Asymptomatic hypoglycaemia in Type 1 diabetes: incidence and risk factors

Real-life hypoglycaemia partially blunts the inflammatory response to experimental hypoglycaemia in people with type 1 diabetes

AIM

To determine whether recent repeated exposure to real-life hypoglycaemia affects the pro-inflammatory response during a hypoglycemia episode.

MATERIALS AND METHODS

This was a post hoc analysis of a hyperinsulinaemic normoglycaemic-hypoglycaemic clamp study, involving 40 participants with type 1 diabetes. Glucose levels 1 week before the clamp were monitored using a Freestyle Libre 1. Blood was drawn during normoglycaemia and hypoglycaemia, and 24 hours after resolution of hypoglycaemia for measurements of inflammatory responses and counterregulatory hormone levels. We determined the relationship between the frequency and duration of spontaneous hypoglycaemia, and time below range (TBR) and the inflammatory response to experimental hypoglycaemia.

RESULTS

On average, participants experienced 0.79 (0.43, 1.14) hypoglycaemia episodes per day, with a duration of 78 (47, 110) minutes and TBR of 5.5% (2.8%, 8.5%). TBR and hypoglycaemia frequency were inversely associated with the increase in circulating granulocyte and lymphocyte counts during experimental hypoglycaemia (P < .05 for all). A protein network consisting of DNER, IF-R, uPA, Flt3L, FGF-5 and TWEAK was negatively associated with hypoglycaemia frequency (P < .05), but not with the adrenaline response. Neither other counterregulatory hormones, nor hypoglycaemia awareness status, was associated with any of the inflammatory parameters markers.

CONCLUSIONS

Repeated exposure to spontaneous hypoglycaemia is associated with blunted effects of subsequent experimental hypoglycaemia on circulating immune cells and the number of inflammatory proteins.

Association between recent exposure to continuous glucose monitoring-recorded hypoglycaemia and counterregulatory and symptom responses to subsequent controlled hypoglycaemia in people with type 1 diabetes

AIM

Experimental hypoglycaemia blunts the counterregulatory hormone and symptom responses to a subsequent episode of hypoglycaemia. In this study, we aimed to assess the associations between antecedent exposure and continuous glucose monitoring (CGM)-recorded hypoglycaemia during a 1-week period and the counterregulatory responses to subsequent experimental hypoglycaemia in people with type 1 diabetes.

MATERIALS AND METHODS

Forty-two people with type 1 diabetes (20 females, mean ± SD glycated haemoglobin 7.8% ± 1.0%, diabetes duration median (interquartile range) 22.0 (10.5-34.9) years, 29 CGM users, and 19 with impaired awareness of hypoglycaemia) wore an open intermittently scanned CGM for 1 week to detect hypoglycaemic exposure before a standardized hyperinsulinaemic-hypoglycaemic [2.8 ± 0.1 mmol/L (50.2 ± 2.3 mg/dl)] glucose clamp. Symptom responses and counterregulatory hormones were measured during the clamp. The study is part of the HypoRESOLVE project.

RESULTS

CGM-recorded hypoglycaemia in the week before the clamp was negatively associated with adrenaline response [β -0.09, 95% CI (-0.16, -0.02) nmol/L, p = .014], after adjusting for CGM use, awareness of hypoglycaemia, glycated haemoglobin and total daily insulin dose. This was driven by level 2 hypoglycaemia [<3.0 mmol/L (54 mg/dl)] [β -0.21, 95% CI (-0.41, -0.01) nmol/L, p = .034]. CGM-recorded hypoglycaemia was negatively associated with total, autonomic, and neuroglycopenic symptom responses, but these associations were lost after adjusting for potential confounders.

CONCLUSIONS

Recent exposure to CGM-detected hypoglycaemia was independently associated with an attenuated adrenaline response to experimental hypoglycaemia in people with type 1 diabetes.

Prevalence and associations of impaired awareness of hypoglycemia in a pediatric type 1 diabetes population - The Norwegian Childhood Diabetes Registry

AIMS

To determine the prevalence and associations of impaired awareness of hypoglycemia (IAH) in pediatric type 1 diabetes.

