Risk of Dementia in Older Patients with Type 2 Diabetes on Dipeptidyl-Peptidase IV Inhibitors Versus Sulfonylureas: A Real-World Population-Based Cohort Study

Association of sodium-glucose cotransporter 2 inhibitors with risk of incident dementia and all-cause mortality in older patients with type 2 diabetes: A retrospective cohort study using the TriNetX US collaborative networks

BACKGROUND

Limited evidence exists to support any specific medication over others to prevent dementia in older patients with type 2 diabetes (T2D). We investigated whether treatment with sodium-glucose cotransporter 2 (SGLT-2) inhibitors is associated with a lower risk of incident dementia and all-cause mortality, relative to dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RA).

METHODS

In this retrospective, active-comparator cohort study, we used data from the TriNetX electronic health records network. Our primary cohort comprised patients with T2D aged ≥50 years, registered between January 2012 and December 2022. Patients with a history of dementia were excluded. We used Kaplan-Meier survival analysis to estimate the incidence of dementia and all-cause mortality in our cohort after they had used glucose-lowering drugs for at least 12 months. Propensity score matching was performed to balance the SGLT-2 inhibitor, DPP-4 inhibitor and GLP-1 RA cohorts. Subgroup analyses for sex and age were also conducted.

RESULTS

Our first cohort comprised 193 948 patients treated with metformin and SGLT-2 inhibitors and an equal number of patients treated with metformin and DPP-4 inhibitors. In this cohort, the risk of dementia and all-cause mortality was lower in patients treated with SGLT-2 inhibitors than in those treated with DPP-4 inhibitors (hazard ratio [HR]: 0.62, 95% confidence interval [CI]: 0.59-0.65, for dementia; HR: 0.54, 95% CI: 0.52-0.56, for all-cause mortality). Our second cohort comprised 165 566 patients treated with metformin and SGLT-2 inhibitors and an equal number of patients treated with metformin and GLP-1 RAs. In this cohort, the risk of dementia and all-cause mortality was lower in those treated with SGLT-2 inhibitors than in those treated with GLP-1 RAs (HR: 0.92, 95% CI: 0.87-0.98, for dementia; HR: 0.88, 95% CI: 0.85-0.91, for all-cause mortality).

CONCLUSIONS

The use of SGLT-2 inhibitor was associated with a lower risk of incident dementia and all-cause mortality in older adults with T2D compared to DPP-4 inhibitor and GLP-1 RA.

Risk of Dementia and Alzheimer's Disease Associated With Antidiabetics: A Bayesian Network Meta-Analysis

INTRODUCTION

Dementia risk is substantially elevated in patients with diabetes. However, evidence on dementia risk associated with various antidiabetic regimens is still limited. This study aims to comprehensively investigate the risk of dementia and Alzheimer's disease (AD) associated with various antidiabetic classes.

METHODS

Cochrane Central Register of Controlled Trials, Embase, MEDLINE (PubMed), and Scopus were searched from inception to March 2024 (PROSPERO CRD 42022365927). Observational studies investigating dementia and AD incidences after antidiabetic initiation were identified. Bayesian network meta-analysis was performed to determine dementia and AD risks associated with antidiabetics. Preferred Reporting Items for Systematic Reviews-Network Meta-Analyses (PRISMA-NMA) guidelines were followed. Statistical analysis was performed and updated in November 2023 and March 2024, respectively.

RESULTS

A total of 1,565,245 patients from 16 studies were included. Dementia and AD risks were significantly lower with metformin and sodium glucose co-transporter-2 inhibitors (SGLT2i). Metformin displayed the lowest risk of dementia across diverse antidiabetics, whereas α-glucosidase inhibitors demonstrated the highest risk. SGLT2i exhibited the lowest dementia risk across second-line antidiabetics. Dementia risk was significantly higher with dipeptidyl peptidase-4 inhibitor (DPP4i), metformin, sulfonylureas, and thiazolidinediones (TZD) compared to SGLT2i in the elderly (≥75 years). Dementia risk associated with metformin was substantially lower, regardless of diabetic complication status or baseline A1C.

