Hypoglycemic episodes and risk of dementia in older patients with type 2 diabetes mellitus

Minimizing the risk of hypoglycemia with vildagliptin: Clinical experience, mechanistic basis, and importance in type 2 diabetes management

Even if the true incidence of hypoglycemia in type 2 diabetes mellitus (T2DM) remains difficult to estimate, with highly variable rates reported in the literature, it is likely more common than previously thought. While most hypoglycemic episodes in T2DM are considered "mild," they still have a substantial clinical impact. Severe hypoglycemia also exists in T2DM, with recent landmark studies prompting much debate about the potential role of severe hypoglycemia in cardiovascular morbidity and mortality, even though there is currently no definitive evidence for causality. The challenge in the treatment of T2DM remains the achievement of optimal glycemic control to lower the risk for long-term complications while avoiding hypoglycemia. Successful treatment strategies should therefore include careful selection of therapies to prevent hypoglycemia, starting early in the disease management process, in order to best preserve counterregulation. The dipeptidyl peptidase-4 inhibitor, vildagliptin, is a good treatment option to minimize the risk of hypoglycemia over time, while maintaining good glucose control. Extensive clinical experience is available for vildagliptin, with data published for all stages of the condition and with the low hypoglycemic potential stemming from a solid mechanistic basis.

Passive case-finding for Alzheimer's disease and dementia in two U.S. communities

Passive surveillance for disease is a public health approach that relies on documentation available within existing health records for the region or community being studied. Its two primary advantages over active case-finding are the lower cost of research and the lower burden on the population under study. The effectiveness of passive case-finding depends on the comprehensiveness of the healthcare coverage in a given community and the adequacy of the available medical records. The Rochester Epidemiology Project has permitted dementia case detection for Olmsted County, Minnesota, using a medical records-linkage system. These data were compared with case ascertainment using direct assessment of individuals in an epidemiological study of the same community. At the Group Health Research Institute, investigators compared dementia and Alzheimer's disease cases detected using an electronic medical record database search with those identified by a parallel active case-finding study. In this article, the advantages and disadvantages of passive case-finding were discussed, and the following conclusion was drawn: the purpose of the study being conducted should determine the case-finding approach that is to be used.

Diabetes, hyperglycemia and the management of cerebrovascular disease

PURPOSE OF REVIEW

Hyperglycemia is frequent in patients with cerebrovascular disease. This review article aims to summarize the recent evidence from observational studies that examined the adverse cerebrovascular effects of dysglycemic states as well as interventional studies assessing intensive management strategies for hyperglycemia.

RECENT FINDINGS

In recent years, diabetes, prediabetic states and insulin resistance and their association with cerebrovascular disease were an important focus of research. The cerebrovascular consequences of these metabolic abnormalities were found to extend beyond ischemic stroke to covert brain infarcts, other structural brain changes and to cognitive impairment with and without dementia. Interventional studies did not reveal that more intensive management of chronic hyperglycemia and of hyperglycemia in the setting of acute stroke improves outcome. There is clear evidence, however, that the overall management of multiple risk factors and behavior modification in patients with dysglycemia may reduce the burden of cerebrovascular disease.

SUMMARY

Observational studies reveal the growing burden and adverse cerebrovascular effects of dysglycemic states. Currently available interventional studies assessing more intensive strategies for the management of hyperglycemia did not prove, however, to be effective. We discuss the current evidence, pathophysiological considerations and management implications.

Frequent hypoglycemia among elderly patients with poor glycemic control

BACKGROUND

Episodes of hypoglycemia are particularly dangerous in the older population. To reduce the risk of hypoglycemia, relaxation of the standard hemoglobin A(1c) (HbA(1c)) goals has been proposed for frail elderly patients. However, the risk of hypoglycemia in this population with higher HbA(1c) levels is unknown.

METHODS

Patients 69 years or older with HbA(1C) values of 8% or greater were evaluated with blinded continuous glucose monitoring for 3 days.

RESULTS

Forty adults (mean [SD] age, 75 [5] years; HbA(1C) value, 9.3% [1.3%]; diabetes duration, 22 [14] years; 28 patients [70%] with type 2 diabetes mellitus; and 37 [93%] using insulin) were evaluated. Twenty-six patients (65%) experienced 1 or more episodes of hypoglycemia (glucose level <70 mg/dL). Among these, 12 (46%) experienced a glucose level below 50 mg/dL and 19 (73%), a level below 60 mg/dL. The average number of episodes was 4; average duration, 46 minutes. Eighteen patients (69%) had at least 1 nocturnal episode (10 pm to 6 am). Of the total of 102 hypoglycemic episodes, 95 (93%) were unrecognized by finger-stick glucose measurements performed 4 times a day or by symptoms.

CONCLUSIONS

Hypoglycemic episodes are common in older adults with poor glycemic control. Raising HbA(1C) goals may not be adequate to prevent hypoglycemia in this population.

Management of diabetes mellitus in the elderly

PURPOSE OF REVIEW

Description of management of diabetes in elderly.

