Elimination of hypoglycemia from the lives of people affected by diabetes

Safety of surgical denervation of the common hepatic artery in insulin-resistant dogs

The objective of this study was to assess the safety of surgical common hepatic artery denervation (CHADN). This procedure has previously been shown to improve glucose tolerance in dogs fed a high-fat high-fructose (HFHF) diet. We assessed the hypoglycemic response of dogs by infusing insulin at a constant rate (1.5 mU/kg/min) for 3 h and monitoring glucose and the counterregulatory hormones (glucagon, catecholamine, and cortisol). After an initial hypoglycemic study, the dogs were randomly assigned to a SHAM surgery (n = 4) or hepatic sympathetic denervation (CHADN, n = 5) and three follow-up studies were performed every month up to 3 months after the surgery. The level of norepinephrine (NE) in the liver and the pancreas was significantly reduced in the CHADN dogs, showing a decrease in sympathetic tone to the splanchnic organs. There was no evidence of any defect of the response to hypoglycemia after the CHADN surgery. Indeed, the extent of hypoglycemia was similar in the SHAM and CHADN groups (~45 mg/dl) for the same amount of circulating insulin (~50 µU/ml) regardless of time or surgery. Moreover the responses of the counterregulatory hormones were similar in extent and pattern during the 3 h of hypoglycemic challenge. Circulating lactate, glycerol, free fatty acids, and beta-hydroxybutyrate were also unaffected by CHADN during fasting conditions or during the hypoglycemia. There were no other notable surgery-induced changes over time in nutrients, minerals, and hormones clinically measured in the dogs nor in the blood pressure and heart rate of the animals. The data suggest that the ablation of the sympathetic nerve connected to the splanchnic bed is not required for a normal counterregulatory response to insulin-induced hypoglycemia and that CHADN could be a safe new therapeutic intervention to improve glycemic control in individuals with metabolic syndrome or type 2 diabetes.

Quality of Life and Glucose Control After 1 Year of Nationwide Reimbursement of Intermittently Scanned Continuous Glucose Monitoring in Adults Living With Type 1 Diabetes (FUTURE): A Prospective Observational Real-World Cohort Study

OBJECTIVE

In 2016, nationwide reimbursement of intermittently scanned continuous glucose monitoring (isCGM) for people living with type 1 diabetes treated in specialist diabetes centers was introduced in Belgium. We undertook a 12-month prospective observational multicenter real-world study to investigate impact of isCGM on quality of life and glycemic control.

RESEARCH DESIGN AND METHODS

Between July 2016 and July 2018, 1,913 adults with type 1 diabetes were consecutively recruited in three specialist diabetes centers. Demographic, metabolic, and quality of life data were collected at baseline, 6 months, and 12 months of standardized clinical follow-up. The primary end point was evolution of quality of life from baseline to 12 months. Secondary outcome measures were, among others, change in HbA_1c, time spent in different glycemic ranges, occurrence of acute diabetes complications, and work absenteeism.

RESULTS

General and diabetes-specific quality of life was high at baseline and remained stable, whereas treatment satisfaction improved (P < 0.0001). Admissions for severe hypoglycemia and/or ketoacidosis were rare in the year before study (n = 63 out of 1,913; 3.3%), but decreased further to 2.2% (n = 37 out of 1,711; P = 0.031). During the study, fewer people reported severe hypoglycemic events (n = 280 out of 1,913 [14.6%] vs. n = 134 out of 1,711 [7.8%]; P < 0.0001) or hypoglycemic comas (n = 52 out of 1,913 [2.7%] vs. n = 18 out of 1,711 [1.1%]; P = 0.001) while maintaining HbA_1c levels. Fewer people were absent from work (n = 111 out of 1,913 [5.8%] vs. n = 49 out of 1,711 [2.9%]; P < 0.0001). Time spent in hypoglycemia significantly decreased in parallel with less time in range and more time in hyperglycemia. Eleven percent (n = 210) of participants experienced skin reactions, leading to stopping of isCGM in 22 participants (1%).

