Partitioning the symptoms of hypoglycaemia using multi-sample confirmatory factor analysis

Survey of Hypoglycemia in Elderly People With Type 2 Diabetes Mellitus in Japan

Background

The number of elderly type 2 diabetes mellitus (T2DM) patients in Japan is increasing continuously. Hypoglycemia is a significant issue in their treatment. However, the actual situation and related details of their hypoglycemia remain unclear. In order to elucidate them, the Japan Physicians Association conducted a large-scale questionnaire survey for physicians and their outpatients all over Japan.

Methods

Targeted elderly T2DM outpatients were 65 years old or older in 2011. Specialized questionnaire survey forms were distributed to both of physicians and patients. The forms for physicians included questions whether patient had hypoglycemia in the last 1 month or 1 year; those for patients included whether they experienced it in the same durations and any of the 28 symptoms that are suggestive of hypoglycemia or pertaining to geriatric syndrome in the last 1 month, as well as questions about knowledge regarding hypoglycemia. We analyzed associations between hypoglycemia and the symptoms, and between hypoglycemia and medications.

Results

Of 15,892 T2DM patients (age, 74.2 ± 6.3 years; diabetes duration, 12.8 ± 8.9 years; HbA1c, 7.0±1.0%), dipeptidyl peptidase-4 inhibitor (DPP-4i) was the most prescribed medication among all oral hypoglycemic agents (OHAs). The frequencies of hypoglycemia in the last 1 month recognized by physicians and experienced by patients were 7.8% and 10.4% (P < 0.0001), and in the last 1 year were 15.5% and 21.1% respectively (P < 0.0001). The most common symptom was “weakness, fatigue/feeling languid” and the majority of all patients reported neuroglycopenic or autonomic symptoms. Regarding monotherapy, hypoglycemia was observed in 32.7% of the patients with insulin, 4% in sulfonylurea (SU), 3.8% in glinide, and 3.5% in pioglitazone. The questions asking knowledge about hypoglycemia revealed that SU or insulin users had significantly more knowledge of hypoglycemia than others (P < 0.001); however, 63% of patients using insulin, and 31% of patients using SU always carried glucose or a similar medication with them.

Conclusions

The present study suggested two types of “hidden hypoglycemia”, one is that physicians did not detect and the other one is that patients were not aware. It is vital that physicians strive to prevent hypoglycemia by paying closer attention to symptoms of “hidden hypoglycemia” in their elderly patients.

Diagnostic tools for post-gastric bypass hypoglycaemia

In spite of its evident success, several late complications can occur after gastric bypass surgery. One of these is post-gastric bypass hypoglycaemia. No evidence-based guidelines exist in the literature on how to confirm the presence of this syndrome. This study aims to describe and compare the tests aimed at making a diagnosis of post-gastric bypass hypoglycaemia and to provide a diagnostic approach based upon the available evidence. A search was conducted in PubMed, Cochrane and Embase. A few questionnaires have been developed to measure the severity of symptoms in post-gastric bypass hypoglycaemia but none has been validated. The gold standard for provocation of a hypoglycaemic event is the oral glucose tolerance test or the liquid mixed meal tolerance test. Both show a high prevalence of hypoglycaemia in post-gastric bypass patients with and without hypoglycaemic complaints as well as in healthy volunteers. No uniformly established cut-off values for glucose concentrations are defined in the literature for the diagnosis of post-gastric bypass hypoglycaemia. For establishing an accurate diagnosis of post-gastric bypass hypoglycaemia, a validated questionnaire, in connection with the diagnostic performance of provocation tests, is the most important thing missing. Given these shortcomings, we provide recommendations based upon the current literature.

Optimal glycaemic control in elderly people with type 2 diabetes: what does the evidence say?

The global prevalence of type 2 diabetes mellitus (T2DM) is rising in an ageing population through a combination of lifestyle changes and greater longevity. However, by excluding participants aged over 70 years, most major interventional trials on which current diabetes therapeutic guidelines are based have failed to provide specific evidence to support the prescribed management of diabetes in elderly people. While diabetes per se has a significant impact on the elderly person, the side effects of medications, particularly hypoglycaemia, prevent optimisation of diabetes treatment. Hypoglycaemia is associated with significant morbidity, to which elderly people are often more vulnerable because of factors such as the effects of ageing, progressive renal impairment, frailty, polypharmacy and cognitive decline. T2DM is associated with accelerated cognitive decline in some individuals, and recurrent severe hypoglycaemia has been implicated as a potential contributory factor. Although the evidence for selection of appropriate glycaemic targets in elderly patients is sparse, it is now acknowledged that prevention of hypoglycaemia must influence individualisation of treatment goals in this vulnerable group. This should also be reflected by the choice of anti-diabetes agents that are initiated when diet and lifestyle advice is ineffective. Recently developed international guidelines, which have specifically addressed the management of diabetes in elderly people, highlight the importance of a pragmatic management approach rather than attempting to achieve a generic glycated haemoglobin goal and are summarised in this article.

Counterregulatory responses to hypoglycemia differ between glimepiride and glyburide in non diabetic individuals

OBJECTIVE

Reported rates of hypoglycemia in patients with type 2 diabetes mellitus are lower with glimepiride as compared to glyburide. The aim of this study was to determine whether physiologic differences in counterregulatory neuroendocrine and metabolic mechanisms during hypoglycemia provide a basis for the observed clinical differences between glimepiride and glyburide.

RESEARCH DESIGN AND METHODS

Non-diabetic volunteers (age 38±2years, BMI 26±1kg/m(2)) were studied in a single-blind fashion during separate 2day randomized protocols consisting of 2h hyperinsulinemic (9pmol/kg/min) euglycemic (4.9±0.1mmol) and hypoglycemic (2.9±0.1mmol/L) clamps. Individuals received biologically equivalent doses of glimepiride (4mg) or glyburide (10mg) 1h prior to each glucose clamp (n=11) as well as a control group of placebo studies. Glucose kinetics were calculated using D-Glucose-6-6d2.

RESULTS

Insulin and C-peptide levels were increased (p<0.05) during euglycemia in both sulfonylurea groups as compared to placebo. However, despite equivalent hypoglycemia, insulin and C-peptide levels were higher (p<0.05) only after glyburide. Glucagon responses and endogenous glucose production (EGP) were decreased (p<0.05) during hypoglycemia following glyburide administration as compared to glimepiride. Glyburide reduced (p<0.05) norepinephrine responses during euglycemic clamps. In addition combined epinephrine and norepinephrine responses during hypoglycemia were reduced (p<0.05) following glyburide as compared to placebo. Leptin levels fell by a greater amount (p<0.05) during hypoglycemia with both sulfonylureas as compared to placebo.

CONCLUSIONS

In summary, glimepiride and glyburide can both similarly increase insulin and C-peptide levels during hyperinsulinemic euglycemia. However, during moderate hyperinsulinemic hypoglycemia (2.9mmol/L) glyburide resulted in increased C-peptide and insulin, but blunted glucagon, sympathetic nervous system and EGP responses. We conclude that glyburide can acutely reduce key neuroendocrine and metabolic counterregulatory defenses during hypoglycemia in healthy individuals.

Diazoxide improves hormonal counterregulatory responses to acute hypoglycemia in long-standing type 1 diabetes

Individuals with long-standing type 1 diabetes (T1D) are at increased risk of severe hypoglycemia secondary to impairments in normal glucose counterregulatory responses (CRRs). Strategies to prevent hypoglycemia are often ineffective, highlighting the need for novel therapies. ATP-sensitive potassium (KATP) channels within the hypothalamus are thought to be integral to hypoglycemia detection and initiation of CRRs; however, to date this has not been confirmed in human subjects. In this study, we examined whether the KATP channel-activator diazoxide was able to amplify the CRR to hypoglycemia in T1D subjects with long-duration diabetes. A randomized, double-blind, placebo-controlled cross-over trial using a stepped hyperinsulinemic hypoglycemia clamp was performed in 12 T1D subjects with prior ingestion of diazoxide (7 mg/kg) or placebo. Diazoxide resulted in a 37% increase in plasma levels of epinephrine and a 44% increase in plasma norepinephrine during hypoglycemia compared with placebo. In addition, a subgroup analysis revealed that the response to oral diazoxide was blunted in participants with E23K polymorphism in the KATP channel. This study has therefore shown for the first time the potential utility of KATP channel activators to improve CRRs to hypoglycemia in individuals with T1D and, moreover, that it may be possible to stratify therapeutic approaches by genotype.

