The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients (TROPHIES): Final patient-reported outcomes at 24 months

AIM

To report health-related patient-reported outcomes (PROs) in people with type 2 diabetes (T2D) initiating their first injectable glucose-lowering medication (GLM) with two commonly prescribed glucagon-like peptide-1 receptor agonists (GLP-1RAs) from the prospective, observational TROPHIES study (The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients).

MATERIALS AND METHODS

TROPHIES was a two-cohort, 24-month study conducted in France, Germany and Italy. Adults with a T2D diagnosis, naïve to injectable treatment for T2D and prescribed dulaglutide or liraglutide as their first injectable GLM, were eligible for inclusion. Study objectives included describing the following PROs associated with the treatment of T2D with GLP-1RAs: health-related quality of life; impact of weight on self-perception; life and work productivity; and patient satisfaction with treatment and injection device. Additional analyses formally compared PRO measures between the treatment cohorts.

RESULTS

Overall, improvements from baseline in PRO scores were observed among people who started dulaglutide or liraglutide. A more pronounced trend of improvement was observed in the dulaglutide cohort for changes from baseline in treatment satisfaction and impact of weight on self-perception, supported by statistically significant differences between treatment cohorts in additional comparative analyses at 12, 18 and 24 months. More positive patient perceptions of the injection device were observed with dulaglutide than with liraglutide.

CONCLUSIONS

Improvements in PROs observed in TROPHIES, which were more evident with dulaglutide than liraglutide, reflect a relevant clinical benefit. From the patients' perspective, satisfaction, and confidence in continuing treatment with GLP-1RAs is likely to contribute to long-term treatment persistence.

The real-world observational prospective study of health outcomes with dulaglutide and liraglutide in patients with type 2 diabetes (TROPHIES): Final, 24-month analysis of time to first significant treatment change, treatment persistence and clinical outcomes

AIMS

To present the final results of the TROPHIES study (The real-world observational prospective study of health outcomes with dulaglutide and liraglutide in patients with type 2 diabetes).

MATERIALS AND METHODS

The prospective, real-world TROPHIES study included patients with type 2 diabetes initiating their first injectable glucose-lowering medication (GLM), dulaglutide or liraglutide, in France, Germany and Italy. The primary endpoint was the time spent on dulaglutide or liraglutide until a significant treatment change over 24 months. Other endpoints measured persistence with treatment, clinical outcomes (glycated haemoglobin [HbA1c] and weight) and treatment patterns. Kaplan-Meier estimates of time to first significant treatment change and persistence with treatment were generated. Propensity-score-based inverse probability of treatment weighting (IPTW) was used to adjust for baseline imbalances in the comparison between cohorts.

RESULTS

The 286 of 1014 patients (28.2%) in the dulaglutide cohort and 448 of 991 patients (45.2%) in the liraglutide cohort had a significant treatment change over 24 months. By IPTW analysis, dulaglutide-initiating patients were less likely to have a significant treatment change (hazard ratio [HR] 0.54, 95% confidence interval [CI] 0.46-0.63) and more likely to be persistent with treatment (HR 0.69, 95% CI 0.56-0.86) over 24 months than liraglutide-initiating patients. Dulaglutide and liraglutide yielded similar HbA1c (-11.80 mmol/mol [1.08%] and -11.91 mmol/mol [1.09%]) and weight (-3.5 kg and -3.3 kg) reductions from baseline to 24 months. Few changes in patterns of treatment with other GLMs were observed in the two cohorts.

CONCLUSIONS

Dulaglutide-initiating patients had a longer time spent without any significant treatment change and higher persistence than those initiating liraglutide. Treatment with either glucagon-like peptide-1 receptor agonist yielded similar and clinically meaningful reductions in HbA1c and body weight.

The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Patients with Type 2 Diabetes (TROPHIES): Patient disposition, clinical characteristics and treatment persistence at 12 months

AIMS

The primary objective of the TROPHIES observational study is to estimate the duration of treatment on dulaglutide or liraglutide without a significant treatment change by 24 months in patients with type 2 diabetes (T2D) initiating their first injectable treatment with these glucagon-like peptide-1 receptor agonists (GLP-1 RAs). This manuscript presents 12-month interim data.