CONCLUSIONS

Nationwide unrestricted reimbursement of isCGM in people with type 1 diabetes treated in specialist diabetes centers results in higher treatment satisfaction, less severe hypoglycemia, and less work absenteeism, while maintaining quality of life and HbA_1c.

Challenges of Diabetes Care in Older People With Type 2 Diabetes and the Role of Basal Insulin

IN BRIEF The use of long-acting basal insulin analogs is a recommended strategy in older people with diabetes because of their lower risk of hypoglycemia compared to intermediate-acting insulins. In this article, we review the results from recent clinical trials of second-generation basal insulin preparations. We conclude that, although these preparations have improved the management of insulin-requiring older people with type 2 diabetes, there is a need for additional and more specific studies to address the complexities of hyperglycemia management in this population.

Dorsomedial hindbrain catecholamine regulation of hypothalamic astrocyte glycogen metabolic enzyme protein expression: Impact of estradiol

The brain astrocyte glycogen reservoir is a vital energy reserve and, in the cerebral cortex, subject among other factors to noradrenergic control. The ovarian steroid estradiol potently stimulates nerve cell aerobic respiration, but its role in glial glycogen metabolism during energy homeostasis or mismatched substrate supply/demand is unclear. This study examined the premise that estradiol regulates hypothalamic astrocyte glycogen metabolic enzyme protein expression during normo- and hypoglycemia in vivo through dorsomedial hindbrain catecholamine (CA)-dependent mechanisms. Individual astrocytes identified in situ by glial fibrillary acidic protein immunolabeling were laser-microdissected from the ventromedial hypothalamic (VMH), arcuate hypothalamic (ARH), and paraventricular hypothalamic (PVH) nuclei and the lateral hypothalamic area (LHA) of estradiol (E)- or oil (O)-implanted ovariectomized (OVX) rats after insulin or vehicle injection, and pooled within each site. Stimulation [VMH, LHA] or suppression [PVH, ARH] of basal glycogen synthase (GS) protein expression by E was reversed in the former three sites by caudal fourth ventricular pretreatment with the CA neurotoxin 6-hydroxydopamine (6-OHDA). E diminished glycogen phosphorylase (GP) protein profiles by CA-dependent [VMH, PVH] or -independent mechanisms [LHA]. Insulin-induced hypoglycemia (IIH) increased GS expression in the PVH in OVX+E, but reduced this protein in the PVH, ARH, and LHA in OVX+O. Moreover, IIH augmented GP expression in the VMH, LHA, and ARH in OVX+E and in the ARH in OVX+O, responses that normalized by 6-OHDA. Results demonstrate site-specific effects of E on astrocyte glycogen metabolic enzyme expression in the female rat hypothalamus, and identify locations where dorsomedial hindbrain CA input is required for such action. Evidence that E correspondingly increases and reduces basal GS and GP in the VMH and LHA, but augments the latter protein during IIH suggests that E regulates glycogen content and turnover in these structures during glucose sufficiency and shortage.

Assessing the effectiveness of 3 months day and night home closed-loop insulin delivery in adults with suboptimally controlled type 1 diabetes: a randomised crossover study protocol

INTRODUCTION

Despite therapeutic advances, many people with type 1 diabetes are still unable to achieve optimal glycaemic control, limited by the occurrence of hypoglycaemia. The objective of the present study is to determine the effectiveness of day and night home closed-loop over the medium term compared with sensor-augmented pump therapy in adults with type 1 diabetes and suboptimal glycaemic control.

METHODS AND ANALYSIS

The study will adopt an open label, three-centre, multinational, randomised, two-period crossover study design comparing automated closed-loop glucose control with sensor augmented insulin pump therapy. The study will aim for 30 completed participants. Eligible participants will be adults (≥18 years) with type 1 diabetes treated with insulin pump therapy and suboptimal glycaemic control (glycated haemoglobin (HbA1c)≥7.5% (58 mmol/mmol) and ≤10% (86 mmol/mmol)). Following a 4-week optimisation period, participants will undergo a 3-month use of automated closed-loop insulin delivery and sensor-augmented pump therapy, with a 4-6 week washout period in between. The order of the interventions will be random. All analysis will be conducted on an intention to treat basis. The primary outcome is the time spent in the target glucose range from 3.9 to 10.0 mmol/L based on continuous glucose monitoring levels during the 3 months free living phase. Secondary outcomes include HbA1c changes; mean glucose and time spent above and below target glucose levels. Further, participants will be invited at baseline, midpoint and study end to participate in semistructured interviews and complete questionnaires to explore usability and acceptance of the technology, impact on quality of life and fear of hypoglycaemia.