Prevalence of and risk factors for hypoglycemic symptoms after gastric bypass and sleeve gastrectomy

OBJECTIVE

To determine the prevalence of and risk factors for postprandial hypoglycemic symptoms among bariatric surgery patients.

METHODS

A questionnaire including the Edinburgh hypoglycemia scale was mailed to patients who underwent either Roux-en-Y gastric bypass (RYGB) or vertical sleeve gastrectomy (VSG) at a single center. Based on the questionnaire, the patients were categorized as having high or low suspicion for post surgical, postprandial hypoglycemic symptoms.

RESULTS

Of the 1119 patients with valid addresses, 40.2% (N = 450) responded. Among the respondents, 34.2% had a high suspicion for symptoms of post bariatric surgery hypoglycemia. In multivariate analyses, in addition to female sex (P = 0.001), RYGB (P = 0.004), longer time since surgery (P = 0.013), and lack of diabetes (P = 0.040), the high suspicion group was more likely to report pre-operative symptoms of hypoglycemia (P < 0.001), compared to the low suspicion group. Similar results were observed when the high suspicion group was restricted to those requiring assistance from others, syncope, seizure with severe symptoms, or medically confirmed hypoglycemia (N = 52).

CONCLUSIONS

One third of patients who underwent RYGB or VSG reported postprandial symptoms concerning for postsurgical hypoglycemia, which was related to the presence of pre-operative hypoglycemic symptoms. Pre-operative screening for hypoglycemic symptoms may identify a group of patients at increased risk of postbariatric surgery hypoglycemia.

Gender-specific co-activation of arginine vasopressin and the hypothalamic-pituitary-adrenal axis during stress

OBJECTIVE

To study the interaction between copeptin and hypothalamic-pituitary-adrenal (HPA) activation in men and women during hypoglycaemic stress.

DESIGN AND PATIENTS

A prospective study in 118 patients (mean age 47·7 ± 13·6 years, n = 52 women) undergoing insulin tolerance testing for suspected pituitary dysfunction.

MEASUREMENTS

Serum copeptin was measured in serially collected blood samples and assessed in relation to ACTH, cortisol and other endocrine parameters.

RESULTS

Symptomatic hypoglycaemia (mean glucose nadir, 1·6 ± 0·5 mmol/l) resulted in a rapid significant increase of serum copeptin. Individuals with impaired pituitary function had lower stress-induced copeptin levels (median, 6·26 pmol/l) than patients with intact pituitary (8·46 pmol/l, P < 0·001). A weak overall correlation between stress-induced copeptin and cortisol levels was observed (rs  = 0·31, P < 0·001). In female individuals, there was a positive correlation between stress-induced copeptin and ACTH (rs  = 0·47, P < 0·001) or cortisol levels (rs  = 0·42, P = 0·002), while in males, no correlation with ACTH levels (rs  = 0·03, P = 0·75) and poor correlation with cortisol levels (rs  = 0·24, P = 0·045) was observed. Patients with central diabetes insipidus showed lowest baseline (2·20 pmol/l) and stimulated copeptin levels (3·68 pmol/l).

CONCLUSIONS

The data from this study indicate that stress-induced release of AVP in women, but not in men, is linked to the co-activation of the hypothalamic-pituitary-adrenal system.

Hypoglycaemia symptoms and impaired awareness of hypoglycaemia in adults with Type 1 diabetes: the association with diabetes duration

AIMS

To examine the association between diabetes duration and hypoglycaemia symptom profiles and the presence of impaired awareness of hypoglycaemia.

METHODS

A cross-sectional study was performed, using validated methods for recording hypoglycaemia symptoms and assessing hypoglycaemia awareness. The associations between symptom intensity, hypoglycaemia awareness and diabetes duration were examined, and the prevalence of impaired awareness was ascertained for Type 1 diabetes of differing durations.

RESULTS

Questionnaires were mailed to 636 adults with Type 1 diabetes, of whom 445 (70%) returned them. A total of 440 completed questionnaires were suitable for analysis. Longer diabetes duration was associated with lower intensity of autonomic symptoms (P for trend <0.001), but no association was observed with neuroglycopenic symptoms. The overall prevalence of impaired awareness of hypoglycaemia in this cohort was 17% (95% CI 14-21%) and increased with diabetes duration, from 3% for duration 2-9 years to 28% for duration ≥30 years (P for trend <0.001). Low autonomic symptom scores were not associated with a higher prevalence of impaired awareness.

CONCLUSIONS

Longer diabetes duration was associated with lower intensity of autonomic symptoms and a higher prevalence of impaired awareness of hypoglycaemia, suggesting that subjective symptoms of hypoglycaemia change over time. These observations underline the need for regular patient education about hypoglycaemia symptomatology and clinical screening for impaired awareness of hypoglycaemia.

Adolescents with Type 1 diabetes mellitus experience psychosensorial symptoms during hypoglycaemia

AIM

To describe mood and psychosensorial symptoms of hypoglycaemia in adolescents with Type 1 diabetes mellitus in two countries with different cultures, Turkey and the USA.

METHODS

We developed a 68-item questionnaire assessing physical, behavioural, mood and psychosensorial symptom frequency and ratings ['good', 'bad', or 'both' (sometimes good, sometimes bad)]. Adolescents with Type 1 diabetes were recruited from paediatric diabetes clinics at the University of North Carolina at Chapel Hill in the USA and Kocaeli University in Turkey. The percentages of participants at each clinic who endorsed individual symptoms, symptom categories and symptom ratings were calculated and compared.

RESULTS

Cronbach's α values were > 0.7 for each real symptom category. No symptom items were excluded from the questionnaire analysis based on item-total correlation results which were all > 0.2. Data were collected from 132 participants (69 from University of North Carolina, 63 from Kocaeli University, 54% male). The mean (SD) age of the participants was 14.9 (1.9) years, HbA1c level was 8.7 (1.8) % and duration of Type 1 diabetes was 5.8 (3.7) years. On average, each physical symptom was experienced by 65.2% of participants, each behavioural symptom by 46.5%, each mood symptom by 42.8%, and each psychosensorial symptom by 48.9%. On average, each physical, behavioral, mood and psychosensorial symptom was rated as 'good' or 'both' by 23.0, 29.1, 36.9 and 37.2% of participants, respectively. There were no symptom differences between the groups in each country.

CONCLUSIONS

In addition to the classic physical symptoms experienced during hypoglycaemia, adolescents with Type 1 diabetes report psychosensorial, mood and behavioral symptoms, and some describe them as positive experiences. Symptom experiences were similar in these two countries with different cultures.

Experiences of hypoglycaemia unawareness amongst people with Type 1 diabetes: A qualitative investigation

OBJECTIVES

To explore the experiences of people who have hypoglycaemia unawareness and its impact on their everyday lives.

METHODS

In-depth interviews with 38 people with Type 1 diabetes who have hypoglycaemia unawareness. Data analysis used an inductive, thematic approach.

RESULTS

Participants reported imposed and self-imposed changes to their lives following onset of hypoglycaemia unawareness including: leaving employment, curtailing pastimes and spending more time at home or being supervised by others. However, some reported getting on with life by downplaying the significance and impact of their condition, which could put their health and safety at risk. Many relied on frequent self-monitoring of blood glucose and/or prompting from others to detect hypoglycaemia. Some expressed concerns about becoming a burden on family and/or responding in irrational and aggressive ways to others' suggestions to test for and treat hypoglycaemia. Participants reported responding best to composed and directive prompts from family. Health professionals mainly advised on clinical aspects, and did not enquire about the emotional and psychosocial impact of hypoglycaemia unawareness.

DISCUSSION

Hypoglycaemia unawareness can have a profound impact on people's confidence, careers and personal relationships. Healthcare professionals should pay more attention during consultations to the emotional and social aspects of living with hypoglycaemia unawareness.

