Conquer Your Diabetes: Prevention, Control and Remission, written by Dr. Martin Abrahamson and Dr. Sanjiv Chopra, Professors of Medicine at Harvard Medical School, delves into the details of overcoming diabetes, including the best approaches to prevention, control, and remission.
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The burden of hypoglycaemia on people with diabetes extends beyond its clinical consequences. Read on to learn about the quality-of-life impact of hypoglycaemia and the unanswered questions that remain.
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Like any diabetes intervention, hybrid closed loops have their strengths and limitations. Read on to learn more about the place of hybrid closed loops in diabetes management.
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The burden of hypoglycaemia on people with diabetes extends beyond its clinical consequences. Read on to learn about the quality-of-life impact of hypoglycaemia and the unanswered questions that remain.
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Reducing the risk of hypoglycaemia depends on having the right information—and using it.
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Children and teens are a lot of wonderful things. “Easy” is not one of them. When dealing with pediatric diabetes, clinicians should prepare for a different clinical picture, different behaviours, and different thresholds for hypoglycaemic symptoms. They should also anticipate a high level of parental stress and worry. With decades of experience treating and researching pediatric diabetes, Tim Jones describes salient issues in pediatric diabetes and hypoglycaemia management—and offers guidance to clinicians treating this population.
Physicians treating pediatric diabetes are a bit like veterinarians: unable to count on their young patients to describe symptoms and feelings, they must rely on third parties (i.e. parents, caregivers, pet owners) to fill in the clinical picture. Parents, for their part, face the daily challenge of subduing their children’s restless energy and willfulness in the service of diabetes management.
Children with diabetes differ in several obvious ways from their adult counterparts. For one thing, their organs are still “under construction”—including that all-important pancreas—and their body systems haven’t matured yet. Accordingly, children may differ from adults in their response to dropping blood glucose—for example, developing a counterregulatory response and subjective symptoms at a higher glucose level than adults.
Children’s behaviour can also complicate diabetes treatment: think of the toddler who refuses to eat after an insulin dose or the preschooler who won’t sit still for a shot. To add a further layer of complication, odd behaviours in children don’t necessarily mean the same thing they do in adults. An adult speaking incoherently raises immediate red flags for hypoglycaemia. A babbling or sputtering child, meanwhile, could be showing signs of low blood glucose—or simply be playing make-believe.
As parents know all too well, adolescence brings its own set of diabetes management challenges. Embarrassed at the mere thought of a hypoglycaemic episode, a teenager may prioritize hypo avoidance over meeting glucose targets. Some teenagers may loosen their vigilance in general, putting themselves at risk of harmful glucose swings in either direction. In fact, the DCCT trial revealed severe hypoglycaemia to be more prevalent in young people than in adults. At the same time, clinicians and parents can find reassurance in knowing that, despite the higher rates, long-term cognitive function did not decline in the youngest cohort of DCCT patients.1
While plenty of adults thrive on diabetes gadgets and gizmos, it’s in children that the technology really comes into its own. By automating key functions of diabetes management, high-tech aids such as insulin pumps and continuous glucose monitoring (CGM) systems sidestep many of children’s unpredictable and confusing behaviours. Several pediatric studies have also found technology to yield modest gains in glucose control. In an analysis of over 16,000 children participating in the type-1 diabetes SWEET registry, for example, pump-treated children had lower HbA1C and required less insulin than children on multiple daily injections.2
As the technology keeps improving, so too do the options for high-tech interventions. In a study conducted earlier this year, children with type 1 diabetes used a remote monitoring system that let them share weekly information about blood glucose, insulin delivery and physical activity with their medical teams. Compared to the control group of conventionally managed children, the remotely monitored group experienced better glucose control and quality of life over the course of the 6-month study.3
Parents may need treatment, too—for anxiety. While it’s natural for the parent of a child with diabetes to worry about hypoglycaemia, the worry often becomes all-consuming, thus weakening the parent’s effectiveness as a guide and steadying force. As several studies have found, this fear of hypoglycaemia (FOH) can compromise diabetes control itself. In one such study, published in the journal Diabetic Medicine, parents with significant FOH-related distress had children with higher blood glucose levels. Perhaps surprisingly, these children also had a higher frequency of problematic hypoglycaemic episodes in the past year.4
For clinicians, monitoring the frequency and severity of hypoglycaemia in patients with diabetes is simply part of good care. It also falls to physicians to explore whether parents are fearful of hypoglycaemia as not all parents will readily admit it. If FOH is an issue, clinicians and diabetes educators need to arm parents with strategies to bring the anxiety down to manageable levels. Proven approaches include systematic hypoglycaemia education and cognitive behavioural therapy to address the FOH head-on.5 At the same time, parents need to be warned that an episode of severe hypoglycaemia puts the child at increased risk of a further episode.