RECENT FINDINGS

Population of older adults is growing and so is the prevalence of diabetes in elderly individuals. Older adults are a heterogeneous group of individuals with varying physical capabilities, cognitive functioning and co-morbidities and life expectancies. Also, older adults with diabetes are at increased risk for some geriatric conditions. Thus, clinicians taking care of elderly with diabetes must take this into consideration and prioritize treatment accordingly.

SUMMARY

Goals of diabetes care in elderly and younger adults are alike, though managing diabetes in elderly requires individualized approach. Fit elderly with life expectancy over 10 years should have HbA1c target similar to younger adults, whereas in frail elderly with multiple co-morbidities, the goal should somewhat be higher. Pharmacological treatment options are similar to younger adults and avoidance of hypoglycemia is an important consideration in choosing therapeutic agents in elderly. Evaluation and treatment of microvascular and macrovascular complications of diabetes in elderly must also be individualized.

ABCC8 polymorphism (Ser1369Ala): influence on severe hypoglycemia due to sulfonylureas

AIMS

Sulfonylureas are categorized according to their binding sites of the ATP-sensitive K+ channel (K(ATP) channel) complex in pancreatic β-cells. The binding sites are classified as A, B and A + B site (both A and B sites), respectively. The Ser1369Ala variant in the sulfonylurea receptor gene ABCC8 which encodes a subunit of the K(ATP) channel complex has been demonstrated to be associated with the hypoglycemic effect of gliclazide, which binds to the A site. However, the hypoglycemic effect of the Ser1369Ala variant on treatment with A + B binding site sulfonylureas, such as glimepiride or glibenclamide, is still uncertain.

MATERIALS & METHODS

In a case-control study, 32 patients with Type 2 diabetes admitted to hospital with severe hypoglycemia and 125 consecutive Type 2 diabetic outpatients without severe hypoglycemia were enrolled. We determined the genotypes of the ABCC8 polymorphism (Ser1369Ala) in the patients with or without severe hypoglycemia. All of the patients were taking glimepiride or glibenclamide.

RESULTS

In the patients treated with glimepiride or glibenclamide, we found no significant differences in the distribution of the Ser1369Ala genotype between patients with or without severe hypoglycemia (p = 0.26). Moreover, the Ala1369 minor allele tended to be less frequent in the hypoglycemic group (31 vs 43%; OR: 1.65; 95% CI: 0.92-2.96; p = 0.09).

CONCLUSION

Our findings suggest that the Ser1369Ala variant is not a major predictive factor of severe hypoglycemia due to glimepiride or glibenclamide, both of which bind to the A + B site. It is likely that severe hypoglycemia due to A + B binding site sulfonylureas will be mediated by other factors, and not the Ala1369 minor allele.

Endocrine, metabolic, nutritional, and toxic disorders leading to dementia

One of the first steps toward the correct diagnosis of dementia is to segregate out the nondegenerative dementias from possible degenerative dementias. Nondegenerative dementias could be due to traumatic, endocrine, metabolic, nutritional, toxic, infective, and immunological causes. They could also be caused by tumors, subdural hematomas, and normal pressure hydrocephalus. Many of the nondegenerative dementias occur at an earlier age and often progress quickly compared to Alzheimer’s disease and other degenerative dementias. Many are treatable or preventable with simple measures. This review aims to give an overview of some of the more important endocrine, metabolic, nutritional, and toxic disorders that may lead to dementia.

Memantine prevents hypoglycemia-induced decrements of the cerebral energy status in healthy subjects

CONTEXT

The risk to develop dementia is significantly increased in diabetes mellitus. Memantine, an N-methyl-D-aspartate receptor antagonist, which is clinically applied in dementia, has been shown to exert neuroprotective effects under hypoglycemic conditions in rats.

OBJECTIVE

We hypothesized that memantine may prevent hypoglycemia-induced decrements in the cerebral high-energy phosphate, i.e. ATP, metabolism to exert its neuroprotective action under these conditions.

DESIGN AND PARTICIPANTS

In a randomized, double-blind crossover design, we applied memantine vs. placebo in 16 healthy male subjects and examined the cerebral high-energy phosphate metabolism by (31)phosphor magnetic resonance spectroscopy, hormonal counterregulation, and neurocognitive performance during hypoglycemic glucose clamp conditions.

RESULTS

We found increments in hormonal counterregulation and reduced neurocognitive performance during hypoglycemia (P < 0.05). Cerebral ATP levels increased upon hypoglycemia in the memantine condition as compared with placebo (P = 0.006) and remained higher after renormalizing blood glucose concentrations (P = 0.018), which was confirmed by ATP to inorganic phosphate ratio (P = 0.046). Phosphocreatine levels and phosphocreatine to inorganic phosphate ratio remained stable throughout the experiments and did not differ between conditions (P > 0.1 for both).