Disease burden evaluation of fall-related events in the elderly due to hypoglycemia and other diabetic complications: a clinical review

A hypoglycemia-induced fall is common in older persons with diabetes. The etiology of falls in this population is usually multifactorial, and includes microvascular and macrovascular complications and age-related comorbidities, with hypoglycemia being one of the major precipitating causes. In this review, we systematically searched the literature that was available up to March 31, 2014 from MEDLINE/PubMed, Embase, and Google Scholar using the following terms: hypoglycemia; insulin; diabetic complications; and falls in elderly. Hypoglycemia, defined as blood glucose <4.0 mmol/L (70 mg/dL) requiring external assistance, occurs in one-third of elderly diabetics on glucose-lowering therapies. It represents a major barrier to the treatment of diabetes, particularly in the elderly population. Patients who experience hypoglycemia are at a high risk for adverse outcomes, including falls leading to bone fracture, seizures, cognitive dysfunction, and prolonged hospital stays. An increase in mortality has been observed in patients who experience any one of these events. Paradoxically, rational insulin therapy, dosed according to a patient’s clinical status and the results of home blood glucose monitoring, so as to achieve and maintain recommended glycemic goals, can be an effective method for the prevention of hypoglycemia and falls in the elderly. Contingencies, such as clinician-directed hypoglycemia treatment protocols that guide the immediate treatment of hypoglycemia, help to limit both the duration and severity of the event. Older diabetic patients with or without underlying renal insufficiency or other severe illnesses represent groups that are at high risk for hypoglycemia-induced falls and, therefore, require lower insulin dosages. In this review, the risk factors of falls associated with hypoglycemia in elderly diabetics were highlighted and management plans were suggested. A target hemoglobin A1c level between 7% and 8% seems to be more appropriate for this population. In addition, the first-choice drugs should have good safety profiles and have the lowest probability of causing hypoglycemia – such as metformin (in the absence of significant renal impairment) and incretin enhancers – while other therapies that may cause more frequent hypoglycemia should be avoided.

Prospective assessment of hypoglycemia symptoms in children and adults with type 1 diabetes

PURPOSE

To compare the characteristics of symptoms of hypoglycemia in children and in adults with type 1 diabetes.

METHODS

Adults with diabetes and parents of children with diabetes who were participants were asked to call a phone system to report episodes of hypoglycemia (presence of symptoms and a blood glucose <4.0 mmol/L). For each episode, blood glucose reading and a scoring of 28 symptoms on a 7-point scale (1 = not present, 7 = very intense) were collected.

RESULTS

Sixty six children (49.2% males, mean age = 12.1±2.4 years, mean age at diagnosis = 7.5±2.9 years) and 53 adults (41.2% males, mean age 38.7±14.5 years, mean age at diagnosis = 17.5±12.9 years) with type 1 diabetes participated. The most common symptoms in adults were hunger, sweating, trembling and weakness. The most common symptoms in children were weakness, trembling and hunger. The 2 most discriminating variables between children and adults were sleepiness and tiredness, which were more common in children (p<0.01). In a comparative factor analysis, 3 factors emerged: factor 1, autonomic and neuroglycopenic; factor 2, behavioural; and factor 3, general malaise. Factors 2 and 3 were significantly more common or intense in children than in adults; MANOVA: F(1, 113) = 6.72, p<0.05 and F(1, 113) = 4.64, p<0.05, respectively.

CONCLUSIONS

Symptoms relating to behaviour and general malaise are more common in children than in adults with type 1 diabetes. The results of this study may assist providers in educating caregivers of children and patients with diabetes how to better recognize episodes of hypoglycemia.

Prevalence of impaired awareness of hypoglycemia and identification of predictive symptoms in children and adolescents with type 1 diabetes

BACKGROUND

In children with type 1 diabetes mellitus (T1DM) the prevalence of impaired awareness of hypoglycemia (IAH) is uncertain. This study aimed to ascertain this with greater precision. Secondary aims were to assess symptoms of hypoglycemia and which of these best predict awareness of hypoglycemia in children.

METHODS

Questionnaires were completed by 98 children with T1DM (mean age 10.6 yr) and their parent(s); hospital admission data for the previous year were collected. Awareness of hypoglycemia was assessed using two questionnaire-based methods that have been validated in adults. For 4 wk, participants performed routine blood glucose measurements and completed questionnaires after each episode of hypoglycemia. Principal components analysis determined how symptoms correlate; multinomial logistic regression models identified which symptom aggregate best predicted awareness status.

RESULTS

The 'Gold' questionnaire classified a greater proportion of the participants as having IAH than the 'Clarke' questionnaire (68.4 vs. 22.4%). Using the 'Clarke' method, but not the 'Gold' method, children with IAH were younger and more likely to require external assistance or hospital admission. Most aged ≥9 yr (98.6%) were able to self-assess awareness status accurately. Puberty and increasing age, augmented symptom scores; duration of diabetes and glycemic control had no effect. In contrast to adults, behavioral symptoms were the best predictors of awareness status.

CONCLUSIONS

IAH affects a substantial minority of children and impending hypoglycemia may be heralded by behavioral symptoms. The 'Clarke' method was more effective at identifying those at increased risk and could be used as a screening tool.

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.

Acute hypoglycemia impairs executive cognitive function in adults with and without type 1 diabetes

OBJECTIVE

Acute hypoglycemia impairs cognitive function in several domains. Executive cognitive function governs organization of thoughts, prioritization of tasks, and time management. This study examined the effect of acute hypoglycemia on executive function in adults with and without diabetes.

RESEARCH DESIGN AND METHODS

Thirty-two adults with and without type 1 diabetes with no vascular complications or impaired awareness of hypoglycemia were studied. Two hyperinsulinemic glucose clamps were performed at least 2 weeks apart in a single-blind, counterbalanced order, maintaining blood glucose at 4.5 mmol/L (euglycemia) or 2.5 mmol/L (hypoglycemia). Executive functions were assessed with a validated test suite (Delis-Kaplan Executive Function). A general linear model (repeated-measures ANOVA) was used. Glycemic condition (euglycemia or hypoglycemia) was the within-participant factor. Between-participant factors were order of session (euglycemia-hypoglycemia or hypoglycemia-euglycemia), test battery used, and diabetes status (with or without diabetes).

RESULTS

Compared with euglycemia, executive functions (with one exception) were significantly impaired during hypoglycemia; lower test scores were recorded with more time required for completion. Large Cohen d values (>0.8) suggest that hypoglycemia induces decrements in aspects of executive function with large effect sizes. In some tests, the performance of participants with diabetes was more impaired than those without diabetes.

CONCLUSIONS

Executive cognitive function, which is necessary to carry out many everyday activities, is impaired during hypoglycemia in adults with and without type 1 diabetes. This important aspect of cognition has not received previous systematic study with respect to hypoglycemia. The effect size is large in terms of both accuracy and speed.

Enhanced carbohydrate craving in patients with poorly controlled Type 2 diabetes mellitus

AIMS

Although hyperphagia is a common manifestation of diabetes mellitus, data on food craving in patients with diabetes are limited. This study compared food craving in patients with Type 2 diabetes mellitus and a control group without diabetes.

METHODS

A total of 210 subjects (105 with Type 2 diabetes and 105 age-, sex- and BMI-matched control subjects) participated in two food craving surveys. The surveys were as follows: the General Food Cravings Questionnaire--Trait, which assesses the general trait of food craving; and the Food Cravings Questionnaire--State, which assesses the state of food craving or current desire for high-carbohydrate or high-fat foods in response to pictures of food. Follow-up Food Cravings Questionnaire--State surveys were administered approximately 3 months later to the subjects with diabetes. Survey results were analysed to assess relationships between food craving and glycaemic control.

RESULTS

The General Food Cravings Questionnaire--Trait scores in the group with Type 2 diabetes and the control group were not significantly different. The group with Type 2 diabetes had higher carbohydrate craving scores, but lower fat craving scores, than the control group. Carbohydrate craving scores in subjects with diabetes were positively correlated with HbA(1c). In follow-up surveys, carbohydrate craving scores declined in patients with improved glycaemic control.

CONCLUSIONS

The surveys showed that patients with Type 2 diabetes had higher carbohydrate cravings and lower fat cravings than the age-, sex- and BMI-matched control group. Carbohydrate craving in patients with diabetes was associated with poor glycaemic control.

Comparison of Optimised MDI versus Pumps with or without Sensors in Severe Hypoglycaemia (the Hypo COMPaSS trial)

BACKGROUND

Severe hypoglycaemia (SH) is one of the most feared complications of type 1 diabetes (T1DM) with a reported prevalence of nearly 40%. In randomized trials of Multiple Daily Injections (MDI) and Continuous Subcutaneous Insulin Infusion (CSII) therapy there is a possible benefit of CSII in reducing SH. However few trials have used basal insulin analogues as the basal insulin in the MDI group and individuals with established SH have often been excluded from prospective studies. In published studies investigating the effect of Real Time Continuous Glucose Monitoring (RT-CGM) benefit in terms of reduced SH has not yet been demonstrated. The primary objective of this study is to elucidate whether in people with T1DM complicated by impaired awareness of hypoglycaemia (IAH), rigorous prevention of biochemical hypoglycaemia using optimized existing self-management technology and educational support will restore awareness and reduce risk of recurrent SH.