MATERIALS AND METHODS

TROPHIES is a prospective, non-comparative, observational study of patients with T2D in Europe, naïve to injectable antihyperglycaemic treatments and initiating dulaglutide or liraglutide. Data on clinical characteristics, GLP-1 RA persistence and treatment patterns of glucose-lowering medication were collected at initiation of first injectable therapy and by 12 months.

RESULTS

By 12 months, 1014 dulaglutide and 991 liraglutide patients were eligible across France, Germany and Italy. Both cohorts presented a high probability [95% confidence interval (CI)] of GLP-1 RA persistence [dulaglutide, 0.88 (0.86 to 0.90); liraglutide, 0.83 (0.80 to 0.85)] and reduction in mean glycated haemoglobin percentage (95% CI) from baseline [dulaglutide, -1.18 (-1.27 to -1.08); liraglutide, -1.15 (-1.26 to -1.05)] with 48.2% of dulaglutide and 41.2% of liraglutide patients reaching their individualized glycated haemoglobin percentage target set by the physician at baseline. Mean weight (95% CI) change from baseline was -3.2 kg (-3.6 to -2.8) for dulaglutide and -3.4 kg (-3.9 to -3.0) for liraglutide. Slight changes in concomitant medications were observed compared with baseline.

CONCLUSIONS

In the real-world setting, dulaglutide and liraglutide cohorts achieved good persistence with similarly improved glycaemic control that was accompanied by weight loss at 12 months, consistent with previous clinical trial results.

Changing the approach to type 2 diabetes treatment: A comparison of glucagon-like peptide-1 receptor agonists and sulphonylureas across the continuum of care

Despite the importance of individualised strategies for patients with type 2 diabetes mellitus (T2DM) and the availability of alternative treatments, including glucagon-like peptide-1 receptor agonists (GLP-1 RAs), sulphonylureas are still widely used in practice. Clinical evidence shows that GLP-1 RAs may provide better and more durable glycaemic control than sulphonylureas, with lower risk of hypoglycaemia. Other reported benefits of GLP-1 RAs include weight loss rather than weight gain (as observed with sulphonylureas), blood pressure reduction and improvement in lipid profiles. In general, the main adverse events with GLP-1 RAs are gastrointestinal in nature. The respective modes of action of GLP-1 RAs and sulphonylureas contribute to differences in the durability of glycaemic control (related to effects on beta-cells) and effects on body weight. Moreover, the glucose-dependent mode of action of GLP-1 RAs, which favours a low incidence of hypoglycaemia, contrasts with the glucose-independent mode of action of sulphonylureas. Evidence from cardiovascular outcomes trials indicates a consistent finding of cardiovascular safety across the GLP-1 RAs and suggests a class benefit for the long-acting GLP-1 RAs in reducing three-point major adverse cardiovascular events, cardiovascular mortality and all-cause mortality. In contrast, potential concerns relating to an increased incidence of adverse cardiovascular events with sulphonylureas have yet to be fully resolved. Recent updates to management guidelines recommend that treatment selection for patients with T2DM should consider clinical trial evidence of cardiovascular safety. Available evidence suggests that this selection should give preference to GLP-1 RAs over sulphonylureas, especially for patients at high cardiovascular risk.

The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients (TROPHIES): Design and Baseline Characteristics

INTRODUCTION

The TROPHIES observational study enrolled patients with type 2 diabetes mellitus (T2DM) initiating their first injectable treatment with the glucagon-like peptide 1 receptor agonists (GLP-1 RAs) dulaglutide or liraglutide. This manuscript focuses on the study design, baseline characteristics of the enrolled population, and factors associated with GLP-1 RA choice.

METHODS

TROPHIES is a prospective, observational, 24-month study conducted in France, Germany, and Italy. Inclusion criteria include adult patients with T2DM, naïve to injectable antihyperglycemic treatments, initiating dulaglutide or liraglutide per routine clinical practice. The primary outcome is the duration of treatment on dulaglutide or liraglutide without a significant treatment change.

