Fear of hypoglycemia in type 1 diabetes managed by continuous subcutaneous insulin infusion: is it associated with poor glycemic control?

Evaluation of the possible impact of the fear of hypoglycemia on diabetes management in children and adolescents with type 1 diabetes mellitus and their parents: a cross-sectional study

PURPOSE

Hypoglycemia represents a significant source of anxiety for children with type 1 diabetes mellitus (T1DM) and their caretakers. Fear of hypoglycemia (FoH) was measured in children and adolescents with T1DM as well as in their parents using an established research instrument, the Hypoglycemia Fear Survey (HFS).

METHODS

This is a two-center, cross-sectional study involving 100 children and adolescents aged 6-18 years old diagnosed with T1DM. One parent of each child also participated in the study. The participants, who were recruited from two different pediatric endocrine outpatient clinics, were asked to complete the translated Greek version of the HFS, which includes one version for children (C-HFS) and one for parents (P-HFS). The association of the questionnaire responses with subjects' characteristics, such as current age, age at diagnosis, duration of diabetes, HbA1c levels, and mode of diabetes treatment were assessed.

RESULTS

Parents exhibited significantly higher mean HFS scores than their children. No significant correlation was found between the P-HFS or the C-HFS scores and the age of the children, duration of diabetes, HbA1c, or mode of treatment.

CONCLUSION

The finding that parents experience higher levels of FoH compared to their children emphasizes the importance of healthcare providers to screen parental FoH and focus on approaches to support them in order to reduce their psychological burden, thus optimizing children's diabetes management.

Impact of Flash Glucose Monitoring on the Fear of Hypoglycemia Phenomenon in Adults with Type 1 Diabetes

Objective: To assess the clinical impact of flash glucose monitoring (FGM) systems on fear of hypoglycemia (FoH) and quality of life in adults with type 1 diabetes mellitus (T1DM). Methods: Prospective quasi-experimental study with a 12-month follow-up. People with T1DM (18-80 years old) and self-monitoring by blood capillary glycemia controls were included. The FH15 questionnaire, a survey validated in Spanish in a comparable study population, was used to diagnose FoH with a cutoff point of 28 points. Results: A total of 181 participants were included, with a FoH prevalence of 69% (n = 123). A mean reduction in FH15 score of -4 points (95% confidence interval [-5.5 to -3]; P < 0.001) was observed, along with an improvement in quality of life (EsDQOL-test (Diabetes Quality of Life, Spanish version), -7 points [-10; -4], P < 0.001) and satisfaction with treatment (Diabetes Treatment Satisfaction questionnaire, self-reported version [DTSQ-s] test, +4.5 points [4; 5.5], P < 0.001). At the end of the follow-up, 64.2% of the participants saw an improved FoH intensity, compared to 35.8% who scored the same or higher. This improvement in FoH status was associated with a higher time-in-range at the end of the follow-up (P = 0.003), as well as a lower time spent in hyperglycemia (P = 0.005). In addition, it was linked to participants with a high baseline FoH levels (P < 0.001) and those who were university degree holders (P = 0.07). Conclusions: FGM is associated with an overall reduction of FoH in adults with T1DM and with an increase in their quality of life. Nevertheless, a significant percentage of patients may experience an increase of this phenomenon leading to clinical repercussions and a profound impact on quality of life.

Relationship between depressive and anxiety symptoms and fear of hypoglycemia among adolescents and adults with type 1 diabetes mellitus

BACKGROUND AND AIMS

Emotional problems including anxiety, depression and fear of hypoglycemia (FOH) are common in patients with type 1 diabetes mellitus (T1DM). The aim of this study was to determine the prevalence of depressive and anxiety symptoms among patients with T1DM and their relation to glycemic control, diabetes complications and to FOH.

METHODS

This study included 325 patients with T1DM. Anxiety and depressive symptoms were assessed by Hospital Anxiety and Depression Scale (HADS) and FOH was assessed by Hypoglycemia Fear Survey II (HFS-II). Glycemic control was assessed by both fasting plasma glucose and HbA1c. A subsample of 75 patients was screened for diabetes complications.

RESULTS

The prevalence of anxiety symptoms, depressive symptoms and FOH was 76.3%, 61.8% and 20% respectively. Female sex was related to depressive symptoms but not to anxiety symptoms. Logistic regression analysis showed that both HbA1c and HFS-II total score were independently correlated with both anxiety symptoms and depressive symptoms. Age showed independent correlation with both HFS-II (total score) and with Hypoglycemia Fear Survey-worry (HFS-W) while HbA1c showed independent correlation with Hypoglycemia Fear Survey-behavior (HFS-B). Both anxiety and depressive symptoms were positively correlated to HFS-B score, HFS-W score and HFS-II total score.

CONCLUSIONS

FOH is not uncommon among Egyptian patients with T1DM and it seems to be one of the factors contributing to the increased prevalence of anxiety and depressive symptoms among those individuals. Addressing and managing the different psychological aspects of diabetes should be integrated within the routine diabetes care services for people with T1DM.

The Hypoglycemic Fear Syndrome: Understanding and Addressing This Common Clinical Problem in Adults With Diabetes

Although a broad literature on fear of hypoglycemia and its impact on people with type 1 or type 2 diabetes has accumulated over the past three decades, there has been surprisingly little guidance concerning how best to tackle this problem in clinical care. The aim of this article is to begin filling this gap by describing the "hypoglycemic fear syndrome," which we define as hypoglycemic fear that has become so overwhelming that it leads to avoidance behaviors and chronically elevated glucose levels. We begin by presenting several illustrative cases, describing the syndrome and how it is most commonly presented in clinical care, and detailing its most common precipitants. We then offer practical, evidence-based strategies for clinical intervention, based on the literature and our clinical experience.

Evaluation of quality of life and physical activity in patients with type 1 diabetes mellitus during the COVID-19 pandemic

Objective

The aim of the study is to compare the quality of life, physical activity, anxiety, depression, fear of hypoglycemia, loneliness perception in patients with type 1 diabetes mellitus and controls.

Subjects and methods

Forty-four patients and 63 controls were included in this cross-sectional study. Quality of life (Short Form 36-SF-36), physical activity level (International Physical Activity Questionnaire-short form), anxiety and depression (Hospital Anxiety and Depression Scale), fear of hypoglycemia (Hypoglycemia Fear Survey), loneliness perception (UCLA Loneliness Scale) were evaluated.

Results

Physical role limitations and general health perception subscale scores of SF-36 questionnaire in patients were significantly higher than the controls (p < 0.05).

