Impaired Awareness Of Hypoglycemia Research Articles

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

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. 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. 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]. 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.

Genetic Variation and Activity of the Renin-Angiotensin System and Severe Hypoglycemia in Type 1 Diabetes

Background The deletion-allele of the angiotensin-converting enzyme (ACE) gene and elevated ACE activity are associated with increased risk of severe hypoglycemia in type 1 diabetes. We explored whether genetic and phenotypic variations in other components of the renin-angiotensin system are similarly associated. Methods Episodes of severe hypoglycemia were recorded in 171 consecutive type 1 diabetic outpatients during a 1-year follow-up. Participants were characterized at baseline by gene polymorphisms in angiotensinogen, ACE, angiotensin-II receptor types 1 (AT1R) and 2 (AT2R), and by plasma angiotensinogen concentration and serum ACE activity. Results Three risk factors for severe hypoglycemia were identified: plasma angiotensinogen concentration in the upper quartile (relative rate [RR] vs. lower quartile 3.1, 95% confidence interval [CI,] 1.4-6.8), serum ACE activity in the upper quartile (RR vs. lower quartile 2.9, 95% CI, 1.3-6.2), and homo- or hemizygosity for the A-allele of the X chromosome-located AT2R 1675G/A polymorphism (RR vs. noncarriers 2.5, 95% CI, 1.4-5.0). The three risk factors contributed independently to prediction of severe hypoglycemia. A backward multiple regression analysis identified a high number of renin-angiotensin system-related risk factors and reduced ability to perceive hypoglycemic warning symptoms (impaired hypoglycemia awareness) as predictors of severe hypoglycemia. Conclusions High renin-angiotensin system activity and the A-allele of the AT2R 1675G/A polymorphism associate with high risk of severe hypoglycemia in type 1 diabetes. A potential preventive effect of renin-angiotensin system blocking drugs in patients with recurrent severe hypoglycemia merits further investigation.

How hypoglycaemia can affect the life of a person with diabetes

Hypoglycaemia is the commonest side-effect of insulin treatment for diabetes, and is the single greatest barrier to achieving and maintaining good glycaemic control. Severe hypoglycaemia (requiring assistance for recovery) is associated with significant morbidity and is feared by most people with type 1 diabetes and their families. It causes stress and anxiety and may influence self-management and glycaemic control. The annual prevalence of severe hypoglycaemia is around 30% in people with type 1 diabetes, and is higher in those with risk factors such as strict glycaemic control, impaired awareness of hypoglycaemia and increasing duration of diabetes. It is also common during sleep (nocturnal hypoglycaemia). Neurological manifestations include coma, convulsions, transient hemiparesis and stroke, while reduced consciousness and cognitive dysfunction may cause accidents and injuries. Cardiac events may be precipitated such as arrhythmias, myocardial ischaemia and cardiac failure. Hypoglycaemia can affect all aspects of life, including employment, driving, recreational activities involving exercise, and travel, and measures should be taken in all of these situations to avoid this potentially dangerous side-effect of insulin therapy.

Delayed Recovery of Cognitive Function Following Hypoglycemia in Adults With Type 1 Diabetes

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

An Evaluation of Methods of Assessing Impaired Awareness of Hypoglycemia in Type 1 Diabetes

We thank Pedersen-Bjergaard et al. (1) for their comments regarding our study (2). In our study, the ability of three methods (Gold et al. [3], Clarke et al. [4], and Pedersen-Bjergaard et al. [5]) to identify impaired awareness of hypoglycemia (IAH) in people with type 1 diabetes was evaluated. The method that was initially described by Pedersen-Bjergaard et al. (5) required patients to respond to the question, “Can you feel when you are low?” and asked them to select …

The Decision Not to Drive During Hypoglycemia in Patients With Type 1 and Type 2 Diabetes According to Hypoglycemia Awareness