METHODS

Nationwide, population-based cross-sectional study with 51 % participation. Participants (n = 1329; 53 % males) aged 2-19 years (median 13.3) with type 1 diabetes ≥ 6 months (median 4.6 years) self-assessed hypoglycemia awareness with a validated questionnaire ('Clarke'). Parents responded for children aged < 9 years (n = 235). We estimated associations between IAH and clinical data in the Norwegian Childhood Diabetes Registry.

RESULTS

The overall prevalence of IAH was 22 %, but gradually decreased from 53 % in preschoolers to 12 % in adolescents aged ≥ 16 years. IAH was associated (adjusted OR; 95 %CI) with episodes of severe hypoglycemia (6.0; 3.04, 11.8) and diabetic ketoacidosis (3.45; 1.37, 8.68) the preceding year, increased fear of hypoglycemia (highest quartile vs. lowest: 2.27; 1.51, 3.40), female sex (1.41; 1.05, 1.90), and HbA1c ≥ 8.5 % (69 mmol/mol) vs. 7.5-8.4 % (58-68 mmol/mol) (1.48; 1.01, 2.18), but not with disease duration, use of insulin pump or continuous glucose monitoring, or HbA1c < 7.5 % (58 mmol/mol).

CONCLUSIONS

IAH is prevalent in pediatric diabetes and more likely reported in young children. IAH is associated with severe hypoglycemia and fear of hypoglycemia, but good metabolic control seems achievable without increased risk of IAH.

Reactive Hypoglycemia in Patients Prior to Cataract Surgery: A Case Series

Cataract surgery is one of the most frequently performed surgical procedures and is often performed under topical anesthesia in conscious patients. Sweating, palpitations, and anxiety may be seen in patients about to undergo surgery. However, these are typical adrenergic symptoms of hypoglycemia and should be further investigated if occurring before surgery. Here, we report five cases of postprandial or reactive hypoglycemia observed in hospital settings just before conducting cataract surgeries in non-diabetic 52-78-year-old patients from 2019 to 2023.

Intermittently scanned continuous glucose monitoring and hypoglycaemia awareness in drivers with diabetes: Insights from the Association of British Clinical Diabetologists Nationwide audit

AIM

Frequent hypoglycaemia results in disruption to usual hypoglycaemic autonomic responses leading to impaired awareness of hypoglycaemia, which is associated with an increased risk of severe hypoglycaemia requiring third-party assistance (SH). The UK Driving and Vehicle Licensing Agency (DVLA) does not permit car driving if they have either a complete loss of hypoglycaemia awareness or more than one SH event a year.

METHODS

The FreeStyle Libre (FSL) Association of British Clinical Diabetologists (ABCD) Nationwide Audit consists of data collected by clinicians during routine clinical work, submitted into a secure web-based tool held within the National Health Service (NHS) N3 network. Analysis of paired baseline and follow-up data for people with type 1 diabetes who also held a driving licence was undertaken.

RESULTS

The study consisted of 6304 people who had data recorded about driving status from 102 UK specialist diabetes centres, of which 4218 held a driving licence: 4178 a group 1, standard licence, 33 a group 2, large lorries and buses, seven a taxi licence; 1819 did not drive. Paired baseline and follow-up data were available for a sub-cohort of 1606/4218. At a mean follow-up of 6.9 months [95% CI (6.8, 7.1)], the Gold score had improved (2.3 ± 1.5 vs. 2.0 ± 1.3 p < .001), and the number of people who experienced an SH episode was also significantly lower (12.1% vs. 2.7%, p < .001).

CONCLUSION

This study suggests that intermittently scanned continuous glucose monitoring may improve impaired awareness of hypoglycaemia and reduce the number of people with type 1 diabetes with a driving licence experiencing a severe hypoglycaemic episode.