ETHICS AND DISSEMINATION

Ethical approval has been obtained at all sites. Before screening, all participants will be provided with oral and written information about the trial. The study will be disseminated by peer-review publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT01961622 (ClinicalTrials.gov).

Sex-specific basal and hypoglycemic patterns of in vivo caudal dorsal vagal complex astrocyte glycogen metabolic enzyme protein expression

Astrocytes contribute to neurometabolic stability through uptake, catabolism, and storage of glucose. These cells maintain the major brain glycogen reservoir, which is a critical fuel supply to neurons during glucose deficiency and increased brain activity. We used a combinatory approach incorporating immunocytochemistry, laser microdissection, and Western blotting to investigate the hypothesis of divergent expression of key enzymes regulating glycogen metabolism and glycolysis during in vivo normo- and/or hypoglycemia in male versus female hindbrain astrocytes. Glycogen synthase (GS) and glycogen phosphorylase (GP) levels were both enhanced in dorsal vagal complex astrocytes from vehicle-injected female versus male controls, with incremental increase in GS exceeding GP. Insulin-induced hypoglycemia (IIH) diminished GS and increased glycogen synthase kinase-3-beta (GSK3β) expression in both sexes, but decreased phosphoprotein phosphatase-1 (PP1) levels only in males. Astrocyte GP content was elevated by IIH in male, but not female rats. Data reveal sex-dependent sensitivity of these enzyme proteins to lactate as caudal hindbrain repletion of this energy substrate fully or incompletely reversed hypoglycemic inhibition of GS and prevented hypoglycemic augmentation of GSK3β and GP in females and males, respectively. Sex dimorphic patterns of glycogen branching and debranching enzyme protein expression were also observed. Levels of the rate-limiting glycolytic enzyme, phosphofructokinase, were unaffected by IIH with or without lactate repletion. Current data demonstrating sex-dependent basal and hypoglycemic patterns of hindbrain astrocyte glycogen metabolic enzyme expression imply that glycogen volume and turnover during glucose sufficiency and shortage may vary accordingly.

Day and night home closed-loop insulin delivery in adults with type 1 diabetes: three-center randomized crossover study

OBJECTIVE

To evaluate the feasibility of day and night closed-loop insulin delivery in adults with type 1 diabetes under free-living conditions.

RESEARCH DESIGN AND METHODS

Seventeen adults with type 1 diabetes on insulin pump therapy (means ± SD age 34 ± 9 years, HbA1c 7.6 ± 0.8%, and duration of diabetes 19 ± 9 years) participated in an open-label multinational three-center crossover study. In a random order, participants underwent two 8-day periods (first day at the clinical research facility followed by 7 days at home) of sensor-augmented insulin pump therapy (SAP) or automated closed-loop insulin delivery. The primary end point was the time when sensor glucose was in target range between 3.9 and 10.0 mmol/L during the 7-day home phase.

RESULTS

During the home phase, the percentage of time when glucose was in target range was significantly higher during closed-loop compared with SAP (median 75% [interquartile range 61-79] vs. 62% [53-70], P = 0.005). Mean glucose (8.1 vs. 8.8 mmol/L, P = 0.027) and time spent above target (P = 0.013) were lower during closed loop, while time spent below target was comparable (P = 0.339). Increased time in target was observed during both daytime (P = 0.017) and nighttime (P = 0.013).

CONCLUSIONS

Compared with SAP, 1 week of closed-loop insulin delivery at home reduces mean glucose and increases time in target without increasing the risk of hypoglycemia in adults with relatively well-controlled type 1 diabetes.