Parents also play a crucial role in helping their older children transition to self-management. If the parent has always taken responsibility, some children may reach adolescence without understanding hypoglycaemia. Parents should be encouraged to provide age-appropriate explanations to their children and help them transition to self-monitoring and self-care.
It goes without saying that anyone involved in caring for the affected child—from parents and babysitters to teachers and daycare workers—should have an action plan to deal with hypoglycaemic episodes. When people have the right information, they feel more in control—and stress levels go down all around.
Dead in bed syndrome understandably strikes terror in the hearts of people with type 1 diabetes and their families. Clinicians, for their part, may find it difficult to discuss the syndrome with patients and thus avoid the topic. Fortunately, the syndrome is rare enough that the key message to patients is reassurance. In this insight piece, a globally recognized clinician and researcher suggests how clinicians might handle the topic.
There are very few things more upsetting, in the life of a physician, than having to speak with the parents of a young person who died. I still remember vividly the day I spoke to the parents of a 21 year old who died from ‘dead in bed’ (DIB) syndrome. They had found me on the Internet, and visited me in my city of Sheffield, UK to learn more about the syndrome. In addition to being devastated, they were angry. It seemed that nobody had told them about the syndrome, and they insisted the family should have been warned of the risks.
What followed was a difficult discussion in which I tried to explain the risks and benefits of bringing up the syndrome to young people with diabetes and their families. I noted that this mode of death was very rare and that discussing it was liable to cause disproportionate fear, thus eroding everyone’s quality of life.
At the same time, I took the parents’ words to heart: is there a way for professionals to discuss the syndrome with families without unduly scaring them?
DIB syndrome denotes the sudden, unexplained nighttime deaths of people under 40 with type 1 diabetes. The patient is found dead in an undisturbed bed after having gone to sleep without undue medical concerns. DIB accounts for an estimated 6% of deaths in people with type 1 diabetes under 40.1 It bears noting that death from any cause is infrequent in this group, making DIB a very rare condition. Indeed, a UK survey, in 1991 of all deaths of people under 40 identified 22 deaths consistent with DIB syndrome—fewer than 1 in 10,000.2 What’s more, sudden unexplained death with no cause found at post-mortem can also occur in young people without diabetes, though one study found that it was about 10 times more frequent in diabetes.
While the etiology of DIB syndrome remains unclear and may vary from case to case, evidence to date suggests that the deaths could be caused by disturbances in cardiac repolarization (and thus rhythm) triggered by nighttime hypoglycaemia, with a possible contribution from cardiac autonomic neuropathy. Although epinephrine, produced when the body responds to hypoglycaemia is an important defence mechanism against severe hypoglycaemia, some studies have suggested that it may contribute to abnormal cardiac repolarization. Genetic studies have not uncovered any significant associations to date, though the numbers may be too small to tease out culprit genes.
So how does a physician discuss this frightening but rare syndrome with families? Let’s start with patients with frequent severe nocturnal hypoglycaemic episodes or parents who have witnessed their child having a nocturnal hypoglycaemic seizure. In my view, it is reasonable to ask whether they worry about nocturnal death from severe hypoglycaemia, then move into a discussion of DIB, emphasizing how rare it is.
And what about patients without a history of severe hypoglycaemia? In our current medicolegal climate, it makes sense to at least enquire whether they ever worry about the possiblity that a severe hypoglycaemic episode during the night might have serious consequences. However, the discussion should focus on reassurance.
In all cases, patients should be educated about strategies to minimize the risk. The greater their sense of control, the less likely they will live in fear. Above all, patients should know about measures to avoid nocturnal hypoglycaemia, such as monitoring blood glucose before going to sleep and larger bedtime snacks to compensate for borderline values. Such measures are especially important in people with IAH. The increasing use of continuous glucose monitoring as a clinical tool would provide further reassurance.