DISCUSSION

Metformin and SGLT2i demonstrated lower dementia risk than other antidiabetic classes. Patient-specific factors may affect this relationship and cautious interpretation is warranted as metformin is typically initiated at an earlier stage with fewer complications. Hence, further large-scaled clinical trials are required.

Expert eValuation of Efficacy and Rationality of Vildagliptin "EVER-Vilda": An Indian Perspective

Vildagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor is effective in reducing HbA1c levels in patients with type 2 diabetes (T2DM) when administered as monotherapy, dual or triple combination therapy. In India, Vildagliptin is commonly prescribed in T2DM patients because it reduces mean amplitude of glycemic excursion (MAGE), has lower risk of hypoglycemia and is weight neutral. Early combination therapy with vildagliptin and metformin is effective and well-tolerated in patients with T2DM, regardless of age or ethnicity. In view of already existing data on vildagliptin and the latest emerging clinical evidence, a group of endocrinologists, diabetologists and cardiologists convened for an expert group meeting to discuss the role and various combinations of vildagliptin in T2DM management. This practical document aims to guide Physicians and Specialists regarding the different available strengths and formulations of vildagliptin for the initiation and intensification of T2DM therapy.

Neuroprotective effects of dipeptidyl peptidase 4 inhibitor on Alzheimer's disease: a narrative review

Insulin resistance in brain and amyloidogenesis are principal pathological features of diabetes-related cognitive decline and development of Alzheimer's disease (AD). A growing body of evidence suggests that maintaining glucose under control in diabetic patients is beneficial for preventing AD development. Dipeptidyl peptidase 4 inhibitors (DDP4is) are a class of novel glucose-lowering medications through increasing insulin excretion and decreasing glucagon levels that have shown neuroprotective potential in recent studies. This review consolidates extant evidence from earlier and new studies investigating the association between DPP4i use, AD, and other cognitive outcomes. Beyond DPP4i's benefits in alleviating insulin resistance and glucose-lowering, underlying mechanisms for the potential neuroprotection with DPP4i medications were categorized into the following sections: (Ferrari et al., Physiol Rev, 2021, 101, 1,047-1,081): the benefits of DPP4is on directly ameliorating the burden of β-amyloid plaques and reducing the formation of neurofibrillary tangles; DPP4i increasing the bioactivity of neuroprotective DPP4 substrates including glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and stromal-derived factor-1α (SDF-1α) etc.; pleiotropic effects of DPP4is on neuronal cells and intracerebral structure including anti-inflammation, anti-oxidation, and anti-apoptosis. We further revisited recently published epidemiological studies that provided supportive data to compliment preclinical evidence. Given that there remains a lack of completed randomized trials that aim at assessing the effect of DPP4is in preventing AD development and progression, this review is expected to provide a useful insight into DPP4 inhibition as a potential therapeutic target for AD prevention and treatment. The evidence is helpful for informing the rationales of future clinical research and guiding evidence-based clinical practice.

Current perspectives on prevention of vascular cognitive impairment and promotion of vascular brain health

INTRODUCTION

The true global burden of vascular cognitive impairment (VCI) is unknown. Reducing risk factors for stroke and cardiovascular disease would inevitably curtail VCI.

AREAS COVERED

The authors review current diagnosis, epidemiology, and risk factors for VCI. VCI increases in older age and by inheritance of known genetic traits. They emphasize modifiable risk factors identified by the 2020 Lancet Dementia Commission. The most profound risks for VCI also include lower education, cardiometabolic factors, and compromised cognitive reserve. Finally, they discuss pharmacological and non-pharmacological interventions.

EXPERT OPINION

By virtue of the high frequencies of stroke and cardiovascular disease the global prevalence of VCI is expectedly higher than prevalent neurodegenerative disorders causing dementia. Since ~ 90% of the global burden of stroke can be attributed to modifiable risk factors, a formidable opportunity arises to reduce the burden of not only stroke but VCI outcomes including progression from mild to the major in form of vascular dementia. Strict control of vascular risk factors and secondary prevention of cerebrovascular disease via pharmacological interventions will impact on burden of VCI. Non-pharmacological measures by adopting healthy diets and encouraging physical and cognitive activities and urging multidomain approaches are important for prevention of VCI and preservation of vascular brain health.