Conclusion

Role limitations due to physical problems and fear of hypoglycemia are increased, and general health perception is impaired in patients with type 1 diabetes mellitus. Physical inactivity is an important symptom in individuals in the pandemic period. In this regard, telerehabilitation approaches will be beneficial for all individuals in increasing physical activity, improving quality of life, and decreasing anxiety, depression and loneliness perception during the pandemic period for all individuals. The importance of a multidisciplinary approach in diabetes management and dealing with problems should be considered in pandemic.

Proof-of-concept Study of Using Supervised Machine Learning Algorithms to Predict Self-care and Glycemic Control in Type 1 Diabetes Patients on Insulin Pump Therapy

OBJECTIVE

Using supervised machine learning algorithms (SMLAs), we built models to predict the probability of type 1 diabetes mellitus (T1DM) patients on insulin pump therapy for meeting insulin pump self-management behavioral (IPSMB) criteria and achieving good glycemic response within six months.

METHODS

This was a single-center retrospective chart review of 100 adult T1DM patients on insulin pump therapy (>6 months). Three SMLAs were deployed: multivariable logistic regression (LR), random forest (RF), and K-nearest neighbor (k-NN); validated using repeated three-fold cross-validation. Performance metrics included AUC-ROC for discrimination and Brier scores for calibration.

RESULTS

Variables predictive of adherence with IPSMB criteria were baseline HbA1c, continuous glucose monitoring (CGM), and sex. The models had comparable discriminatory power (LR=0.74; RF=0.74; k-NN=0.72), with the random forest model showing better calibration (Brier=0.151). Predictors of the good glycemic response included baseline HbA1c, entering carbohydrates, and following the recommended bolus dose, with models comparable in discriminatory power (LR=0.81, RF=0.80, k-NN=0.78) but the random forest model being better calibrated (Brier=0.099).

CONCLUSION

These proof-of-concept analyses demonstrate the feasibility of using SMLAs to develop clinically relevant predictive models of adherence with IPSMB criteria and glycemic control within six months. Subject to further study, non-linear prediction models may perform better.

Impact of continuous glucose monitoring in youth with type 1 diabetes aged 15-21 years

BACKGROUND

People with type 1 diabetes (T1D) aged <21 years are eligible for subsidised continuous glucose monitoring (CGM) products under the Australian National Diabetes Services Scheme. There are few real-world published studies to evaluate the benefits of CGM in young adults.

AIMS

To perform a real-world observation study among youth with T1D to evaluate CGM use and benefits of CGM.

METHODS

Patients at the Westmead Hospital Young Adult Diabetes Clinic aged 15-21 years who commenced CGM before July 2018 were followed for 6 months post commencement of CGM. Differences in HbA1c and glucose metrics at baseline and follow up are compared between those commencing CGM and those that did not.

RESULTS

Forty-four (38%) of 115 eligible patients commenced CGM. Demographic characteristics and baseline HbA1c did not differ significantly between those started on CGM and those that did not. At 6 months, 18 (41%) of 44 patients still used CGM, with discomfort and inconvenience the most common reasons for dropout. In CGM continuers, at 6 months compared with baseline, there was no change in HbA1c (8.2% vs 8.0%; P = 0.8), coefficient of variation of glucose (38% vs 39%; P = 0.5) or percentage time in range (52% vs 58%; P = 0.3). Six-month follow-up HbA1c in CGM non-users deteriorated significantly compared with users. Mean hypoglycaemia fear scores (worry scale) were significantly decreased from baseline at 6 months (33 vs 18; P < 0.01).

CONCLUSION

There are high rates of discontinuation in CGM use among youth with T1D. At 6 months of CGM use, there was no significant change in glycaemic control, although HbA1c in non-users deteriorated significantly. Worry of hypoglycaemia was significantly decreased among those who continued CGM.

Basal-IQ technology in the real world: satisfaction and reduction of diabetes burden in individuals with type 1 diabetes

AIM

To describe person-reported outcomes of the Basal-IQ predictive low-glucose-suspend system (Tandem Diabetes Care, San Diego, CA, USA) in real-world use.

METHODS

Adults with type 1 diabetes/caregivers of minors with type 1 diabetes completed the Diabetes Impact and Device Satisfaction questionnaire (11 items scored on 10-point Likert scales) prior to Basal-IQ system initiation, and at 2, 4 and 6 months post-initiation. Analysis was stratified by previous insulin treatment method. Beta mixed models were used to measure change in device satisfaction (e.g. trust, ease of use) and diabetes impact (e.g. hypoglycaemia fear, poor sleep) scores between time points, adjusting for baseline covariates.

RESULTS

A total of 967 adults and caregivers [54% women, mean (sd) age 36 (17) years, 57% Tandem pump users, 27% non-Tandem pump users, 17% multiple daily injection users] completed surveys. Device satisfaction significantly increased from baseline to 2 months in all groups (P<0.001 multiple daily injection and non-Tandem pump users; P=0.048 Tandem pump users), and was sustained from 2 to 6 months in all groups. Diabetes impact decreased significantly from baseline to 2 months in all groups (P<0.001 for all), was sustained from 2 to 6 months in multiple daily injection and Tandem pump users, and increased slightly at 4 months/decreased at 6 months in non-Tandem users.

CONCLUSION

The Basal-IQ system increased device satisfaction and reduced diabetes impact in all users in the first 2 months of use, and satisfaction was sustained over 6 months, with small fluctuations.

The impact of hypoglycaemia on quality of life outcomes among adults with type 1 diabetes: A systematic review

Hypoglycaemia is a common barrier to optimal glycaemic management and often feared among adults with type 1 diabetes. The aim of this systematic review was to summarize current evidence regarding the impact of hypoglycaemia on quality of life (QoL) and related outcomes. Electronic searches of MEDLINE, PsycINFO, CINAHL, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials were conducted. Peer-reviewed empirical studies investigating the relationship between hypoglycaemia and QoL were eligible for inclusion. Thirty studies met the inclusion criteria. Extracted data was summarized in a narrative synthesis according to Synthesis Without Meta-Analysis guidelines. None of the studies examined the impact of hypoglycaemia on general QoL. There was no association between hypoglycaemia and diabetes-specific QoL in four of the 30 studies. Severe hypoglycaemia was associated with greater fear of hypoglycaemia and diabetes distress, and lower general emotional well-being, but not with depression, anxiety, or health status. Self-treated hypoglycaemia was associated with greater fear of hypoglycaemia. With the exception of fear of hypoglycaemia, this review shows mixed associations between hypoglycaemia and psychological outcomes. Further research is needed to investigate the impact of hypoglycaemia on other domains of QoL.