RESULTS

The analysis included 2181 patients (dulaglutide, 1130; liraglutide, 1051) (cutoff date May 15, 2019). The population was 56% male with mean [standard deviation (SD)] patient characteristics at baseline as follows: age, 59.2 (11.0) years; body mass index (BMI), 33.9 (6.6) kg/m²; T2DM duration, 8.5 (6.9) years; and glycated hemoglobin (HbA1c), 8.2 (1.3)%. Between-cohort demographic and clinical characteristics were balanced. The mean (SD) HbA1c and BMI values for French, German, and Italian patients were, respectively, 8.6 (1.4)%, 8.2 (1.4)%, 8.0 (0.8)%; 33.3 (6.1) kg/m², 36.0 (7.2) kg/m², and 32.6 (5.9) kg/m².

CONCLUSION

This study analysis at baseline provides an opportunity to evaluate between-country differences in baseline HbA1c, weight, macrovascular complications, and factors driving GLP-1 RA selection for patients with T2DM in daily practice.

The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients (TROPHIES): Baseline Patient-Reported Outcomes

INTRODUCTION

Although patient-reported outcome (PRO) measures provide important information beyond clinical data, studies that assess the PROs of type 2 diabetes mellitus (T2DM) patients initiating injectable glucose-lowering medications in routine clinical practice are limited. We describe the perspectives of patients based on a diversified panel of generic and disease-specific PRO measures at the time of enrollment (baseline) in the TROPHIES study.

METHODS

TROPHIES is a 24-month prospective observational study performed in France, Germany, and Italy in patients with T2DM who initiated their first injectable glucose-lowering medication with once-weekly dulaglutide or once-daily liraglutide. To better understand the perspectives of these patients regarding their overall health, treatment satisfaction, and quality of life and work, the patients' responses to the following questionnaires were collected at baseline before they initiated treatment with dulaglutide or liraglutide: EQ-5D-5L (scale: 0-1), EQ-VAS (visual analog scale: 0-100), Impact of Weight on Self-Perceptions Questionnaire (IW-SP; scale: 0-100), Diabetes Treatment Satisfaction Questionnaire Status (DTSQs; scale: 0-36), and Diabetes Productivity Measure (DPM; scale: 0-100). Analyses were descriptive in nature, with higher scores reflecting better outcomes.

RESULTS

Data from patients at the time of enrollment were analyzed. At baseline, patients initiating dulaglutide (N = 1130) or liraglutide (N = 1051) rated their quality of life in terms of mean EQ-5D-5L index as 0.84 and 0.83, and in terms of mean EQ-VAS as 67.5 and 67.5, respectively. The mean baseline scores in patients initiating dulaglutide or liraglutide were 59.8 and 61.3 for IW-SP, 24.6 and 25.8 for DTSQs, 78.6 and 79.5 for DPM Life Productivity, and 87.5 and 86.8 for DPM Work Productivity, respectively.

CONCLUSION

The information from this varied panel of PRO instruments collected at baseline complements clinical outcomes data.

Rapid-Acting Insulin Analogues Versus Regular Human Insulin: A Meta-Analysis of Effects on Glycemic Control in Patients with Diabetes

INTRODUCTION

The aim of this meta-analysis was to investigate the impact of rapid-acting insulin analogues (RAIAs) and regular human insulin (RHI) on glycemic control, including long- and short-term glycemic variability as measured by glycated haemoglobin (HbA1c) and pre- and postprandial glucose (PPG).

METHODS

PubMed was searched for studies published between 1999 and 29 June 2016. Randomised controlled trials of patients with diabetes that assessed the effects of RAIAs or RHI on glycemic control, focusing on preprandial glucose, PPG and HbA1c, were included. Only studies that reported both means and standard deviations for those outcomes were analysed; from these data, weighted mean differences and 95% confidence intervals were generated to yield overall point estimates. The primary outcomes of the meta-analysis were the mean differences between RAIAs and RHI at the end of the study in PPG, preprandial glucose, and HbA1c.