In recent years, there has been an ongoing discussion on the relationship between diabetes and driving. As driving performance will inevitably decline at lower levels of glycemia, patients' decisions concerning driving or taking corrective action when hypoglycemia occurs immediately before or during driving seems paramount. Twenty-four type 1 diabetic patients with normal awareness of hypoglycemia (T1Norm group), 21 type 1 diabetic patients with impaired awareness of hypoglycemia (T1Imp group), and 20 type 2 diabetic patients with normal awareness of hypoglycemia (T2 group) were studied. They were asked whether they felt hypoglycemic and whether they would currently drive during experimental euglycemia (5.0 mmol/l) and hypoglycemia (2.7 mmol/l). In the T1Norm group, 1 patient (4.2%) decided to drive during hypoglycemia. In the T1Imp group, 9 patients (42.9%) said they would drive in the hypoglycemic condition. In the T2 group, 5 patients (25%) would drive. This was more frequently the case for patients on oral hypoglycemic agents (chi2 = 4.44; P = 0.04). No effect of sex (chi2 = 0.78; P = 0.38) or age (chi2 = 0.22; P = 0.64) was noted. Patients with type 1 diabetes and impaired awareness of hypoglycemia frequently decided to drive while hypoglycemic, whereas patients with type 1 diabetes and normal awareness of hypoglycemia appeared to make safe decisions concerning hypoglycemia and driving. Strikingly, patients with type 2 diabetes and normal hypoglycemia awareness frequently made potentially dangerous decisions as well, particularly when using oral hypoglycemic agents. Therefore, early, clear, and consistent education is imperative.

Driving and insulin‐treated diabetes: who knows the rules and recommendations?

AbstractIn the UK the Driving and Vehicle Licensing Agency (DVLA) provides statutory regulations and guidance for safe practice for patients with insulin‐treated diabetes and their health professionals. An increased risk of road traffic accidents may be associated with complications such as acute hypoglycaemia, peripheral neuropathy and amputations. Previous studies have assessed patient knowledge and adherence. The aim of this study was to simultaneously assess whether patients and their health professionals are aware of and follow this guidance.An anonymous questionnaire was given to all patients attending a secondary care diabetes clinic over a three‐week period. A second web‐based questionnaire was e‐mailed to primary and secondary care health care professionals (HCPs) involved in diabetes care throughout Grampian.In all, 117 patients with insulin‐treated diabetes completed the questionnaire and 106 HCPs from primary and secondary care completed the web‐based questionnaire. The majority of patients (95%) were aware that they were obliged to inform the DVLA of their insulin treatment and 92% had done so. Only 15% of patients always tested and 24% would never test a blood glucose prior to driving. Ninety‐four percent of patients recognised symptoms of hypoglycaemia most of the time. Only 17% would wait the recommended 45 minutes before driving again after an episode of hypoglycaemia. All HCPs knew that patients are obliged to inform the DVLA of their insulin treatment. Sixty‐two percent of HCPs knew patients should test before every journey. Thirteen percent of HCPs thought it safe to drive with blood glucose &lt;4mmol/L. Eight percent of HCPs did not know that impaired awareness of hypoglycaemia might be a contraindication to driving.Greater availability of information to health professionals about minimising the risks associated with driving and diabetes is required if patients with insulin‐treated diabetes are to become better informed and understand driving regulations and recommendations for safe driving in the UK. Copyright © 2007 John Wiley &amp; Sons.

An Evaluation of Methods of Assessing Impaired Awareness of Hypoglycemia in Type 1 Diabetes