Psychosocial factors associated with HbA1c in adults with insulin pump-treated type 1 diabetes: a systematic review

AIMS

To identify currently available studies on the association between psychosocial factors and HbA_1c in adults with insulin pump-treated type 1 diabetes, by performing a systematic review of the literature.

METHODS

MEDLINE, Embase, CINAHL and PsycINFO were searched for original studies on the association between psychosocial factors and HbA_1c in ≥ 50 adult, non-pregnant, insulin pump users with type 1 diabetes.

RESULTS

The search resulted in 1777 unique records, of which eight were eligible for inclusion. All identified studies were observational, with sample sizes ranging from 51 to 214. Seven different psychosocial factors were investigated in the eight studies. Study analysis suggested that HbA_1c may be associated with diabetes numeracy and quality of life. There were no indications of associations between HbA_1c and fear of hypoglycaemia or self-efficacy. Results regarding associations between HbA_1c and coping style, diabetes distress and locus of control were inconsistent.

CONCLUSIONS

This systematic review summarizes the currently limited information on the association between psychosocial factors and HbA_1c during insulin pump therapy. The evidence base of the included studies was weak, and this review highlights the need for more research in these areas, with improved methodological and theoretical frameworks, including exploration of a broader spectrum of psychosocial variables and their potential association with HbA_1c and other metabolic outcomes. (PROSPERO International prospective register of systematic reviews registration no: CRD42020145705).

Health anxiety and illness-related fears across diverse chronic illnesses: A systematic review on conceptualization, measurement, prevalence, course, and correlates

BACKGROUND

Patients with chronic diseases commonly report fears of illness or symptoms recurring or worsening. These fears have been addressed from an illness-specific perspective (e.g., fear of cancer recurrence), a generic illness perspective (e.g., fear of progression), and a psychiatric perspective (DSM-5 illness anxiety disorder and somatic symptom disorder). The broader concept of health anxiety (HA) can also be applied to patients with a chronic disease. This review was conducted to investigate the conceptual, theoretical, measurement-overlap, and differences between these distinct perspectives. We also aimed to summarize prevalence, course, and correlates of these fears in different chronic illnesses.

METHODS

We used PsycINFO, PubMED, CINAHL, Web of Science, SCOPUS, and PSYNDEX to conduct a systematic review of studies pertaining to these fears in chronic illness published from January 1996 to October 2017. A total of 401 articles were retained.

RESULTS

There were commonalities across different conceptualizations and diseases: a high prevalence of clinical levels of fears (>20%), a stable course over time, and a deleterious impact on quality of life. Reviewed studies used definitions, models, and measures that were illness-specific, with only a minority employing a psychiatric perspective, limiting cross-disease generalizability. There appears to be some applicability of DSM-5 disorders to the experience of fear of illness/symptoms in patients with a chronic illness. While conceptualizing HA on a continuum ranging from mild and transient to severe may be appropriate, there is a lack of agreement about when the level of fear becomes 'excessive.' The definitions, models, and measures of HA across chronic illnesses involve affective, cognitive, behavioral, and perceptual features.

CONCLUSIONS

The concept of HA may offer a unifying conceptual perspective on the fears of illness/symptoms worsening or returning commonly experienced by those with chronic disease.

Establishment of the T1D Exchange Quality Improvement Collaborative (T1DX-QI)

The T1D Exchange established a learning platform by evaluating the current state of care and engaging 10 diabetes clinics in collaborative quality improvement (QI) activities. Participating clinics are sharing data and best practices to improve care delivery for people with type 1 diabetes. This article describes the design and initial implementation of this platform, known as the T1D Exchange Quality Improvement Collaborative. This effort has laid a foundation for learning from variation in type 1 diabetes care delivery via QI methodology and has demonstrated success in improving processes through iterative testing cycles and transparent sharing of data.

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.

Psychosocial benefits of insulin pump therapy in children with diabetes type 1 and their families: The pumpkin multicenter randomized controlled trial

OBJECTIVE

Continuous subcutaneous insulin infusion (CSII) is on the rise among pediatric patients with type 1 diabetes mellitus. Metabolic effects alone cannot explain this rising popularity. From the patient's perspective, the main benefits of CSII may be found in subjective psychosocial health outcomes (patient-reported outcomes [PRO]).

SUBJECTS AND METHODS

In a multicenter open randomized controlled trial, children and adolescents aged 6 to16 years currently treated with multiple daily injections (MDI) were randomized 1:1, stratified by center, to either starting with CSII immediately after the baseline interview or to continuing MDI while waiting 6 months for transmission to CSII. The primary outcomes were patient-reported diabetes-specific health-related quality of life (DHRQOL) and diabetes burden of the main caregiver. Secondary outcomes were caregiver stress, fear of hypoglycemia, satisfaction with treatment, and HbA1c.

RESULTS

Two-hundred and eleven patients were randomized between February 2011 and October 2014, and 186 caregivers and 170 patients were analyzed using the intention-to-treat principle for primary outcomes. Children 8 to 11 years in the CSII group reported improved DHRQOL at follow-up compared to MDI (median difference [MD] 9.5, 95% confidence interval [CI] 3.6-16.7, P = 0.004). There were no treatment differences in the adolescent age-group 12 to 16 years (MD 2.7; 95% CI -3.2-9.5; P = 0.353). The main caregivers of the CSII group reported a significant decline of overall diabetes burden at follow-up compared to the MDI group (MD 0; 95% CI -1-0; P = 0.029). Secondary PROs also were in favor of CSII.

CONCLUSIONS

CSII has substantial psychosocial benefits. PROs demonstrate these benefits. Registered as NCT01338922 at clinicaltrials.gov.

Adaptive fuzzy integral sliding mode control of blood glucose level in patients with type 1 diabetes: In silico studies

Currently, artificial pancreas is an alternative treatment instead of insulin therapy for patients with type 1 diabetes mellitus. Closed-loop control of blood glucose level (BGL) is one of the difficult tasks in biomedical engineering field due to nonlinear time-varying dynamics of insulin-glucose relation that is combined with time delays and model uncertainties. In this paper, we propose a novel adaptive fuzzy integral sliding mode control scheme for BGL regulation. System dynamics is identified online using fuzzy logic systems. The presented method is evaluated in silico studies by nine different virtual patients in three different groups for two continuous days. Simulation results demonstrate effective performance of the proposed control scheme of BGL regulation in presence of simultaneous meal and physical exercise disturbances. Comparison of the proposed control method with proportional-integral-derivative (PID) control and model predictive control (MPC) shows a superiority of the adaptive fuzzy integral sliding mode control with regard to two conventional methods of BGL regulation (PID and MPC) and sliding mode control.