RESULTS

Twenty-seven studies (n = 7452) were included. The difference in PPG between RAIA- and RHI-treated patients was significant-in favour of RAIAs-in patients with type 1 diabetes (T1D) [- 22.2 mg/dL; 95% confidence interval (CI) - 27.4, - 17.0 mg/dL; P < 0.0001] but not in those with type 2 diabetes (T2D). For preprandial glucose, there was a non-significant trend favouring RHIs in T1D; no data were available for patients with T2D. In patients with T1D, the between-group difference in end-of-treatment (EOT) HbA1c favoured RAIAs (- 0.13%; 95% CI - 0.18, - 0.08%; P < 0.0001), but was not significant in patients with T2D. The main study limitations were the small number and heterogeneity of the included studies.

CONCLUSIONS

These results demonstrate that RAIAs are more effective at reducing PPG and improving HbA1c than RHIs in T1D. More data are required to assess the effect of these agents on glucose control in T2D. In patients with diabetes, the risk of complications is increased by poor control of blood glucose levels and high blood glucose variability. Complications may include cardiovascular disease, eye problems and amputation. Control and variability of blood glucose levels can be evaluated using a range of measures, including (i) glycated haemoglobin (HbA1c) level at the end of the treatment period; (ii) change in HbA1c level during the treatment period; (iii) fasting plasma glucose level; (iv) postprandial glucose (PPG) level; (v) change in blood glucose level after a meal. PPG levels following a meal are an important measure of overall metabolic control in diabetes, and reduction of glycemic variability (GV) can be achieved via reductions in PPG. Both rapid-acting insulin analogues (RAIAs; aspart, glulisine and lispro) and regular human insulin (RHI) are widely used in the management of diabetes. Using data from 27 randomised controlled trials involving more than 7000 patients, we investigated the impact of RAIAs and RHI on measures of glycemic control and variability in patients with type 1 diabetes (T1D) or type 2 diabetes (T2D). Our results show that, in patients with T1D, RAIAs are more effective than RHI at reducing PPG excursions and HbA1c. This indicates that glycemic control is better with RAIAs than with RHI. More data are required to assess the effects of RAIAs and RHI on glycemic control and variability in patients with T2D.

PLAIN LANGUAGE SUMMARY

In patients with diabetes, the risk of complications is increased by poor control of blood glucose levels and high blood glucose variability. Complications may include cardiovascular disease, eye problems and amputation. Control and variability of blood glucose levels can be evaluated using a range of measures, including (i) glycated haemoglobin (HbA1c) level at the end of the treatment period; (ii) change in HbA1c level during the treatment period; (iii) fasting plasma glucose level; (iv) postprandial glucose (PPG) level; (v) change in blood glucose level after a meal. PPG levels following a meal are an important measure of overall metabolic control in diabetes, and reduction of glycemic variability (GV) can be achieved via reductions in PPG. Both rapid-acting insulin analogues (RAIAs; aspart, glulisine and lispro) and regular human insulin (RHI) are widely used in the management of diabetes. Using data from 27 randomised controlled trials involving more than 7000 patients, we investigated the impact of RAIAs and RHI on measures of glycemic control and variability in patients with type 1 diabetes (T1D) or type 2 diabetes (T2D). Our results show that, in patients with T1D, RAIAs are more effective than RHI at reducing PPG excursions and HbA1c. This indicates that glycemic control is better with RAIAs than with RHI. More data are required to assess the effects of RAIAs and RHI on glycemic control and variability in patients with T2D.

Incidence of severe hypoglycemia and possible associated factors in pediatric patients with type 1 diabetes in the real-life, post-Diabetes Control and Complications Trial setting: A systematic review

BACKGROUND/OBJECTIVE

In 1993, the Diabetes Control and Complications Trial (DCCT) found that intensive antihyperglycemic therapy was effective in the primary and secondary prevention of microvascular complications in patients with type 1 diabetes (T1D) but was associated with a 3-fold greater rate of severe hypoglycemia (SH) than conventional therapy. The aim of this analysis was to determine whether, in the real-world setting, the incidence of SH in pediatric patients with T1D has changed since 1993.