Evaluating the Performance of a Novel Embedded Closed-loop System

The objective was to assess the reliability of a novel automated closed-loop glucose control system developed within the AP@home consortium in adults with type 1 diabetes. Eight adults with type 1 diabetes on insulin pump therapy (3 men; ages 40.5 ± 14.3 years; HbA1c 8.2 ± 0.8%) participated in an open-label, single-center, single-arm, 12-hour overnight study performed at the clinical research facility. A standardized evening meal (80 g CHO) accompanied by prandial insulin boluses were given at 19:00 followed by an optional snack of 15 g at 22:00 without insulin bolus. Automated closed-loop glucose control was started at 19:00 and continued until 07:00 the next day. Basal insulin delivery (Accu-Chek Spirit, Roche) was automatically adjusted by Cambridge model predictive control algorithm, running on a purpose-built embedded device, based on real-time continuous glucose monitor readings (Dexcom G4 Platinum). Closed-loop system was operational as intended over 99% of the time. Overnight plasma glucose levels (22:00 to 07:00) were within the target range (3.9 to 8.0 mmol/l) for 75.4% (37.5, 92.9) of the time without any time spent in hypoglycemia (<3.9 mmol/l). Mean overnight glucose was 7.8 ± 1.3 mmol/l. For the entire 12-hour closed-loop period (19:00 until 07:00) plasma glucose levels were within the target range (3.9 to 10.0 mmol/l) for 84.4% (63.3, 100) of time. There were no adverse events noted during the trial. We observed a high degree of reliability of the automated closed-loop system. The time spent in target glucose level overnight was comparable to results of previously published studies. Further developments to miniaturize the system for home studies are warranted.

Starting glargine in insulin-naïve type 2 diabetic patients based on body mass index is safe

AIM: To evaluate the safety of four insulin titration algorithms in a homogeneous population of insulin-naïve type 2 diabetic patients.

METHODS: We conducted a 24-wk, open, single-center study with 92 insulin-naïve type 2 diabetes patients who failed treatment with one or two oral drugs. The patients were randomized to one of the four following algorithms: LANMET (n = 26) and LANMET PLUS (n = 22) algorithms, whose patients received a fixed initial insulin dose of 10 U, and DeGold (n = 23) and DeGold PLUS (n = 21) algorithms, whose patients’ initial insulin dose was based on their body mass index (BMI). In addition, patients in the PLUS groups had their insulin titrated twice a week from 2 to 8 U. In the other two groups, the titration was also performed also twice a week, but in a fixed increments of 2 U. The target fasting glucose levels for both groups was 100 mg/dL.

RESULTS: There was no significant difference in efficacy parameters. There was no significant difference when comparing moderate hypoglycemia events in algorithms starting with a 10 U fixed dose and algorithms based on BMI. However, there was a significant increase in moderate hypoglycemia events among the PLUS treated patients when the LANMET and DeGold algorithms were compared with the 2 fast-titration PLUS algorithms. We observed 12 hypoglycemia events in the first group, which corresponded to 0.94 events/patient per year, and we observed 42 events in the second group, which corresponded to 2.81 events/patient per year (P < 0.037). No further significant differences were observed when other comparisons between the algorithms were carried out.

CONCLUSION: Starting insulin glargine based on BMI is safe, but fast titration algorithms increase the risk of moderate hypoglycemia.

Restoration of self-awareness of hypoglycemia in adults with long-standing type 1 diabetes: hyperinsulinemic-hypoglycemic clamp substudy results from the HypoCOMPaSS trial

OBJECTIVE

Impaired awareness of hypoglycemia (IAH) and defective counterregulation significantly increase severe hypoglycemia risk in type 1 diabetes (T1D). We evaluated restoration of IAH/defective counterregulation by a treatment strategy targeted at hypoglycemia avoidance in adults with T1D with IAH (Gold score ≥4) participating in the U.K.-based multicenter HypoCOMPaSS randomized controlled trial.