A longitudinal study of fear of hypoglycaemia in adults with type 1 diabetes

AIMS

To investigate fear of hypoglycaemia (FoH) longitudinally in a cross-sectional study of adult patients with type 1 diabetes. Specifically, we investigated two subgroups of patients who over 4 years either showed a substantial increase or decrease in level of FoH to identify factors associated with changes in FoH.

METHODS

The Swedish version of the Hypoglycaemia Fear Survey (HFS) along with a questionnaire to assess hypoglycaemia history was sent by mail to 764 patients in 2010. The responders in 2010 (n = 469) received another set of the same two questionnaires in 2014. HbA1c, insulin regimen, weight and creatinine from 2010 and 2014 were obtained from medical records. Those with an absolute difference in HFS scores ≥ 75th percentile were included in the subgroup analyses. Statistical analyses included one-sample t tests, chi-square and McNemar's test.

RESULTS

The absolute difference in the HFS total score (n = 347) between 2010 and 2014 was m = ±7.6, SD ± 6. In the increased FoH group, more patients reported a high level of moderate hypoglycaemic episodes as well as impaired awareness of hypoglycaemia in 2014 compared with the decreased FoH group. There were more subjects in the increased FoH group with insulin pumps in 2014 and in 2010. In the decreased FoH group, more patients had a high frequency of daily self-monitoring of blood glucose (SMBG) in 2010 and in 2014.

CONCLUSIONS

Fear of hypoglycaemia is stable across time for most patients. Changes in fear level are associated with changes in hypoglycaemia frequency. Thus, asking patients about changes in hypoglycaemia experiences is of great importance.

A cluster randomised trial, cost-effectiveness analysis and psychosocial evaluation of insulin pump therapy compared with multiple injections during flexible intensive insulin therapy for type 1 diabetes: the REPOSE Trial

BACKGROUND

Insulin is generally administered to people with type 1 diabetes mellitus (T1DM) using multiple daily injections (MDIs), but can also be delivered using infusion pumps. In the UK, pumps are recommended for patients with the greatest need and adult use is less than in comparable countries. Previous trials have been small, of short duration and have failed to control for training in insulin adjustment.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of pump therapy compared with MDI for adults with T1DM, with both groups receiving equivalent structured training in flexible insulin therapy.

DESIGN

Pragmatic, multicentre, open-label, parallel-group cluster randomised controlled trial, including economic and psychosocial evaluations. After participants were assigned a group training course, courses were randomly allocated in pairs to either pump or MDI.

SETTING

Eight secondary care diabetes centres in the UK.

PARTICIPANTS

Adults with T1DM for > 12 months, willing to undertake intensive insulin therapy, with no preference for pump or MDI, or a clinical indication for pumps.

INTERVENTIONS

Pump or MDI structured training in flexible insulin therapy, followed up for 2 years. MDI participants used insulin analogues. Pump participants used a Medtronic Paradigm^® Veo^TM (Medtronic, Watford, UK) with insulin aspart (NovoRapid, Novo Nordisk, Gatwick, UK).

MAIN OUTCOME MEASURES

Primary outcome - change in glycated haemoglobin (HbA_1c) at 2 years in participants whose baseline HbA_1c was ≥ 7.5% (58 mmol/mol). Key secondary outcome - proportion of participants with HbA_1c ≤ 7.5% at 2 years. Other outcomes at 6, 12 and 24 months - moderate and severe hypoglycaemia; insulin dose; body weight; proteinuria; diabetic ketoacidosis; quality of life (QoL); fear of hypoglycaemia; treatment satisfaction; emotional well-being; qualitative interviews with participants and staff (2 weeks), and participants (6 months); and ICERs in trial and modelled estimates of cost-effectiveness.

RESULTS

We randomised 46 courses comprising 317 participants: 267 attended a Dose Adjustment For Normal Eating course (132 pump; 135 MDI); 260 were included in the intention-to-treat analysis, of which 235 (119 pump; 116 MDI) had baseline HbA_1c of ≥ 7.5%. HbA_1c and severe hypoglycaemia improved in both groups. The drop in HbA_1c% at 2 years was 0.85 on pump and 0.42 on MDI. The mean difference (MD) in HbA_1c change at 2 years, at which the baseline HbA_1c was ≥ 7.5%, was -0.24% [95% confidence interval (CI) -0.53% to 0.05%] in favour of the pump (p = 0.098). The per-protocol analysis showed a MD in change of -0.36% (95% CI -0.64% to -0.07%) favouring pumps (p = 0.015). Pumps were not cost-effective in the base case and all of the sensitivity analyses. The pump group had greater improvement in diabetes-specific QoL diet restrictions, daily hassle plus treatment satisfaction, statistically significant at 12 and 24 months and supported by qualitative interviews.

LIMITATION

Blinding of pump therapy was not possible, although an objective primary outcome was used.

CONCLUSION

Adding pump therapy to structured training in flexible insulin therapy did not significantly enhance glycaemic control or psychosocial outcomes in adults with T1DM.

RESEARCH PRIORITY

To understand why few patients achieve a HbA_1c of < 7.5%, particularly as glycaemic control is worse in the UK than in other European countries.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN61215213.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 20. See the NIHR Journals Library website for further project information.

Model-Fusion-Based Online Glucose Concentration Predictions in People with Type 1 Diabetes

Accurate predictions of glucose concentrations are necessary to develop an artificial pancreas (AP) system for people with type 1 diabetes (T1D). In this work, a novel glucose forecasting paradigm based on a model fusion strategy is developed to accurately characterize the variability and transient dynamics of glycemic measurements. To this end, four different adaptive filters and a fusion mechanism are proposed for use in the online prediction of future glucose trajectories. The filter fusion mechanism is developed based on various prediction performance indexes to guide the overall output of the forecasting paradigm. The efficiency of the proposed model fusion based forecasting method is evaluated using simulated and clinical datasets, and the results demonstrate the capability and prediction accuracy of the data-based fusion filters, especially in the case of limited data availability. The model fusion framework may be used in the development of an AP system for glucose regulation in patients with T1D.

Influence of health locus of control and fear of hypoglycaemia on glycaemic control and treatment satisfaction in people with Type 1 diabetes on insulin pump therapy

AIM

To assess the influence of health locus of control and fear of hypoglycaemia on metabolic control and treatment satisfaction in people with Type 1 diabetes mellitus on continuous subcutaneous insulin infusion.