METHODS

A systematic literature search of PubMed for prospective or retrospective observational studies (≥250 participants) on SH epidemiology or related topics in pediatric patients with T1D, published between October 1993 and June 2016, identified 35 articles (involving >55 000 participants). SH incidence data were analyzed in approximate 5-year blocks: 1993-2000, 2001-2005, 2006-2010, and 2011-2016. Information on factors that might influence the incidence of SH was also collected.

RESULTS

A trend for a marked reduction in the incidence of SH in the post-DCCT setting (from 62.0 per 100 patient-years to 1.21-30 per 100 patient-years) was apparent. Factors that could have influenced this temporal trend in SH incidence included the increased use of new types of, and methods of administering, insulin, in particular rapid-acting insulin analogs and continuous subcutaneous insulin infusion.

CONCLUSIONS

SH in pediatric patients with T1D has declined in incidence since the DCCT but remains a common problem. The optimal use of new insulin therapies/regimens/technologies, improved education, and dedicated specialized management teams are needed to help reduce the risk of SH in this population.

Utilization Patterns of Glucagon-Like Peptide-1 Receptor Agonists in Patients with Type 2 Diabetes Mellitus in Italy: A Retrospective Cohort Study

INTRODUCTION

Real-world evidence on glucagon-like peptide-1 receptor agonist (GLP-1 RAs) usage is emerging in different European countries but is lacking in Italy. This retrospective cohort study aimed to describe the real-world drug utilization patterns in patients initiating GLP-1 RAs for treating T2DM in Italy.

METHODS

Adults aged ≥ 20 years and with ≥ 1 oral antidiabetic drug (alone or in combination with insulin) other than GLP-1 RAs in the 6 months prior to initiating exenatide twice daily (exBID), exenatide once weekly (exQW), dulaglutide once weekly (DULA), liraglutide once daily (LIRA) or lixisenatide once daily (LIXI) between March and July 2016 were retrospectively identified in the Italian IMS LifeLink™ longitudinal prescriptions database (retail pharmacy data). Patients with ≥ 6-month follow-up (defined as evidence of any prescription activity) were included. Proportions of patients who remained persistent (continued treatment until discontinuation/switch) in the first 6 months and of those who discontinued or switched to a different GLP-1 RA over the entire follow-up were recorded. For each treatment, the average daily/weekly dosage (ADD/AWD) while persistent during the available follow-up was calculated.

RESULTS

We identified 7319 patients: 92 exBID, 970 exQW, 3368 DULA, 2573 LIRA and 316 LIXI. Across treatments, 89% patients were ≥ 50 years old, 54% were males, and the median follow-up duration ranged between 8.1 and 8.7 months. At 6 months, 35% exBID, 47% exQW, 62% DULA, 50% LIRA and 40% LIXI patients remained persistent. Over the entire follow-up, median persistence days varied from 73 (exBID) to > 300 days (DULA). The mean ± SD ADD/AWD was exBID: 17.7 ± 2.1 µg/day; exQW: 2.1 ± 0.1 mg/week; DULA: 1.5 ± 0.2 mg/week; LIRA: 1.5 ± 0.2 mg/day; LIXI: 21.0 ± 5.5 µg/day.

CONCLUSIONS

This real-world analysis suggests differences exist in persistence between patients treated with various GLP-1 RAs. Among the investigated treatments, patients prescribed exBID recorded the lowest and those prescribed DULA the highest persistence with therapy.

FUNDING

Eli Lilly and Co., Indianapolis, IN, USA.

Patient preferences in Italy: health state utilities associated with attributes of weekly injection devices for treatment of type 2 diabetes

OBJECTIVES

Several glucagon-like peptide-1 receptor agonists are administered as weekly injections for treatment of type 2 diabetes (T2D). These medications vary in their injection processes, and a recent study in the UK found that these differences had an impact on patient preference and health state utilities. The purpose of this study was to replicate the UK study in Italy to examine preferences of an Italian patient sample, while allowing for comparison between utilities in the UK and Italy.