RESEARCH DESIGN AND METHODS

Eighteen subjects with T1D and IAH (mean ± SD age 50 ± 9 years, T1D duration 35 ± 10 years, HbA1c 8.1 ± 1.0% [65 ± 10.9 mmol/mol]) underwent stepped hyperinsulinemic-hypoglycemic clamp studies before and after a 6-month intervention. The intervention comprised the HypoCOMPaSS education tool in all and randomized allocation, in a 2 × 2 factorial study design, to multiple daily insulin analog injections or continuous subcutaneous insulin infusion therapy and conventional glucose monitoring or real-time continuous glucose monitoring. Symptoms, cognitive function, and counterregulatory hormones were measured at each glucose plateau (5.0, 3.8, 3.4, 2.8, and 2.4 mmol/L), with each step lasting 40 min with subjects kept blinded to their actual glucose value throughout clamp studies.

RESULTS

After intervention, glucose concentrations at which subjects first felt hypoglycemic increased (mean ± SE from 2.6 ± 0.1 to 3.1 ± 0.2 mmol/L, P = 0.02), and symptom and plasma metanephrine responses to hypoglycemia were higher (median area under curve for symptoms, 580 [interquartile range {IQR} 420-780] vs. 710 [460-1,260], P = 0.02; metanephrine, 2,412 [-3,026 to 7,279] vs. 5,180 [-771 to 11,513], P = 0.01). Glycemic threshold for deterioration of cognitive function measured by four-choice reaction time was unchanged, while the color-word Stroop test showed a degree of adaptation.

CONCLUSIONS

Even in long-standing T1D, IAH and defective counterregulation may be improved by a clinical strategy aimed at hypoglycemia avoidance.

β2-Adrenergic receptor agonist administration promotes counter-regulatory responses and recovery from hypoglycaemia in rats

AIMS/HYPOTHESIS

We have previously reported that local activation of β2-adrenergic receptors (B2ARs) in the ventromedial hypothalamus (VMH) enhances hypoglycaemic counter-regulation. This study examines whether peripheral delivery of a selective B2AR agonist could also promote counter-regulatory responses and thereby has potential therapeutic value to limit hypoglycaemia risk.

METHODS

Conscious male Sprague-Dawley rats received an intra-arterial injection of the B2AR specific agonist, formoterol, or a control solution either before a hyperinsulinaemic-hypoglycaemic clamp study or immediately before recovery from insulin-induced hypoglycaemia. In addition, the capacity of a VMH-targeted microinjection of a B2AR antagonist to limit the anti-insulin effect of the B2AR agonist was assessed.

RESULTS

Systemic delivery of B2AR agonist markedly reduced the exogenous glucose infusion rate (GIR) required during the hypoglycaemic clamp study. This effect was mediated by blockade of insulin's inhibitory effect on endogenous glucose production. Local blockade of B2ARs within the VMH using a specific antagonist partially diminished the effect of systemic activation of B2ARs during hypoglycaemia at least in part by diminishing the adrenaline (epinephrine) response to hypoglycaemia. Peripheral B2AR agonist injection also enhanced glucose recovery from insulin-induced hypoglycaemia.

CONCLUSIONS/INTERPRETATION

Systemic B2AR agonist administration acts to limit insulin-induced hypoglycaemia by offsetting insulin's inhibitory effect on hepatic glucose production. This effect appears to be predominately mediated via a direct effect on liver B2ARs, but a small stimulatory effect on B2ARs within the VMH cannot be excluded. Our data suggest that formoterol may have therapeutic value to limit the risk of hypoglycaemia in patients with diabetes.

Options for combination therapy in type 2 diabetes: comparison of the ADA/EASD position statement and AACE/ACE algorithm