Subjective recognition of the warning symptoms of hypoglycemia is fundamental to allow self-treatment and prevent progression to severe hypoglycemia (1,2). Recognition of the onset of these premonitory symptoms constitutes awareness of hypoglycemia (3). With increasing duration of insulin therapy, many people with type 1 diabetes experience a change in their hypoglycemia awareness associated with either a reduction in symptom intensity or a change in symptom profile or both (3–6). Impaired awareness of hypoglycemia (IAH) is associated with a sixfold greater frequency of severe hypoglycemia and is a recognized risk factor for this problem (7,8). Accurate identification of individuals with IAH is important to allow modification of glycemic targets and to adjust insulin therapy to minimize hypoglycemia risk. Three methods have been proposed to assess awareness of hypoglycemia for clinical application (7–9) but to date have not been compared directly. The present study was performed in a randomly selected cohort of individuals with type 1 diabetes to assess the concordance between these methods in ascertaining the prevalence of IAH and whether the methods have equivalent sensitivity in identifying affected individuals. A total of 140 participants were recruited; 80 completed the study. Those who completed the study were significantly older than those who did not ( n = 60) (mean ± SD age 47.6 ± 12.7 vs. 41.1 ± 12.6 years, respectively, P = 0.04). No differences in duration of diabetes ( P = 0.7) or in glycemic control ( P = 0.35) were observed between these two groups. All completed a questionnaire to assess awareness of hypoglycemia using each of the methods presented by Gold et al. …

The effect of an education programme (HyPOS) to treat hypoglycaemia problems in patients with type 1 diabetes

In a randomized, prospective multi-centre trial, the effect of a specific training programme (HyPOS) for patients with hypoglycaemia problems was compared with a control group (CG), receiving a standardized education programme aiming at avoidance of hypoglycaemia by optimization of insulin therapy. A total of 164 type 1 diabetes patients (age 46.0 +/- 12.5 yrs, HbA(1c) 7.3 +/- 1.0%, 50% male) were randomized. Hypoglycaemia awareness was measured by the hypoglycaemia awareness questionnaire (HAQ) and by a visual analogue scale (VAS). There were no baseline differences. After a 6-month follow-up, hypoglycaemia awareness significantly improved in HyPOS compared to that in the CG (Delta HAQ 0.7 [95% CL 0.1-1.2], p = 0.024, Delta VAS 0.8 [95% CL 0.2 - 1.2], p = 0.015). In HyPOS, the threshold for detection of low blood glucose (Delta 0.2 mmol/L [95% CL 0.03 - 0.04], p = 0.02) and the treatment of low blood glucose (Delta 4.6 g [95% CL 1.6 - 7.6], p = 0.03) increased significantly. The number of undetected hypogylcaemic episodes (Delta - 1.4 episodes per week [95% CL 0.4-2.5], p = 0.01) and the rate of mild hypoglycaemia dropped significantly in HyPOS (Delta 2.1% [95% CL 0.5-5.3], p = 0.015). The numbers of severe (Delta 0.3 events per patient per year [95% CL - 0.04-1.0], p = 0.037) and very severe hypoglycaemic episodes (Delta 0.3 events per patient per year [95% CL - 0.1-0.7], p = 0.09) were lower in HyPOS, but these differences were not significant. Compared to the CG, HyPOS demonstrates additional benefits in terms of improving impaired hypoglycaemia awareness, reducing mild hypoglycaemia, detecting low blood glucose, and treating low blood glucose.

The effects of acute hypoglycaemia on memory acquisition and recall and prospective memory in type 1 diabetes

Global memory performance is impaired during acute hypoglycaemia. This study assessed whether moderate hypoglycaemia disrupts learning and recall in isolation, and utilised a novel test of prospective memory which may better reflect the role of memory in daily life than conventional tests. Thirty-six subjects with type 1 diabetes participated, 20 with normal hypoglycaemia awareness (NHA) and 16 with impaired hypoglycaemia awareness (IHA). Each underwent a hypoglycaemic clamp with target blood glucose 2.5 mmol/l. Prior to hypoglycaemia, subjects attempted to memorise instructions for a prospective memory task, and recall was assessed during hypoglycaemia. Subjects then completed the learning and immediate recall stages of three conventional memory tasks (word recall, story recall, visual recall) during hypoglycaemia. Euglycaemia was restored and delayed memory for the conventional tasks was tested. The same procedures were completed in euglycaemic control studies (blood glucose 4.5 mmol/l). Hypoglycaemia impaired performance significantly on the prospective memory task (p = 0.004). Hypoglycaemia also significantly impaired both immediate and delayed recall for the word and story recall tasks (p < 0.01 in each case). There was no significant deterioration of performance on the visual memory task. The effect of hypoglycaemia did not differ significantly between subjects with NHA and IHA. Impaired performance on the prospective memory task during hypoglycaemia demonstrates that recall is disrupted by hypoglycaemia. Impaired performance on the conventional memory tasks demonstrates that learning is also disrupted by hypoglycaemia. Results of the prospective memory task support the relevance of these findings to the everyday lives of people with diabetes.