MATERIALS AND METHODS

Participants with T2D in Italy valued health states in time trade-off interviews. All health states had the same description of T2D, but differed in description of the treatment process. As in the original UK study, the first health state described an oral treatment regimen, while additional health states added a weekly injection. The injection health states differed in three injection-related attributes: requirements for reconstituting the medication, waiting during medication preparation, and needle handling.

RESULTS

Interviews were completed by 238 patients (58.8% male; mean age = 60.2 years; 118 from Milan, 120 from Rome). The oral treatment health state had a mean (SD) utility of 0.90 (0.10). The injection health states had significantly (p < 0.0001) lower utilities, which ranged from 0.87 (requirements for reconstitution, waiting, and handling) to 0.89 (weekly injection with none of these requirements). Differences in health state utility scores suggest that each administration requirement was associated with a disutility (ie, negative utility difference): -0.006 (reconstitution), -0.006 (needle handling), -0.011 (reconstitution, needle handling), and -0.022 (reconstitution, waiting, needle handling).

CONCLUSION

Disutilities associated with the injection device characteristics were similar to those reported with the UK sample. Results suggest that injection device attributes may be important to some patients with T2D, and it may be useful for clinicians to consider these attributes when choosing medication for patients initiating these weekly treatments.

Impaired endothelial antithrombotic activity following short-term interruption of continuous subcutaneous insulin infusion in type1 diabetic patients

Review of literature has shown an increased rate of thrombotic complications in diabetic patients with frequent episodes of hyperketonemia. However, the mechanisms by which ketosis promotes vascular disease in diabetic patients are unclear.It was the aim of this study to investigate early changes in haemostatic parameters and oxidative stress markers during the hyperketonemic status which follows the interruption of continuous subcutaneous insulin infusion (CSII) in type I diabetic patients. Eight CSII-treated type I diabetic patients underwent a 4-hour pump arrest. Blood glucose, insulin and 3-hydroxybutirate were measured to verify the metabolic response. A vein-occlusive (VO) test was performed for the determination of tPA and PAI-1 activities and their antigen levels before and after the CSII arrest. Coagulation factor VII and VIII were evaluated by one-stage PT and PTT method, respectively.TF, vWF, tPA and PAI-1 antigens were determined by ELISA, whereas tPA and PAI-1 activities using chromogenic methods. Plasma malondialdehyde (MDA) and protein carbonyl groups (PCG) levels were determined by HPLC and spectrophotometry, respectively. After the insulin deprivation phase, post-VO tPA antigen level significantly decreased (P=0.0391), whereas TF and post-VO PAI-1 activity and antigen levels significantly increased (P=0.0156 and P=0.0234, respectively). Plasma MDA and PCG levels were 1.88-fold and 1.74-fold higher than baseline values, respectively. In conclusion, the impairment of the fibrinolytic potential and the increases in TF, MDA and PCG levels may enhance the risk of both arterial and venous thrombosis during ketosis.Thus, early detection of hyperketonemia in DM patients could contribute to the prevention of life-threatening vascular events.

Group of signs: a new method to evaluate glycemic variability

BACKGROUND

Glycemic variability is an important parameter used to resolve potential clinical problems in diabetic patients. It is known that glycemic variability generates oxidative stress and potentially contributes to the development of macro- and microvascular complications in diabetes. By controlling glycemic variability, it is possible to reduce these complications and to set the therapy for all patients with diabetes. The aims of this study were to (1) propose a new standardized, objective, and flexible approach to measure glycemic variability by a continuous glucose monitoring system (CGMS)-the group of signs (GOS) method; (2) compare the correlation between mean amplitude of glucose excursion (MAGE), a well-known index of glycemic variability calculated by the physician and the MAGE defined with the GOS method, in order to validate the GOS; and (3) suggest new indexes of glycemic variability.

METHODS

We tested the GOS algorithm on data collected by a CGMS every 5 minutes for 24 hours on 50 patients. Consequently, for 8 patients we calculated and compared the physician's MAGE in the standard way and by the GOS method.