In patients with prolonged QT intervals at rest, medications associated with further prolongation should be discontinued. Some studies suggest that medications that act on the renin-antiogensin system, such as ACE inhibitors and angiotensin receptor blockers, have beneficial effects on cardiovascular autoregulation and may thus reduce the risk of DIB syndrome.3
On a health-systems level, coordinated collection of data from people who died of DIB syndrome—for instance, through patient registries—will enable us to identify at-risk individuals and better understand the condition.
Dogs serve an important role in enhancing human health and well-being, from guiding people with disabilities and calming people on the autism spectrum to sensing allergens and other potential medical emergencies—such as hypoglycaemia. The use of diabetes alert dogs (DADs) has been steadily gaining in popularity, and research is yielding new insights into their benefits and limitations. In this article, an expert on hypoglycaemia detection strategies provides a balanced overview of DADs and evidence-based guidance on their use.
Dogs help humans in many ways: they provide companionship, comfort, and motivation to be more physically active. Service dogs go a step further and help people stay safe. It’s hardly surprising, then, that so many people with diabetes have taken an interest in diabetes alert dogs (DADs)—dogs trained to smell chemical changes in the human body when blood glucose falls outside the normal range.
I believe that DADs have value. At the same time, they should not be regarded as a panacea or substitute for vigilant glucose monitoring with reliable technologies. In order to provide informed advice to their patients, health providers need to understand how DADs have fared in scientific studies and to balance this information with the well-established contribution of dogs to human well-being.
Early detection of hypoglycemia is critical for the prevention of more severe and potentially dangerous episodes. Patients and their families, especially parents of children with type 1 diabetes, are understandably eager to find better tools to avoid severe hypoglycaemia. While technologies such as continuous glucose monitoring (CGM) can help in this regard, a growing number of people with type 1 diabetes are turning to DADs, in some cases as a substitute for CGM.
DADs are especially popular with people who have impaired awareness of hypoglycaemia (IAH), defined as a compromised ability to perceive or experience hypoglycemic symptoms. DADs can alert these individuals to check their blood glucose and treat hypoglycaemia before it becomes serious. While DADs cannot and should not replace glucose monitoring devices, they provide an extra layer of protection—at least in theory.
In practice, it can take time and (in some cases) a lot of money to find a well-trained DAD. As with all purchases, caveat emptor applies here, as there are no standards regulating the training and performance of DADs. Ideally, the dog should be no younger than 1.5 years, adequately trained to perform distinct “alert behaviours”, and obtained from an organization willing to provide references from past clients.1
There’s a further reason for caution: while patient surveys and anecdotal reports almost uniformly praise DADs for their ability to detect lows and improve diabetes control,2,3 clinical-trial evidence for the accuracy of DADs remains scant and inconclusive. Here’s what we know so far.
Only a few studies have tested the accuracy of DADs under experimental conditions. In one study, trained dogs were largely unable to identify a “hypoglycaemic scent” in skin swabs obtained from subjects with type 1 diabetes (who were not the owners of the dogs).4 However, a later, similar study found that DADs’ ability to recognize hypoglycaemia in human perspiration samples was statistically significant.5
In a different type of study, 18 DAD owners completed diaries of DAD alerts during the first year after they obtained their dogs.6 Diary readings included daily blood glucose readings and DAD alerts (in response to perceived low or high glucose). Results showed that DAD alerts had a sensitivity of just 57%, with a slightly better sensitivity to low than to high glucose, and a specificity just under 50%.6 In addition, high variability was observed across DADs, suggesting that dog’s detection abilities may vary widely.
Because CGM readings are a reliable method of detecting hypoglycaemia, it makes sense to study how DADs compare to CGM. At least two studies have done just that. In the first, participants reported a high level of satisfaction with their DADs, but the dogs provided timely alerts in just 36% cases of hypoglycaemia (sensitivity), and showed a high rate of false positives.7 Time to detection was also significantly longer with DADs than with CGM (median difference of 22 minutes).7 The second study also found low sensitivity and specificity (with high inter-dog variability), and rate-of-change analyses indicated that the dogs were responding to absolute blood glucose levels rather than rapid changes in glucose.8
Most diabetes health providers already have or will soon have patients interested in using DADs and need to be prepared to discuss the science behind DAD performance in a balanced way. While the evidence to date suggests that DADs are not as accurate as tools such as CGM, an appraisal of DADs must also consider their demonstrated benefits which include improvements in quality of life and diabetes control. . We cannot discount these positive reports and more research is needed to understand how DADs help people to manage their diabetes more effectively.