Frequency and risk factors of severe hypoglycemia in insulin-treated type 2 diabetes: a literature survey

Intensive treatment regimens including early initiation of insulin treatment are important to prevent late complications in type 2 diabetes. The assumed risk of severe hypoglycemia (SH) is a major barrier to initiation of insulin treatment. To assess the relevance of this risk we evaluated the frequency of SH as reported in the literature. Using Medline and Embase search we identified 11 studies (5 retrospective and 6 prospective) including at least 50 patients with insulin-treated type 2 diabetes followed for at least 6 months in which frequency of SH was reported. The incidence of SH in the retrospective studies varied from 15 to 73 episodes per 100 patient-year with a proportion of the patients having one or more episodes between 1.4 to 15%. In the prospective studies, both incidence rate and proportion of the patients having one or more episodes of SH were lower than in the retrospective studies. Only few studies looked into the impact of risk factors on the rate of SH. Impaired hypoglycemia awareness, high age, long duration of diabetes and insulin therapy increased the risk, while no association was found with HbA1c and insulin dose. The present knowledge of SH in insulin-treated type 2 diabetes is characterized by the paucity of data and the heterogeneity of the few studies available. Large and long-lasting studies with SH as primary endpoint are warranted in order to further clarify the occurrence of SH and influence of the risk factors in unselected patients with insulin-treated type 2 diabetes.

The Insertion/Deletion Polymorphism in the Angiotensin-converting Enzyme Gene and Hypoglycemia Awareness in Patients with Type 1 Diabetes

Impaired hypoglycemia awareness affects approximately 25% of all patients with type 1 diabetes (T1DM). Duration of diabetes and tight glycemic control represent main risk factors of impaired hypoglycemia awareness. However, even among patients with good glycemic control and longstanding T1DM, awareness of hypoglycemia may be intact. Genetic factors might explain some of this remaining variability. Recently, the insertion/deletion ( I/ D) polymorphism in angiotensin converting enzyme gene ( ACE) was shown to be associated with significantly higher risk of hypoglycemic events in subjects with T1DM. Here, we studied the effects of genetic polymorphisms in the ACE on impaired hypoglycemia awareness in 231 Caucasian T1DM patients. Hypoglycemia awareness status was determined using standardized questionnaires (Clarke et al. and Edinburgh Hypoglycemia Scale). ACE I/ D genotype was determined by PCR amplification of the respective fragments from intron 16 of the ACE and size fractionation (I allele frequency=0.49; P=0.74 for Hardy-Weinberg equilibrium). In the logistic regression analysis, significant risk factors of impaired hypoglycemia awareness were duration of diabetes, C-peptide and HbA (1c) (all P<0.01). However, no significant effect of the I/ D polymorphism on impaired hypoglycemia awareness was observed with and without adjustment for age, diabetes duration, C-peptide and HbA (1c). Even though the study provides a relatively large dataset, it is possible that small differences may have been missed.