Treating patients with diabetes is one of the most challenging and important activities a physician (primary care physician or specialist) can undertake. A key to successful therapy for type 2 diabetes is the insight that this condition is progressive and that the need for additional agents over time is normative. The ability to individualize therapy by patient and medication characteristics comes from experience and knowledge of pertinent clinical studies. However, guidelines from expert bodies such as the American Diabetes Association/European Association for the Study of Diabetes and American Association of Clinical Endocrinologists/American College of Endocrinology can help clinicians of all levels of expertise to approach therapy choices more rationally. There is unity across these guidelines about the role and benefits of metformin as first-line pharmacological treatment, probability of good efficacy, low risk of hypoglycemia, modest weight loss, and overall long-term data. Unfortunately, this unity does not extend to recommendations for subsequent pharmacological agents and their use in combination to intensify treatment when insulin is not (yet) appropriate. Across both statements, some drug classes seem more prominent, and looking at their benefit-risk profile, it is clear why this is the case. The most profound recent change in diabetes therapy has been the introduction of incretin therapies. Incretin therapies minimize 2 important adverse effects seen with many other therapies: hypoglycemia and weight gain. These agents have increased the range of options available for early intensification of treatment of type 2 diabetes. In combination with more established therapies, there are more opportunities than ever to accommodate patient preferences while improving glycemic control and harnessing extraglycemic benefits of a second (or third) agent.

Hypoglycemia requiring ambulance services in patients with type 2 diabetes is associated with increased long-term mortality

OBJECTIVE

To report population burden of hypoglycemia requiring ambulance services and long term outcomes thereafter, among people with type 2 diabetes (T2D).

METHODS

We retrieved all ambulance calls made by T2D for hypoglycemia in Olmsted County, Minnesota, between January 1, 2003, and December 31, 2009.

RESULTS

Seven hundred eighteen calls were made by 503 T2D (age 69 ± 12 years, 51% male), of which 328 (65%) were on insulin (INS), 54 (11%) on insulin + noninsulin agents (NIAI), 95 (19%) on sulphonylurea alone or in combination with other noninsulin agents (SFU), 21 (4%) on nonsulphonylurea noninsulin agents (NSFU), and 5 (1%) on no therapy (excluded from further analysis). NSFU had lower repeated calls (INS 25%, NIAI 26%, SFU 12%, NSFU 5%; P = .02), emergency room transportation (ERT) (INS 62%, NIAI 67%, SFU 68%, NSFU 38%; P = .06), and hospitalizations (INS 31%, NIAI 46%, SFU 38%, NSFU 19%; P = .02) compared to other groups. In multivariable mortality model, increased age (P<.001) was associated with an increased risk of death, whereas hypoglycemia predisposing comorbidities (chronic liver disease, end stage renal disease, adrenal insufficiency) (P = .06) were associated with a borderline increased risk, but no association was found with treatment group, repeated calls, ERT, hospitalization and baseline diabetic end organ complications.

CONCLUSION

To our knowledge, we report the first estimate of hypoglycemia requiring ambulance services among T2D, in contemporary clinical practice. NSFU cohort was associated with lower repeated calls, ERT, and hospitalizations compared to other therapeutic programs. Predictors of mortality post-hypoglycemia were age and hypoglycemia predisposing comorbidities.

Population-based study of hypoglycemia in patients with type 1 diabetes mellitus requiring emergency medical services

OBJECTIVE

To report the population burden of hypoglycemia necessitating emergency medical services (EMS) and the long-term outcomes in patients with type 1 diabetes mellitus (T1DM) receiving different insulin treatments.

METHODS

We retrieved all EMS calls because of hypoglycemia in patients with T1DM in Olmsted County, Minnesota, between January 1, 2003, and December 31, 2009, and reviewed the related medical records.

RESULTS

During the 7-year study period, 531 EMS calls were made involving 208 patients with T1DM (112 men, 96 women; mean age 47 ± 13 years). Of the 208 patients, 137 (66%) were receiving multiple daily insulin (MDI) injections, 50 (24%) were receiving continuous subcutaneous insulin infusion, 15 (7%) were receiving simple insulin (SI), 4 (2%) were treated with metformin + MDI, and 2 (1%) were not receiving treatment for diabetes (after pancreas transplantation). The last 2 groups were excluded from further analysis because of small sample size. The remaining 3 treatment groups differed by age (P<.02), with the oldest patients receiving SI. Repeated calls, emergency department transportation (EDT), and hospitalization had a 33%, 49%, and 18% frequency, respectively, and did not differ among the treatment groups. In a multivariate model, mortality was significantly associated with treatment type (the SI group had a higher risk for mortality than did the MDI group [P = .03] after exclusion of 27 patients who changed treatment during follow-up), age (P<.0001), and EDT (P = .04).