CONCLUSION

Our data demonstrate that memantine preserves the cerebral energy status during experimentally induced hypoglycemia in healthy subjects. An improved neuronal energy status may thus be involved in the neuroprotective effect under these conditions and may qualify memantine as potential future option to combat cognitive impairments and dementia in diabetes.

Incretin therapies in the management of elderly patients with type 2 diabetes mellitus

Aging is characterized by a progressive increase in the prevalence of type 2 diabetes mellitus (T2DM), which approaches 20% by age 70 years. Older patients with T2DM are a very heterogeneous group with multiple comorbidities, an increased risk of hypoglycemia, and a greater susceptibility to adverse effects of antihyperglycemic drugs, making treatment of T2DM in this population challenging. The risk of severe hypoglycemia likely represents the greatest barrier to T2DM care in the elderly. Although recent guidelines recommend more flexibility in treating this population with individualized targets, inadequate glycemic control is still closely linked to poor outcome in elderly patients. Incretins (glucose-dependent insulinotropic polypeptide [GIP] and glucagon-like peptide-1 [GLP-1]) are hormones released post-meal from intestinal endocrine cells that stimulate insulin secretion and suppress postprandial glucagon secretion in a glucose-dependent manner. "Incretin therapies," comprising the injectable GLP-1 analogs and oral dipeptidyl peptidase-4 (DPP-4) inhibitors, are promising new therapies for use in older patients because of their consistent efficacy and low risk of hypoglycemia. However, data with these new agents are still scarce in this population, which has not been particularly well represented in clinical trials, highlighting the need for additional specific studies. The objective of this article is to provide an overview of the available data and potential role of these novel incretin therapies in managing T2DM in the elderly. With the exception of the DPP-4 inhibitor vildagliptin, there is no published trial to date dedicated to this population, although a few studies are currently ongoing. Therefore, available data from elderly subgroups of individual studies were also reviewed when available, as well as pooled analyses by age subgroups across clinical programs conducted with incretin therapies.

R D Lawrence Lecture 2010. The brain as a target organ in Type 2 diabetes: exploring the links with cognitive impairment and dementia

Type 2 diabetes is associated with cognitive impairment and dementia, but the precise underlying mechanisms remain unresolved. Very high blood glucose concentrations are associated with mood changes and poor memory function, possibly by causing alterations in cerebral blood flow or osmotic changes in neurones, and correction of acute hyperglycaemia appears beneficial. Chronic hyperglycaemia may cause structural changes in the brain, such as cerebral microvascular disease, and there are strong associations between the presence of retinal microvascular abnormalities and cognitive function. Functional insulin deficiency in the brain may also be a factor, but trials with rosiglitazone in people with diabetes and other trials in people with Alzheimer's disease have shown no specific benefit of insulin sensitization. There is an association between hypoglycaemia and cognitive impairment in people with Type 2 diabetes; part of that association may simply be a consequence of the fact that people with cognitive impairment find it more difficult to manage their diabetes and so are more prone to hypoglycaemia. The potential for hypoglycaemia to cause harm to the brain has been debated for many years, and the issue remains unresolved. An ongoing prospective study of risk factors for cognitive impairment in people with Type 2 diabetes (Edinburgh Type 2 Diabetes Study) should improve our understanding of the aetiology of cognitive impairment and inform the design of future intervention trials.

Cognitive function, dementia and type 2 diabetes mellitus in the elderly

Increasing numbers of people are developing type 2 diabetes mellitus, but interventions to prevent and treat the classic microvascular and macrovascular complications have improved, so that people are living longer with the condition. This trend means that novel complications of type 2 diabetes mellitus, which are not targeted by current management strategies, could start to emerge. Cognitive impairment and dementia could come into this category. Type 2 diabetes mellitus is associated with a 1.5-2.5-fold increased risk of dementia. The etiology of dementia and cognitive impairment in people with type 2 diabetes mellitus is probably multifactorial. Chronic hyperglycemia is implicated, perhaps by promoting the development of cerebral microvascular disease. Data suggest that the brains of older people with type 2 diabetes mellitus might be vulnerable to the effects of recurrent, severe hypoglycemia. Other possible moderators of cognitive function include inflammatory mediators, rheological factors and dysregulation of the hypothalamic-pituitary-adrenal axis. Cognitive function should now be included as a standard end point in randomized trials of therapeutic interventions in patients with type 2 diabetes mellitus.

Pharmacologic amelioration of severe hypoglycemia-induced neuronal damage

Hypoglycemia is a common complication for insulin treated people with diabetes. Severe hypoglycemia, which occurs in the setting of excess or ill-timed insulin administration, has been shown to cause brain damage. Previous pre-clinical studies have shown that memantine (an N-methyl-d-aspartate receptor antagonist) and erythropoietin can be neuroprotective in other models of brain injury. We hypothesized that these agents might also be neuroprotective in response to severe hypoglycemia-induced brain damage. To test this hypothesis, 9-week old, awake, male Sprague-Dawley rats underwent hyperinsulinemic (0.2 U kg(-1)min(-1)) hypoglycemic clamps to induce severe hypoglycemia (blood glucose 10-15 mg/dl for 90 min). Animals were randomized into control (vehicle) or pharmacological treatments (memantine or erythropoietin). One week after severe hypoglycemia, neuronal damage was assessed by Fluoro-Jade B and hematoxylin and eosin staining of brain sections. Treatment with both memantine and erythropoietin significantly decreased severe hypoglycemia-induced neuronal damage in the cortex by 35% and 39%, respectively (both p<0.05 vs. controls). These findings demonstrate that memantine and erythropoietin provide a protective effect against severe hypoglycemia-induced neuronal damage.