No association between metformin initiation and incident dementia in older adults newly diagnosed with diabetes

BACKGROUND

Metformin has been suggested to reduce dementia risk; however, most epidemiologic studies have been limited by immortal time bias or confounding due to disease severity.

OBJECTIVES

To investigate the association of metformin initiation with incident dementia using strategies that mitigate these important sources of bias.

METHODS

Residents of Ontario, Canada ≥66 years newly diagnosed with diabetes from January 1, 2008 to December 31, 2017 entered this retrospective population-based cohort. To consider the indication for metformin monotherapy initiation, people with hemoglobin A1c of 6.5%-8.0% and estimated glomerular filtration rate ≥45 mL/min/1.73 m2 were selected. Using the landmark method to address immortal time bias, exposure was grouped into "metformin monotherapy initiation within 180 days after new diabetes diagnosis" or "no glucose-lowering medications within 180 days." To address disease latency, 1-year lag time was applied to the end of the 180-day landmark period. Incident dementia was defined using a validated algorithm for Alzheimer's disease and related dementias. Adjusted hazard ratios (aHR) and confidence intervals (CIs) were estimated from propensity-score weighted Cox proportional hazard models.

RESULTS

Over mean follow-up of 6.77 years from cohort entry, metformin initiation within 180 days after new diabetes diagnosis (N = 12,331; 978 events; 65,762 person-years) showed no association with dementia risk (aHR [95% CI] = 1.05 [0.96-1.15]), compared to delayed or no glucose-lowering medication initiation (N = 22,369; 1768 events; 117,415 person-years).

CONCLUSION

Early metformin initiation was not associated with incident dementia in older adults newly diagnosed with diabetes. The utility of metformin to prevent dementia was not supported.

Anti-diabetics and the Prevention of Dementia: A Systematic Review

Type 2 diabetes mellitus (T2DM) is a worldwide epidemic that is only increasing as the years progress, and as of 2019, affecting over 37 million. T2DM is a chronic condition caused by reduced insulin secretion and increased insulin resistance. Due to insulin not operating at optimal conditions, blood glucose rises and remains high, thus disturbing metabolic hemostasis. Many complications can arise from T2DM, such as coronary vascular disease, kidney damage, eye damage, and, quite significantly, dementia. It is theorized that dementia from T2DM stems from the fact that the brain is susceptible to hyperglycemic conditions, which are promoted by the increase in insulin resistance of target cells in the central nervous system. This directly affects cognitive processes and memory, which correlates to decreased temporal and front lobes volume. The risk of diabetic complications can be minimized with therapeutic interventions such as oral-antidiabetic (OAD) agents and insulin. Several OADs are on the market, but the first-line agent is metformin, a biguanide that decreases glucose production and increases insulin sensitivity. This paper aims to determine if currently prescribed OADs can help slow cognitive decline and reduce the risk and incidence of dementia as a complication of T2DM. Studies found that, for the most part, all OADs except sulfonylureas (SU) significantly slowed the decline of cognitive function and reduced the risk and incidence of dementia. SU's were shown to increase the risk of dementia in most studies. Of all the OADs, thiazolidinediones may be the most beneficial drug class for reducing the risk of dementia in T2DM patients. Future research should focus on whether early intervention with specific classes of OADs can not only improve glycemic control, leading to decreased hyperglycemia but also prevent the build-up of damaged brain tissue and help to reduce the risk and incidence of dementia in patients with T2DM.

Association of sulfonylureas with the risk of dementia: A population-based cohort study

BACKGROUND

Sulfonylureas are oral glucose-lowering medications positioned as a second-line therapy for type 2 diabetes. Evidence relating them to cognitive decline has been mixed. The objective was to determine whether sulfonylurea use was associated with a differential risk of dementia compared with dipeptidyl peptidase-4 (DPP4) inhibitor use.