CONCLUSION

The population burden of EMS-requiring hypoglycemia in patients with T1DM is high. Medical resource utilization was similar among the 3 treatment groups. Mortality was higher in the SI group (limited by small sample size) and among patients requiring EDT and increased with advancing age. Further research could be directed toward understanding the effect of expert evaluation of high-risk patients on long-term outcomes.

Omitting Follow-up Food After Initial Hypoglycaemic Treatment Does not Increase the Likelihood of Repeat Hypoglycaemia

INTRODUCTION

Guidelines for self-treatment of hypoglycaemia specify initial treatment with quick-acting carbohydrate until blood glucose levels normalize and then follow-up with longer-acting carbohydrate. The few studies investigating follow-up show 29-57% omission or undertreatment with follow-up carbohydrate but do not investigate the association of this with repeat hypoglycaemia. This study aimed to develop, validate and administer a questionnaire to delineate this association. The timeframe targeted was 2 h post primary hypoglycaemic event (PPHE), the time influenced by long-acting carbohydrate.

METHODS

A questionnaire was generated, test-retest reliability assessed, and it was piloted on convenience samples from the target population. The final version was administered to all insulin-treated individuals attending an outpatient diabetes clinic over 4 weeks (169).

RESULTS

Questionnaire development: readability (69.6-standard/easy), test-retest reliability (Cohen's kappa 0.57-0.91) and return rate (72.2%) were all acceptable. Questionnaire data: questionnaires were returned by 122 participants (63 males/59 females). Method of insulin administration was subcutaneous insulin injections (91%) and continuous subcutaneous insulin infusion (CSII) (9%). Repeat hypoglycaemia within 2 h PPHE was reported by 8.2% of respondents. There was no significant difference for age, gender and diabetes duration between those reporting repeat hypoglycaemia and those without. Consumption of follow-up longer-acting carbohydrate was reported by 58.2% of responders with 48% of these using long-acting and 52% medium-acting carbohydrate foods. Method of insulin administration and consumption of follow-up food were significantly associated with repeat hypoglycaemia (P = 0.015, 0.039) but presence or absence of symptoms and duration of action of carbohydrate were not significantly associated (P = 0.103, 0.629). Hierarchical logistic regression analysis showed omission of follow-up food PPHE was not a significant predictor of increased likelihood of repeat hypoglycaemia within 2 h PPHE, irrespective of method of insulin administration (P = 0.085).

CONCLUSION

This study supports guidelines that recommend judicious, rather than routine use of follow-up longer-acting carbohydrate PPHE.

Defective counterregulation and hypoglycemia unawareness in diabetes: mechanisms and emerging treatments

For people with diabetes, hypoglycemia remains the limiting factor in achieving glycemic control. This article reviews recent advances in how the brain senses and responds to hypoglycemia. Novel mechanisms by which individuals with insulin-treated diabetes develop hypoglycemia unawareness and impaired counterregulatory responses are outlined. Prevention strategies for reducing the incidence of hypoglycemia are discussed.

Evaluating the accuracy and large inaccuracy of two continuous glucose monitoring systems

OBJECTIVE

This study evaluated the accuracy and large inaccuracy of the Freestyle Navigator (FSN) (Abbott Diabetes Care, Alameda, CA) and Dexcom SEVEN PLUS (DSP) (Dexcom, Inc., San Diego, CA) continuous glucose monitoring (CGM) systems during closed-loop studies.

RESEARCH DESIGN AND METHODS

Paired CGM and plasma glucose values (7,182 data pairs) were collected, every 15-60 min, from 32 adults (36.2±9.3 years) and 20 adolescents (15.3±1.5 years) with type 1 diabetes who participated in closed-loop studies. Levels 1, 2, and 3 of large sensor error with increasing severity were defined according to absolute relative deviation greater than or equal to ±40%, ±50%, and ±60% at a reference glucose level of ≥6 mmol/L or absolute deviation greater than or equal to ±2.4 mmol/L,±3.0 mmol/L, and ±3.6 mmol/L at a reference glucose level of <6 mmol/L.