Severe sulfonylurea-induced hypoglycemia: a problem of uncritical prescription and deficiencies of diabetes care in geriatric patients

OBJECTIVE

Severe sulfonylurea-induced hypoglycemia (SH) remains a life-threatening and under-reported condition. We investigated the incidence of SH and clinical characteristics of patients with type 2 diabetes mellitus (T2DM) to demonstrate typical risk constellations.

METHODS

In a prospective population-based observational study, all consecutive cases of SH in the period 2000 - 2009 in a German area with 200,000 inhabitants were registered. Severe hypoglycemia was defined as a symptomatic event requiring treatment with intravenous glucose and was confirmed by a blood glucose measurement of < 50 mg/dl.

RESULTS

A mean incidence of seven episodes of SH per year and 100,000 inhabitants was registered. The 139 hypoglycemic individuals had been treated with glimepiride (n = 98), glibenclamide (n = 40) or gliquidone (n = 1). No preparation showed a constant dose-effect relationship, SH occurring within a wide dose range. The patients were characterized as follows: age 77.5 + or - 9.4 years, duration of diabetes 11 + or - 7 years, body mass index 26.3 + or - 4.9 kg/m(2), HbA1c 6.6 + or - 1.3%, creatinine clearance 46 + or - 24 ml/min with renal insufficiency in 73% and co-medication 7 + or - 3 drugs. Two-thirds of all subjects lived independently at home whereas a third were cared for by a home nursing service or received care in nursing homes. In all, 30% had participated in diabetes education programs. In 31%, systematic blood glucose monitoring was performed.

CONCLUSIONS

Uncritical prescription of sulfonylureas neglecting crucial contraindications - particularly renal insufficiency - and deficiencies of diabetes care contributed substantially to the risk of SH in the mainly geriatric patients. There is a need for alternative therapeutic concepts that minimize the risk of hypoglycemia in geriatric patients with T2DM.

Hypoglycemia: an overview of fear of hypoglycemia, quality-of-life, and impact on costs

BACKGROUND

The clinical goal in the treatment of diabetes is to achieve good glycemic control. Tight glycemic control achieved with intensive glucose lowering treatment reduces the risk of long-term micro- and macro-vascular complications of diabetes, resulting in an improvement in quality-of-life for the patient and decreased healthcare costs. The positive impact of good glycemic control is, however, counterbalanced by the negative impact of an increased incidence of hypoglycemia.

METHODS

A search of PubMed was conducted to identify published literature on the impact of hypoglycemia, both on patient quality-of-life and associated costs to the healthcare system and society.

RESULTS

In people with type 1 or type 2 diabetes, hypoglycemia is associated with a reduction in quality-of-life, increased fear and anxiety, reduced productivity, and increased healthcare costs. Fear of hypoglycemia may promote compensatory behaviors in order to avoid hypoglycemia, such as decreased insulin doses, resulting in poor glycemic control and an increased risk of serious health consequences. Every non-severe event may be associated with a utility loss in the range of 0.0033-0.0052 over 1 year, further contributing to the negative impact.

LIMITATIONS

This review is intended to provide an overview of hypoglycemia in diabetes and its impact on patients and society, and consequently it is not a comprehensive evaluation of all studies reporting hypoglycemic episodes.

CONCLUSION

To provide the best possible care for patients and a cost-effective treatment strategy for healthcare decision-makers, a treatment that provides good glycemic control with a limited risk of hypoglycemia would be a welcome addition to diabetes management options.

GLP-1 agonists and dipeptidyl-peptidase IV inhibitors

Novel therapeutic options for type 2 diabetes based on the action of the incretin hormone glucagon-like peptide-1 (GLP-1) were introduced in 2005. Incretin-based therapies consist of two classes: (1) the injectable GLP-1 receptor agonists solely acting on the GLP-1 receptor and (2) dipeptidyl-peptidase inhibitors (DPP-4 inhibitors) as oral medications raising endogenous GLP-1 and other hormone levels by inhibiting the degrading enzyme DPP-4. In type 2 diabetes therapy, incretin-based therapies are attractive and more commonly used due to their action and safety profile. Stimulation of insulin secretion and inhibition of glucagon secretion by the above-mentioned agents occur in a glucose-dependent manner. Therefore, incretin-based therapies have no intrinsic risk for hypoglycemias. GLP-1 receptor agonists allow weight loss; DPP-4 inhibitors are weight neutral. This review gives an overview on the mechanism of action and the substances and clinical data available.