METHODS

Using administrative data from residents in Ontario, Canada, adults aged ≥66 years who were new users of a sulfonylurea or a DPP4 inhibitor from June 14, 2011, to March 31, 2021 entered this population-based retrospective cohort study. Dementia was ascertained using a validated algorithm for Alzheimer's disease and related dementias. Propensity-score weighted Cox proportional hazards models were used to obtain adjusted hazard ratios (aHR) and confidence intervals (CI) for time to incident dementia. The observation window started at 1 year after cohort entry to mitigate protopathic bias due to delayed diagnosis. The primary analysis used an intention-to-treat exposure definition. A separate propensity-score weighted analysis was conducted to explore within-class differences in dementia risk among sulfonylurea new users selected from the primary cohort.

RESULTS

Among 107,806 DPP4 inhibitor new users and 37,030 sulfonylurea new users, sulfonylureas compared with DPP4 inhibitors were associated with a higher risk of dementia (18.4/1000 person-years; aHR [95% CI] = 1.09 [1.04-1.15]) over a mean follow-up of 4.82 years from cohort entry. Glyburide compared to gliclazide exhibited a higher dementia risk (aHR [95% CI] = 1.17 [1.03-1.32]).

CONCLUSION

New use of a sulfonylurea especially glyburide was associated with a higher dementia risk compared with new use of a DPP4 inhibitor in older adults with diabetes.

Research landscape and emerging trends of diabetes-associated cognitive dysfunction: a bibliometric analysis

Background

Diabetes-associated cognitive dysfunction (DACD) is a common and serious complication in diabetes and has a high impact on the lives of both individuals and society. Although a number of research has focused on DACD in the past two decades, there is no a study to systematically display the knowledge structure and development of the field. Thus, the present study aimed to show the landscape and identify the emerging trends of DACD research for assisting researchers or clinicians in grasping the knowledge domain faster and easier and focusing on the emerging trends in the field.

Methods

We searched the Web of Science database for all DACD-related studies between 2000 and 2022. Bibliometric analysis was conducted using the VOSviewer, CiteSpace, Histcite, and R bibliometric package, revealing the most prominent research, countries, institutions, authors, journals, co-cited references, and keywords.

Results

A total of 4,378 records were selected for analysis. We found that the volume of literature on DACD has increased over the years. In terms of the number of publications, the USA ranked first. The most productive institutions were the University of Washington and the University of Pittsburgh. Furthermore, Biessels GJ was the most productive author. Journal of Alzheimers Disease, Diabetes Care, and Frontiers in Aging Neuroscience had the most publications in this field. The keywords"dementia," "alzheimers-disease," "cognitive impairment" and "diabetes" are the main keywords. The burst keywords in recent years mainly included "signaling pathway" and "cognitive deficit."

Conclusion

This study systematically illustrated advances in DACD over the last 23 years. Current findings suggest that exploring potential mechanisms of DACD and the effect of anti-diabetes drugs on DACD are the hotspots in this field. Future research will also focus on the development of targeted drugs that act on the DACD signaling pathway.

Newer glucose-lowering drugs and risk of dementia: A systematic review and meta-analysis of observational studies

BACKGROUND

Preclinical studies have suggested potential beneficial effects of newer glucose-lowering drugs (GLDs) including dipeptidyl peptidase (DPP)-4 inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), and sodium glucose co-transporter-2 (SGLT2) inhibitors, in protecting humans against cognitive decline and dementia. However, population studies aiming to demonstrate such cognitive benefits from newer GLDs have produced mixed findings. This meta-analysis aimed to evaluate the association between newer GLDs and risk of dementia in adults with type 2 diabetes (T2D).

METHODS

Electronic databases were searched up to March 11, 2022 to include observational studies that examined the association between DPP-4 inhibitors, GLP-1RAs, and SGLT2 inhibitors and risk of dementia (including all-cause dementia, Alzheimer's disease [AD], and vascular dementia [VD]) in people with T2D. We conducted a random-effects meta-analysis to calculate the relative risk (RR) with 95% confidence interval (CI) for each class of newer GLD.