RESULTS

Comparison between the two methods has shown high correlations, from a minimum correlation of 86% to a maximum of 98%, with p values <0.01 (Pearson test).

CONCLUSIONS

Preliminary data suggest that the proposed algorithm is a valid, efficient, and reliable method able to calculate the standard MAGE on CGMS data systematically and to create other alternative glycemic variability indexes.

Impaired endothelial antithrombotic activity following short-term interruption of continuous subcutaneous insulin infusion in type 1 diabetic patients

Review of literature has shown an increased rate of thrombotic complications in diabetic patients with frequent episodes of hyperketonemia. However, the mechanisms by which ketosis promotes vascular disease in diabetic patients are unclear. It was the aim of this study to investigate early changes in haemostatic parameters and oxidative stress markers during the hyperketonemic status which follows the interruption of continuous subcutaneous insulin infusion (CSII) in type I diabetic patients. Eight CSII-treated type I diabetic patients underwent a 4-hour pump arrest. Blood glucose, insulin and 3-hydroxybutirate were measured to verify the metabolic response. A vein-occlusive (VO) test was performed for the determination of tPA and PAI-1 activities and their antigen levels before and after the CSII arrest. Coagulation factor VII and VIII were evaluated by one-stage PT and PTT method, respectively. TF, vWF, tPA and PAI-1 antigens were determined by ELISA, whereas tPA and PAI-1 activities using chromogenic methods. Plasma malondialdehyde (MDA) and protein carbonyl groups (PCG) levels were determined by HPLC and spectrophotometry, respectively. After the insulin deprivation phase, post-VO tPA antigen level significantly decreased (P = 0.0391), whereas TF and post-VO PAI-1 activity and antigen levels significantly increased (P = 0.0156 and P = 0.0234, respectively). Plasma MDA and PCG levels were 1.88-fold and 1.74-fold higher than baseline values, respectively. In conclusion, the impairment of the fibrinolytic potential and the increases in TF, MDA and PCG levels may enhance the risk of both arterial and venous thrombosis during ketosis. Thus, early detection of hyperketonemia in DM patients could contribute to the prevention of life-threatening vascular events.

Control oriented model of insulin and glucose dynamics in type 1 diabetics

The aim of the study was to realize a mathematical model of insulin-glucose relationship in type I diabetes and test its effectiveness for the design of control algorithms in external artificial pancreas. A new mathematical model, divided into glucose and insulin sub-models, was developed from the so-called "minimal model". The key feature is the representation of insulin sensitivity so as to permit the personalisation of the parameters. Real-time applications are based on an insulin standardised model. Clinical data were used to estimate model parameters. Root mean square error between simulated and real blood glucose profiles (G(rms)) was used to evaluate system efficacy. Results from parameter estimation and insulin standardisation showed a good capability of the model to identify individual characteristics. Simulation results with a G(rms) 1.30 mmol/l in the worst case testified the capacity of the model to accurately represent glucose-insulin relationship in type 1 diabetes allowing self tuning in real time.

Nonlinear model predictive control of glucose concentration in subjects with type 1 diabetes

A nonlinear model predictive controller has been developed to maintain normoglycemia in subjects with type 1 diabetes during fasting conditions such as during overnight fast. The controller employs a compartment model, which represents the glucoregulatory system and includes submodels representing absorption of subcutaneously administered short-acting insulin Lispro and gut absorption. The controller uses Bayesian parameter estimation to determine time-varying model parameters. Moving target trajectory facilitates slow, controlled normalization of elevated glucose levels and faster normalization of low glucose values. The predictive capabilities of the model have been evaluated using data from 15 clinical experiments in subjects with type 1 diabetes. The experiments employed intravenous glucose sampling (every 15 min) and subcutaneous infusion of insulin Lispro by insulin pump (modified also every 15 min). The model gave glucose predictions with a mean square error proportionally related to the prediction horizon with the value of 0.2 mmol L(-1) per 15 min. The assessment of clinical utility of model-based glucose predictions using Clarke error grid analysis gave 95% of values in zone A and the remaining 5% of values in zone B for glucose predictions up to 60 min (n = 1674). In conclusion, adaptive nonlinear model predictive control is promising for the control of glucose concentration during fasting conditions in subjects with type 1 diabetes.

