Hypoglycaemia and dementia in diabetic patients

Using Hypothesis-Led Machine Learning and Hierarchical Cluster Analysis to Identify Disease Pathways Prior to Dementia: Longitudinal Cohort Study

BACKGROUND

Dementia development is a complex process in which the occurrence and sequential relationships of different diseases or conditions may construct specific patterns leading to incident dementia.

OBJECTIVE

This study aimed to identify patterns of disease or symptom clusters and their sequences prior to incident dementia using a novel approach incorporating machine learning methods.

METHODS

Using Taiwan's National Health Insurance Research Database, data from 15,700 older people with dementia and 15,700 nondementia controls matched on age, sex, and index year (n=10,466, 67% for the training data set and n=5234, 33% for the testing data set) were retrieved for analysis. Using machine learning methods to capture specific hierarchical disease triplet clusters prior to dementia, we designed a study algorithm with four steps: (1) data preprocessing, (2) disease or symptom pathway selection, (3) model construction and optimization, and (4) data visualization.

RESULTS

Among 15,700 identified older people with dementia, 10,466 and 5234 subjects were randomly assigned to the training and testing data sets, and 6215 hierarchical disease triplet clusters with positive correlations with dementia onset were identified. We subsequently generated 19,438 features to construct prediction models, and the model with the best performance was support vector machine (SVM) with the by-group LASSO (least absolute shrinkage and selection operator) regression method (total corresponding features=2513; accuracy=0.615; sensitivity=0.607; specificity=0.622; positive predictive value=0.612; negative predictive value=0.619; area under the curve=0.639). In total, this study captured 49 hierarchical disease triplet clusters related to dementia development, and the most characteristic patterns leading to incident dementia started with cardiovascular conditions (mainly hypertension), cerebrovascular disease, mobility disorders, or infections, followed by neuropsychiatric conditions.

CONCLUSIONS

Dementia development in the real world is an intricate process involving various diseases or conditions, their co-occurrence, and sequential relationships. Using a machine learning approach, we identified 49 hierarchical disease triplet clusters with leading roles (cardio- or cerebrovascular disease) and supporting roles (mental conditions, locomotion difficulties, infections, and nonspecific neurological conditions) in dementia development. Further studies using data from other countries are needed to validate the prediction algorithms for dementia development, allowing the development of comprehensive strategies to prevent or care for dementia in the real world.

Modulatory effects of moringa (Moringa oleifera L.) leaves infested with African mistletoe (Tapinanthus bangwensis L.) on the antioxidant, antidiabetic, and neurochemical indices in high sucrose diet-induced diabetic-like phenotype in fruit flies (Drosophila melanogaster M.)

Moringa is a common medicinal plant tree with mistletoe infestation and its leaf is widely used as food and traditional medication in alleviating several metabolic and neurodegenerative diseases. Hence, this study investigated the influence of African mistletoe on the antioxidant, antidiabetic, and neuroprotective activities of infested moringa leaf in sucrose induced diabetes in Drosophila melanogaster model. Glucose and triglycerides were evaluated in the flies' hemolymph and all other parameters were evaluated in the tissues. A significant (p < .05) decrease in survival rate and increase in the level of glucose and triglycerides in flies fed with 30% of sucrose when compared with control was obtained. Treated flies had significant (p < .05) positive alteration in the level of glucose, triglycerides, antioxidants (both enzymatic and nonenzymatic), and enzyme activities when compared with normal and sucrose control flies. This study suggests that mistletoe infestation did not alter the antioxidant, antidiabetic, and neuroprotective effects of the moringa leaf. PRACTICAL APPLICATIONS: This present study has shown that mistletoe infestation did not alter the protective activities of moringa leaf, hence, moringa with or without mistletoe infestation could be taken as functional food to mitigate several metabolic diseases.

Insulin-producing cells from mesenchymal stromal cells: Protection against cognitive impairment in diabetic rats depends upon implant site

Diabetes mellitus (DM) is a serious public health problem and can cause long-term damage to the brain, resulting in cognitive impairment in these patients. Insulin therapy for type 1 DM (DM1) can achieve overall blood glucose control, but glycemic variations can occur during injection intervals, which may contribute to some complications. Among the additional therapies available for DM1 treatment is the implantation of insulin-producing cells (IPCs) to attenuate hyperglycemia and even reverse diabetes. Here, we studied the strategy of implanting IPCs obtained from mesenchymal stromal cells (MSCs) from adipose tissue, comparing two different IPC implant sites, subcapsular renal (SR) and subcutaneous (SC), to investigate their putative protection against hippocampal damage, induced by STZ, in a rat DM1 model. Both implants improved hyperglycemia and reduced the serum content of advanced-glycated end products in diabetic rats, but serum insulin was not observed in the SC group. The SC-implanted group demonstrated ameliorated cognitive impairment (evaluated by novel object recognition) and modulation of hippocampal astroglial reactivity (evaluated by S100B and GFAP). Using GFP+ cell implants, the survival of cells at the implant sites was confirmed, as well as their migration to the pancreas and hippocampus. The presence of undifferentiated MSCs in our IPC preparation may explain the peripheral reduction in AGEs and subsequent cognitive impairment recovery, mediated by autophagic depuration and immunomodulation at the hippocampus, respectively. Together, these data reinforce the importance of MSCs for use in neuroprotective strategies, and highlight the logistic importance of the subcutaneous route for their administration.