Asymptomatic hypoglycaemia (AH) is where clinical and biochemical realities diverge.
Defined as a plasma glucose level below 3.0 mmol/L (54 mg/dL) without any of the typical symptoms of hypoglycaemia, AH tends to occur more commonly in people with a history of frequent hypoglycaemic episodes.1 While not synonymous with impaired awareness of hypoglycaemia (IAH), asymptomatic hypoglycaemia may both lead to and result from IAH.
AH has been recognized since the pre-technological era of diabetes management, and every decade has brought new insights into the phenomenon. In an illuminating 1990 study,2 66 subjects on conventional insulin regimens for type 1 diabetes recorded their blood glucose levels at specified intervals during a 3-week period. Subjects were asked to report whether they “felt hypoglycaemic” at sampling times and to collect extra samples if they felt low at any time during the study period.
The study found that biochemical hypoglycaemia was present in only 29% of the symptomatic episodes, while only 16% of the biochemical episodes were accompanied by symptoms. These dramatic divergences between biochemical and clinical realities underscored the unreliability of symptoms as an indicator of low blood glucose.
Modern-day research has corroborated this reality. Based on accumulated evidence to date, experts believe that AH accounts for up to three-quarters of all hypoglycaemic events in type 1 diabetes. The figure for type 2 diabetes is likely lower.
I have found AH to be particularly frequent in patients with HbA1c in or close to the target range, who do not bring glucose data to the consultation. They may not measure much and may be heavily burdened by AH without knowing it.
While generally mild from a biochemical standpoint, AH episodes still take a toll on the body. It is also worth noting that non-severe bouts of hypoglycaemia, including silent hypoglycaemia, account for a significant minority of expenses associated with diabetes.3
How much does a history of hypoglycaemia play into AH? A recent study addressed the question. The prospective observational trial, which involved 153 unselected subjects with type 1 diabetes, explored the association between hypoglycaemic exposure, AH, and the resultant risk of severe hypoglycaemia.1 Over a 6-day period, subjects underwent blinded continuous glucose monitoring (CGM) and their hypoglycaemia symptoms were recorded, with the proportion of AH events as the main outcome measure.
Most (87%) patients presented with at least one episode of biochemical hypoglycaemia during the study period, with an average of 6 events per patient. Patients were segmented into 4 groups based on the number of hypoglycaemic events during the recording period: 1, 2-3, 4-6 and ≥7 events. These events occurred without symptoms in 57%, 61%, 65%, and 80% of cases, respectively (p < 0.001), demonstrating a significant association between hypoglycaemic exposure and AH. In addition, a higher fraction of AH events predicted a greater risk of severe hypoglycaemia (IRR 1.3, p = 0.003).
Asymptomatic hypoglycaemia remains underrecognized by primary care physicians, who often lack the knowledge and training to ask patients about it. Indeed, a 2012 review of studies on hypoglycaemia found that physicians were not consistently prompting people with diabetes to discuss or track their silent lows.4
Asking patients about their symptomatic episodes—a standard clinical approach—does not uncover the true hypoglycaemic burden. Assessing symptoms and glucose data jointly, as done in the above-mentioned study, is a much sounder practice as it enables physicians to get a sense of the frequency of asymptomatic events, which are associated with IAH and increased risk of severe hypoglycaemia. Particular attention should be given to patients with a history of frequent hypoglycaemia, who stand to derive the greatest benefit from therapeutic strategies to reduce the risk of future episodes.
I always collect SMBG data and try to map the occurrence of AH in the recent data. If I suspect frequent AH, I use blinded CGM together with a detailed diary. This will often lead to interventions such as review of insulin therapy, adjustment of glycaemic target, or behavioural or dietary changes.
An awareness of hunger prompts people to open the refrigerator. The same process allows people to limit the damage of hypoglycaemia: a mental awareness of symptoms gives people a chance to take corrective action.