RESULTS

Ten studies (from nine articles) involving 819,511 individuals with T2D were included. Three studies found that SGLT2 inhibitor users had a lower risk of all-cause dementia than non-SGLT2 inhibitor users (RR, 0.62; 95% CI, 0.39-0.97). Five studies found that users versus nonusers of GLP-1RAs were associated with a significant reduction in the risk of all-cause dementia (RR, 0.72; 95% CI, 0.54-0.97). However, a meta-analysis for AD and VD was unavailable for SGLT2 inhibitors and GLP-1RAs because only one study was included for each drug. In seven studies, users vs. nonusers of DPP-4 inhibitors were significantly associated with a decreased risk of all-cause dementia (RR, 0.84; 95% CI, 0.74-0.94) and VD (RR, 0.59; 95% CI, 0.47-0.75) but not AD (RR, 0.82; 95% CI, 0.63-1.08).

CONCLUSION

Newer GLDs were associated with a decreased risk of all-cause dementia in people with T2D. Because of the observational nature and significant heterogeneity between studies, the results should be interpreted with caution. Further research is warranted to confirm our findings.

Association of Sodium-Glucose Cotransporter 2 Inhibitors With Time to Dementia: A Population-Based Cohort Study

OBJECTIVE

Type 2 diabetes (T2D) increases dementia risk, but clear evidence to recommend interventions that can mitigate that risk remains lacking. This population-based retrospective cohort study aimed to determine whether new use of sodium-glucose cotransporter 2 (SGLT2) inhibitors compared with dipeptidyl peptidase 4 (DPP-4) inhibitors was associated with lower dementia risk.

RESEARCH DESIGN AND METHODS

Ontario residents aged ≥66 years who were new users of an SGLT2 inhibitor or a DPP-4 inhibitor from 1 July 2016 to 31 March 2021 entered the cohort. Incident dementia was identified using a validated algorithm for Alzheimer's disease and related dementias. Propensity score-weighted Cox proportional hazards models were used to obtain adjusted hazard ratios (aHR) and CIs for time to incident dementia. To address reverse causality and disease latency, the observation window started at 1-year lag time from cohort entry. The primary analysis followed intention-to-treat exposure definition, and a secondary as-treated analysis was performed.

RESULTS

Among 106,903 individuals, SGLT2 inhibitors compared with DPP-4 inhibitors were associated with lower risk of dementia (14.2/1,000 person-years; aHR 0.80 [95% CI 0.71-0.89]) over a mean follow-up of 2.80 years from cohort entry. When stratified by different SGLT2 inhibitors, dapagliflozin exhibited the lowest risk (aHR 0.67 [95% CI 0.53-0.84]), followed by empagliflozin (aHR 0.78 [95% CI 0.69-0.89]), whereas canagliflozin showed no association (aHR 0.96 [95% CI 0.80-1.16]). The as-treated analysis observed a larger association (aHR 0.66 [95% CI 0.57-0.76]) than the intention-to-treat analysis.

CONCLUSIONS

SGLT2 inhibitors showed an association with lower dementia risk in older people with T2D. Randomized controlled trials are warranted.

Effects of hypoglycaemic therapy on frailty: a multi-dimensional perspective

INTRODUCTION

The prevalence of diabetes is increasing in older people. With increasing age, frailty emerges as a new complication leading to disability. Frailty does not only include physical dysfunction but also involves negative impact on cognition and mood. Triad of impairments (TOI) is a new concept that includes physical frailty, dementia and depression to reflect the wider spectrum of frailty.

AREAS COVERED

Little is known about effects of hypoglycaemic agents on frailty syndrome. A literature search was performed on studies, which reported effects of hypoglycaemic agents on the component of the TOI.

EXPERT OPINION

It appears that most hypoglycaemic agents have some effects on frailty, although the results of clinical studies are inconsistent. Metformin seems to have a consistent and a positive effect on physical frailty. Its effects on cognitive function, however, are inconclusive but tend to be positive. Metformin appeared to improve depressive symptoms. Other agents such as incretins, thiazolidinediones, and sodium glucose transporter-2 inhibitors have some positive effects on cognition and depression. Sulfonylureas, glinides, or insulin have either negative or neutral effects on TOI components. The negative effects of insulin could be partially explained by the negative psychological factors and the frequent episodes of hypoglycemia associated with such therapy.