Relationship between CGM-derived nocturnal hypoglycemia and subjective sleep quality in people with type 1 diabetes

This pilot study explores the relationship between nocturnal hypoglycemia (NH) and subjective sleep quality in people with type 1 diabetes (T1D). Twenty-seven adults with T1D wore a Freestyle Libre Pro CGM and recorded subjective sleep quality daily, as assessed by a single Likert scale question. Frequency, duration, area under the curve (AUC) of NH (00:00-06:00) defined as sensor glucose below threshold (< 3.9 mmol/L; < 3 mmol/L) for ≥ 15 min, nocturnal mean glucose, Time in Range (3.9-10 mmol/L), and coefficient of variation were calculated. Twenty-seven adults, 18 (66.7%) women, with median (IQR) age of 27 (26, 32) years and HbA1c of 7.6 (7.1, 8.1) participated. Nights with NH < 3.9 mmol/L resulted in a lower (worse) sleep score than nights without NH [Mean (SD): 3.3 (1.2) vs 3.5 (1.0), p = 0.03). A higher frequency and longer duration but not AUC [adjusted OR (95% CI) 0.52 (0.38, 0.72), 0.961 (0.932, 0.991), 0.999 (0.998, 1.001) respectively)], of NH < 3.9 mmol/L, were associated with a lower sleep score. NH < 3.0 mmol/L metrics were not associated with sleep quality. Recurrent NH < 3.9 mmol/L, rather than prolonged NH < 3.0 mmol/L, seems associated with subjective sleep quality, implying that those with the highest burden of NH are likely unaware of it.

Current and future therapies to treat impaired awareness of hypoglycemia

In order to achieve optimal glycemic control, intensive insulin regimes are needed for individuals with Type 1 Diabetes (T1D) and insulin-dependent Type 2 Diabetes (T2D). Unfortunately, intensive glycemic control often results in insulin-induced hypoglycemia. Moreover, recurrent episodes of hypoglycemia result in both the loss of the characteristic warning symptoms associated with hypoglycemia and an attenuated counterregulatory hormone responses. The blunting of warning symptoms is known as impaired awareness of hypoglycemia (IAH). Together, IAH and the loss of the hormonal response is termed hypoglycemia associated autonomic failure (HAAF). IAH is prevalent in up to 25% in people with T1D and up to 10% in people with T2D. IAH and HAAF increase the risk of severe hypoglycemia 6-fold and 25-fold, respectively. To reduce this risk for severe hypoglycemia, multiple different therapeutic approaches are being explored that could improve awareness of hypoglycemia. Current therapies to improve awareness of hypoglycemia include patient education and psychoeducation, the use of novel glycemic control technology, pancreas/islet transplantation, and drug therapy. This review examines both existing therapies and potential therapies that are in pre-clinical testing. Novel treatments that improve awareness of hypoglycemia, via improving the counterregulatory hormone responses or improving hypoglycemic symptom recognition, would also shed light on the possible neurological mechanisms that lead to the development of IAH. To reduce the risk of severe hypoglycemia in people with diabetes, elucidating the mechanism behind IAH, as well as developing targeted therapies is currently an unmet need for those that suffer from IAH.

Nocturnal Glucose Patterns with and without Hypoglycemia in People with Type 1 Diabetes Managed with Multiple Daily Insulin Injections

Nocturnal hypoglycemia (NH) is a potentially dangerous and underestimated complication of insulin therapy. In this study, we aimed to determine which patterns of nocturnal glucose profiles are associated with NH in patients with type 1 diabetes (T1D) managed with multiple daily insulin injections. A dataset of continuous glucose monitoring (CGM) recordings obtained from 395 adult subjects with T1D was used for modeling. The clustering of CGM data was performed using a hierarchical clustering algorithm. Ten clusters without hypoglycemia and six clusters with NH episode(s) were identified. The differences among the clusters included initial and final glucose levels, glucose change during the night, and the presence of uptrends or downtrends. Post-midnight hyperglycemia was revealed in 5 out of 10 clusters without NH; in patterns with downtrends, initially elevated glucose prevented NH episodes. In clusters with initially near-normal glucose levels and downtrends, most episodes of NH were observed from midnight to 4 a.m.; if glucose was initially elevated, the episodes occurred at 2-4 a.m. or 4-6 a.m., depending on the time of the start of the downtrend. The results demonstrate the diversity of nocturnal glucose profiles in patients with T1D, which highlights the need for a differentiated approach to therapy adjustment.

