Banting Memorial Lecture 2014* Technology and diabetes care: appropriate and personalized

New technical approach to the diabetes therapy

Optimal glycemic control remains challenging in individuals with type 1 diabetes. With the comprehensive clinical evidence on safety and efficiency, the adoption of continuous glucose monitoring (CGM), insulin pumps, and control algorithms merging the two into closed-loop systems is rapidly increasing. Particularly the CGM and intermittently scanned CGM improved diabetes management outcomes in large populations. A meaningful translation from clinical trials in highly controlled settings to numerous evaluations of closed-loop technology in the unrestricted home environment ended with its commercialization and use in routine clinical practice. Although it is still not a cure, the closed-loop currently seems to be the most promising advancement in the treatment of diabetes, with promising results also reported from routine clinical practice in children and adults with type 1 diabetes. We summarize different aspects of a technological approach to diabetes care, list currently available devices and systems in the pipeline, and the key supporting clinical evidence for their use. We consider human factors associated with technology use and the importance of health economics to support implementation and reimbursement.

Is insulin pump therapy effective in Type 1 diabetes?

There continues to be uncertainty about the effectiveness in Type 1 diabetes of insulin pump therapy (continuous subcutaneous insulin infusion, CSII) vs. multiple daily insulin injections (MDI). This narrative review discusses the reasons for this uncertainty, summarizes the current evidence base for CSII and suggests some future research needs. There are difficulties in interpreting trials of CSII because effectiveness varies widely due to factors such as differing baseline control, suboptimal use of best CSII practices, and psychological factors, for example, high external locus of control, non-adherence and lack of motivation. Many summary meta-analyses are also misleading because of poor trial selection (e.g. short duration, obsolete pumps, low baseline rate of hypoglycaemia) and reliance on mean effect size for decision-making. Both MDI and CSII can achieve strict glycaemic control without hypoglycaemia in some people with Type 1 diabetes, especially those who are motivated and have undergone structured diabetes education, and with high levels of ongoing input from healthcare professionals. CSII is particularly effective in those people with Type 1 diabetes who have not achieved target HbA_1c levels without disabling hypoglycaemia using best attempts with MDI, and here there can be valuable and substantial improvement. Insulin pumps are safe, effective and accepted when used in newly diagnosed diabetes, particularly in children, where MDI may not be practicable. Future research needs include more studies on mortality associated with insulin pumps where registry data have suggested lower rates vs. MDI; and psychological strategies to improve non-adherence and suboptimal glycaemic outcomes on CSII.

Update on the General Practice Optimising Structured Monitoring to Improve Clinical Outcomes in Type 2 Diabetes (GP-OSMOTIC) trial: statistical analysis plan for a multi-centre randomised controlled trial

BACKGROUND

General Practice Optimising Structured Monitoring to Improve Clinical Outcomes in Type 2 Diabetes (GP-OSMOTIC) is a multicentre, individually randomised controlled trial aiming to compare the use of intermittent retrospective continuous glucose monitoring (r-CGM) to usual care in patients with type 2 diabetes attending general practice. The study protocol was published in the British Medical Journal Open and described the principal features of the statistical methods that will be used to analyse the trial data. This paper provides greater detail on the statistical analysis plan, including background and justification for the statistical methods chosen, in accordance with SPIRIT guidelines.

OBJECTIVE

To describe in detail the data management process and statistical methods that will be used to analyse the trial data.

METHODS

An overview of the trial design and primary and secondary research questions are provided. Sample size assumptions and calculations are explained, and randomisation and data management processes are described in detail. The planned statistical analyses for primary and secondary outcomes and sub-group analyses are specified along with the intended table layouts for presentation of the results.

CONCLUSION

In accordance with best practice, all analyses outlined in the document are based on the aims of the study and have been pre-specified prior to the completion of data collection and outcome analyses.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12616001372471 . Registered on 3 August 2016.

GP-OSMOTIC trial protocol: an individually randomised controlled trial to determine the effect of retrospective continuous glucose monitoring (r-CGM) on HbA1c in adults with type 2 diabetes in general practice

INTRODUCTION

Optimal glycaemia can reduce type 2 diabetes (T2D) complications. Observing retrospective continuous glucose monitoring (r-CGM) patterns may prompt therapeutic changes but evidence for r-CGM use in T2D is limited. We describe the protocol for a randomised controlled trial (RCT) examining intermittent r-CGM use (up to 14 days every three months) in T2D in general practice (GP).

METHODS AND ANALYSIS

General Practice Optimising Structured MOnitoring To achieve Improved Clinical Outcomes is a two-arm RCT asking 'does intermittent r-CGM in adults with T2D in primary care improve HbA1c?'

PRIMARY OUTCOME

Absolute difference in mean HbA1c at 12 months follow-up between intervention and control arms.