Effect of metformin on neurodegenerative disease among elderly adult US veterans with type 2 diabetes mellitus

OBJECTIVE

This study aimed to evaluate the association between metformin treatment and the risk of neurodegenerative disease (ND) among elderly adults with type 2 diabetes mellitus (T2DM).

DESIGN/SETTING/PARTICIPANTS

This retrospective longitudinal cohort study examined the effects of the length of metformin exposure on ND among elderly US veterans with T2DM and insulin treatment using the Veterans Affairs electronic medical record database.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary clinical outcome was defined as diagnosis of ND including dementia, Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and mild cognitive impairment during the follow-up period. The secondary clinical outcomes were separately measured by AD, PD, HD, dementia and mild cognitive impairment.

RESULT

Adjusted by propensity score weight, a total of 5528 patients (mean age, 63.2±10.9 years; male, 98%; white, 60%) with a median follow-up of 5.2 years were selected. Those with ND or other mental disorders at baseline or who were on insulin for less than two-thirds of the study period were excluded. The incidence rate of ND was 11.48 per 1000 person-years among patients with metformin treatment, compared with 25.45 per 1000 person-years for those without metformin. Compared with no metformin use, 2-4 years and >4 years of metformin exposure were significantly associated with lower risk of ND (adjusted HR (aHR)=0.62, 95% CI 0.45 to 0.85; aHR=0.19, 95% CI 0.12 to 0.31, respectively), while metformin exposure in the first 2 years showed no significant influence.

CONCLUSION

We conclude that long-term metformin therapy (>2 years) was associated with lower incidence of ND among elderly veterans with T2DM. We need to conduct a study with more representative population and more robust method for causal inferences. Further investigation into the mechanism involved is needed along with randomised trials to confirm a potential neuroprotective effect of metformin.

Changes of myelin basic protein in the hippocampus of an animal model of type 2 diabetes

In this study, we observed chronological changes in the immunoreactivity and expression level of myelin basic protein (MBP), one of the most abundant proteins in the central nervous system, in the hippocampus of Zucker diabetic fatty (ZDF) rats and their control littermates (Zucker lean control; ZLC). In the ZLC group, body weight steadily increased with age; the body weight of the ZDF group, however, peaked at 30 weeks of age, and subsequently decreased. Based on the changes of body weight, animals were divided into the following six groups: early (12-week), middle (30-week), and chronic (52-week) diabetic groups and their controls. MBP immunoreactivity was found in the alveus, strata pyramidale, and lacunosum-moleculare of the CA1 region, strata pyramidale and radiatum of the CA3 region, and subgranular zone, polymorphic layer, and molecular layer of the dentate gyrus. MBP immunoreactivity was lowest in the hippocampus of 12-week-old rats in the ZLC group, and highest in 12-week-old rats in the ZDF group. Diabetes increased MBP levels in the 12-week-old group, while MBP immunoreactivity decreased in the 30-week-old group. In the 52-week-old ZLC and ZDF groups, MBP immunoreactivity was detected in the hippocampus, similar to the 30-week-old ZDF group. Western blot results corroborated with immunohistochemical results. These results suggested that changes in the immunoreactivity and expression of MBP in the hippocampus might be a compensatory response to aging, while the sustained levels of MBP in diabetic animals could be attributed to a loss of compensatory responses in oligodendrocytes.

New views and possibilities of antidiabetic drugs in treating and/or preventing mild cognitive impairment and Alzheimer's Disease

Mounting evidence suggests that diabetes mellitus (DM) is associated with mild cognitive impairment (MCI), vascular dementia and Alzheimer's disease (AD). Biological, clinical and epidemiological data support a close link between DM and AD. Increasingly, studies have found that several antidiabetic agents can promote neurogenesis, and clinically ameliorate cognitive and memory impairments in different clinical settings. Data has shown that these antidiabetic drugs positively affect mitochondrial and synaptic function, neuroinflammation, and brain metabolism. Evidence to date strongly suggests that these antidiabetic drugs could be developed as disease-modifying therapies for MCI and AD in patients with and without diabetes.

Hypoglycaemia in diabetes: do we think enough of the cause? An observational study on prevalence and causes of hypoglycaemia among patients with type 2 diabetes in an out-patient setting in Sri Lanka

BACKGROUND

Hypoglycaemia is a feared experience for people with diabetes. We aimed to study the prevalence and causes of hypoglycaemia among Sri Lankans with diabetes.