METHODS/DESIGN

This is a multicentre prospective RCT comparing hypoglycaemia avoidance with optimized MDI and CSII with or without RT-CGM in a 2×2 factorial design in people with type 1 diabetes who have IAH. The primary outcome measure for this study is the difference in IAH (Gold score) at 24 weeks. Secondary outcomes include biomedical measures such as HbA1c, SH incidence, blinded CGM analysis, self monitored blood glucose (SMBG) and response to hypoglycaemia in gold standard clamp studies. Psychosocial measures including well-being and quality of life will also be assessed using several validated and novel measures. Analysis will be on an intention-to-treat basis.

DISCUSSION

Most existing RCTs using this study's interventions have been powered for change in HbA1c rather than IAH or SH. This trial will demonstrate whether IAH can be reversed and SH prevented in people with T1DM in even those at highest risk by using optimized conventional management and existing technology.

TRIAL REGISTRATION

ISRCTN52164803 Eudract No: 2009-015396-27.

Metabolic neuroimaging of the brain in diabetes mellitus and hypoglycaemia

Functional neuroimaging techniques can be used to study changes in regional brain activation, using changes in surrogate markers such as regional cerebral perfusion and rates of glucose uptake or metabolism. These approaches are shedding new light on two major health problems: the increasing burden of type 2 diabetes mellitus (T2DM), which is driven by the rising prevalence of insulin resistance and obesity; and recurrent intractable problematic hypoglycaemia, which is driven by the cognitive impairment that can occur in association with iatrogenic hypoglycaemic episodes. Some patients with diabetes mellitus lose awareness of being hypoglycaemic, which puts them at risk of severe hypoglycaemia as they are unlikely to take action to prevent the condition worsening. Involvement of corticolimbic brain and centres serving higher executive functions as well as the hypothalamus has been demonstrated in both situations and has implications for therapy. This Review describes the relevant principles of functional neuroimaging techniques and presents data supporting the notion that the dysregulation of central pathways involved in metabolic regulation, reward and appetite could contribute to problematic hypoglycaemia during therapy for diabetes mellitus and to insulin-resistant obesity and T2DM. Understanding these dysregulations could enable the development of novel clinical interventions.

Severe hypoglycemia symptoms, antecedent behaviors, immediate consequences and association with glycemia medication usage: Secondary analysis of the ACCORD clinical trial data

BACKGROUND

Hypoglycemia is a common complication of diabetes treatment. This paper describes symptoms, predecessors, consequences and medications associated with the first episode of severe hypoglycemia among ACCORD participants with type 2 diabetes, and compares these between intensive (Int: goal A1C <6.0%) and standard (Std, goal A1C 7-7.9%) glycemia intervention groups.

METHODS

Information about symptoms, antecedents, and consequences was collected at the time participants reported an episode of severe hypoglycemia. Data on medications prescribed during the clinical trial was used to determine the association of particular diabetes drug classes and severe hypoglycemia.

RESULTS

The most frequently reported symptoms in both glycemia group were weakness/fatigue (Int 29%; Std 30%) and sweating (Int 26%; Std 27%), followed by confusion/disorientation (Int 22%; Std 29%) and shakiness (Int 21%; Std 19%). Approximately half of all events were preceded by a variation in food intake (Int 48%; Std 58%). The most common consequences were confusion (Int 37%; Std 34%), loss of consciousness (Int 25%; Std 25%), and hospitalization (Int 18%; Std 24%). The highest rates of hypoglycemia were found among those participants treated with insulin only (Int 6.09/100 person yrs; Std 2.64/100 person yrs) while the lowest were among those prescribed oral agents only (Int 1.93/100 person yrs; Std 0.20/100 person yrs).

CONCLUSIONS

Severe hypoglycemia episodes were frequently preceded by a change in food intake, making many episodes potentially preventable. Symptoms of confusion/disorientation and loss of consciousness were frequently seen. The highest rates of hypoglycemia were seen with prescription of insulin, either alone or in combination with other medications.

CLINICAL TRIAL REGISTRATION

Number: NCT00000620.

Insulin analogues and severe hypoglycaemia in type 1 diabetes

INTRODUCTION

The effect of insulin analogues on glycaemic control is well-documented, whereas the effect on avoidance of severe hypoglycaemia remains tentative. We studied the frequency of severe hypoglycaemia in unselected patients with type 1 diabetes treated with insulin analogues, human insulin, or mixed regimens.

METHODS

A questionnaire was posted from six Danish diabetes clinics to 6112 unselected patients with type 1 diabetes and filled in by 3861 patients (63.2%). Primary endpoint was number of episodes of severe hypoglycaemia in the preceding year. Mild hypoglycaemia was also reported.

RESULTS

The frequency of severe hypoglycaemic episodes per patient-year in patients receiving long-acting insulin analogues was 1.47±0.18 versus 1.09±0.10 in patients on long-acting human insulin (p=0.01). The frequency of severe hypoglycaemic episodes per patient-year was 1.09±0.11 in patients on short-acting insulin analogues versus 1.26±0.13 in patients on short-acting human insulin (p=0.15), which was statistically significant in an adjusted analysis.

CONCLUSIONS

Severe hypoglycaemia is more frequent in patients with type 1 diabetes treated with long-acting insulin analogues. Confounding by indication may be involved. Clinical intervention trials using insulin analogues in patients prone to severe hypoglycaemia are highly needed.

The impact of hypoglycaemia on quality of life and related patient-reported outcomes in Type 2 diabetes: a narrative review

As a common side effect of insulin treatment for diabetes, hypoglycaemia is a constant threat and can have far-reaching and potentially devastating consequences, including immediate physical injury as well as more pervasive cognitive, behavioural and emotional effects. Moreover, as a significant limiting factor in achieving optimal glycaemic control, exposure to hypoglycaemia can influence diabetes self-management. Although hypoglycaemia is known to occur in Type 2 diabetes, its morbidity and impact on the individual are not well recognized. The aim of the current review is to examine published evidence to achieve a synthesis of the scope and significance of the potential detriment caused by hypoglycaemia to individuals with Type 2 diabetes. The implications of these observations for treatment and research have also been considered. A narrative review was performed of empirical papers published in English since 1966, reporting the effect of hypoglycaemia on quality of life and related outcomes (including generic and diabetes-specific quality of life, emotional well-being and health utilities) in Type 2 diabetes. Research demonstrates the potential impact of hypoglycaemia on the lives of people with Type 2 diabetes, from an association with depressive symptoms and heightened anxiety, to impairment of the ability to drive, work and function in ways that are important for quality of life. Few studies consider hypoglycaemia as an explanatory variable in combination with quality of life or related primary endpoints. As a consequence, there is a pressing need for high-quality research into the overall impact of hypoglycaemia on the lives of people with Type 2 diabetes.

Medically minimising the impact of hypoglycaemia in type 2 diabetes: a review

INTRODUCTION

Some therapies for type 2 diabetes (T2DM) are limited by hypoglycaemia, and this underestimated side effect carries an associated morbidity and financial burden. Large trials that have examined strict glycaemic control and cardiovascular outcomes in T2DM have highlighted the potential harm of exposure to hypoglycaemia in people with coronary heart disease.

AREAS COVERED

The responses to, and the morbidity associated with, hypoglycaemia in T2DM are discussed with identification of people most at risk of severe hypoglycaemia. The evidence base for non-pharmacological strategies and the risks of hypoglycaemia associated with various treatment modalities are examined. This review provides the clinician with a rational approach to the selection of different anti-diabetes drugs to minimize the risk of hypoglycaemia.

EXPERT OPINION

When managing T2DM, insulin and insulin secretagogues should be used judiciously and glycaemic targets individualized to avoid hypoglycaemia. Incretin mimetics present a lower risk of hypoglycaemia with similar efficacy as traditional agents in treating hyperglycaemia. The potential relationship between hypoglycaemia and precipitation of acute cardiovascular events is a highly topical area of research and may help determine what glycaemic targets are appropriate in people with T2DM.

The effect of antecedent hypoglycaemia on β₂-adrenergic sensitivity in healthy participants with the Arg16Gly polymorphism of the β₂-adrenergic receptor

AIMS/HYPOTHESIS

Homozygosity for glycine at codon 16 (GlyGly) of the β(2)-adrenergic receptor may alter receptor sensitivity upon chronic stimulation and has been implicated in the pathogenesis of hypoglycaemia unawareness. We compared the effect of antecedent hypoglycaemia on β(2)-adrenergic receptor sensitivity between GlyGly participants and those with arginine 16 homozygosity (ArgArg) for the β(2)-adrenergic receptor.