Diabetes and Driving

The issue of traffic safety of patients with diabetes is rising on political as well as scientific levels. Driving by diabetic patients may be impaired by three factors: hyperglycemia, hypoglycemia, and diabetes complications. Management of diabetic patients is progressively aiming at near normoglycemia (1,2). Consequently, the rate of hypoglycemia and hypoglycemia unawareness has markedly increased (3–8). These factors could pose an increased threat to diabetic patients’ fitness to drive. Current legal restrictions regarding diabetes and driving privileges vary throughout the world, but laws are generally prompted by the impending danger of hypoglycemia during driving. To research the various aspects of diabetes and driving, several study methods have been applied. In consideration of dissenting opinions and laws, rules, and regulations, we will discuss in this article the currently available data on diabetes and driving, potential pitfalls in research, and give recommendations for future research. In modern traffic, the increasing age of drivers (9) and their medical conditions can be risk factors for traffic incidents and accidents. The amounting prevalence of diabetes also leads to an increased number of diabetic drivers. Driving by diabetic patients may be impaired by three factors: hyperglycemia, hypoglycemia, and diabetes complications. In recent years, it has become apparent that acute hyperglycemia, and possibly also chronic hyperglycemia, may be associated with cognitive function loss (10–15). However, the cognitive dysfunction occurring during hypoglycemia is most striking (16–18). After the Diabetes Control and Complications Trial (1) and the U.K. Prospective Diabetes Study (2), which showed that diabetes complications are reduced with tight glucose control, management of diabetic patients is progressively aiming at near normoglycemia. Consequently, the rate of hypoglycemia has increased. We now know that even a single episode of hypoglycemia leads to impaired hypoglycemia awareness (19). Hypoglycemia unawareness currently affects ∼25% …

Frequency and risk factors of severe hypoglycaemia in insulin‐treated Type 2 diabetes: a cross‐sectional survey

The reported risk of severe hypoglycaemia in insulin-treated Type 2 diabetes is highly variable and few studies have evaluated the influence of risk factors. We assessed the incidence and the influence of potential risk factors for severe hypoglycaemia in a questionnaire survey in subjects with insulin-treated Type 2 diabetes receiving currently recommended multifactorial intervention. Consecutive patients with insulin-treated Type 2 diabetes (n = 401) completed a questionnaire about occurrence of hypoglycaemia in the past, hypoglycaemia awareness and socio-demographic factors. A zero-inflated negative binomial model was used to assess the influence of potential risk factors on the rate of severe hypoglycaemia. The overall incidence of severe hypoglycaemia in the preceding year was 0.44 episodes/person year. Sixty-six (16.5%) patients had experienced at least one event. The risk of any episode of severe hypoglycaemia positively correlated with impaired hypoglycaemia awareness, being married and long duration of diabetes. The risk of repeated episodes of severe hypoglycaemia positively correlated with the presence of peripheral neuropathy, while long duration of diabetes prior to insulin treatment and treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor antagonists (ARBs) were associated with reduced risk. C-peptide concentration and HbA1c were not associated with the risk of severe hypoglycaemia. In this cohort of insulin-treated Type 2 diabetic patients, the incidence of severe hypoglycaemia is higher than reported in most studies, corresponding to about one-third of that in Type 1 diabetes. Impaired hypoglycaemia awareness is the most important risk factor for severe hypoglycaemia.

The Glu23Lys polymorphism in KCNJ11 and impaired hypoglycaemia awareness in patients with type 1 diabetes

Impaired awareness of hypoglycaemia affects approximately 25% of all patients with type 1 diabetes (T1D). Duration of diabetes and tight glycaemic control represent the main risk factors for hypoglycaemia unawareness. However, even among patients with good glycaemic control and longstanding T1D, awareness of hypoglycaemia may be intact. Genetic factors might explain some of this remaining variability, and genes involved in central glucose sensing should represent plausible candidates. Some evidence indicates that ventromedial hypothalamus glucose-responsive neurons require the potassium inward rectifier (KIR) 6.2 subunit of the K(ATP) channel to sense glucose. Therefore, the effects of the Glu23Lys polymorphism in the KCNJ11 (KIR6.2) gene (potassium inwardly rectifying channel, subfamily J, member 11) on impaired hypoglycaemia awareness in 217 patients with T1D were studied. Hypoglycaemia awareness status was determined using standardized questionnaires. Genotyping of the Glu23Lys in a cohort of T1D subjects was done using the TaqMan allelic discrimination assay (frequency of the Lys-allele = 0.35; P = 0.57 for Hardy-Weinberg equilibrium). The study confirms that diabetes duration, C-peptide, and HbA(1c) represent risk factors for impaired hypoglycaemia awareness. However, no significant effect of the Glu23Lys polymorphism on impaired hypoglycaemia awareness was observed with or without adjustment for age, diabetes duration, C-peptide, and HbA(1c). Even though the study provides a relatively large dataset, it is possible that small differences may have been missed.