The complex interplay of cardiovascular system and cognition: how to predict dementia in the elderly?

Prevalence of dementing illnesses is expected to grow due to aging of the population throughout the world. Vascular dementia and Alzheimer's disease share several risk factors and are nowadays considered two ends of a continuum rather than two distinct entities. Traditional cardiovascular risk markers such as diabetes, dyslipidemia, hypertension, metabolic syndrome and adiposity in mid-life are harbingers of cognitive decline, Alzheimer's disease and vascular dementia later in life. In aged populations, only diabetes has been more constantly associated with the development of cognitive dysfunction, while other risk markers have shown more mixed results. Normal aging, co-morbidities and other changes connected to cognitive decline make the interpretation of the risk markers in the elderly challenging and probably explain these contradictory findings. Control of cardiovascular risk factors has been linked to beneficial effects in terms of cognition in cross-sectional and prospective follow up studies, but the results of interventional trials have been disappointing. More research in this area is needed, specifically, placebo-controlled randomized trials in both mid-life and late-life with cognitive dysfunction as a primary endpoint.

Cognitive dysfunction in patients with type 2 diabetes

People with diabetes mellitus are at increased risk of cognitive dysfunction and dementia. This review explores the nature and severity of cognitive changes in patients with type 2 diabetes. Possible risk factors such as hypo- and hyperglycemia, vascular risk factors, micro- and macrovascular complications, depression and genetic factors will be examined, as well as findings from brain imaging and autopsy studies. We will show that type 2 diabetes is associated with modest cognitive decrements in non-demented patients that evolve only slowly over time, but also with an increased risk of more severe cognitive deficits and dementia. There is a dissociation between these two 'types' of cognitive dysfunction with regard to affected age groups and course of development. Therefore, we hypothesize that the mild and severe cognitive deficits observed in patients with type 2 diabetes reflect separate processes, possibly with different risk factors and aetiologies.

Glucose control in the older patient: from intensive, to effective and safe

Older adults represent an extensive proportion of Type 2 diabetic patients. Managing diabetes in this population is challenging, because complex comorbidity and disability often mean that guidelines are not suitable on an individual basis. Recent evidence has raised animated discussion of the possibility that intensive glucose control may cause more harm than benefit, especially in older adults. The benefit of glycemic control on microvascular diabetic complications has been consistently demonstrated, but the evidence of benefit on macrovascular disease is not uniform in all studies. Glycemic control appears to prevent the development of cardiovascular events, but is less helpful in secondary prevention, when cardio- and cerebro-vascular diseases are established. In addition, treating hyperglycemia in critically ill patients (most of them over 60 years old) with a target close to normal glucose values has been shown to increase morbidity and mortality. It is possible that the attempt to reach euglycemia is not the best goal, in either older non-diabetic critically ill patients or older diabetic adults. The risks associated with hypoglycemia, which induces a counter-regulatory response with prolonged QT interval and cardiac arrhythmias in patients with established cardiovascular disease, should be carefully considered. The reported association of hypoglycemia with dementia and falls should also be examined. In the older adult, prudent, personalized therapy, with less rigid targets for patients at higher risk of hypoglycemia, is essential. The use of agents with a good safety profiles and with the least possibility of causing hypoglycemia is warranted.

Glycemic control and extended hemodialysis survival in patients with diabetes mellitus: comparative results of traditional and time-dependent Cox model analyses

BACKGROUND AND OBJECTIVES

The benefits and risks of aggressive glycemic control in diabetes mellitus complicated by end-stage kidney failure remain uncertain but have importance because of the large patient population with inferior overall prognosis. Recent large observational studies with differing methodologies reached somewhat contrasting conclusions regarding the association of hemoglobin A1c with survival in diabetic chronic hemodialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study supplements the authors' previous analysis (which found no correlation) by extending the follow-up period to 3 years and using time-dependent survival models with repeated measures. Among 24,875 nationally distributed study patients, 94.5% had type 2 diabetes, allowing additional analysis in the subset with type 1 diabetes. Data were collected at baseline and every quarter to a maximum of 3 years' follow-up.

RESULTS

Adjusted standard and time-dependent Cox models indicated that only extremes of glycemia were associated with inferior survival. There was no effect modification by serum albumin levels, a marker of protein nutrition status, and no trend associated with random glucose measurements in a post hoc analysis. In type 1 diabetic patients, upper extreme hemoglobin A1c values indicated lower survival risk.

CONCLUSIONS

Sustained extremes of glycemia were only variably and weakly associated with decreased survival in this population. In the absence of randomized, controlled trials, these results suggest that aggressive glycemic control cannot be routinely recommended for all diabetic hemodialysis patients on the basis of reducing mortality risk. Physicians are encouraged to individualize glycemic targets based on potential risks and benefits in diabetic ESRD patients.