SECONDARY OUTCOMES

(a) r-CGM per cent time in target (4-10 mmol/L) range, at baseline and 12 months; (b) diabetes-specific distress (Problem Areas in Diabetes).

ELIGIBILITY

Aged 18-80 years, T2D for ≥1 year, a (past month) HbA1c>5.5 mmol/mol (0.5%) above their individualised target while prescribed at least two non-insulin hypoglycaemic therapies and/or insulin (therapy stable for the last four months). Our general glycaemic target is 53 mmol/mol (7%) (patients with a history of severe hypoglycaemia or a recorded diagnosis of hypoglycaemia unawareness will have a target of 64 mmol/mol (8%)).Our trial compares r-CGM use and usual care. The r-CGM report summarising daily glucose patterns will be reviewed by GP and patient and inform treatment decisions. Participants in both arms are provided with 1 hour education by a specialist diabetes nurse.The sample (n=150/arm) has 80% power to detect a mean HbA1c difference of 5.5 mmol/mol (0.5%) with an SD of 14.2 (1.3%) and alpha of 0.05 (allowing for 10% clinic and 20% patient attrition).

ETHICS AND DISSEMINATION

University of Melbourne Human Ethics Sub-Committee (ID 1647151.1). Dissemination will be in peer-reviewed journals, conferences and a plain-language summary for participants.

TRIAL REGISTRATION NUMBER

>ACTRN12616001372471; Pre-results.

Behavioral Patterns and Associations with Glucose Control During 12-Week Randomized Free-Living Clinical Trial of Day and Night Hybrid Closed-Loop Insulin Delivery in Adults with Type 1 Diabetes

OBJECTIVES

We evaluated patterns of meal intake, insulin bolus delivery, and fingerstick glucose measurements during hybrid closed-loop and sensor-augmented pump (SAP) therapy, including associations with glucose control.

METHODS

Data were retrospectively analyzed from pump-treated adults with type 1 diabetes who underwent, in random order, 12 weeks free-living closed-loop (n = 32) and 12 weeks SAP (n = 33) periods. We quantified daily patterns of main meals, snacks, prandial insulin boluses, correction boluses, and fingerstick glucose measurements by analyzing data recorded on the study glucometer and on study insulin pump.

RESULTS

We analyzed 1942 closed-loop days and 2530 SAP days. The total number of insulin boluses was reduced during closed-loop versus SAP periods by mean 1.0 per day (95% confidence interval 0.6-1.4, P < 0.001) mainly because of a reduced number of correction boluses by mean 0.7 per day (0.4-1.0, P < 0.001). Other behavioral patterns were unchanged. The carbohydrate content of snacks but not the number of snacks was positively correlated with (1) glycemic variability as measured by standard deviation of sensor glucose (closed-loop P < 0.05; SAP P < 0.01), (2) mean sensor glucose (P < 0.05), and (3) postintervention HbA1c (P < 0.05). Behavioral patterns explained 47% of between-subject variance in glucose variability during SAP period and 30%-33% of variance of means sensor glucose and postintervention HbA1c.

CONCLUSION

Fewer correction boluses are delivered during closed-loop period. The size of snacks appears to worsen glucose control possibly because of carbohydrate-rich content of snacks. Modifiable behavioral patterns may be important determinants of glucose control.

"It Is Definitely a Game Changer": A Qualitative Study of Experiences with In-home Overnight Closed-Loop Technology Among Adults with Type 1 Diabetes

BACKGROUND

This qualitative study explored trial participants' experiences of four nights of in-home closed loop.

METHODS

Sixteen adults with type 1 diabetes, who completed a randomized crossover trial, were interviewed after four consecutive nights of closed-loop. Interviews were audio recorded, transcribed, and analyzed with a coding framework developed to identify the main themes.

RESULTS

Participants had a mean age of 42 ± 10 years, nine were women; mean diabetes duration was 27 ± 7 years, and all were using insulin pumps. Overall, first impressions were positive. Participants found closed-loop easy to use and understand. Most experienced more stable overnight glucose levels, although for some these were similar to usual care or higher than they expected. Compared with their usual treatment, they noticed the proactive nature of the closed-loop, being able to predict trends and deliver micro amounts of insulin. Most reported technical glitches or inconveniences during one or more nights, such as transmission problems, problematic connectivity between devices, ongoing alarms despite addressing low glucose levels, and sensor inaccuracy. Remote monitoring by the trial team and their own hypoglycemic awareness contributed to feelings of trust and safety. Although rare, safety concerns were raised, related to feeling unsure whether the system would respond in time to falling glucose levels.

CONCLUSIONS

This study provides relevant insights for implementation of closed-loop in the real world. For people with diabetes who are less familiar with technology, remote monitoring for the first few days may provide reassurance, strengthen their trust/skills, and make closed-loop an acceptable option for more people with type 1 diabetes.