Effects of Hypoglycemia on Cardiovascular Function in Patients with Diabetes

Hypoglycemia is common in patients with type 1 and type 2 diabetes (T1D, T2D), treated with insulin or sulfonylureas, and has multiple short- and long-term clinical implications. Whether acute or recurrent, hypoglycemia significantly affects the cardiovascular system with the potential to cause cardiovascular dysfunction. Several pathophysiological mechanisms have been proposed linking hypoglycemia to increased cardiovascular risk, including hemodynamic changes, myocardial ischemia, abnormal cardiac repolarization, cardiac arrhythmias, prothrombotic and proinflammatory effects, and induction of oxidative stress. Hypoglycemia-induced changes can promote the development of endothelial dysfunction, which is an early marker of atherosclerosis. Although data from clinical trials and real-world studies suggest an association between hypoglycemia and cardiovascular events in patients with diabetes, it remains uncertain whether this association is causal. New therapeutic agents for patients with T2D do not cause hypoglycemia and have cardioprotective benefits, whereas increasing the use of new technologies, such as continuous glucose monitoring devices and insulin pumps, has the potential to reduce hypoglycemia and its adverse cardiovascular outcomes in patients with T1D.

Sustained heart rate-corrected QT prolongation during recovery from hypoglycaemia in people with type 1 diabetes, independently of recovery to hyperglycaemia or euglycaemia

AIM

To investigate changes in cardiac repolarization abnormalities (heart rate-corrected QT [QT_c ] [primary endpoint], T-wave abnormalities) and heart-rate variability measures in people with type 1 diabetes during insulin-induced hypoglycaemia followed by recovery hyperglycaemia versus euglycaemia.

METHODS

In a randomized crossover study, 24 individuals with type 1 diabetes underwent two experimental clamps with three steady-state phases during electrocardiographic monitoring: (1) a 45-minute euglycaemic phase (5-8 mmol/L), (2) a 60-minute insulin-induced hypoglycaemic phase (2.5 mmol/L), and (3) 60-minute recovery in either hyperglycaemia (20 mmol/L) or euglycaemia (5-8 mmol/L).

RESULTS

All measured markers of arrhythmic risk indicated increased risk during hypoglycaemia. These findings were accompanied by a decrease in vagal tone during both hyperglycaemia and euglycaemia clamps. Compared with baseline, the QT_c interval increased during hypoglycaemia, and 63% of the participants exhibited a peak QT_c of more than 500 ms. The prolonged QT_c interval was sustained during both recovery phases with no difference between recovery hyperglycaemia versus euglycaemia. During recovery, no change from baseline was observed in heart-rate variability measures.

CONCLUSIONS

In people with type 1 diabetes, insulin-induced hypoglycaemia prolongs cardiac repolarization, which is sustained during a 60-minute recovery period independently of recovery to hyperglycaemia or euglycaemia. Thus, vulnerability to serious cardiac arrhythmias and sudden cardiac death may extend beyond a hypoglycaemic event, regardless of hyperglycaemic or euglycaemic recovery.

Psychometric properties of an innovative smartphone application to investigate the daily impact of hypoglycemia in people with type 1 or type 2 diabetes: The Hypo-METRICS app

INTRODUCTION

The aim of this study was to determine the acceptability and psychometric properties of the Hypo-METRICS (Hypoglycemia MEasurement, ThResholds and ImpaCtS) application (app): a novel tool designed to assess the direct impact of symptomatic and asymptomatic hypoglycemia on daily functioning in people with insulin-treated diabetes.

MATERIALS AND METHODS

100 adults with type 1 diabetes mellitus (T1DM, n = 64) or insulin-treated type 2 diabetes mellitus (T2DM, n = 36) completed three daily 'check-ins' (morning, afternoon and evening) via the Hypo-METRICs app across 10 weeks, to respond to 29 unique questions about their subjective daily functioning. Questions addressed sleep quality, energy level, mood, affect, cognitive functioning, fear of hypoglycemia and hyperglycemia, social functioning, and work/productivity. Completion rates, structural validity, internal consistency, and test-retest reliability were explored. App responses were correlated with validated person-reported outcome measures to investigate convergent (rs>±0.3) and divergent (rs<±0.3) validity.