Impaired awareness of hypoglyclycaemia (IAH) robs people of this opportunity. Defined as a reduced ability to realize that plasma glucose is falling, IAH typically occurs in people with long-standing diabetes and/or recurrent exposure to hypoglycaemia.1 In this group, the thresholds for counterregulatory responses and clinical symptoms get reset to lower levels of blood glucose.1
Not surprisingly, IAH increases the risk of severe hypoglycaemia (SH)—defined as an episode that requires assistance from someone else or results in loss of consciousness—by a factor of six in people with type 1 diabetes. The converse also holds true: having SH episodes increases the risk of IAH. Thus, the two phenomena coexist in a negative feedback loop.
Fortunately, hypoglycaemia awareness can be restored. The basic strategy is conceptually simple, though not easy to implement: do everything possible to avoid future episodes of hypoglycaemia. Research has established that avoiding glucose levels under 3 mmol/L (54 mg/dL) is associated with restored subjective awareness of hypoglycaemia.2
But how? Research has shown that patient education is key. Though informal education can certainly work, structured education programmes supporting flexible self-management of insulin regimens provide a reliable framework to jump-start the process. Based on a range of studies, we know that structured education in flexible insulin therapy can restore subjective awareness of hypoglycaemia to the point that the risk of SH goes down by over 60%.3-4
Technology, in turn, can add a layer of protection against SH, including in people with IAH. Specifically, insulin pump therapy has been shown to reduce SH by about 75%5 and continuous glucose monitoring (CGM) by 60-70%.6-7 Glucose-sensor technology can further potentiate the SH-reducing benefits of pump therapy.8 Of course, the technology only provides this protection if used as intended and does not offer guarantees. In a retrospective study of type 1 diabetes patients with problematic hypoglycaemia awareness, for example, CGM reduced SH but did not restore awareness of hypoglycaemia.9 Futhermore, not everyone with IAH can engage with available technology to effect a cure.10
If education and technology do not achieve the desired objectives, islet cell transplantation offers another avenue of hope. In a study of patients with IAH and intractable SH, islet cell transplantation not only led to freedom from SH events, but yielded significant improvements in overall glucose control and condition-specific quality of life.11
In the real world, people do not always behave like their textbook counterparts. For various reasons, patients may resist interventions that will ultimately make their lives easier. Some patients are reluctant to engage with technological solutions, perhaps because of previous negative experiences or fear of being unable to manage the technology. Age and socioeconomic barriers may also come into play.
For example, a recent study analyzed attendance patterns of adults with Type 1 who had been invited to attend the Dose Adjustment For Normal Eating (DAFNE) structured education program in London, UK. The analysis showed that attendance was significantly higher in patients with higher baseline HbA1c level (OR 1.96), younger age (OR 0.98), and lower social deprivation (OR 0.52).12 These findings suggest that older patients and those with socioeconomic challenges may need extra support and/or alternative engagement strategies to overcome their reluctance to attend.
In another study, patients with type 1 diabetes who had received instruction in use of bolus advisors during a structured education course were interviewed right at the end of the course and 6 months later. Participants who considered their mathematical skills to be poor relied heavily on advisors, while others preferred using advisors because they saved time and effort in calculating doses.13 The follow-up interviews revealed that patients who lost the habit of calculating their own doses lost skill and confidence, thus becoming increasingly dependent on their advisors.13
It is likely that technological solutions have a lower efficacy and uptake in those who stand to benefit most from those very solutions.10 There is a clear need for simple calculation strategies supported by encouragement and follow-up training. It also bears noting that IAH itself has a negative effect on adherence to insulin regimens.14 This stands to reason, given that people who lack hypoglycaemia symptoms may also have trouble recognizing the seriousness of the problem and prioritizing its avoidance.15 Researchers are investigating how psychological approaches may help overcome this barrier.16
Identifying people at high risk of SH because of IAH is a key responsibility for health care professionals supporting people with diabetes. Simple questions about how well the patient recognises the onset of hypoglycaemia, whether this happens with a blood sugar above or below 3 mmol/l (54 mg/dl), and who first notices a person’s hypoglycaemia can help identify this high-risk group.
Care providers must consider that each patient comes with unique abilities and challenges, thus calling for a personalized approach to care. Identifying IAH and promoting patient knowledge and actions to avoid hypoglycaemia are key to improving the safety of insulin therapy.