METHODS

People with Type 1 diabetes on continuous subcutaneous insulin infusion for at least 1 year, sub-classified as an 'acceptable glucose control' group [HbA_1c ≤ 58 mmol/mol (7.5%)] and a 'suboptimum glucose control' group [HbA_1c > 58 mmol/mol (7.5%)], were consecutively enrolled in a multicentre cross-sectional study. Questionnaires were administered to assess health locus of control [Multidimensional Health Locus of Control (MHLC) scale, with internal and external subscales], fear of hypoglycaemia [Hypoglycaemia Fear Survey II (HFS-II)] and treatment satisfaction [Diabetes Treatment Satisfaction Questionnaire (DTSQ)].

RESULTS

We enrolled 214 participants (mean ± sd age 43.4 ± 12.1 years). The suboptimum glucose control group (n = 127) had lower mean ± sd internal MHLC and DTSQ scores than the acceptable glucose control group (19.6 ± 5.2 vs 21.0 ± 5.0, P = 0.04 and 28.8 ± 4.8 vs 30.9 ± 4.5, P < 0.001). HFS-II scores did not differ between the two groups. Internal MHLC score was negatively associated with HbA_1c (r = -0.15, P < 0.05) and positively associated with the number of mild and severe hypoglycaemic episodes (r = 0.16, P < 0.05 and r = 0.18, P < 0.001, respectively) and with DTSQ score (r = 0.17, P < 0.05). HFS-II score was negatively associated with DTSQ score (r = -0.18, P < 0.05) and positively with number of severe hypoglycaemic episodes (r = 0.16, P < 0.5).

CONCLUSIONS

In adults with Type 1 diabetes receiving continuous subcutaneous insulin infusion, high internal locus represents the most important locus of control pattern for achieving good metabolic control.

Fear of hypoglycemia: Influence on glycemic variability and self-management behavior in young adults with type 1 diabetes

PURPOSE

The purpose of this study was to examine how fear of hypoglycemia (FOH) is associated with glycemic variability (GV) and self-management behavior in young adults (aged 18-35) with type 1 diabetes (T1DM).

PROCEDURES

Using a prospective repeated-measures design, in 35 young adults, within- and between-person and temporal associations of FOH, specific self-management behaviors, and GV were measured. The data were collected using questionnaires and real-time measures using daily diaries, insulin pump downloads, actigraphy, and continuous glucose monitoring.

FINDINGS

FOH was associated with greater glycemic variability. Significant temporal associations emerged. Concurrent day (glucose SD, p=.011) and previous-evening fear levels were associated with GV (glucose SD, p=.007). FOH was also associated with greater calorie intake (r=.492, p=.003) and less physical activity (light activity, r=-.341, p=.045).

CONCLUSIONS

The significant associations of FOH with GV, dietary patterns, and physical activity provide evidence for FOH as an important psychological factor associated with diabetes care.

Fear of hypoglycaemia and self-management in type 1 diabetes

Aims

We studied the association between fear of hypoglycaemia (FoH) and various diabetes self-management practices.

Methods

Data from 798 individuals with type 1 diabetes participating in the FinnDiane Study were included. Self-reported questionnaires were used to assess FoH and self-management practices (e.g. dietary intake, insulin administration, physical activity). For glycaemic control, we used both the latest HbA_1c measurements and the serial HbA_1c measurements from the medical files. Factor analysis was used to reveal underlying constructs within the food frequency section of the diet questionnaire.

Results

In all, 44% and 63% of men and women reported FoH, respectively. In men, FoH was associated with higher mean serial HbA_1c levels, higher number of reported self-monitoring of blood glucose (SMBG), higher carbohydrate intake, and lower scores in the "high-fat" factor. In women, FoH was associated with a higher number of reported SMBGs and higher energy intake. No difference was observed in physical activity and insulin administration.

Conclusions

FoH has various implications for the self-management of diabetes. More studies are however needed to assess on one hand the association between FoH and diabetes self-management, and on the other hand, FoH and its long term consequences, such as the emergence of diabetic complications and mortality.

Fear of hypoglycemia in adults with type 1 diabetes: impact of therapeutic advances and strategies for prevention - a review

PURPOSE

This review summarizes the current state of the science related to fear of hypoglycemia (FOH) in adults with type 1 diabetes. Fear of hypoglycemia is a critical deterrent to diabetes self-management, psychological well-being, and quality of life. We examine the influence of contemporary treatment regimens, technology, and interventions to identify gaps in knowledge and opportunities for research and practice.

BASIC PROCEDURES

A literature search was conducted of MEDLINE, PsycINFO, and EMBASE. Fifty-three studies that examined fear of hypoglycemia were included.

MAIN FINDINGS

Fear of hypoglycemia influences diabetes management and quality of life. Gender and age differences exist in experiences and responses. Responses vary from increased vigilance to potentially immobilizing distress. Fear of hypoglycemia is greater at night and may contribute to poor sleep quality. Strategies to reduce fear of hypoglycemia have had varying success. Newer technologies hold promise but require further examination.

CONCLUSIONS

Fear of hypoglycemia remains a problem, despite advances in technology, insulin analogs, and evidence-based diabetes management. Clinical care should consistently include assessment for its influence on diabetes self-management and psychological health. Further research is needed regarding the influence of newer technologies and individualized strategies to reduce fear of hypoglycemia while maintaining optimal glucose control.

Anxiety in children and adolescents with type 1 diabetes

Although anxiety is a normal and developmentally appropriate experience of childhood and anxiety disorders are among the most commonly diagnosed disorders, the prevalence of anxiety symptomatology and anxiety disorders in children with type 1 diabetes (T1D) is not well documented. Most studies have focused on anxiety-related syndromes associated with T1D including fear of hypoglycemia, specific phobia of needles (i.e., needle anxiety), and anxiety related to uptake of new and sophisticated diabetes technology (e.g., continuous glucose monitors, continuous subcutaneous infusion therapy), but the extant literature is sparse, and more research is greatly needed. Identification, prevention, and treatment of anxiety are critical to providing comprehensive diabetes care and management. This review provides a summary of the literature focused on anxiety in children and adolescents with T1D with suggestions for future research and clinical implications.

Glycemic Control, Self-Efficacy and Fear of Hypoglycemia Among Iranian Children with Type 1 Diabetes

OBJECTIVE

This study was designed to test the reliability of a Persian version of 2 questionnaires to assess the level of fear of hypoglycemia (FoH) and self-efficacy in diabetes management and their association with glycated hemoglobin (A1C) and parents' demographic characteristics in a sample of children with type 1 diabetes.

DESIGN

We assessed 61 children with type 1 diabetes (35 boys and girls, 6.0 to 12.7 years of age) using the Hypoglycemia Fear Survey-Child version (HFS-C) and Self-Efficacy for Diabetes Scale-Child version (SED-C). Their glycemic control was evaluated by A1C levels.