RESULTS

Participants' mean±SD age was 54±16 years, diabetes duration was 23±13 years, and most recent HbA1c was 56.6±9.8 mmol/mol. Participants submitted mean±SD 191±16 out of 210 possible 'check-ins' (91%). Structural validity was confirmed with multi-level confirmatory factor analysis showing good model fit on the adjusted model (Comparative Fit Index >0.95, Root-Mean-Square Error of Approximation <0.06, Standardized Root-Mean-square Residual<0.08). Scales had satisfactory internal consistency (all ω≥0.5), and high test-retest reliability (rs≥0.7). Convergent and divergent validity were demonstrated for most scales.

CONCLUSION

High completion rates and satisfactory psychometric properties demonstrated that the Hypo-METRICS app is acceptable to adults with T1DM and T2DM, and a reliable and valid tool to explore the daily impact of hypoglycemia.

Investigating the day-to-day impact of hypoglycaemia in adults with type 1 or type 2 diabetes: design and validation protocol of the Hypo-METRICS application

INTRODUCTION

Hypoglycaemia is a frequent adverse event and major barrier for achieving optimal blood glucose levels in people with type 1 or type 2 diabetes using insulin. The Hypo-RESOLVE (Hypoglycaemia-Redefining SOLutions for better liVEs) consortium aims to further our understanding of the day-to-day impact of hypoglycaemia. The Hypo-METRICS (Hypoglycaemia-MEasurement, ThResholds and ImpaCtS) application (app) is a novel app for smartphones. This app is developed as part of the Hypo-RESOLVE project, using ecological momentary assessment methods that will minimise recall bias and allow for robust investigation of the day-to-day impact of hypoglycaemia. In this paper, the development and planned psychometric analyses of the app are described.

METHODS AND ANALYSIS

The three phases of development of the Hypo-METRICS app are: (1) establish a working group-comprising diabetologists, psychologists and people with diabetes-to define the problem and identify relevant areas of daily functioning; (2) develop app items, with user-testing, and implement into the app platform; and (3) plan a large-scale, multicountry study including interviews with users and psychometric validation. The app includes 7 modules (29 unique items) assessing: self-report of hypoglycaemic episodes (during the day and night, respectively), sleep quality, well-being/cognitive function, social interactions, fear of hypoglycaemia/hyperglycaemia and work/productivity. The app is designed for use within three fixed time intervals per day (morning, afternoon and evening). The first version was released mid-2020 for use (in conjunction with continuous glucose monitoring and activity tracking) in the Hypo-METRICS study; an international observational longitudinal study. As part of this study, semistructured user-experience interviews and psychometric analyses will be conducted.

ETHICS AND DISSEMINATION

Use of the novel Hypo-METRICS app in a multicountry clinical study has received ethical approval in each of the five countries involved (Oxford B Research Ethics Committee, CMO Region Arnhem-Nijmegen, Ethikkommission der Medizinischen Universität Graz, Videnskabsetisk Komite for Region Hovedstaden and the Comite Die Protection Des Personnes SUD Mediterranne IV). The results from the study will be published in peer review journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

NCT04304963.

Continuous Glucose Monitoring (CGM) Readings During Patient-Reported Symptomatic Hypoglycemia: Assessment of the Advanced Technologies and Treatments for Diabetes Consensus Definition of CGM-Recorded Hypoglycemia