METHODS

One thousand patients with diabetes attending a private sector diabetic clinic were interviewed using a structured questionnaire. Hypoglycaemic episodes within the preceding month were inquired and severity was graded according to clinical features and/or capillary blood glucose levels.

RESULTS

Mean age 55.0 years (± 12.5), 58.6% were males, mean diabetes duration 10.6 years (± 8.1), mean FPG 7.48 mmol/l (± 2.79) and mean HbA1c 7.82% (± 1.71) (62 mmol/mol). Of them, 26.1%. (mild 20.7%, moderate 3.9%, and severe 1.5%) experienced symptomatic hypoglycaemia. Sudden change diet (46.7%), unaccustomed exercise (15.7%) and increase in antihyperglycaemic therapy dosage (14.9%) were the recognized causes. Cause was not recognized by 16.3%. Non-prescribed native food items accounted for hypoglycaemia in 16.9% of patients (Momordica charantia 54.5%, Costus speciosus 52.3%, Salacia prinoides 11.4%, Coccinia grandis 6.8%, Adenanthera pavonina 4.5%). Severity of hypoglycaemia was positively correlated to age and duration of diabetes but not to HbA_1C.

CONCLUSION

Hypoglycaemia is common among patients with diabetes. Patients need advice on regular diet and exercise. Consumption of non-prescribed native foods should be considered as a possible cause.

Effect of recurrent severe hypoglycemia on cognitive performance in adult patients with diabetes: A meta-analysis

The purpose of this study was to investigate the existence and extent of cognitive impairment in adult diabetes mellitus (DM) patients with episodes of recurrent severe hypoglycemia, by using meta-analysis to synthesize data across studies. PubMed, EMBASE and Cochrane library search engines were used to identify studies on cognitive performance in DM patients with recurrent severe hypoglycemia. Random-effects meta-analysis was performed on seven eligible studies using an inverse-variance method. Effect sizes, which are the standardized differences between the experimental group and the control group, were calculated. Of the 853 studies, 7 studies met the inclusion criteria. Compared with control subjects, the adult DM patients with episodes of recurrent severe hypoglycemia demonstrated a significantly lowered performance on memory in both types of DM patients, and poor performance of processing speed in type 2 DM patients. There was no significant difference between adult DM patients with and those without severe hypoglycemia in other cognitive domains such as general intelligence, executive function, processing speed and psychomotor efficiency. Our results seem to confirm the hypothesis that cognitive dysfunction is characterized by worse memory and processing speed in adult DM patients with a history of recurrent severe hypoglycemia, whereas general intelligence, executive function, and psychomotor efficiency are spared.

Glucagon-Like Peptide-1 (GLP-1) Treatment Ameliorates Cognitive Impairment by Attenuating Arc Expression in Type 2 Diabetic Rats

Background

Glucagon-like peptide-1 (GLP-1) has been reported to exert some beneficial effects on the central nervous system (CNS). However, the effect of GLP-1 on cognitive impairment associated with type 2 diabetes is not well known. This study investigated the effect of GLP-1 on ameliorating memory deficits in type 2 diabetic rats.

Material/Methods

Type 2 diabetic rats were induced by a high-sugar, high-fat diet, followed by streptozotocin (STZ) injection and then tested in the Morris Water Maze (MWM) 1 week after the induction of diabetes. The mRNA expression of Arc, APP, BACE1, and PS1 were determined by real-time quantitative PCR, and the Arc protein was analyzed by immunoblotting and immunohistochemistry.

Results

Type 2 diabetic rats exhibited a significant decline in learning and memory in the MWM tests, but GLP-1 treatment was able to protect this decline and significantly improved learning ability and memory. The mRNA expression assays showed that GLP-1 treatment markedly reduced Arc, APP, BACE1, and PS1 expressions, which were elevated in the diabetic rats. Immunoblotting and immunohistochemistry results also confirmed that Arc protein increased in the hippocampus of diabetic rats, but was reduced after GLP-1 treatment.

Conclusions

Our findings suggest that GLP-1 treatment improves learning and memory deficits in type 2 diabetic rats, and this effect is likely through the reduction of Arc expression in the hippocampus.

Towards the concept of disease-modifier in post-stroke or vascular cognitive impairment: a consensus report

BACKGROUND

Vascular cognitive impairment (VCI) is a complex spectrum encompassing post-stroke cognitive impairment (PSCI) and small vessel disease-related cognitive impairment. Despite the growing health, social, and economic burden of VCI, to date, no specific treatment is available, prompting the introduction of the concept of a disease modifier.