METHODS

We enrolled 16 healthy participants, who were either GlyGly (n = 8) or ArgArg (n = 8). They participated randomly in two 2 day experiments. Day 1 consisted of two 2-h hyperinsulinaemic hypoglycaemic (2.8 mmol/l) or euglycaemic (4.8 mmol/l) glucose clamps. On day 2, we measured the forearm vasodilator response to the β(2)-adrenergic receptor agonist salbutamol and the dose of isoprenaline required to increase the heart rate by 25 bpm (IC(25)).

RESULTS

The vasodilator response to salbutamol tended to be greater after antecedent hypoglycaemia than after euglycaemia (p = 0.078), consistent with increased β(2)-adrenergic receptor sensitivity. This effect was driven by a significant increase in β(2)-adrenergic receptor sensitivity following hypoglycaemia compared with euglycaemia in ArgArg participants (p = 0.019), whereas no such effect was observed in the GlyGly participants. Antecedent hypoglycaemia tended to decrease the IC(25) in ArgArg participants, whereas the reverse occurred in the GlyGly participants (GlyGly vs ArgArg group p = 0.047).

CONCLUSION/INTERPRETATION

Antecedent hypoglycaemia did not affect β(2)-adrenergic receptor sensitivity in healthy GlyGly participants, but increased it in ArgArg participants. If these results also hold for participants with type 1 diabetes, such an increase in β(2)-adrenergic receptor sensitivity may potentially reduce the risk of repeated hypoglycaemia and the subsequent development of hypoglycaemia unawareness in ArgArg diabetic participants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00160056.

Modeling the consistency of hypoglycemic symptoms: high variability in diabetes

BACKGROUND

The aim of the present study was to examine symptoms of hypoglycemia, to develop a method to quantify individual differences in the consistency of symptom reporting, and to investigate which factors affect these differences.

METHODS

Participants recorded their symptoms with every episode of hypoglycemia over a 9-12-month period. A novel logistic-type latent variable model was developed to quantify the consistency of each individual's symptom complex and was used to analyze data from 59 subjects (median age, 57.5 years [range, 22-74 years], 65% male, 77% type 1 diabetes) who had experienced 19 or more hypoglycemic episodes. The association between the calculated consistency parameter and age, sex, type and duration of diabetes, and C-peptide and serum angiotensin converting enzyme concentration was examined using a generalized linear model. Analyses were performed under a Bayesian framework, using Markov chain Monte-Carlo methodology.

RESULTS

Individuals exhibited substantial differences in between-episode consistency of their symptom reports, with only a small number of individuals exhibiting high levels of consistency. Men were more consistent than women. No other factors affected consistency in patients with normal hypoglycemia awareness.

CONCLUSIONS

By using a novel stochastic model as a quantitative tool to compare the consistency of hypoglycemic symptom reporting, much greater intra-individual variability in symptom reporting was identified than has been recognized previously. This is relevant when instructing patients on identification of hypoglycemic symptoms and in interpreting symptomatic responses during experimentally induced hypoglycemia.

The impact of eating behavior on psychological symptoms typical of reactive hypoglycemia. A pilot study comparing women with polycystic ovary syndrome to controls

The idea that diet can affect mood and behavior in women with polycystic ovary syndrome (PCOS) by altering blood glucose levels has become popular in recent years. This paper describes an online survey (N=462) of 24 women with PCOS, 299 healthy control women, 47 women who possibly had undiagnosed PCOS, and 92 men. The groups were compared for symptoms of mood and behavioral symptoms typical of reactive (postprandial) hypoglycemia. The outcome measures were two questionnaires that measure states associated with hypoglycemia: the Hypoglycemia Symptom Checklist-7 (HSC-7), which measures behavioral symptoms and the Mood Adjective Checklist (MACL), which measures emotional states. Controlling for age and body mass index (BMI) using between-groups analysis of covariance (ANCOVA), the women with PCOS scored significantly higher than the other three groups (p<0.001) on the outcome measures. These differences remained statistically significant in a subset of twelve women with PCOS compared to twelve healthy control women closely matched for age, BMI, and eating behavior. The findings are suggestive of hypoglycemia-related mood and behavioral problems in PCOS. Future research should test whether blood glucose levels correlate with these symptoms in PCOS, and whether a low glycemic index ('low-GI') diet improves the symptoms.

Treatment of severe diabetic hypoglycemia with glucagon: an underutilized therapeutic approach

Tight glycemic control is important in reducing and delaying vascular complications in type 1 and 2 diabetes patients; however, the benefits achieved through strict metabolic control are counterbalanced by an increased risk of hypoglycemia. Glucagon is an effective therapy for treating severe hypoglycemia. Available as an emergency kit, glucagon is an essential tool for rapid response, but remains underappreciated and underused. This article reviews the role of glucagon in treating severe hypoglycemia and discusses the need for better education on glucagon for people with diabetes and their caregivers in order to alleviate fears of hypoglycemia and of administering glucagon in the event of an emergency.

Brain glucosamine boosts protective glucoprivic feeding

The risk of iatrogenic hypoglycemia is increased in diabetic patients who lose defensive glucoregulatory responses, including the important warning symptom of hunger. Protective hunger symptoms during hypoglycemia may be triggered by hypothalamic glucose-sensing neurons by monitoring changes downstream of glucose phosphorylation by the specialized glucose-sensing hexokinase, glucokinase (GK), during metabolism. Here we investigated the effects of intracerebroventricular (ICV) infusion of glucosamine (GSN), a GK inhibitor, on food intake at normoglycemia and protective feeding responses during glucoprivation and hypoglycemia in chronically catheterized rats. ICV infusion of either GSN or mannoheptulose, a structurally different GK inhibitor, dose-dependently stimulated feeding at normoglycemia. Consistent with an effect of GSN to inhibit competitively glucose metabolism, ICV coinfusion of d-glucose but not l-glucose abrogated the orexigenic effect of ICV GSN at normoglycemia. Importantly, ICV infusion of a low GSN dose (15 nmol/min) that was nonorexigenic at normoglycemia boosted feeding responses to glucoprivation in rats with impaired glucose counterregulation. ICV infusion of 15 nmol/min GSN also boosted feeding responses to threatened hypoglycemia in rats with defective glucose counterregulation. Altogether our findings suggest that GSN may be a potential therapeutic candidate for enhancing defensive hunger symptoms during hypoglycemia.

Effects of antecedent GABAA activation with alprazolam on counterregulatory responses to hypoglycemia in healthy humans

OBJECTIVE

To date, there are no data investigating the effects of GABA(A) activation on counterregulatory responses during repeated hypoglycemia in humans. The aim of this study was to determine the effects of prior GABA(A) activation using the benzodiazepine alprazolam on the neuroendocrine and autonomic nervous system (ANS) and metabolic counterregulatory responses during next-day hypoglycemia in healthy humans.

RESEARCH DESIGN AND METHODS

Twenty-eight healthy individuals (14 male and 14 female, age 27 +/- 6 years, BMI 24 +/- 3 kg/m(2), and A1C 5.2 +/- 0.1%) participated in four randomized, double-blind, 2-day studies. Day 1 consisted of either morning and afternoon 2-h hyperinsulinemic euglycemia or 2-h hyperinsulinemic hypoglycemia (2.9 mmol/l) with either 1 mg alprazolam or placebo administered 30 min before the start of each clamp. Day 2 consisted of a single-step hyperinsulinemic-hypoglycemic clamp of 2.9 mmol/l.

RESULTS

Despite similar hypoglycemia (2.9 +/- 1 mmol/l) and insulinemia (672 +/- 108 pmol/l) during day 2 studies, GABA(A) activation with alprazolam during day 1 euglycemia resulted in significant blunting (P < 0.05) of ANS (epinephrine, norepinephrine, muscle sympathetic nerve activity, and pancreatic polypeptide), neuroendocrine (glucagon and growth hormone), and metabolic (glucose kinetics, lipolysis, and glycogenolysis) counterregulatory responses. GABA(A) activation with alprazolam during prior hypoglycemia caused further significant (P < 0.05) decrements in subsequent glucagon, growth hormone, pancreatic polypeptide, and muscle sympathetic nerve activity counterregulatory responses.

CONCLUSIONS

Alprazolam activation of GABA(A) pathways during day 1 hypoglycemia can play an important role in regulating a spectrum of key physiologic responses during subsequent (day 2) hypoglycemia in healthy man.