RESULTS

Median absolute relative deviation was 9.9% for FSN and 12.6% for DSP. Proportions of data points in Zones A and B of Clarke error grid analysis were similar (96.4% for FSN vs. 97.8% for DSP). Large sensor over-reading, which increases risk of insulin over-delivery and hypoglycemia, occurred two- to threefold more frequently with DSP than FSN (once every 2.5, 4.6, and 10.7 days of FSN use vs. 1.2, 2.0, and 3.7 days of DSP use for Level 1-3 errors, respectively). At levels 2 and 3, large sensor errors lasting 1 h or longer were absent with FSN but persisted with DSP.

CONCLUSIONS

FSN and DSP differ substantially in the frequency and duration of large inaccuracy despite only modest differences in conventional measures of numerical and clinical accuracy. Further evaluations are required to confirm that FSN is more suitable for integration into closed-loop delivery systems.

Hypoglycemia-associated autonomic failure in diabetes

The concept of hypoglycemia-associated autonomic failure (HAAF) in diabetes posits that recent antecedent hypoglycemia, as well as sleep or prior exercise, causes both defective glucose counterregulation (by attenuating the adrenomedullary epinephrine response, in the setting of absent insulin and glucagon responses) and hypoglycemia unawareness (by attenuating the sympathoadrenal, largely the sympathetic neural, response) and thus a vicious cycle of recurrent hypoglycemia. Albeit with different time courses, the pathophysiology of defense against hypoglycemia - no decrease in therapeutic insulin, no increase in glucagon and an attenuated increase in sympathoadrenal activity - is the same in type 1 diabetes and advanced type 2 diabetes. Hypoglycemia unawareness is reversible by 2-3 weeks of scrupulous avoidance of hypoglycemia in most affected patients. The pathophysiology of HAAF in diabetes explains why the incidence of hypoglycemia increases as patients approach the absolute endogenous insulin deficient end of the disease, provides a comprehensive set of risk factors including those indicative of HAAF, and leads logically to the practice of hypoglycemia risk factor reduction. Because of the risk of hypoglycemic mortality, presumably from cardiac arrhythmias, glycemic goals in diabetes should be individualized, based in part on the risk of hypoglycemia. By practicing hypoglycemia risk reduction - addressing the issue, applying the principles of aggressive glycemic therapy and considering both the conventional risk factors and those indicative of HAAF - it is possible to both improve glycemic control and reduce the risk of hypoglycemia in many patients with diabetes.

Clinical evaluation of a novel test strip technology for blood glucose monitoring: accuracy at hypoglycaemic glucose levels

AIM

To evaluate OneTouch® Verio™ test strip performance at hypoglycaemic blood glucose (BG) levels (<3.9 mmol/L [<70 mg/dL]) at seven clinical studies.

METHODS

Trained clinical staff performed duplicate capillary BG monitoring system tests on 700 individuals with type 1 and type 2 diabetes using blood from a single fingerstick lancing. BG reference values were obtained using a YSI 2300 STAT™ Glucose Analyzer. The number and percentage of BG values within ±0.83 mmol/L (±15 mg/dL) and ±0.56 mmol/L (±10 mg/dL) were calculated at BG concentrations of <3.9 mmol/L (<70 mg/dL), <3.3 mmol/L (<60 mg/dL), and <2.8 mmol/L (<50 mg/dL).

RESULTS

At BG concentrations <3.9 mmol/L (<70 mg/dL), 674/674 (100%) of meter results were within ±0.83 mmol/L (±15 mg/dL) and 666/674 (98.8%) were within ±0.56 mmol/L (±10 mg/dL) of reference values. At BG concentrations <3.3 mmol/L (<60 mg/dL), and <2.8 mmol/L (<50 mg/dL), 358/358 (100%) and 270/270 (100%) were within ±0.56 mmol/L (±10 mg/dL) of reference values, respectively.

CONCLUSION

In this analysis of data from seven independent studies, OneTouch Verio test strips provide highly accurate results at hypoglycaemic BG levels.