CONSENSUS AND SUGGESTIONS

Within this clinical spectrum, VCI and PSCI remain advancing conditions as neurodegenerative diseases with progression of both vascular and degenerative lesions accounting for cognitive decline. Disease-modifying strategies should integrate both pharmacological and non-pharmacological multimodal approaches, with pleiotropic effects targeting (1) endothelial and brain-blood barrier dysfunction; (2) neuronal death and axonal loss; (3) cerebral plasticity and compensatory mechanisms; and (4) degenerative-related protein misfolding. Moreover, pharmacological and non-pharmacological treatment in PSCI or VCI requires valid study designs clearly stating the definition of basic methodological issues, such as the instruments that should be used to measure eventual changes, the biomarker-based stratification of participants to be investigated, and statistical tests, as well as the inclusion and exclusion criteria that should be applied.

CONCLUSION

A consensus emerged to propose the development of a disease-modifying strategy in VCI and PSCI based on pleiotropic pharmacological and non-pharmacological approaches.

Association between hypoglycemia and dementia in patients with type 2 diabetes

In addition to increased risks of macrovascular and microvascular complications, patients with type 2 diabetes mellitus (T2DM) usually also are at increased risk for cognitive impairment and dementia. Hypoglycemia, a common consequence of diabetes treatment, is considered an independent risk factor for dementia in patients with T2DM. Hypoglycemia and dementia are clinically underestimated and are related to poor outcomes; thus, they may compromise the life expectancy of patients with T2DM. Epidemiological evidence of hypoglycemia-associated cognitive decline and dementia is highly varied. Acute, severe hypoglycemic episodes induce chronic subclinical brain damage, cognitive decline, and subsequent dementia. However, the effects of recurrent moderate hypoglycemia on cognitive decline and dementia remain largely uninvestigated. Poor glycemic control (including fluctuation of hemoglobin A1C [HbA1c] and glucose values) and the viscous circle of bidirectional associations between dementia and hypoglycemia may be clinically relevant. The possible pathophysiological hypotheses include post-hypoglycemic neuronal damage, inflammatory processes, coagulation defects, endothelial abnormalities, and synaptic dysfunction of hippocampal neurons during hypoglycemia episodes. This article reviews previous findings, provides insight into the detection of groups at high risk of hypoglycemia-associated dementia, and proposes specific strategies to minimize the potential burdens associated with hypoglycemia-related neurocognitive disorders in patients with T2DM.

Treadmill exercise is associated with reduction of reactive microgliosis and pro-inflammatory cytokine levels in the hippocampus of type 2 diabetic rats

OBJECTIVES

In the present study, we investigated the effects of treadmill exercise on microglial activation and the subsequent release of tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and IL-1-beta in the hippocampus in a rat model of type 2 diabetes.

METHODS

At 30 weeks of age, diabetic (Zucker diabetic fatty, ZDF) rats and their littermate control (Zucker lean control, ZLC) rats were either placed on a stationary treadmill or made to run for 1 hour/day at 12-16 m/minute on five consecutive days, for 10 weeks. Once the rats reached 40 weeks, they were perfused and their hippocampus collected for immunohistochemistry or hippocampus collected fresh for the Western blotting or enzyme-linked immunosorbent assay (ELISA).

RESULTS

The whole blood glucose levels in exercised ZDF rats were significantly higher than in the sedentary or exercised ZLC rats, but were significantly lower than in the sedentary ZDF rats. In the sedentary ZLC and exercised ZLC rats, ionised calcium-binding adapter molecule 1 (Iba-1) immunoreactive microglia showed normal morphology which had small cytoplasm with ramified processes. In the sedentary ZDF rats, some Iba-1 immunoreactive microglia showed abnormal morphology which had hypertrophied cytoplasm with retracted processes. However, exercised ZDF rats had small cytoplasm with highly ramified processes. Levels of TNF-alpha, IL-6 and IL-1beta in the hippocampal homogenates were significantly increased in sedentary ZDF rats compared to sedentary ZLC rats, respectively. However, TNF-alpha, IL-6 and IL-1beta levels in the exercised ZDF rats were significantly decreased compared with those of sedentary ZDF rats, respectively.

DISCUSSION

These results suggest that exercise in type 2 diabetic rats reduces microglial activation and the subsequent increase of pro-inflammatory cytokine levels in the hippocampus.

Severe hypoglycemia is associated with antidiabetic oral treatment compared with insulin analogs in nursing home patients with type 2 diabetes and dementia: results from the DIMORA study

OBJECTIVES

Severe hypoglycemia is associated with cognitive decline and dementia in older persons with type 2 diabetes. The role of antidiabetic treatments on severe hypoglycemia is unknown in dementia. The aims were to determine the prevalence of severe hypoglycemic events and investigate associations among severe hypoglycemic and specific antidiabetic treatments (classes of oral agents and types of insulin analogs) in a large sample of nursing home patients with diabetes according to dementia status.

DESIGN

Cross-sectional observational study.

SETTING

A total of 150 nursing homes across Italy.

PARTICIPANTS

A total of 2258 patients with type 2 diabetes (dementia = 1138, no dementia = 1120).