Cardiovascular risk factors, cerebrovascular disease burden, and healthy brain aging

Cardiovascular risk factors have been associated with 2 common manifestation of unhealthy brain in older people, cognitive impairment and depression. The evidence for these effects is almost entirely observational, but links hypertension, smoking, hypercholesterolemia, diabetes mellitus, and hyperhomocysteinemia with cognitive impairment and depression. Unfortunately randomized trials evaluating interventions for these risk factors on the outcomes of cognition or mood have either been inconclusive or negative. However, as there are considerable other health benefits from targeting cardiovascular risk factors, these interventions should be more widely adopted, which would also probably result in positive outcomes for the brain.

The evolving place of incretin-based therapies in type 2 diabetes

Treatment options for type 2 diabetes based on the action of the incretin hormone glucagon-like peptide-1 (GLP-1) were first introduced in 2005. These comprise the injectable GLP-1 receptor agonists solely acting on the GLP-1 receptor on the one hand and orally active dipeptidyl-peptidase inhibitors (DPP-4 inhibitors) raising endogenous GLP-1 and other hormone levels by inhibiting the degrading enzyme DPP-4. In adult medicine, both treatment options are attractive and more commonly used because of their action and safety profile. The incretin-based therapies stimulate insulin secretion and inhibit glucagon secretion in a glucose-dependent manner and carry no intrinsic risk of hypoglycaemia. GLP-1 receptor agonists allow weight loss, whereas DPP-4 inhibitors are weight neutral. This review gives an overview of the mechanism of action and the substances and clinical data available.

Role of vildagliptin in managing type 2 diabetes mellitus in the elderly

BACKGROUND

The prevalence of type 2 diabetes (T2DM) increases with age. Older patients have an increased likelihood for T2DM-related morbidity and mortality. The objective of this review is to provide an overview of the challenges in managing T2DM in the elderly, with an emphasis on prevention of hypoglycaemia and the role of the DPP-4 inhibitor vildagliptin in this patient population.

METHODS

A search of PubMed was conducted (from 2003 to 2010) to identify English-language articles relevant to the management of elderly patients with T2DM, with an emphasis on vildagliptin treatment. A limitation of this review is that it does not provide an overview of the entire class of dipeptidyl-peptidase-4 (DPP-4) inhibitors.

FINDINGS

Management of T2DM in elderly patients is complicated by numerous factors, including a high prevalence of cardiovascular risk factors and other comorbidities and a high frequency of polypharmacy issues. Hypoglycaemia may pose the greatest barrier to optimal glycaemic control in elderly patients, who are less likely to recognise and respond to hypoglycaemic episodes, leading to increased frequency and severity of events. Data on the DPP-4 inhibitor vildagliptin indicate that reductions in A1C in elderly patients are at least as good as those observed in younger patients and are achieved with minimal risk of hypoglycaemia. T2DM in older individuals is associated with relative hyperglucagonaemia and elevated postprandial glucose (PPG). Vildagliptin treatment appears to address both these defects. Vildagliptin improves the ability of alpha- and beta-cells to respond appropriately to changes in plasma glucose levels. This, in the face of high glucose levels, results in reduced inappropriate glucagon secretion and PPG excursions. In the face of low glucose, however, the protective glucagon response is well-preserved. These factors help explain the efficacy and minimal risk of hypoglycaemia observed with vildagliptin in elderly patients.

CONCLUSION

The elderly population with T2DM poses unique treatment challenges and have not been particularly well-represented in clinical trials, highlighting the need for additional studies to better define appropriate glucose targets and to ascertain the best strategies for achieving and maintaining appropriate glycaemic levels. Because vildagliptin does not expose patients to hypoglycaemic risk, it seems particularly suited to oral therapy of T2DM in the elderly.

Key considerations around the risks and consequences of hypoglycaemia in people with type 2 diabetes

Hypoglycaemia and its consequences represent a significant risk for many people who have type 2 diabetes, and hypoglycaemia is currently under-recognised and commonly avoidable. Current clinical guidelines recommend the targeting of tight glycaemic control and this strategy may also be associated with an increased risk of hypoglycaemia. Hypoglycaemia impacts on morbidity, mortality and quality of life of people with type 2 diabetes, and improved recognition of the symptoms of hypoglycaemia will allow effective treatment and reduce the risk of progression to more severe episodes. A common cause of hypoglycaemia in people with type 2 diabetes is glucose-lowering medication, in particular, those which raise insulin independently of ambient glucose concentration such as sulphonylureas and exogenous insulin. The recently published National Institute for Health and Clinical Excellence guideline recommends the use of Dipeptidyl peptidase-4 inhibitors or thiazolidinediones (glitazones) as alternative second-line therapy instead of a sulphonylurea in those patients who are at significant risk of hypoglycaemia and its consequences.