Identification of factors associated with impaired hypoglycaemia awareness in patients with type 1 and type 2 diabetes mellitus

To assess clinical factors associated with impaired hypoglycaemia awareness (HA). Survey of 241 type 1 and type 2 diabetic patients hospitalised in a diabetes department for a diabetes education program. Demographic, diabetes and psychiatric characteristics and subjective hypoglycaemic symptoms were recorded by a self-report questionnaire. Age and body mass index (BMI) was greater and glycated haemoglobin was lower in diabetic patients reporting impaired HA, however, these latter differences became not significant when age was included as a covariate. There were significantly more current smokers among those with impaired HA and controlling for age accentuated this difference. Current treatment by insulin was not associated with impaired HA. Backward stepwise logistic regression showed that type 2 diabetic patients were twice as likely to have impaired HA than type 1 diabetic patients (OR = 2.195, 95% CI: 1.017-4.734, P = 0.04). Moreover, higher age, current smoking and type 2 diabetes interacted significantly in increasing the likelihood of impaired HA. Among those with impaired HA more patients experienced drowsiness and nervousness and less patients reported tremor during the hypoglycaemic episodes. No other symptoms were associated with impaired HA. Type 2 diabetic patients, whether on insulin or not, and especially if they are of advanced age and if they smoke, are at increased risk of impaired HA.

Morbidity of hypoglycemia in type 1 diabetes

Hypoglycemia is a common side effect of intensive insulin therapy in patients with type 1 diabetes. Mild hypoglycemia is any episode that can be self-treated, while a severe episode requires external help for recovery. Acute hypoglycemia produces autonomic and neuroglycopenic symptoms, including cognitive impairment and mood changes, while sympathoadrenal stimulation can provoke acute hemodynamic changes with alterations in regional vascular perfusion and a risk of cardiac dysrhythmias. Neurological manifestations include coma, convulsions and focal abnormalities. Long-term morbidities associated with hypoglycemia include impaired awareness of hypoglycemia, counterregulatory hormonal deficiencies, hypoglycemia-associated autonomic failure, and, in rare cases, permanent cognitive impairment. Hypoglycemia affects all aspects of life for the person with type 1 diabetes, including employment, social interactions, driving, sport and leisure activities, and sleep. Appreciation of the potential morbidities of hypoglycemia should encourage physicians to utilize therapeutic regimens that decrease the risk of severe hypoglycemia.

Hypoglycaemia is uncommon with a combination of antidiabetic drugs and bedtime NPH insulin for type 2 diabetes

AbstractThe aim of this study was to ascertain the risk of hypoglycaemia when treating type 2 diabetes with a single daily dose of isophane (NPH) insulin, administered at bedtime, in combination with oral antidiabetic drugs.The frequency of mild (self‐treated) and severe (requiring external help) hypoglycaemia was estimated, both retrospectively and prospectively, in 41 people with type 2 diabetes who were taking oral antidiabetic drugs in combination with bedtime isophane insulin. The median (range) age, duration of diabetes and insulin therapy of the group were 63 (33–79) years, 11 (1–34) years and 17 (1–60) months respectively, with a mean (±SD) HbA1c of 7.9 (±0.9)%.The results showed that 20 people (49%) had experienced one or more episodes of mild hypoglycaemia since commencing insulin therapy. None had experienced severe hypoglycaemia either since conversion to insulin therapy or during the three‐month prospective assessment. The frequency of symptomatic hypoglycaemia recorded prospectively was not related to age, HbA1c, or duration of diabetes. In those with a history of hypoglycaemia, impaired awareness of hypoglycaemia was sought using historical evidence and a validated scale, and was identified in only two (10%) individuals.In conclusion, satisfactory glycaemic control can be obtained using combination therapy in people with type 2 diabetes without being associated with severe hypoglycaemia, and mild symptomatic hypoglycaemia appears to be uncommon. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Assessment of hypoglycaemia awareness using continuous glucose monitoring.