MEASUREMENTS

Diagnosis of dementia before nursing home admission. Data were collected regarding functional status, glycemic control, antidiabetic treatments, comorbidities, and biochemical and clinical measurements. Logistic regression models with severe hypoglycemia as the dependent variable were used to test associations with antidiabetic agents.

RESULTS

Patients had a mean age (SD) of 82 (8) years, body mass index (BMI) of 25.4 (4.8), fasting plasma glucose (FPG) of 7.5 (3.0) mmol/L, postprandial glucose (PPG) of 10.3 (3.6) mmol/L, HbA1c of 7.1% (54 mmol/L), and impairments in activities of daily living (ADLs) of 3.7 (2.1). Severe hypoglycemia was more prevalent in patients with dementia (18%) compared with patients without dementia (8%). Patients with dementia were older, showed greater ADL impairments, greater number of comorbidities, lower FPG, and higher PPG compared with those without dementia. Adjusted logistic regression models in patients with dementia showed that rapid- and long-acting insulin analogs were associated with reduced odds ratio (OR) (OR 0.333; 95% confidence interval [CI] 0.184-0.602; OR 0.248, 95% CI 0.070-0.882, respectively), whereas sulphonylureas and combined metformin + sulphonylurea were associated with increased ORs (OR 8.805, 95% CI 4.260-18.201; OR 6.639; 95% CI 3.273-14.710, respectively) of experiencing severe hypoglycemia. No correlations were found in patients without dementia.

CONCLUSION

In older nursing home patients with type 2 diabetes, severe hypoglycemia was significantly higher in dementia. Our findings suggest that sulphonylureas should be used with caution, whereas rapid- and long-acting insulin analogs seem safer.

Recommendations to prescribe in complex older adults: results of the CRIteria to assess appropriate Medication use among Elderly complex patients (CRIME) project

The occurrence of several geriatric conditions may influence the efficacy and limit the use of drugs prescribed to treat chronic conditions. Functional and cognitive impairment, geriatric syndromes (i.e. falls or malnutrition) and limited life expectancy are common features of old age, which may limit the efficacy of pharmacological treatments and question the appropriateness of treatment. However, the assessment of these geriatric conditions is rarely incorporated into clinical trials and treatment guidelines. The CRIME (CRIteria to assess appropriate Medication use among Elderly complex patients) project is aimed at producing recommendations to guide pharmacologic prescription in older complex patients with a limited life expectancy, functional and cognitive impairment, and geriatric syndromes, and providing physicians with a tool to improve the quality of prescribing, independent of setting and nationality. To achieve these aims, we performed the following: (i) Existing disease-specific guidelines on pharmacological prescription for the treatment of diabetes, hypertension, congestive heart failure, atrial fibrillation and coronary heart disease were reviewed to assess whether they include specific indications for complex patients; (ii) a literature search was performed to identify relevant articles assessing the pharmacological treatment of complex patients; (iii) A total of 19 new recommendations were developed based on the results of the literature search and expert consensus. In conclusion, the new recommendations evaluate the appropriateness of pharmacological prescription in older complex patients, translating the recommendations of clinical guidelines to patients with a limited life expectancy, functional and cognitive impairment, and geriatric syndromes. These recommendations cannot represent substitutes for careful clinical consideration and deliberation by physicians; the recommendations are not meant to replace existing clinical guidelines, but they may be used to help physicians in the prescribing process.

Diabetes drugs and neurological disorders: new views and therapeutic possibilities

Type 2 diabetes is a metabolic disease characterised by insulin resistance with hyperglycaemia and dyslipidaemia. It is associated with increased risk of stroke and vascular dementia, and might contribute to the development of Alzheimer's disease. Recent studies have shown that several antidiabetic drugs can promote neuronal survival and lead to a significant clinical improvement of memory and cognition in different clinical settings. We discuss these emerging data, with a focus on metformin, thiazolidinediones, and the more recently developed compounds targeting the glucagon-like peptide-1 receptor. Data show that these antidiabetic drugs affect brain metabolism, neuroinflammation, and regeneration. Evidence thus far strongly indicates that these antidiabetic drugs could be developed as disease-modifying therapies for human brain diseases in patients with and without diabetes.

Brain aging and AD-like pathology in streptozotocin-induced diabetic rats

OBJECTIVE

Numerous epidemiological studies have linked diabetes mellitus (DM) with an increased risk of developing Alzheimer's disease (AD). However, whether or not diabetic encephalopathy shows AD-like pathology remains unclear.

RESEARCH DESIGN AND METHODS

Forebrain and hippocampal volumes were measured using stereology in serial coronal sections of the brain in streptozotocin- (STZ-) induced rats. Neurodegeneration in the frontal cortex, hypothalamus, and hippocampus was evaluated using Fluoro-Jade C (FJC). Aβ aggregation in the frontal cortex and hippocampus was tested using immunohistochemistry and ELISA. Dendritic spine density in the frontal cortex and hippocampus was measured using Golgi staining, and western blot was conducted to detect the levels of synaptophysin. Cognitive ability was evaluated through the Morris water maze and inhibitory avoidant box.

