = 4.0 mmol/l (72 mg/dl)] was lower with glargine vs. NPH (7.2 +/- 0.5 and 13.2 +/- 0.6 episodes/patient-month, P < 0.05). After 1 year, NPH treatment resulted in no change of responses to hypoglycaemia, whereas with glargine plasma glucose, thresholds and maximal responses of plasma adrenaline and symptoms to hypoglycaemia improved (P < 0.05).

CONCLUSIONS

The simpler glargine regimen decreases the percentage of HbA(1c) and frequency of hypoglycaemia and improves responses to hypoglycaemia more than NPH. Thus, glargine appears more suitable than NPH as basal insulin for intensive treatment of T1 DM.

Effects of whole-body vibration exercise on the endocrine system of healthy men

Whole-body vibration is reported to increase muscle performance, bone mineral density and stimulate the secretion of lipolytic and protein anabolic hormones, such as GH and testosterone, that might be used for the treatment of obesity. To date, as no controlled trial has examined the effects of vibration exercise on the human endocrine system, we performed a randomized controlled study, to establish whether the circulating concentrations of glucose and hormones (insulin, glucagon, cortisol, epinephrine, norepinephrine, GH, IGF-1, free and total testosterone) are affected by vibration in 10 healthy men [age 39 +/- 3, body mass index (BMI) of 23.5 +/- 0.5 kg/m2, mean +/- SEM]. Volunteers were studied on two occasions before and after standing for 25 min on a ground plate in the absence (control) or in the presence (vibration) of 30 Hz whole body vibration. Vibration slightly reduced plasma glucose (30 min: vibration 4.59 +/- 0.21, control 4.74 +/- 0.22 mM, p=0.049) and increased plasma norepinephrine concentrations (60 min: vibration 1.29 +/- 0.18, control 1.01 +/- 0.07 nM, p=0.038), but did not change the circulating concentrations of other hormones. These results demonstrate that vibration exercise transiently reduces plasma glucose, possibly by increasing glucose utilization by contracting muscles. Since hormonal responses, with the exception of norepinephrine, are not affected by acute vibration exposure, this type of exercise is not expected to reduce fat mass in obese subjects.

Alternative routes of insulin delivery

Attempts at replicating physiological insulin secretion, as a means of restoring the normal metabolic milieu and thereby minimizing the risk of diabetic complications, has become an essential feature of insulin treatment. However, despite advances in the production, purification, formulation and methods of delivery of insulin which have occurred in recent years, this has met with limited success. The current advocacy of intensive insulin therapy regimens involving multiple daily subcutaneous injection places a heavy burden of compliance on patients and has prompted interest in developing alternative, less invasive routes of delivery. To date, attempts to exploit the nasal, oral, gastrointestinal and transdermal routes have been mainly unsuccessful. The respiratory tree, with a large surface area, offers the greatest potential for the delivery of polypeptide drugs and there is renewed interest in administrating insulin by the intrapulmonary route. Current pulmonary drug delivery systems include a variety of pressurized metered dose inhalers, dry powder inhalers, nebulizers and aqueous mist inhalers. Recent clinical studies suggest a possible role for inhaled insulin in fulfilling meal-related insulin requirements in persons with Type 1 and Type 2 diabetes. Most experience with inhaled insulin has been obtained using either dry powder formulation in the Nektar Pulmonary Inhaler/Exubera device (Nektar Therapeutics Inc., San Carlos, CA, Aventis, Bridgewater, NJ, Pfizer, NY) or a liquid aerosol formulation in the AERx Insulin Diabetes Management System (Aradigm Corp., Hayward, CA, NovoNordisk A/S, Copenhagen, Denmark). If long-term safety and efficacy is confirmed, inhalation may become the first non-subcutaneous route of insulin administration for widespread clinical use. Despite overwhelming interest and investment in administering insulin via the oral route, success is not expected in the short term. Attempts at utilizing the buccal mucosa and skin are also continuing. Pancreatic transplantation will remain limited to those patients receiving a kidney transplant and immunotherapy. Islet cell transplantation is at an early though encouraging stage following the availability of new less toxic immunosuppressive agents. True insulin independence will require further advances in the combined fields of cell biology and genetics to ensure freedom from both the need for lifelong administration of insulin and the complications of diabetes.