RESULTS

The internal consistency of the Persian version of HFS-C and SED-C were very good. Our results showed that children older than 10 years of age report lower levels of FoH, which are related to higher levels of self-efficacy (r=-.30, p=0.025 and r=-.30, p=0.02, respectively). Of the children, 42.3% of girls and 31.4% of boys reported that low blood sugar is a big problem for them. These findings suggest that FoH is a significant concern for this target group. Only 19.7% of children had controlled diabetes based on A1C levels. There was no significant association between higher A1C levels and other variables, including HFS-C, SED-C and parents' demographic characteristics.

CONCLUSIONS

The Persian version of HFS-C and SED-C are reliable and valid measures of the fear of hypoglycemia and of self-efficacy in children with type 1 diabetes, and these questionnaires could be used in our country for identifying those children who may need diabetes education and other supports. The association between greater self-efficacy and lower fear of hypoglycemia suggests that addressing self-efficacy in diabetes education courses may be effective in helping to overcome FoH.

Variations in the quality and sustainability of long-term glycaemic control with continuous subcutaneous insulin infusion

AIMS

To investigate the pattern of changes in HbA1c in people with Type 1 diabetes managed by long-term Continuous subcutaneous insulin infusion.

METHODS

We studied HbA1c changes using computerized clinic records in 35 adult people with Type 1 diabetes and an elevated HbA1c (≥ 64 mmol/mol, 8.0%) on multiple daily insulin injections, who were then switched to continuous subcutaneous insulin infusion for at least 5 years.

RESULTS

We identified three subgroups with similar baseline HbA1c but different long-term responses to pump therapy: group A--those with improvement followed by deterioration (57%); group B--those with improvement that was sustained throughout the 5 years (31%); and group C-those where HbA1c did not change significantly from baseline (12%). The patients in group C had a higher BMI: 31.0 ± 5.2 vs. 25.9 ± 3.3 vs. 25.2 ± 3.1 kg/m² (group C vs. group A and group B; P = 0.02).

CONCLUSIONS

Improved glycaemic control with continuous subcutaneous insulin infusion was maintained over 5 years by 88% of people with Type 1 diabetes in this study, but there were variations in the long-term efficacy, with some people improving and worsening, others maintaining strict control and a few subcutaneous insulin infusion 'non-responders'.

Understanding the construct of fear of hypoglycemia in pediatric type 1 diabetes

OBJECTIVE

Fear of hypoglycemia (FoH) can be a significant barrier to glycemic control in pediatric type 1 diabetes (T1D). This study aimed to explore underlying constructs of the Hypoglycemia Fear Survey (HFS) for parents (PHFS) and children (CHFS).

METHODS

Data were aggregated from five studies of 259 youth with T1D and 250 parents. Exploratory Factor Analysis was used to determine the underlying factors of the CHFS and PHFS.

RESULTS

Similar four-factor solutions were found for the CHFS and PHFS. Both subscales consisted of two factors: Behavior Subscale (1) behaviors used to keep blood glucose (BG) high to prevent hypoglycemia (Maintain High BG) and (2) other actions to avoid hypoglycemia (Avoidance); Worry Subscale (1) concerns about helplessness (Helplessness) and (2) negative social consequences associated with hypoglycemia (Social Consequences).

CONCLUSIONS

 These constructs provide a more comprehensive understanding of pediatric FoH and have implications for interventions aimed at reducing FoH in this population.

The Relative Effectiveness of Pumps Over MDI and Structured Education (REPOSE): study protocol for a cluster randomised controlled trial

INTRODUCTION

People with type 1 diabetes (T1DM) require insulin therapy to sustain life, and need optimal glycaemic control to prevent diabetic ketoacidosis and serious long-term complications. Insulin is generally administered using multiple daily injections but can also be delivered using an infusion pump (continuous subcutaneous insulin infusion), a more costly option with benefits for some patients. The UK National Institute for Health and Care Excellence (NICE) recommend the use of pumps for patients with the greatest need, citing insufficient evidence to approve extension to a wider population. Far fewer UK adults use pumps than in comparable countries. Previous trials of pump therapy have been small and of short duration and failed to control for training in insulin adjustment. This paper describes the protocol for a large randomised controlled trial comparing pump therapy with multiple daily injections, where both groups are provided with high-quality structured education.

METHODS AND ANALYSIS

A multicentre, parallel group, cluster randomised controlled trial among 280 adults with T1DM. All participants attended the week-long dose adjustment for normal eating (DAFNE) structured education course, and receive either multiple daily injections or pump therapy for 2 years. The trial incorporates a detailed mixed-methods psychosocial evaluation and cost-effectiveness analysis. The primary outcome will be the change in glycosylated haemoglobin (HbA1c) at 24 months in those participants whose baseline HbA1c is at or above 7.5% (58 mmol/mol). The key secondary outcome will be the proportion of participants reaching the NICE target of an HbA1c of 7.5% (58 mmol/mol) or less at 24 months.

ETHICS AND DISSEMINATION

The protocol was approved by the Research Ethics Committee North West, Liverpool East and received Medicines and Healthcare products Regulatory Agency (MHRA) clinical trials authorisation. Each participating centre gave National Health Service R&D approval. We shall disseminate study findings to study participants and through peer reviewed publications and conference presentations, including lay user groups.

TRIAL REGISTRATION NUMBER

ISRCTN 61215213.

Multivariable adaptive identification and control for artificial pancreas systems

A constrained weighted recursive least squares method is proposed to provide recursive models with guaranteed stability and better performance than models based on regular identification methods in predicting the variations of blood glucose concentration in patients with Type 1 Diabetes. Use of physiological information from a sports armband improves glucose concentration prediction and enables earlier recognition of the effects of physical activity on glucose concentration. Generalized predictive controllers (GPC) based on these recursive models are developed. The performance of GPC for artificial pancreas systems is illustrated by simulations with UVa-Padova simulator and clinical studies. The controllers developed are good candidates for artificial pancreas systems with no announcements from patients.