RESULTS

Rats are characterized by insulin deficiency accompanied with polydipsia, polyphagia, polyuria, and weight loss after STZ injection. The number of FJC-positive cells significantly increased in discrete brain regions of the diabetic rats compared with the age-matched control rats. Hippocampal atrophy, Aβ aggregation, and synapse loss were observed in the diabetic rats compared with the control rats. The learning and memory of the diabetic rats decreased compared with those of the age-matched control rats.

CONCLUSIONS

Our results suggested that aberrant metabolism induced brain aging as characterized by AD-like pathologies.

Linagliptin as add-on therapy to insulin for patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a highly prevalent, progressive disease that often is poorly controlled. The combination of an incretin-based therapy and insulin is a promising approach to optimize the management of glycemic control without hypoglycemia and weight gain. Linagliptin, a recently approved oral dipeptidyl peptidase-4 inhibitor, has a unique pharmacological profile. The convenient, once-daily dosing does not need adjustment in patients with hepatic and/or renal impairment. In clinical studies linagliptin shows an important reduction of blood glucose with an overall safety profile similar to that of placebo. So far, the combination of linagliptin and insulin has been tested in three major clinical studies in different populations. It has been shown that linagliptin is an effective and safe add-on therapy to insulin in patients with T2DM. The efficacy and safety of this combination was also shown in vulnerable, elderly T2DM patients and in patients with T2DM and renal impairment. Favorable effects regarding the counteraction of hypoglycemia make linagliptin especially interesting as an add-on therapy to insulin. This review aims to present the existing clinical studies on the efficacy and safety of linagliptin as add-on therapy to insulin in patients with T2DM in the context of current literature. Additionally, the possible advantages of linagliptin as an add-on therapy to insulin in relation to cardiovascular safety, patient-centered therapy and the prevention of hypoglycemia, are discussed.

Association between hypoglycemia and dementia in a biracial cohort of older adults with diabetes mellitus

IMPORTANCE

Hypoglycemia commonly occurs in patients with diabetes mellitus (DM) and may negatively influence cognitive performance. Cognitive impairment in turn can compromise DM management and lead to hypoglycemia.

OBJECTIVE

To prospectively evaluate the association between hypoglycemia and dementia in a biracial cohort of older adults with DM.

DESIGN AND SETTING

Prospective population-based study.

PARTICIPANTS

We studied 783 older adults with DM (mean age, 74.0 years; 47.0% of black race/ethnicity; and 47.6% female) who were participating in the prospective population-based Health, Aging, and Body Composition Study beginning in 1997 and who had baseline Modified Mini-Mental State Examination scores of 80 or higher.

MAIN OUTCOME MEASURES

Dementia diagnosis was determined during the follow-up period from hospital records indicating an admission associated with dementia or the use of prescribed dementia medications. Hypoglycemic events were determined during the follow-up period by hospital records.

RESULTS

During the 12-year follow-up period, 61 participants (7.8%) had a reported hypoglycemic event, and 148 (18.9%) developed dementia. Those who experienced a hypoglycemic event had a 2-fold increased risk for developing dementia compared with those who did not have a hypoglycemic event (34.4% vs 17.6%, P < .001; multivariate-adjusted hazard ratio, 2.1; 95% CI, 1.0-4.4). Similarly, older adults with DM who developed dementia had a greater risk for having a subsequent hypoglycemic event compared with participants who did not develop dementia (14.2% vs 6.3%, P < .001; multivariate-adjusted hazard ratio, 3.1; 95% CI, 1.5-6.6). Further adjustment for stroke, hypertension, myocardial infarction, and cognitive change scores produced similar results.

CONCLUSION AND RELEVANCE

Among older adults with DM, there seems to be a bidirectional association between hypoglycemia and dementia.

Association between hypoglycemia and dementia in a biracial cohort of older adults with diabetes mellitus

IMPORTANCE

Hypoglycemia commonly occurs in patients with diabetes mellitus (DM) and may negatively influence cognitive performance. Cognitive impairment in turn can compromise DM management and lead to hypoglycemia.

OBJECTIVE

To prospectively evaluate the association between hypoglycemia and dementia in a biracial cohort of older adults with DM.

DESIGN AND SETTING

Prospective population-based study.

PARTICIPANTS

We studied 783 older adults with DM (mean age, 74.0 years; 47.0% of black race/ethnicity; and 47.6% female) who were participating in the prospective population-based Health, Aging, and Body Composition Study beginning in 1997 and who had baseline Modified Mini-Mental State Examination scores of 80 or higher.

MAIN OUTCOME MEASURES

Dementia diagnosis was determined during the follow-up period from hospital records indicating an admission associated with dementia or the use of prescribed dementia medications. Hypoglycemic events were determined during the follow-up period by hospital records.