Prevalence of impaired awareness of hypoglycaemia and frequency of hypoglycaemia in insulin-treated type 2 diabetes

AIMS

The present study sought to ascertain the prevalence of impaired awareness of hypoglycaemia (IAH) in people with insulin-treated Type 2 diabetes (T2DM) and its effect on risk of hypoglycaemia.

METHODS

Data were obtained from 122 people with insulin-treated T2DM (63 male; mean (SD) HbA1c 8.4% (1.5); median (inter quartile range, IQR) age, 67 (58-72) years; duration of T2DM 15 (10-20) years; duration of insulin therapy, 6 (4-9) years). A questionnaire was used to evaluate hypoglycaemia awareness status and estimate the frequency of severe hypoglycaemia (SH) in the preceding year. Capillary blood glucose was monitored prospectively over a 4-week period to document biochemical hypoglycaemia.

RESULTS

The prevalence of IAH was 9.8%. In the subgroup with IAH the incidence of SH in the preceding year was 17-fold higher than those with normal hypoglycaemia awareness (0.83 (1.12) vs. 0.05 (0.28) episodes per patient; p<0.001 (n=122)) and had a five-fold higher incidence of biochemical hypoglycaemia (2.43 (4.39) vs. 0.46 (1.21) episodes; p<0.001 (n=63)).

CONCLUSION

The prevalence of IAH in insulin-treated T2DM was associated with higher frequencies of SH and biochemical hypoglycaemia. Therefore the presence of IAH in those with insulin-treated T2DM should be evaluated at clinical review.

Vascular endothelial growth factor during hypoglycemia in patients with type 1 diabetes mellitus: relation to cognitive function and renin-angiotensin system activity

In healthy adults, levels of vascular endothelial growth factor (VEGF) increase in response to mild hypoglycemia. VEGF is implicated in glucose transport over the blood-brain barrier, and the increase during hypoglycemia has been positively correlated with preservation of cognitive function during hypoglycemia. High activity in the renin-angiotensin system (RAS) is associated with an increased risk of severe hypoglycemia in patients with type 1 diabetes mellitus. Renin-angiotensin system possibly exerts its mechanism in hypoglycemia via VEGF. We studied the impact of mild hypoglycemia on plasma VEGF in patients with type 1 diabetes mellitus and high or low RAS activity and analyzed associations between VEGF levels and cognitive function during hypoglycemia. Eighteen patients with type 1 diabetes mellitus-9 with high and 9 with low RAS activity-underwent a single-blinded, placebo-controlled, crossover study with either mild hypoglycemia or stable glycemia. Cognitive function was assessed by the California Cognitive Assessment Package and the Alzheimer Quick Test. Nadir plasma glucose was 2.2 (0.3) mmol/L. During the control study, plasma VEGF did not change. During hypoglycemia, plasma VEGF increased from 39 to 58 pg/L in the high-RAS group (P = .004) and from 76 to 109 pg/L in the low-RAS group (P = .01), with no difference between RAS groups (P = .9). A weak association between reduced preservation of cognitive function during hypoglycemia and low VEGF response was observed. Plasma VEGF levels increase during mild, short-term hypoglycemia in patients with type 1 diabetes mellitus. The VEGF response is not dependent on RAS activity and only weakly associated with preservation of cognitive function during hypoglycemia. Thus, the previously described association between low RAS activity and better cognitive performance during hypoglycemia does not seem to be mediated by VEGF.

Effects of differing antecedent increases of plasma cortisol on counterregulatory responses during subsequent exercise in type 1 diabetes

OBJECTIVE

Antecedent hypoglycemia can blunt neuroendocrine and autonomic nervous system responses to next-day exercise in type 1 diabetes. The aim of this study was to determine whether antecedent increase of plasma cortisol is a mechanism responsible for this finding.

RESEARCH DESIGN AND METHODS

For this study, 22 type 1 diabetic subjects (11 men and 11 women, age 27 +/- 2 years, BMI 24 +/- 1 kg/m(2), A1C 7.9 +/- 0.2%) underwent four separate randomized 2-day protocols, with overnight normalization of blood glucose. Day 1 consisted of morning and afternoon 2-h hyperinsulinemic- (9 pmol x kg(-1) x min(-1)) euglycemic clamps (5.1 mmol/l), hypoglycemic clamps (2.9 mmol/l), or euglycemic clamps with a physiologic low-dose intravenous infusion of cortisol to reproduce levels found during hypoglycemia or a high-dose infusion, which resulted in further twofold greater elevations of plasma cortisol. Day 2 consisted of 90-min euglycemic cycling exercise at 50% Vo(2max).

RESULTS

During exercise, glucose levels were equivalently clamped at 5.1 +/- 0.1 mmol/l and insulin was allowed to fall to similar levels. Glucagon, growth hormone, epinephrine, norepinephrine, and pancreatic polypeptide responses during day 2 exercise were significantly blunted following antecedent hypoglycemia, low- and high-dose cortisol, compared with antecedent euglycemia. Endogenous glucose production and lipolysis were also significantly reduced following day 1 low- and high-dose cortisol.

CONCLUSIONS

Antecedent physiologic increases in cortisol (equivalent to levels occurring during hypoglycemia) resulted in blunted neuroendocrine, autonomic nervous system, and metabolic counterregulatory responses during subsequent exercise in subjects with type 1 diabetes. These data suggest that prior elevations of cortisol may play a role in the development of exercise-related counterregulatory failure in those with type 1 diabetes.

Cognitive performance, symptoms and counter-regulation during hypoglycaemia in patients with type 1 diabetes and high or low renin-angiotensin system activity

INTRODUCTION

High basal renin-angiotensin system (RAS) activity is associated with increased risk of severe hypoglycaemia in type 1 diabetes. We tested whether this might be explained by more pronounced cognitive dysfunction during hypoglycaemia in patients with high RAS activity than in patients with low RAS activity.

MATERIALS AND METHODS

Nine patients with type 1 diabetes and high and nine with low RAS activity were subjected to hypoglycaemia and euglycaemia in a cross-over study using an intravenous insulin infusion protocol. Cognitive function, electroencephalography, auditory evoked potentials and hypoglycaemic symptoms were recorded.

RESULTS

At a hypoglycaemic nadir of 2.2 (SD 0.3) mmol/L the high RAS group displayed significant deterioration in cognitive performance during hypoglycaemia in the three most complex reaction time tasks. In the low RAS group, hypoglycaemia led to cognitive dysfunction in only one reaction time task. The high RAS group reported lower symptom scores during hypoglycaemia than the low RAS group, suggesting poorer hypoglycaemia awareness.

CONCLUSION

High RAS activity is associated with increased cognitive dysfunction and blunted symptoms during mild hypoglycaemia compared to low RAS activity. This may explain why high RAS activity is a risk factor for severe hypoglycaemia in type 1 diabetes.

Hypoglycaemia: an overview

Hypoglycaemia is a frequent side-effect of treatment with insulin and sulfonylureas for people with diabetes, threatening potentially serious morbidity and preventing optimal glycaemic control. Fear of hypoglycaemia and development of syndromes such as impaired awareness and counterregulatory deficiency provide additional hazards for intensification of treatment. Rapid lowering of HbA1c may be potentially dangerous in type 2 diabetes because of the adverse cardiovascular effects induced by hypoglycaemia. Hypoglycaemia can disrupt many everyday activities such as driving, work performance and recreational pursuits. Measures to reduce the risk of hypoglycaemia are labour-intensive and require substantial resources.

Comparing hormonal and symptomatic responses to experimental hypoglycaemia in insulin- and sulphonylurea-treated Type 2 diabetes

AIMS

Patients with diabetes rely on symptoms to identify hypoglycaemia. Previous data suggest patients with Type 2 diabetes develop greater symptomatic and hormonal responses to hypoglycaemia at higher glucose concentrations than non-diabetic controls and these responses are lowered by insulin treatment. It is unclear if this is as a result of insulin therapy itself or improved glucose control. We compared physiological responses to hypoglycaemia in patients with Type 2 diabetes patients treated with sulphonylureas (SUs) or insulin (INS) with non-diabetic controls (CON).

METHODS

Stepped hyperinsulinaemic hypoglycaemic clamps were performed on 20 subjects with Type 2 diabetes, 10 SU-treated and 10 treated with twice-daily premixed insulin, and 10 age- and weight-matched non-diabetic controls. Diabetic subjects were matched for diabetes duration, glycated haemoglobin (HbA(1c)) and hypoglycaemia experience. We measured symptoms, counterregulatory hormones and cognitive function at glucose plateaux of 5, 4, 3.5, 3 and 2.5 mmol/l.