Toward defining a cutoff score for elevated fear of hypoglycemia on the hypoglycemia fear survey worry subscale in patients with type 2 diabetes

OBJECTIVE To determine a cutoff score for clinically meaningful fear of hypoglycemia (FoH) on the Hypoglycemia Fear Survey Worry subscale (HFS-W). RESEARCH DESIGN AND METHODS Data on the HFS-W, history of hypoglycemia, emotional well-being (World Health Organization-5 well-being index), and distress about diabetes symptoms (Diabetes Symptom Checklist-Revised) were available from Dutch patients with type 2 diabetes who were treated with oral medication or insulin (n = 1,530). Four criteria were applied to define a threshold for clinically meaningful FoH: 1) modal score distribution (MD criterion), 2) scores 2 SDs above the mean (SD criterion), 3) concurrent validity with severe hypoglycemia and suboptimal well-being (CV criterion), and 4) an elevated score (≥3) on more than one HFS-W item (elevated item endorsement [EI criterion]). Associations between the outcomes of these approaches and a history of severe hypoglycemia and suboptimal well-being were studied. RESULTS Of the 1,530 patients, 19% had a HFS-W score of 0 (MD criterion), and 5% reported elevated FoH (HFS-W ≥ mean + 2 SD; SD criterion). Patients with severe hypoglycemia reported higher HFS-W scores than those without (25 ± 20 vs. 15 ± 17; P < 0.001). Patients with suboptimal well-being reported higher HFS-W scores than those with satisfactory well-being (20 ± 18 vs. 13 ± 15; P < 0.001, CV criterion). Elevated FoH (defined by the EI criterion) was seen in 26% of patients. The SD and EI criteria were the strongest associated with history of severe hypoglycemia. The EI criterion was the strongest associated with suboptimal well-being. CONCLUSIONS Although no definite cutoff score has been determined, the EI criterion may be most indicative of clinically relevant FoH in this exploratory study. Further testing of the clinical relevance of this criterion is needed.

Safety of nighttime 2-hour suspension of Basal insulin in pump-treated type 1 diabetes even in the absence of low glucose

OBJECTIVE

An integrated sensor-augmented pump system has been introduced that interrupts basal insulin infusion for 2 h if patients fail to respond to low-glucose alarms. It has been suggested that such interruptions of basal insulin due to falsely low glucose levels detected by sensor could lead to diabetic ketoacidosis. We hypothesized that random suspension of basal insulin for 2 h in the overnight period would not lead to clinically important increases in blood β-hydroxybutyrate levels despite widely varying glucose values prior to the suspension.

RESEARCH DESIGN AND METHODS

Subjects measured blood glucose and blood β-hydroxybutyrate levels using a meter each night at 9:00 p.m., then fasted until the next morning. On control nights, the usual basal rates were continued; on experimental nights, the basal insulin infusion was reprogrammed for a 2-h zero basal rate at random times after 11:30 p.m.

RESULTS

In 17 type 1 diabetic subjects (mean age 24 ± 9 years, diabetes duration 14 ± 11 years, A1C level 7.3 ± 0.5% [56 mmol/mol]), blood glucose and blood β-hydroxybutyrate levels were similar at 9:00 p.m. on suspend nights (144 ± 63 mg/dL and 0.09 ± 0.07 mmol/L) and nonsuspend nights (151 ± 65 mg/dL and 0.08 ± 0.06 mmol/L) (P = 0.39 and P = 0.47, respectively). Fasting morning blood glucose levels increased after suspend nights compared with nonsuspend nights (191 ± 68 vs. 141 ± 75 mg/dL, P < 0.0001), and the frequency of fasting hypoglycemia decreased the morning following suspend nights (P < 0.0001). Morning blood β-hydroxybutyrate levels were slightly higher after suspension (0.13 ± 0.14 vs. 0.09 ± 0.11 mmol/L, P = 0.053), but the difference was not clinically important.

CONCLUSIONS

Systems that suspend basal insulin for 2 h are safe and do not lead to clinically significant ketonemia even if the blood glucose level is elevated at the time of the suspension.

Caffeine and glucose homeostasis during rest and exercise in diabetes mellitus

Caffeine is a substance that has been used in our society for generations, primarily for its effects on the central nervous system that causes wakefulness. Caffeine supplementation has become increasingly more popular as an ergogenic aid for athletes and considerable scientific evidence supports its effectiveness. Because of their potential to alter energy metabolism, the effects of coffee and caffeine on glucose metabolism in diabetes have also been studied both epidemiologically and experimentally. Predominantly targeting the adenosine receptors, caffeine causes alterations in glucose homeostasis by decreasing glucose uptake into skeletal muscle, thereby causing elevations in blood glucose concentration. Caffeine intake has also been proposed to increase symptomatic warning signs of hypoglycemia in patients with type 1 diabetes and elevate blood glucose levels in patients with type 2 diabetes. Other effects include potential increases in glucose counterregulatory hormones such as epinephrine, which can also decrease peripheral glucose disposal. Despite these established physiological effects, increased coffee intake has been associated with reduced risk of developing type 2 diabetes in large-scale epidemiological studies. This review paper highlights the known effects of caffeine on glucose homeostasis and diabetes metabolism during rest and exercise.

Fear of hypoglycaemia in patients with type 1 diabetes: do patients and diabetologists feel the same way?

AIM

This study described and compared the perception of hypoglycaemia in both patients with type 1 diabetes and diabetologists.

METHODS

This was an observational cross-sectional study undertaken in France in 2011. Data for what hypoglycaemia represents and practices related to it were collected using a questionnaire completed by patients with type 1 diabetes (all>12 years of age) and their diabetologists. Agreement between patients and physicians was evaluated by the intraclass correlation coefficient (ICC) and Gwet's coefficient (GC).

RESULTS

A total of 485 patients were enrolled by 118 diabetologists. Half the patients thought that hypoglycaemia was always symptomatic. According to both patients and diabetologists, hypoglycaemia impaired quality of life, caused anxiety and was disturbing, especially at night. Clinical symptoms of hypoglycaemia (sweating, shakiness, anxiety) were linked to patient's age and diabetes duration. Regarding hypoglycaemia frequency, agreement was good for severe hypoglycaemia (GC: 0.61 and 0.72 for diurnal and nocturnal hypoglycaemia, respectively) and poor for mild hypoglycaemia (ICC: 0.44 and 0.40, respectively). Diabetologists correctly evaluated the impact of hypoglycaemia on quality of life, but overestimated the hypoglycaemia-induced burden and anxiety. Counteractive behaviours were frequent: 23% of patients decreased their insulin dose, 20% increased their sugar intake and 12% ate extra snacks. Diabetologists were generally aware of these measures, but not of how often patients used them.

CONCLUSION

Diabetologists and patients do not share enough information about hypoglycaemia. Fear of hypoglycaemia and counteractive behaviours should be looked for by diabetologists. Systematic advice and specially adapted education should also be provided to increase patients' awareness of hypoglycaemia.

The effect of short-term use of the Guardian RT continuous glucose monitoring system on fear of hypoglycaemia in patients with type 1 diabetes mellitus

AIM

This study examines whether the short-term use of a continuous glucose monitor (CGM) can reduce the fear of hypoglycaemia in individuals with type 1 diabetes mellitus (T1DM).