Aim: Continuous glucose monitoring (CGM) is widely used in clinical practice and research to detect hypoglycemia. A consensus definition of CGM-recorded hypoglycemia is made by a group of international experts under the auspice of the Advanced Technologies and Treatments for Diabetes (ATTD). The purpose of this study is to compare the definition with patient-reported hypoglycemia. Methods: In a prospective, observational study of 186 patients with type 1 diabetes using blinded Medtronic iPro 2 CGM for 6 days, every patient-reported symptomatic hypoglycemic event and interstitial glucose (IG) values at the registration time were classified according to the ATTD definition of CGM-recorded hypoglycemia. For comparison between CGM and self-monitored blood glucose (SMBG) values, the International Hypoglycemia Study Group (IHSG) classification of hypoglycemia and chi-square test were used. Results: A total of 321 events of symptomatic hypoglycemia were reported by 68% of the patients, corresponding to 2.0 ± 2.3 events (mean ± standard deviation) per patient-week. A total of 206 (64%) events met the CGM consensus definition. In the remaining 115 (36%) not-confirmed events, 5 events had an IG <3.9 mmol/L, which lasted <15 min. The overall mean IG value was 3.6 ± 1.1 mmol/L (median 3.1, range 2.2-10.4). In symptomatic hypoglycemic events with both CGM and SMBG data, SMBG confirmed significantly more symptomatic hypoglycemic events than CGM (P < 0.001). Conclusion: CGM-recorded hypoglycemia according to the consensus definition is present at two thirds of all patient-reported events when recorded by the Medtronic iPro 2 system. The recommended minimum duration of a hypoglycemic event of 15 min is supported by the study. SMBG measurements detect significantly more symptomatic hypoglycemic events than Medtronic iPro 2 CGM.

Toward an Optimal Definition of Hypoglycemia with Continuous Glucose Monitoring

BACKGROUND AND OBJECTIVE

As continuous glucose monitoring (CGM) becomes common in research and clinical practice, there is a need to understand how CGM-based hypoglycemia relates to hypoglycemia episodes defined conventionally as patient reported hypoglycemia (PRH). Data show that CGM identify many episodes of low interstitial glucose (LIG) that are not experienced by patients, and so the aim of this study is to use different PRH simulations to optimize CGM parameters of threshold (h) and duration (d) to provide the best PRH detection performance.

METHODS

The algorithm uses particle Markov chain Monte Carlo optimization to identify the optimal h and d which maximize an objective function for detecting PRH. We tested our algorithm by creating three different cases of PRH simulations.

RESULTS

We added three types of simulated PRH events to 10 weeks of anonymized CGM data from 96 type 1 diabetes people to see if the algorithm can detect the optimal parameters set out in the simulations. In simulation 1, we changed the locations of PRHs with respect to LIG episodes in the CGM signal to simulate random optimal LIG parameters for every individual. In simulation 2, the PRHs are CGM glucose <3.9 mmol/L followed by at least 20 min of rise > 0.11 mmol/L/min. Simulation 3 is like simulation 2 but with glucose threshold of 3.0 mmol/L. The median [interquartile range] of deviation between the optimized (found by the algorithm) and the optimal (known) h and d are -0.07% [-0.4, 1.9] and -1.3% [-5.9, 6.8], respectively across the subjects for simulation 1. The mean [min max] of the optimized LIG parameters are h = 3.8 [3.7, 3.8] mmol/L and d = 12 [10, 14] min for simulation 2 and they are h = 3.0 [2.9, 3] mmol/L and d = 10 [8, 14] min for simulation 3 across a 10-fold cross validation.

CONCLUSIONS

This work demonstrates the feasibility of the algorithm to find the best-fit definition of CGM-based hypoglycemia for PRH detection. In a prospective clinical study collecting CGM and PRH, the current algorithm will be used to optimize the definition of hypoglycemia with respect to PRH with the ambition of using the resulted definition as a surrogate for PRH in clinical practice.