RESULTS

Symptomatic responses to hypoglycaemia occurred at higher blood glucose concentrations in SU-treated than INS-treated patients [3.5 (0.4) vs. 2.6 (0.5) mmol/l SU vs. INS; P = 0.001] or controls [SU vs. CON 3.5 (0.4) vs. 3.0 (0.6) mmol/l; P = 0.05]. They also had a greater increase in symptom scores at hypoglycaemia [13.6 (11.3) vs. 3.6 (6.1) vs. 5.1 (4.3) SU vs. INS vs. CON; P = 0.017]. There were no significant differences in counterregulatory hormone responses or impairment of cognitive function among groups.

CONCLUSIONS

Sulphonylurea-treated subjects are more symptomatic of hypoglycaemia at a higher glucose level than insulin-treated subjects. This may protect them from severe hypoglycaemia but hinder attainment of glycaemic goals.

Effects of intensive therapy and antecedent hypoglycemia on counterregulatory responses to hypoglycemia in type 2 diabetes

OBJECTIVE

The physiology of counterregulatory responses during hypoglycemia in intensively treated type 2 diabetic subjects is largely unknown. Therefore, the specific aims of the study tested the hypothesis that 1) 6 months of intensive therapy to lower A1C <7.0% would blunt autonomic nervous system (ANS) responses to hypoglycemia, and 2) antecedent hypoglycemia will result in counterregulatory failure during subsequent hypoglycemia in patients with suboptimal and good glycemic control.

RESEARCH DESIGN AND METHODS

Fifteen type 2 diabetic patients (8 men/7 women) underwent 6-month combination therapy of metformin, glipizide XL, and acarbose to lower A1C to 6.7% and 2-day repeated hypoglycemic clamp studies before and after intensive therapy. A control group of eight nondiabetic subjects participated in a single 2-day repeated hypoglycemic clamp study.

RESULTS

Six-month therapy reduced A1C from 10.2 +/- 0.5 to 6.7 +/- 0.3%. Rates of hypoglycemia increased to 3.2 episodes per patient/month by study end. Hypoglycemia (3.3 +/- 0.1 mmol/l) and insulinemia (1,722 +/- 198 pmol/l) were similar during all clamp studies. Intensive therapy reduced (P < 0.05) ANS and metabolic counterregulatory responses during hypoglycemia. Antecedent hypoglycemia produced widespread blunting (P < 0.05) of neuroendocrine, ANS, and metabolic counterregulatory responses during subsequent hypoglycemia before and after intensive therapy in type 2 diabetic patients and in nondiabetic control subjects.

CONCLUSIONS

Intensive oral combination therapy and antecedent hypoglycemia both blunt physiological defenses against subsequent hypoglycemia in type 2 diabetes. Prior hypoglycemia of only 3.3 +/- 0.1 mmol/l can result in counterregulatory failure in type 2 diabetic patients with suboptimal control and can further impair physiological defenses against hypoglycemia in intensively treated type 2 diabetes.

Development and psychometric testing of the Clinician Readiness for Measuring Outcomes Scale

BACKGROUND

If allied health professionals are to begin measuring outcomes routinely, a change in attitudes and behaviour is necessary. However, individuals need to be ready to change and often move through several stages before practice change is observed.

AIM

To develop and test the psychometric properties of a questionnaire that determines clinicians' readiness to measure outcomes.

METHODS

A study of instrument development, validation and reliability. Ten expert allied health professionals were involved in content validity testing. A further 396 allied health professionals completed the questionnaire to establish content and construct validity, internal consistency and temporal reliability (or stability). Of these 396 allied health professionals, 70 participated in the temporal reliability assessment. Content validity was established using the Content Validity Index (CVI). Construct validity was determined using confirmatory factor analysis (CFA) and internal consistency was ascertained using Cronbach's alpha. Temporal reliability was confirmed using intraclass correlation coefficients (ICC 3,1).

RESULTS

A 30-item questionnaire was developed, reflecting the five stages of change from the Transtheoretical Model of Change, and commonly cited barriers to outcome measurement. Content validity was excellent (CVI = 0.96). Using CFA, a two-factor model provided best fit. Based on CFA results, four items were dropped resulting in a 26-item questionnaire (range 26-156). Internal consistency reliability was excellent (alpha = 0.94). Temporal (stability) reliability ICC (3,1) was very good (r = 0.86, P = 0.0001).

CONCLUSIONS

The final 26-item questionnaire takes 10 minutes to complete and 5 minutes to score. The Clinician Readiness for Measuring Outcomes Scale provides educators with useful information about clinician readiness and helps identify strategies for affecting behaviour change.

Living with cystic fibrosis-related diabetes or type 1 diabetes mellitus: a comparative study exploring health-related quality of life and patients' reported experiences of hypoglycaemia

OBJECTIVES

To compare patients with type 1 diabetes mellitus (T1DM) or cystic fibrosis-related diabetes (CFRD) on frequency and severity of symptoms suggestive of hypoglycaemia and diabetes-specific health-related quality of life (HRQoL).

METHODS

This was a cross-sectional comparison study. Participants with T1DM or CFRD completed a questionnaire that assessed symptoms suggestive of hypoglycaemia and diabetes-specific HRQoL, and recorded episodes of low blood sugars in a prospective diary. Comparisons of responses were conducted, and Pearson product correlations were determined between HRQoL scores and other continuous variables. HRQoL scores were compared between the groups after adjusting for confounding factors.

RESULTS

Diabetes in cystic fibrosis (CF) patients had a less negative impact on HRQoL than in T1DM patients. Both groups experienced hypoglycaemia, but loss of consciousness or needing help was more common in T1DM patients. Symptoms suggestive of hypoglycaemia were less of a problem for CFRD patients in terms of severity, with T1DM patients having more neuroglycopenic symptoms.

DISCUSSION

Although the same percentage of patients in both groups reported experiencing hypoglycaemia, severity (e.g. symptoms and loss of consciousness) was higher for those with T1DM. Symptoms of hypoglycaemia appear to have a significant impact on HRQoL, and could account for the worse HRQoL in T1DM patients.

Effects of the selective serotonin reuptake inhibitor fluoxetine on counterregulatory responses to hypoglycemia in individuals with type 1 diabetes

OBJECTIVE

Previous work has demonstrated that chronic administration of the serotonin reuptake inhibitor (SSRI) fluoxetine augments counterregulatory responses to hypoglycemia in healthy humans. However, virtually no information exists regarding the effects of fluoxetine on integrated physiological counterregulatory responses during hypoglycemia in type 1 diabetes. Therefore, the specific aim of this study was to test the hypothesis that 6-week use of the SSRI fluoxetine would amplify autonomic nervous system (ANS) counterregulatory responses to hypoglycemia in individuals with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Eighteen type 1 diabetic patients (14 men/4 women aged 19-48 years with BMI 25 +/- 3 kg/m(2) and A1C 7.0 +/- 0.4%) participated in randomized, double-blind 2-h hyperinsulinemic (9 pmol . kg(-1) . min(-1))-hypoglycemic clamp studies before and after 6 weeks of fluoxetine administration (n = 8) or identical placebo (n = 10). Glucose kinetics was determined by 3-tritiated glucose. Muscle sympathetic nerve activity (MSNA) was determined by microneurography.

RESULTS

Hypoglycemia (2.8 +/- 0.1 mmol/l) and insulinemia (646 +/- 52 pmol/l) were similar during all clamp studies. ANS, neuroendocrine, and metabolic counterregulatory responses remained unchanged in the placebo group. However, fluoxetine administration significantly (P < 0.05) increased key ANS (epinephrine, norepinephrine, and MSNA), metabolic (endogenous glucose production and lipolysis), and cardiovascular (systolic blood pressure) counterregulatory responses during hypoglycemia.

CONCLUSIONS

This study has demonstrated that 6-week administration of the SSRI fluoxetine can amplify ANS and metabolic counterregulatory mechanisms during moderate hypoglycemia in patients with type 1 diabetes. These data also suggest that the use of fluoxetine may be useful in increasing epinephrine responses during hypoglycemia in clinical practice.

Effects of acute insulin-induced hypoglycaemia on psychomotor function: people with type 1 diabetes are less affected than non-diabetic adults

AIMS/HYPOTHESIS

We examined the effects of acute insulin-induced hypoglycaemia on psychomotor function in non-diabetic volunteers and in adults with type 1 diabetes.