METHODS

Twelve participants with T1DM were fitted with a Guardian® REAL-Time CGM and assigned to either an alarm (low glucose alarm set at 4.5 mmol/L) or no alarm condition for 3 days, with both treatments administered following a counterbalanced study design. The participants completed the Hypoglycaemia Fear Survey on three separate occasions, before their CGM was fitted as well as following the alarm and no alarm conditions.

RESULTS

The alarm treatment reduced the incidence of hypoglycaemic episodes (CGM readings≤3.5 mmol/L; 1.1±0.5 versus 1.9±0.5; mean±SEM) and the relative time spent below this hypoglycaemic threshold (0.9±0.4% versus 2.6±1.0%) but did not alter the fear of hypoglycaemia (78.6±7.0, 75.8±5.2 and 79.3±5.8 at baseline and following the alarm and no alarm treatments, respectively; p>0.05). CGM overestimated blood glucose levels by 0.8±0.2 mmol/L for blood glucose readings less than, or equal to, 5 mmol/L.

CONCLUSIONS

Short-term use of the Guardian® REAL-Time CGM has no clinically significant effect on fear of hypoglycaemia possibly due, in part, to the inaccuracies of CGMs at low blood glucose levels.

Management of diabetes mellitus: is the pump mightier than the pen?

Continuous subcutaneous insulin infusion (CSII, or insulin pump therapy) reduces HbA1c levels and hypoglycaemia in patients with type 1 diabetes mellitus (T1DM) compared with multiple daily insulin injections (MDI). The greatest reduction in HbA(1c) levels with CSII occurs in patients with the worst glycaemic control; therefore, the most appropriate and cost-effective use of CSII in adults with T1DM is in those who have continued, elevated HbA(1c) levels or disabling hypoglycaemic episodes with MDI (including the use of long-acting insulin analogues and structured patient education). The disadvantages of CSII include higher costs than MDI and the risk of ketosis in the event of pump failure. In children with T1DM, CSII may be used when MDI is considered impractical or inappropriate. Pumps are not generally recommended for patients with type 2 diabetes mellitus but may improve control in some subgroups. A new generation of smaller insulin infusion pumps with an integrated cannula, called patch pumps, could improve uptake of CSII in general. The important clinical question is not whether CSII is more efficacious than MDI in general adult T1DM, but whether CSII further improves glycaemic control when this control continues to be poor with MDI, and evidence exists that in most cases it does.

Closed-loop insulin delivery for treatment of type 1 diabetes

Type 1 diabetes is one of the most common endocrine problems in childhood and adolescence, and remains a serious chronic disorder with increased morbidity and mortality, and reduced quality of life. Technological innovations positively affect the management of type 1 diabetes. Closed-loop insulin delivery (artificial pancreas) is a recent medical innovation, aiming to reduce the risk of hypoglycemia while achieving tight control of glucose. Characterized by real-time glucose-responsive insulin administration, closed-loop systems combine glucose-sensing and insulin-delivery components. In the most viable and researched configuration, a disposable sensor measures interstitial glucose levels, which are fed into a control algorithm controlling delivery of a rapid-acting insulin analog into the subcutaneous tissue by an insulin pump. Research progress builds on an increasing use of insulin pumps and availability of glucose monitors. We review the current status of insulin delivery, focusing on clinical evaluations of closed-loop systems. Future goals are outlined, and benefits and limitations of closed-loop therapy contrasted. The clinical utility of these systems is constrained by inaccuracies in glucose sensing, inter- and intra-patient variability, and delays due to absorption of insulin from the subcutaneous tissue, all of which are being gradually addressed.

Safe glycemic management during closed-loop treatment of type 1 diabetes: the role of glucagon, use of multiple sensors, and compensation for stress hyperglycemia

Patients with type 1 diabetes mellitus (T1DM) must make frequent decisions and lifestyle adjustments in order to manage their disorder. Automated treatment would reduce the need for these self-management decisions and reduce the risk for long-term complications. Investigators in the field of closed-loop glycemic control systems are now moving from inpatient to outpatient testing of such systems. As outpatient systems are developed, the element of safety increases in importance. One such concern is the risk for hypoglycemia, due in part to the delayed onset and prolonged action duration of currently available subcutaneous insulin preparations. We found that, as compared to an insulin-only closed-loop system, a system that also delivers glucagon when needed led to substantially less hypoglycemia. Though the capability of glucagon delivery would mandate the need for a second hormone chamber, glucagon in small doses is tolerated very well. People with T1DM often develop hyperglycemia from emotional stress or medical stress. Automated closed-loop systems should be able to detect such changes in insulin sensitivity and adapt insulin delivery accordingly. We recently verified the adaptability of a model-based closed-loop system in which the gain factors that govern a proportional-integral-derivative-like system are adjusted according to frequently measured insulin sensitivity. Automated systems can be tested by physical exercise to increase glucose uptake and insulin sensitivity or by administering corticosteroids to reduce insulin sensitivity. Another source of risk in closed-loop systems is suboptimal performance of amperometric glucose sensors. Inaccuracy can result from calibration error, biofouling, and current drift. We found that concurrent use of more than one sensor typically leads to better sensor accuracy than use of a single sensor. For example, using the average of two sensors substantially reduces the proportion of large sensor errors. The use of more than two allows the use of voting algorithms, which can temporarily exclude a sensor whose signal is outlying. Elements such as the use of glucagon to minimize hypoglycemia, adaptation to changes in insulin sensitivity, and sensor redundancy will likely increase safety during outpatient use of closed-loop glycemic control systems.

Assessing fear of hypoglycemia in children with Type 1 diabetes and their parents

This article summarizes the literature on fear of hypoglycemia in pediatric Type 1 diabetes and the assessment of this fear in both children with Type 1 diabetes and their parents. The most common instrument for assessing fear of hypoglycemia in this population is the children's and parent's versions of the Hypoglycemia Fear Survey (HFS), although studies using other assessment measures are also reviewed. Studies using this survey have identified variables contributing to fear of hypoglycemia in children with Type 1 diabetes and their parents, such as history of frequent or traumatic hypoglycemia, as well as trait anxiety. In addition to this summary of the literature, new data are presented supporting the reliability of hypoglycemic fear assessment in younger children and comparing fear of hypoglycemia in children in different age groups (6-18 years old) and their parents. Also reviewed are studies investigating the relationship between fear of hypoglycemia and diabetes control, which have yielded inconsistent results. Given the potential importance of fear of hypoglycemia in pediatric diabetes, there has been limited research in this area.