Time in range: A best practice guide for UK diabetes healthcare professionals in the context of the COVID-19 global pandemic

The emergence of continuous glucose monitoring has driven improvements in glycaemic control and quality of life for people with diabetes. Recent changes in access to continuous glucose monitoring systems within UK health services have increased the number of people able to benefit from these technologies. The COVID-19 pandemic has created an opportunity for diabetes healthcare professionals to use continuous glucose monitoring technology to remotely deliver diabetes services to support people with diabetes. This opportunity can be maximized with improved application and interpretation of continuous glucose monitoring-generated data. Amongst the diverse measures of glycaemic control, time in range is considered to be of high value in routine clinical care because it is actionable and is visibly responsive to changes in diabetes management. Importantly, it is also been linked to the risk of developing complications associated with diabetes and can be understood by people with diabetes and healthcare professionals alike. The 2019 International Consensus on Time in Range has established a series of target glucose ranges and recommendations for time spent within these ranges that is consistent with optimal glycaemic control. The recommendations cover people with type 1 or type 2 diabetes, with separate targets indicated for elderly people or those at higher risk from hypoglycaemia, as well as for women with type 1 diabetes during pregnancy. The aim of this best practice guide was to clarify the intent and purpose of these international consensus recommendations and to provide practical insights into their implementation in UK diabetes care.

Clinical approaches to treat impaired awareness of hypoglycaemia

Impaired awareness of hypoglycaemia (IAH) affects between 25% and 30% of all people with type 1 diabetes (T1D) and markedly increases risk of severe hypoglycaemia. This greatly feared complication of T1D impairs quality of life and has a recognised morbidity. People with T1D have an increased propensity to hypoglycaemia as a result of fundamental physiological defects in their ability to respond appropriately to a fall in blood glucose levels. With repeated exposure to low glucose, many then develop a condition referred to as IAH, where there is a reduced ability to perceive the onset of hypoglycaemia and take appropriate corrective action. The management of individuals with IAH relies initially on its identification in the clinic through a detailed exploration of the frequency of hypoglycaemia and an assessment of the individual's ability to recognise these episodes. In this review article, we will address the clinical strategies that may help in the management of the patient with IAH once identified, who may or may not also suffer from problematic hypoglycaemia. The initial focus is on how to identify such patients and then on the variety of approaches involving educational programmes and technological approaches that may be taken to minimise hypoglycaemia risk. No single approach can be advocated for all patients, and it is the role of the health care professional to identify the clinical strategy that best enables their patient to achieve this goal.

Postexercise Glycemic Control in Type 1 Diabetes Is Associated With Residual β-Cell Function

OBJECTIVE

To investigate the impact of residual β-cell function on continuous glucose monitoring (CGM) outcomes following acute exercise in people with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

Thirty participants with T1D for ≥3 years were recruited. First, participants wore a blinded CGM unit for 7 days of free-living data capture. Second, a 3-h mixed-meal test assessed stimulated C-peptide and glucagon. Peak C-peptide was used to allocate participants into undetectable (Cpep_und <3 pmol/L), low (Cpep_low 3-200 pmol/L), or high (Cpep_high >200 pmol/L) C-peptide groups. Finally, participants completed 45 min of incline treadmill walking at 60% VO_2peak followed by a further 48-h CGM capture.

RESULTS

CGM parameters were comparable across groups during the free-living observation week. In the 12- and 24-h postexercise periods (12 h and 24 h), the Cpep_high group had a significantly greater amount of time spent with glucose 3.9-10 mmol/L (12 h, 73.5 ± 27.6%; 24 h, 76.3 ± 19.2%) compared with Cpep_low (12 h, 43.6 ± 26.1%, P = 0.027; 24 h, 52.3 ± 25.0%, P = 0.067) or Cpep_und (12 h, 40.6 ± 17.0%, P = 0.010; 24 h, 51.3 ± 22.3%, P = 0.041). Time spent in hyperglycemia (12 h and 24 h glucose >10 and >13.9 mmol/L, P < 0.05) and glycemic variability (12 h and 24 h SD, P < 0.01) were significantly lower in the Cpep_high group compared with Cpep_und and Cpep_low. Change in CGM outcomes from pre-exercise to 24-h postexercise was divergent: Cpep_und and Cpep_low experienced worsening (glucose 3.9-10 mmol/L: -9.1% and -16.2%, respectively), with Cpep_high experiencing improvement (+12.1%) (P = 0.017).

CONCLUSIONS

Residual β-cell function may partially explain the interindividual variation in the acute glycemic benefits of exercise in individuals with T1D. Quantifying C-peptide could aid in providing personalized and targeted support for exercising patients.