Smooth muscle-generated methylglyoxal impairs endothelial cell-mediated vasodilatation of cerebral microvessels in type 1 diabetic rats

BACKGROUND AND PURPOSE

Endothelial cell-mediated vasodilatation of cerebral arterioles is impaired in individuals with Type 1 diabetes (T1D). This defect compromises haemodynamics and can lead to hypoxia, microbleeds, inflammation and exaggerated ischaemia-reperfusion injuries. The molecular causes for dysregulation of cerebral microvascular endothelial cells (cECs) in T1D remains poorly defined. This study tests the hypothesis that cECs dysregulation in T1D is triggered by increased generation of the mitochondrial toxin, methylglyoxal, by smooth muscle cells in cerebral arterioles (cSMCs).

EXPERIMENTAL APPROACH

Endothelial cell-mediated vasodilatation, vascular transcytosis inflammation, hypoxia and ischaemia-reperfusion injury were assessed in brains of male Sprague-Dawley rats with streptozotocin-induced diabetes and compared with those in diabetic rats with increased expression of methylglyoxal-degrading enzyme glyoxalase-I (Glo-I) in cSMCs.

KEY RESULTS

After 7-8 weeks of T1D, endothelial cell-mediated vasodilatation of cerebral arterioles was impaired. Microvascular leakage, gliosis, macrophage/neutrophil infiltration, NF-κB activity and TNF-α levels were increased, and density of perfused microvessels was reduced. Transient occlusion of a mid-cerebral artery exacerbated ischaemia-reperfusion injury. In cSMCs, Glo-I protein was decreased, and the methylglyoxal-synthesizing enzyme, vascular adhesion protein 1 (VAP-1) and methylglyoxal were increased. Restoring Glo-I protein in cSMCs of diabetic rats to control levels via gene transfer, blunted VAP-1 and methylglyoxal increases, cECs dysfunction, microvascular leakage, inflammation, ischaemia-reperfusion injury and increased microvessel perfusion.

CONCLUSIONS AND IMPLICATIONS

Methylglyoxal generated by cSMCs induced cECs dysfunction, inflammation, hypoxia and exaggerated ischaemia-reperfusion injury in diabetic rats. Lowering methylglyoxal produced by cSMCs may be a viable therapeutic strategy to preserve cECs function and blunt deleterious downstream consequences in T1D.

Immunosensors for Biomarker Detection in Autoimmune Diseases

Autoimmune diseases occur when the immune system generates proinflammatory molecules and autoantibodies that mistakenly attack their own body. Traditional diagnosis of autoimmune disease is primarily based on physician assessment combined with core laboratory tests. However, these tests are not sensitive enough to detect early molecular events, and quite often, it is too late to control these autoimmune diseases and reverse tissue damage when conventional tests show positivity for disease. It is fortunate that during the past decade, research in nanotechnology has provided enormous opportunities for the development of ultrasensitive biosensors in detecting early biomarkers with high sensitivity. Biosensors consist of a biorecognition element and a transducer which are able to facilitate an accurate detection of proinflammatory molecules, autoantibodies and other disease-causing molecules. Apparently, novel biosensors could be superior to traditional metrics in assessing the drug efficacy in clinical trials, especially when specific biomarkers are indicative of the pathogenesis of disease. Furthermore, the portability of a biosensor enables the development of point-of-care devices. In this review, various types of biomolecule sensing systems, including electrochemical, optical and mechanical sensors, and their applications and future potentials in autoimmune disease treatment were discussed.

Type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is an expanding global health problem, closely linked to the epidemic of obesity. Individuals with T2DM are at high risk for both microvascular complications (including retinopathy, nephropathy and neuropathy) and macrovascular complications (such as cardiovascular comorbidities), owing to hyperglycaemia and individual components of the insulin resistance (metabolic) syndrome. Environmental factors (for example, obesity, an unhealthy diet and physical inactivity) and genetic factors contribute to the multiple pathophysiological disturbances that are responsible for impaired glucose homeostasis in T2DM. Insulin resistance and impaired insulin secretion remain the core defects in T2DM, but at least six other pathophysiological abnormalities contribute to the dysregulation of glucose metabolism. The multiple pathogenetic disturbances present in T2DM dictate that multiple antidiabetic agents, used in combination, will be required to maintain normoglycaemia. The treatment must not only be effective and safe but also improve the quality of life. Several novel medications are in development, but the greatest need is for agents that enhance insulin sensitivity, halt the progressive pancreatic β-cell failure that is characteristic of T2DM and prevent or reverse the microvascular complications. For an illustrated summary of this Primer, visit: http://go.nature.com/V2eGfN.