METHODS

Non-diabetic adults (n = 20) and adults with type 1 diabetes mellitus (n = 16) each underwent a euglycaemic-hyperinsulinaemic glucose clamp on two separate occasions. Arterialised blood glucose was maintained for 1 h at either 4.5 mmol/l (euglycaemia) or 2.5 mmol/l (hypoglycaemia). During this time participants underwent neuropsychological tests to assess psychomotor function.

RESULTS

During hypoglycaemia the non-diabetic participants showed a significant deterioration in the following: (1) four-choice reaction time (p = 0.008); (2) grooved pegboard (a test of manual dexterity; p = 0.004); (3) hand steadiness (p = 0.003); (4) pursuit rotor (a test of fine motor function, attention and coordination; p = 0.018); and (5) test of total body coordination (p = 0.004). No significant differences were observed between euglycaemia and hypoglycaemia in hand-grip (p = 0.897) and line tracing time (p = 0.480) tests. In type 1 diabetes mellitus patients, only four-choice reaction time (p = 0.023) and pursuit rotor (p = 0.045) were impaired significantly during hypoglycaemia.

CONCLUSIONS/INTERPRETATION

Although acute hypoglycaemia caused significant impairment of several psychomotor functions in non-diabetic adults, a lower magnitude of impairment was observed in those with type 1 diabetes. The mechanism underlying this discrepant effect of hypoglycaemia on psychomotor function remains unknown, but may be related to the difference in sympathoadrenal activation observed between the groups. People with type 1 diabetes may also have had a behavioural advantage of over non-diabetic participants derived from their previous exposure to hypoglycaemia or potentially the disparate results arose from hypoglycaemia-induced cerebral adaptation.

Blocking NMDA receptor signaling does not decrease hormonal counterregulation to hypoglycemia in humans

In animals, blocking of glutamate signaling at the N-methyl-D-aspartate (NMDA) receptor reduces the neuroendocrine counterregulation to hypoglycemia. Hence, it has been proposed that increased excitatory glutamatergic input to the hypothalamus signals enforced central nervous energy demand under conditions of reduced supply. We examined the effect of the NMDA receptor antagonist memantine on hypoglycemia counterregulation in healthy humans. Hypoglycemic clamp experiments were performed in 10 healthy men after oral administration of 20 mg memantine and placebo. Counterregulatory hormones were measured during baseline and a clamp period of 120 min with hypoglycemia of 2.4 mmol/l lasting for 50 min. In addition, symptoms related to glycemic changes were assessed. Unexpectedly, the counterregulatory responses to hypoglycemia of adrenocorticotropin, cortisol and epinephrine were not decreased but tended to be increased by memantine, while norepinephrine and growth hormone were not affected. Glucagon levels were increased by memantine treatment during baseline and throughout the hypoglycemic period. After memantine administration, subjects also experienced more neuroglycopenic symptoms during hypoglycemia, whereas differences in autonomic symptoms did not reach significance. Contrasting with findings in animals, blocking the NMDA receptor does not decrease the counterregulatory responses to hypoglycemia in humans. Our data do not support the view that in humans, enhanced glutamate signaling during hypoglycemia supports the satisfaction of increased central nervous energy demands by enforcing hormonal counterregulation.

Effects of a selective serotonin reuptake inhibitor, fluoxetine, on counterregulatory responses to hypoglycemia in healthy individuals

OBJECTIVE

Hypoglycemia commonly occurs in intensively-treated diabetic patients. Repeated hypoglycemia blunts counterregulatory responses, thereby increasing the risk for further hypoglycemic events. Currently, physiologic approaches to augment counterregulatory responses to hypoglycemia have not been established. Therefore, the specific aim of this study was to test the hypothesis that 6 weeks' administration of the selective serotonin reuptake inhibitor (SSRI) fluoxetine would amplify autonomic nervous system (ANS) and neuroendocrine counterregulatory mechanisms during hypoglycemia.

RESEARCH DESIGN AND METHODS

A total of 20 healthy (10 male and 10 female) subjects participated in an initial single-step hyperinsulinemic (9 pmol . kg(-1) . min(-1))-hypoglycemic (means +/- SE 2.9 +/- 0.1 mmol/l) clamp study and were then randomized to receive 6 weeks' administration of fluoxetine (n = 14) or identical placebo (n = 6) in a double-blind fashion. After 6 weeks, subjects returned for a second hypoglycemic clamp. Glucose kinetics were determined by three-tritiated glucose, and muscle sympathetic nerve activity (MSNA) was measured by microneurography.

RESULTS

Despite identical hypoglycemia (2.9 +/- 0.1 mmol/l) and insulinemia during all clamp studies, key ANS (epinephrine, norepinephrine, and MSNA but not symptoms), neuroendocrine (cortisol), and metabolic (endogenous glucose production, glycogenolysis, and lipolysis) responses were increased (P < 0.01) following fluoxetine.

CONCLUSIONS

This study demonstrated that 6 weeks' administration of the SSRI fluoxetine can amplify a wide spectrum of ANS and metabolic counterregulatory responses during hypoglycemia in healthy individuals. These data further suggest that serotonergic transmission may be an important mechanism in modulating sympathetic nervous system drive during hypoglycemia in healthy individuals.

Prevalence of impaired awareness of hypoglycaemia in adults with Type 1 diabetes

AIMS

Impaired awareness of hypoglycaemia (IAH) is thought to affect approximately 25% of people with Type 1 diabetes. While this estimate was based on retrospective information from patients in several small studies performed several years ago, validated methods of assessment have not been used in a large hospital clinic-based population to ascertain the prevalence in the present era.

METHODS

Five hundred and eighteen people with Type 1 diabetes were recruited by random selection over a 2-year period. Participants completed a questionnaire documenting baseline characteristics and assessment of their awareness status using the method described by Gold et al. The number of episodes of severe hypoglycaemia they had experienced in the preceding year was recorded retrospectively.

RESULTS

IAH was present in 19.5% of the cohort. Compared to those with normal awareness of hypoglycaemia, those with IAH were significantly older [mean +/- standard deviation (sd); 39.3 +/- 12.9 vs. 45.9 +/- 13.5 years, P < 0.001], had a longer duration of diabetes [median (interquartile range) 14 (8-22) vs. 23 (14-32) years, P < 0.001], and had a six-fold higher frequency of severe hypoglycaemia in the previous year [0.38 +/- 1.04 (25th-75th centile 0-0) vs. 2.36 +/- 4.81 (25th-75th centile 0-2) episodes per person, P < 0.001].

CONCLUSIONS

The present survey of a large hospital-based clinic population has confirmed that a significant proportion of people with Type 1 diabetes (19.5%) continue to have IAH. Despite improvements in insulin therapies, intensification of insulin regimens and innovative patient education, the prevalence of IAH remains high in Type 1 diabetes.

Delayed recovery of cognitive function following hypoglycemia in adults with type 1 diabetes: effect of impaired awareness of hypoglycemia

OBJECTIVE

Recovery times of cognitive functions were examined after exposure to hypoglycemia in people with diabetes with and without impaired hypoglycemia awareness.

RESEARCH DESIGN AND METHODS

A total of 36 subjects with type 1 diabetes were studied (20 with normal hypoglycemia awareness [NHA] and 16 with impaired hypoglycemia awareness [IHA]). A hyperinsulinemic glucose clamp was used to lower blood glucose to 2.5 mmol/l (45 mg/dl) (hypoglycemia) for 1 h or to maintain blood glucose at 4.5 mmol/l (81 mg/dl) (euglycemia) on separate occasions. Cognitive tests were applied during each experimental condition and were repeated at 10- to 15-min intervals for 90 min after euglycemia had been restored.

RESULTS

In the NHA group, performance was impaired on all cognitive tasks during hypoglycemia and remained impaired for up to 75 min on the choice reaction time (CRT) task (P = 0.03, eta(2) = 0.237). In the IHA group, performance did not deteriorate significantly during hypoglycemia. When all subjects were analyzed within the same general linear model, performance was impaired during hypoglycemia on all tasks. Significant impairment during recovery persisted for up to 40 min on the CRT task (P = 0.04, eta(2) = 0.125) with a significant glycemia-awareness interaction for CRT after one hour of hypoglycemia (P = 0.045, eta(2) = 0.124). Performance on the trail-making B task was impaired for up to 10 min after euglycemia was restored (P = 0.024, eta(2) = 0.158).

CONCLUSIONS

Following hypoglycemia, the recovery time for different cognitive tasks varied considerably. In the IHA group, performance was not significantly impaired during hypoglycemia. The state of awareness of hypoglycemia may influence cognitive function during and after hypoglycemia.