Cognitive decline: the relevance of diabetes, hyperlipidaemia and hypertension

Cognitive decline including mild cognitive impairment describes a heterogeneous condition with cognitive changes between normal ageing and dementia. Cognitive impairment can be promoted or caused by treatable somatic factors. In this review, three important cardiovascular risk factors, diabetes mellitus, hypercholesterolaemia and hypertension, and their association with cognitive decline, are assessed. Though there are many hints of a causal association between diabetes mellitus and the development of cognitive decline, definitive proof of a protective effect of antidiabetic treatment by controlled or randomised placebo-controlled studies is needed. In midlife, elevated cholesterol levels comprise a risk factor for cognitive decline. In elderly subjects, cholesterol levels decline and are not clearly associated with cognitive impairment. The evidence for treatment of hypercholesterolaemia by statins solely for prevention of cognitive decline remains unclear. There is an age-dependent relationship between blood pressure and cognitive impairment. Midlife hypertension is associated with an increased risk of developing cognitive decline and antihypertensive treatment may therefore be beneficial, whereas hypertension later in life does not carry the same risk of cognitive dysfunction. Diagnosis of these somatic factors is essential in cognitive impairment, as diligent treatment may improve cognitive performance and postpone the manifestation of dementia.

Approach to managing hypoglycemia in elderly patients with diabetes

Hypoglycemia is a common clinical problem in elderly patients with diabetes. Aging modifies the counterregulatory and symptomatic responses to hypoglycemia. Hypoglycemia in the elderly is not only due to tight blood sugar control, but also due to a multitude of other factors. Hypoglycemia often occurs with insulin, sulfonylureas, or meglitinide therapy. However, other causes may also contribute to hypoglycemia, such as decreased cognition, renal impairment, or polypharmacy. The presenting features of hypoglycemia may be atypical and misinterpreted, resulting in delayed treatment. Morbidity is greater in elderly patients, and the risk of progression to severe hypoglycemia is high because of their altered symptom profile, diminished symptom intensity, and altered glycemic thresholds. Hypoglycemia seems to be the main limiting factor in their glycemic control. In this article we discuss strategies to prevent hypoglycemic episodes.

Avoiding hypoglycaemia while achieving good glycaemic control in type 2 diabetes through optimal use of oral agent therapy

BACKGROUND

Patients with type 2 diabetes appear to be at relatively low risk of severe hypoglycaemia and hypoglycaemia unawareness in the early stages of disease. However, declining endogenous insulin secretory capacity due to beta-cell dysfunction/failure eventually produces vulnerability similar to type 1 diabetes. Severe hypoglycaemia itself is associated with serious morbidity and sometimes mortality, and represents an important barrier to achieving glycaemic goals and thus may reduce the protection from diabetes-related morbidity provided by good glycaemic control. Achieving an optimal balance of good glycaemic control and low risk of hypoglycaemia is key to providing optimum care in individuals with type 2 diabetes. This article discusses the issues related specifically to hypoglycaemia associated with oral agent therapy and how these agents may be best employed to provide an optimal balance between hypoglycaemia and good glycaemic control.

METHODS

Embase and Medline searches from 1998 to 2009 using the search terms DPP-4 inhibitors, metformin, oral agents, sulphonylureas, thiazolidinediones AND hypoglycaemia were conducted to identify relevant articles. The limitations inherent in this retrospective, narrative review of previously published publications chosen at the author's discretion are acknowledged.

FINDINGS

Failure to address even mild hypoglycaemia and glycaemic control early in the course of the disease may compromise the success of treatment in the longer term. Metformin, thiazolidinediones and DPP-4 inhibitors, either as monotherapy or in combination with each other, have a well-characterised low propensity to cause hypoglycaemia compared with other therapies.

CONCLUSIONS

Metformin, thiazolidinediones and DPP-4 inhibitors appear to be the most appropriate oral options for minimising the risk of hypoglycaemia. Early and ongoing attention to hypoglycaemia should form an integral part of any long-term glucose control strategy.

Insulin resistance, diabetes and cognitive function: consequences for preventative strategies

Cognitive decline and dementia both place a heavy burden on patients and their relatives, and any means of preventing such age-related changes are worthy of consideration. Those who have the metabolic syndrome with or without diabetes suffer more often from dysexecutive problems and slower psychomotor speed than do other patients. In epidemiological studies, diabetes has appeared to be a risk factor for all types of dementia, including vascular dementia, although the role of the metabolic syndrome in the risk of Alzheimer's disease is still a matter of debate. The possible mechanisms of cognitive alterations are multiple, and may differ according to age group and duration of diabetes or the metabolic syndrome. Drug interventional trials addressing the prevention of cognitive decline through action on the metabolic syndrome are disappointing-albeit scarce at this time. Lifestyle interventions in middle-aged or younger-elderly subjects should also be implemented in the general population.

Comorbid depression is associated with an increased risk of dementia diagnosis in patients with diabetes: a prospective cohort study

BACKGROUND

Both depression and diabetes have been found to be risk factors for dementia. This study examined whether comorbid depression in patients with diabetes increases the risk for dementia compared to those with diabetes alone.