RESULTS

During the 12-year follow-up period, 61 participants (7.8%) had a reported hypoglycemic event, and 148 (18.9%) developed dementia. Those who experienced a hypoglycemic event had a 2-fold increased risk for developing dementia compared with those who did not have a hypoglycemic event (34.4% vs 17.6%, P < .001; multivariate-adjusted hazard ratio, 2.1; 95% CI, 1.0-4.4). Similarly, older adults with DM who developed dementia had a greater risk for having a subsequent hypoglycemic event compared with participants who did not develop dementia (14.2% vs 6.3%, P < .001; multivariate-adjusted hazard ratio, 3.1; 95% CI, 1.5-6.6). Further adjustment for stroke, hypertension, myocardial infarction, and cognitive change scores produced similar results.

CONCLUSION AND RELEVANCE

Among older adults with DM, there seems to be a bidirectional association between hypoglycemia and dementia.

Relationship between blood pressure, cognitive function and education level in elderly patients with diabetes: a preliminary study

AIMS

This study aimed to assess the relationship between blood pressure and cognitive function in elderly patients with diabetes mellitus (DM).

METHODS

A total of 32 patients with DM aged ≥ 65 years (seven women and 25 men; mean ± SD age: 74.3 ± 6.4 years) were included in this cross-sectional study. Relationships between blood pressure and neuropsychological tests were determined using Spearman's rank correlations (ρ) and multivariable linear regression models.

RESULTS

Lower diastolic blood pressure was associated with lower scores on the Frontal Assessment Battery (ρ=0.32, P=0.02), longer times to complete the Trail Making Test Part B (ρ=0.51, P=0.003), lower scores for the Finger Tapping Test (ρ=0.36, P=0.046) and less verbal fluency (ρ=0.36, P=0.047). In multivariable models, these relationships were attenuated after adjusting for levels of education.

CONCLUSION

There was an association between lower diastolic blood pressure and poorer executive function in this cohort of elderly DM patients. These results underline the importance of systematic cognitive evaluation in elderly patients with DM, and suggest that a too-low diastolic blood pressure may have deleterious effects on mental function. Larger studies in the future are required to confirm these preliminary results.

Avoiding hypoglycemia: a key to success for glucose-lowering therapy in type 2 diabetes

Type 2 diabetes carries a risk for hypoglycemia, particularly in patients on an intensive glucose control plan as a glucose-lowering strategy, where hypoglycemia may be a limitation for the therapy and also a factor underlying clinical inertia. Glucose-lowering medications that increase circulating insulin in a glucose-independent manner, such as insulin and sulfonylurea therapy, are the most common cause of hypoglycemia. However, other factors such as a delayed or missed meal, physical exercise, or drug or alcohol consumption may also contribute. Specific risk factors for development of hypoglycemia are old age, long duration of diabetes, some concomitant medication, renal dysfunction, hypoglycemia unawareness, and cognitive dysfunction. Hypoglycemia is associated with acute short-term symptoms related to either counterregulation, such as tachycardia and sweating, or to neuroglycopenia, such as irritability, confusion, and in severe cases stupor, coma, and even death. However, there are also long-term consequences of hypoglycemia such as reduced working capacity, weight gain, loss of self-confidence with reduced quality of life, and increased risk for cardiovascular diseases. For both the patients, the health care system, and the society at large, hypoglycemia carries a high cost. Strategies to mitigate the risk of hypoglycemia include awareness of the condition; education of patients, relatives, and health care providers; and selecting appropriate glucose-lowering medication that also judges the risk for hypoglycemia to prevent this complication. This article summarizes the current knowledge of hypoglycemia and its consequences with a special emphasis on its consequences for the choice of glucose-lowering therapy.

GERODIAB: Glycaemic control and 5-year morbidity/mortality of type 2 diabetic patients aged 70 years and older: 1. Description of the population at inclusion

AIMS

The GERODIAB study is the first French multicentre, prospective, observational study that aims, through a 5-year cohort follow-up, to evaluate the link between glycaemic control and morbidity/mortality of type 2 diabetic (T2D) patients aged 70 years and older. This first report describes the study population at inclusion.

PATIENTS AND METHODS

A total of 987 T2D autonomous patients, aged ≥70 years, were recruited between June 2009 and July 2010 at 56 investigator centres. Their general parameters, diabetes characteristics and standard geriatric parameters were recorded.

RESULTS

The patients' mean age was 77±5 years, with 65.2% aged 75 years or more. The mean BMI was close to 30 kg/m(2). Hypertension was found in 89.7% of patients, and 85.0% had at least one cholesterol abnormality. The mean duration of the diabetes was around 18 years, and the mean HbA(1c) level was about 7.5%. During the previous six months, 33.6% of patients had experienced one or several hypoglycaemias. Also, 26% of patients presented with diabetic retinopathy, 37.3% had a GFR<60 mL/min, 31.2% had coronary insufficiency, 10.1% had heart failure, 15.8% had cerebrovascular involvement and 25.6% had peripheral vascular disease of the lower extremities. In addition, 30.5% of patients had orthostatic hypotension, 12.4% had malnutrition and 28.8% had cognitive impairment, all of which were often diagnosed at inclusion. Three-quarters of patients were taking an oral antidiabetic drug and nearly six in every 10 patients were using insulin.