To investigate the possibility of assessing hypoglycaemia awareness in patients with Type 1 diabetes using continuous glucose monitoring. Twenty patients with Type 1 diabetes were investigated. Ten patients with Type 1 diabetes and strongly impaired hypoglycaemia awareness were compared with 10 patients with intact hypoglycaemia awareness regarding quality of hypoglycaemia perception (number of undetected hypoglycaemic episodes per 24 h, glucose level < 3.3 mmol/l). Hypoglycaemia detection was assessed using the event function of the Continuous Glucose Monitoring System (CGMS; Medtronic MiniMed, Northridge, CA, USA). Patients were instructed to enter an event upon suspecting being hypoglycaemic. Satisfactory CGMS performance could be achieved [mean r = 0.893 between calibration measurements and CGMS data, mean absolute difference (MAD) = 20.6%], although artefacts were observable and had to be controlled. Hypoglycaemia unaware patients showed a significantly higher total number of hypoglycaemic episodes (P < 0.05), number of undetected hypoglycaemic episodes (P < 0.01), and mean glucose levels (P < 0.05). Even in aware patients, undetected hypoglycaemia was observable. No significant differences regarding occurrence of nocturnal hypoglycaemia were observable. The possibility of direct assessment of hypoglycaemia awareness using continuous glucose monitoring was demonstrated. Its application in clinical practice could be of use for assessing hypoglycaemia perception and evaluating the impact of treatment changes on hypoglycaemia awareness.

Hypoglycaemia in insulin-treated Type 2 diabetes: frequency, symptoms and impaired awareness.

Hypoglycaemia is considered to be less common in people with insulin-treated Type 2 diabetes than in Type 1 diabetes. A retrospective survey was made of 215 people with insulin-treated Type 2 diabetes to quantify the frequency and nature of hypoglycaemia experienced. The frequencies of mild (self-treated) and severe (required assistance) hypoglycaemia during the preceding year were estimated retrospectively. The usual symptoms of hypoglycaemia and state of awareness of hypoglycaemia were scored using validated questionnaires and any history suggestive of impaired hypoglycaemia awareness was documented. In this cohort, 157 (73%) had experienced hypoglycaemia since commencing insulin, the frequency of which increased with duration of diabetes and of insulin therapy and was inversely related to current HbA1c (all P < 0.05). During the preceding year, 32 individuals (15%) had experienced severe hypoglycaemia, with an estimated incidence for the entire group of 0.28 episodes/patient/year. Principal components analysis revealed two underlying symptom groups (autonomic and neuroglycopenic), similar to those reported previously by young adults with Type 1 diabetes, but the total symptom score declined with advancing age. Of the 157 with a history of hypoglycaemia, the 13 (8%) individuals who gave a history of impaired awareness of hypoglycaemia had experienced a ninefold higher incidence of severe hypoglycaemia than those with normal awareness, and reported experiencing mainly neuroglycopenic symptoms. While the overall frequencies of mild and severe hypoglycaemia were lower in insulin-treated Type 2 diabetes than have been reported previously in Type 1 diabetes, the risk of hypoglycaemia was greater with increasing duration of diabetes and of insulin therapy. Although impaired awareness of hypoglycaemia was uncommon, it was associated with a higher incidence of severe hypoglycaemia.