Closing the loop: the adicol experience

The objective of the project Advanced Insulin Infusion using a Control Loop (ADICOL) was to develop a treatment system that continuously measures and controls the glucose concentration in subjects with type 1 diabetes. The modular concept of the ADICOL's extracorporeal artificial pancreas consisted of a minimally invasive subcutaneous glucose system, a handheld PocketPC computer, and an insulin pump (D-Tron, Disetronic, Burgdorf, Switzerland) delivering subcutaneously insulin lispro. The present paper describes a subset of ADICOL activities focusing on the development of a glucose controller for semi-closed-loop control, an in silico testing environment, clinical testing, and system integration. An incremental approach was adopted to evaluate experimentally a model predictive glucose controller. A feasibility study was followed by efficacy studies of increasing complexity. The ADICOL project demonstrated feasibility of a semi-closed-loop glucose control during fasting and fed conditions with a wearable, modular extracorporeal artificial pancreas.

The artificial pancreas

In type 1 diabetes an absolute deficiency of insulin secretion requires exogenous insulin supply to guarantee the patient's life avoiding ketoacidotic coma and to prevent the chronic complications of diabetes. In order to obtain a more physiological replacement therapy different approaches have been pursued since the early 70s to create an artificial wearable pancreas able to deliver insulin according to the blood glucose values as determined by continuous monitoring. Four components are considered essential for the realisation of an artificial pancreas: the sampling system, the glucose sensor, the mathematical models and the related algorithms for the calculation of the insulin doses and the infusion system for the insulin delivery. At present the still unsolved issues are mainly represented by the availability of reliable continuous glucose monitor and control algorithms, while the new technologies allow for the miniaturisation of the system.

A model of the endogenous glucose balance incorporating the characteristics of glucose transporters

This paper describes the development and preliminary test of a model of the endogenous glucose balance that incorporates the characteristics of the glucose transporters GLUT1, GLUT3 and GLUT4. In the modeling process the model is parameterized with nine parameters that are subsequently estimated from data in the literature on the hepatic- and endogenous- balances at various combinations of blood glucose and insulin levels. The ability of the resulting endogenous balance to fit blood glucose measured from patients was tested on 20 patients. The fit obtained with this model compared favorably with the fit obtained with the endogenous balance currently incorporated in the DIAS system.

Cardiovascular risk factors in type 2 diabetes: the role of hyperglycaemia

Macrovascular complications are the most important causes of morbidity, mortality and disability in people with Type 2 diabetes mellitus. Although other known risk factors for macrovascular disease (e.g. dyslipidaemia, hypertension, obesity) often co-exist, diabetes itself is an important risk factor for accelerated development of atherosclerosis. Hyperglycaemia, hyperinsulinaemia and insulin resistance may each play a major role in the onset and development of atherosclerotic disease, which causes arterial wall dysfunction, haematological disturbances and lipid abnormalities through two mechanisms: oxidative stress and non-enzymatic glycation. Hyperglycaemia induces damage to the endothelium through activation of mitogen-activated protein kinase, protein kinase C and transcription factor nuclear factor (NF)-kappaB and through increased levels of pro-adhesion proteins such as intracellular adhesion molecule (ICAM)-1. The arterial wall tone is shifted towards vasoconstriction by hyperglycaemia, which is also associated with vascular smooth muscle cell proliferation and increased intimal wall thickness. Alteration of the coagulation system towards thrombophilia is observed in Type 2 diabetes and a series of lipid abnormalities that facilitate the development of atherosclerosis is evident. In Type 2 diabetes, undiagnosed disease and unrecognized postprandial hyperglycaemia are becoming the most relevant issues in reducing the risk of vascular complications and cardiovascular mortality; improved glycaemic control may reduce the incidence of macrovascular complications.