CONCLUSION

This population can be considered representative of elderly, autonomous T2D patients, and its follow-up should clarify the link between glycaemic control and mortality/morbidity.

The association of diabetes and dementia and possible implications for nondiabetic populations

Diabetes and prediabetic states have consistently been shown to be risk factors for cognitive decline, mild cognitive impairment and dementia. The importance of these findings is that diabetes and diabetes-related factors are modifiable, potentially permitting interventions aimed at postponing or preventing dementia. However, diabetes control cannot yet be implemented universally in diabetic subjects as a strategy for dementia prevention since the mechanisms by which diabetes impairs brain function and cognition are not fully understood. It is not clear which of the diabetes-related factors is crucial to this relationship. In addition, strict diabetic control has been demonstrated to carry risk for certain diabetic populations. The aim of the current article is to discuss current understanding of the relationships of diabetes and some of its characteristics with dementia, and suggest future questions to be answered.

Choosing targets for glycaemia, blood pressure and low-density lipoprotein cholesterol in elderly individuals with diabetes mellitus

Diabetes mellitus in the 'elderly' poses unique management challenges that contribute to conflicting priorities. Individualized management requires taking into account each patient's medical history, functional ability, home care situation, life expectancy and his/her health beliefs; individuals value trade-offs (e.g. quantity versus quality of life, and side effects as well as risks versus long-term benefits) differently. Moreover, this decision making relies on imperfect evidence. Target goals for three intermediate outcomes - glycaemic control (glycosylated haemoglobin [HbA(1c)]), blood pressure control and lipid control (low-density lipoprotein cholesterol [LDL-C]) - help keep management on track. Of these, glycaemic control is usually the most complex. Glycaemic control alleviates symptoms of hyperglycaemia and can improve micro- and macrovascular outcomes. Tight glycaemic control (HbA(1c) <7%) clearly improves microvascular outcomes. However, hypoglycaemia and polypharmacy are the main drawbacks of tight control. Factors that influence the benefits and drawbacks include age, longevity and co-morbidities, including the geriatric 'syndromes' of frailty and falls. We favour the explicit risk-stratified approach of the Department of Veterans Affairs/Department of Defense (VA/DoD) guidelines, which set HbA(1c) target ranges based on physiological age or the presence/severity of major co-morbidities and microvascular complications. There are clear benefits of blood pressure and cholesterol control (primarily reduction of macrovascular events, but also microvascular events), and their overall cost effectiveness exceeds that of glycaemic control. Issues with treatment for hypertension include potential side effects of drugs, a potential increased risk of falls and risks of polypharmacy. Nevertheless, the evidence for a blood pressure target of <140/80 mmHg is reasonably strong if it can be achieved safely. In general, we recommend use of an HMG-CoA reductase inhibitor (statin) and an LDL-C target of <100 mg/dL, especially if an individual cannot tolerate a moderate dose of a statin.

Impaired hippocampal glucoregulation in the cannabinoid CB1 receptor knockout mice as revealed by an optimized in vitro experimental approach

Several techniques exist to study the rate of glucose uptake and metabolism in the brain but most of them are not sufficiently robust to permit extensive pharmacological analysis. Here we optimized an in vitro measurement of the simultaneous accumulation of the metabolizable and non-metabolizable (3)H and (14)C d-glucose analogues; permitting convenient large-scale studies on glucose uptake and metabolism in brain slices. Next, we performed an extensive pharmacological characterization on the putative glucoregulator role of the endocannabinoid system in the hippocampal slices of the rat, and the wild-type and the CB(1) cannabinoid receptor (CB(1)R) knockout mice. We observed that (3)H-3-O-methylglucose is a poor substrate to measure glucose uptake in the hippocampus. (3)H-2-deoxyglucose is a better substrate but its uptake is still lower than that of (14)C-U-d-glucose, from which the slices constantly metabolize and dissipate (14)C atoms. Thus, uptake and the metabolism values are not to be used as standalones but as differences between a control and a treatment. The CB(1)R knockout mice exhibited ∼10% less glucose uptake and glucose carbon atom dissipation in comparison with the wild-type mice. This may represent congenital defects as acute treatments of the rat and mouse slices with cannabinoid agonists, antagonists and inhibitors of endocannabinoid uptake/metabolism failed to induce robust changes in either the uptake or the metabolism of glucose. In summary, we report here an optimized technique ideal to complement other metabolic approaches of high spatiotemporal resolution. This technique allowed us concluding that CB(1)Rs are at least indirectly involved in hippocampal glucoregulation.