METHODS

We conducted a prospective cohort study of 3,837 primary care patients with diabetes (mean age 63.2 +/- 13.2 years) enrolled in an HMO in Washington State. The Patient Health Questionnaire (PHQ-9) was used to assess depression at baseline, and ICD-9 diagnoses for dementia were used to identify cases of dementia. Cohort members with no previous ICD-9 diagnosis of dementia prior to baseline were followed for a 5-year period. The risk of dementia for patients with both major depression and diabetes at baseline relative to patients with diabetes alone was estimated using cause-specific Cox proportional hazard regression models that adjusted for age, gender, education, race/ethnicity, diabetes duration, treatment with insulin, diabetes complications, nondiabetes-related medical comorbidity, hypertension, BMI, physical inactivity, smoking, HbA(1c), and number of primary care visits per month.

RESULTS

Over the 5-year period, 36 of 455 (7.9%) patients with major depression and diabetes (incidence rate of 21.5 per 1,000 person-years) versus 163 of 3,382 (4.8%) patients with diabetes alone (incidence rate of 11.8 per 1,000 person-years) had one or more ICD-9 diagnoses of dementia. Patients with comorbid major depression had an increased risk of dementia (fully adjusted hazard ratio 2.69, 95% CI 1.77, 4.07).

CONCLUSIONS

Patients with major depression and diabetes had an increased risk of development of dementia compared to those with diabetes alone. These data add to recent findings showing that depression was associated with an increased risk of macrovascular and microvascular complications in patients with diabetes.

Minimizing the risk of hypoglycemia in patients with type 2 diabetes mellitus

Hypoglycemia is a major barrier to achieving glycemic goals in patients with diabetes. Both acute and chronically recurrent hypoglycemic events appear to have long-term consequences for patients with type 2 diabetes mellitus (T2DM). Chronically recurrent hypoglycemia may lead to an impairment of the counterregulatory system, with the potential for the development of hypoglycemia unawareness syndrome, increased severe hypoglycemia-associated hospitalization, and increased mortality. Hypoglycemic events may also have negative implications in cardiovascular disease and/or dementia. Avoidance of hypoglycemia by treating with appropriate, individualized regimens for patients with T2DM should be a primary focus of physicians. Utilizing traditional agents (eg, metformin and thiazolidinediones) that do not promote hypoglycemia, in combination with newer agents such as dipeptidyl peptidase-4 inhibitors and incretin mimetics, could offer a therapeutic advantage when trying to help patients reach their hemoglobin A(1c) goal without the added risk of hypoglycemia.

On what evidence-base do we recommend self-monitoring of blood glucose?

Self-monitoring of blood glucose (SMBG) has been considered one major breakthrough in diabetes therapy because, for the first time, patients were able to determine their blood glucose levels during daily life. It seems obvious that this must be of advantage to disease management and clinical outcome, but it has become a nightmare for those trying to provide evidence. Randomised controlled trials have yielded inconsistent results on a benefit of SMBG-based treatment strategies not only in type 2 but - surprisingly - also in type 1 and gestational diabetes. Despite this, SMBG is being considered indispensible in intensive insulin treatment, but is being debated for other clinical settings. When considering the non-RCT based reasons for recommending SMBG in type 1 and gestational diabetes it becomes apparent that the same reasons also apply to type 2 diabetes.

Adding liraglutide to oral antidiabetic drug therapy: onset of treatment effects over time

AIM

To investigate the onset of treatment effects over time observed for liraglutide in combination with oral antidiabetic drugs (OADs).

METHODS

This analysis included patients from three phase 3, 26-week, randomised, double-blind, parallel-group trials. Prior to randomisation, patients underwent a run-in and titration period with metformin (Liraglutide Effect and Action in Diabetes-2, LEAD-2), glimepiride (LEAD-1) or metformin plus rosiglitazone (LEAD-4). Patients were then randomised to receive liraglutide (0.6, 1.2 or 1.8 mg once-daily), active comparator and/or placebo. For this analysis, only the 1.2 mg and 1.8 mg liraglutide doses were included. Outcome measures included change in HbA(1c), fasting plasma glucose (FPG), weight and systolic blood pressure (SBP). The safety profile was also investigated.

RESULTS

Significant reductions in HbA(1c) were observed within 8 weeks of treatment with liraglutide plus OADs (p < 0.0001) and maintained until week 26. Furthermore, liraglutide plus OADs led to significant reductions in FPG within 2 weeks (p < 0.0001) and sustained over 26 weeks. Adding liraglutide to metformin or metformin plus rosiglitazone also led to early reductions and maintained reductions in body weight (within 8 weeks, p < 0.0001); however, liraglutide treatment plus glimepiride was weight neutral. Rapid reductions in SBP were observed for liraglutide plus OADs (within 2 weeks, p < 0.05-0.001) and maintained for 26 weeks. Some patients experienced nausea, which for the majority it diminished within 2 weeks.

CONCLUSION

Liraglutide treatment combined with OADs led to rapid improvements in FPG and SBP. Early reductions in HbA(1c) and body weight were also observed. Adding liraglutide to OADs early on may therefore be a good treatment option for patients with type 2 diabetes.