Rate of fall of blood glucose and physiological responses of counterregulatory hormones, clinical symptoms and cognitive function to hypoglycaemia in Type I diabetes mellitus in the postprandial state

AIMS/HYPOTHESIS

The aim of this study was to establish the effect of a rate of decreasing plasma glucose concentrations on responses to hypoglycaemia, i.e. release of counterregulatory hormones, perception of symptoms, deterioration of cognitive function, and rates of forearm noradrenaline spillover, in the postprandial condition and in the sitting position.

METHODS

We studied 11 subjects with Type I (insulin-dependent) diabetes mellitus, twice during clamped insulin-induced hypoglycaemia (2.4 mmol/l) after eating in the sitting position. On one occasion, plasma glucose was decreased at the rate of 0.1+/-0.003 mmol x min(-1) x l(-1) (fast fall), on the other at the rate of 0.03+/-0.001 mmol x min(-1) x l(-1) (slow fall). Subjects underwent a control euglycaemic clamp study as well.

RESULTS

In response to fast-fall as compared to slow-fall hypoglycaemia, which was about 30 min longer, cognitive tasks were performed as follows: Trail-Making B, PASAT 2 s, Digit Vigilance Test and Verbal Memory deteriorated more, adrenaline increased less (2.8+/-0.5 vs 3.5+/-0.7 nmol/l, p=0.03), forearm noradrenaline spillover was greater (6.5+/-1.0 vs 5.2+/-0.4 pmol x min(-1) x 100 ml(-1), p=0.04), and symptoms were no different. After recovery from hypoglycaemia, cognitive function was still deteriorated compared to the baseline with no difference between fast and slow-fall hypoglycaemia. The evident response of glucagon to postprandial hypoglycaemia contrasted with the blunted or absent response in the fasting state.

CONCLUSION/INTERPRETATION

In the postprandial condition and sitting position, fast-fall hypoglycaemia is more dangerous than slow-fall, because it deteriorates cognitive function more, and activates responses of counterregulatory hormones less than slow-fall hypoglycaemia.

Basal-bolus insulin therapy in Type 1 diabetes: comparative study of pre-meal administration of a fixed mixture of insulin lispro (50%) and neutral protamine lispro (50%) with human soluble insulin

AIMS

To ascertain whether pre-meal administration of 50% insulin lispro and 50% neutral protamine lispro (NPL), given as a fixed mixture (Humalog Mix50, human soluble (regular) insulin as a basal-bolus regimen in people with Type 1 diabetes. Both regimens included bedtime human isophane (NPH) insulin.

METHODS

This was a multinational, multicentre, randomized, open-label, two-period crossover comparison of two insulin treatments for two 12-week periods in 109 patients with Type 1 diabetes. The protocol provided preliminary evaluations of dose requirements and recommendations for insulin dose adjustment when switching regimens on the basis of blood glucose (BG) values. Eight-point BG profiles, frequency of hypoglycaemia, HbA1c, insulin dose, time of injection, and frequency of snacking were assessed during each treatment.

RESULTS

Total daily insulin dose was similar for both treatments, but the total pre-meal doses were higher (P < 0.001) and the bedtime dose of isophane was lower (P < 0.001) with Mix50. The pre-meal dose before breakfast and lunch, although statistically different (P = 0.006 and P < 0.001, respectively), was of similar magnitude, but the pre-evening meal dose was higher with Mix50 (P < 0.001). Median (interquartile range) time of insulin injection before meals was: Mix50 4.2 (25th percentile = 1.0; 75th percentile = 6.3) min, human soluble insulin 24.6 (25th percentile = 16.6; 75th percentile = 30.0) min. Pre-meal and bedtime BG concentrations did not differ between treatments. The BG 2 h after the evening meal was lower with Mix50 (8.40 +/- 2.95 mmol/l vs. 9.60 +/- 3.47 mmol/l) (P = 0.049). BG after breakfast and lunch, mean HbA1c, frequency of hypoglycaemia, frequency of snacks, and body weight were not different.

CONCLUSION

The use of Mix50 in a basal-bolus regimen achieved similar control of pre-meal BG to human soluble insulin, and overall glycaemic control and hypoglycaemia risk were equivalent. This suggests that Mix50 can provide an adequate supply of insulin to control BG between meals while providing the convenience of injecting immediately before meals.