Potential Roles of Glucagon-Like Peptide-1 and Its Analogues in Dementia Targeting Impaired Insulin Secretion and Neurodegeneration

Dementia is a chronic, irreversible condition marked by memory loss, cognitive decline, and mental instability. It is clinically related to various progressive neurological diseases, including Parkinson’s disease, Alzheimer’s disease, and Huntington’s. The primary cause of neurological disorders is insulin desensitization, demyelination, oxidative stress, and neuroinflammation accompanied by various aberrant proteins such as amyloid-β deposits, Lewy bodies accumulation, tau formation leading to neurofibrillary tangles. Impaired insulin signaling is directly associated with amyloid-β and α-synuclein deposition, as well as specific signaling cascades involved in neurodegenerative diseases. Insulin dysfunction may initiate various intracellular signaling cascades, including phosphoinositide 3-kinase (PI3K), c-Jun N-terminal kinases (JNK), and mitogen-activated protein kinase (MAPK). Neuronal death, inflammation, neuronal excitation, mitochondrial malfunction, and protein deposition are all influenced by insulin. Recent research has focused on GLP-1 receptor agonists as a potential therapeutic target. They increase glucose-dependent insulin secretion and are beneficial in neurodegenerative diseases by reducing oxidative stress and cytokine production. They reduce the deposition of abnormal proteins by crossing the blood-brain barrier. The purpose of this article is to discuss the role of insulin dysfunction in the pathogenesis of neurological diseases, specifically dementia. Additionally, we reviewed the therapeutic target (GLP-1) and its receptor activators as a possible treatment of dementia.

A review of the components of exercise prescription for sarcopenic older adults

PURPOSE

To synthesize the details of the exercises/exercise program prescribed for the improvement of muscle mass/muscle strength/physical performance among sarcopenic older adults.

METHODS

A systematic literature search was conducted in five electronic databases and the details of exercises such as single component or multicomponent exercise program, frequency/week, intensity, duration of the exercise program, type of exercises, progression, adverse events reported, outcome measures used, and whether technology or other educational aids were used to deliver the program were extracted.

RESULTS

A total of 10,045 records were identified and 27 records were included. Resistance exercises were included in all the studies, with the frequency ranging from 1 to 5/week, intensity ranging from 20 to 80% of 1 repetition maximum (RM), or 6-14 points on ratings of perceived exertion (RPE), and duration per session ranging from 20 to 75 min. The intensity of aerobic exercises ranged from 50 to 70% of heart rate max or a level of 7-17 in RPE with a duration ranging from 6 to 30 min per session for 2-5 days/week. For balance exercises, the intensity was mentioned as the level of effort 3 on a scale of 10, and the time duration per session ranged from 5 to 30 min for a frequency of 2/3 per week.

CONCLUSION

This review synthesized the components of exercise prescription for sarcopenic older adults which would help practitioners and researchers in selecting the frequency, intensity, duration, type, mode, and progression while prescribing exercises.

In vivo therapeutic exploring for Mori folium extract against type 2 diabetes mellitus in rats

BACKGROUND

The study was aimed to investigate the potential therapeutic effect of Mori folium aqueous extracts (MFAE) on type 2 diabetes mellitus (T2DM) in vivo.

METHODS AND RESULTS

A rat model of T2DM was established with the combination of high sugar and high-fat diet (HSFD) and streptozotocin (STZ). The T2DM rats were administrated with low (2 g.kg-1) and high (5 g.kg-1) doses of MFAE for 60 consecutive days. The biochemical indices of glucose metabolism disorders, insulin resistance and oxidative stress were observed. The results indicated that MFAE significantly promoted the synthesis of hepatic glycogen, reduced the levels of fasting blood glucose and fasting blood insulin, and improved the insulin sensitivity index (ISI). MFAE administration also remarkably increased the levels of superoxide dismutase (SOD) and reduced the levels of malondialdehyde (MDA).

CONCLUSION

MFAE showed a therapeutic effect on T2DM with the bioative effect of improve glucose metabolism disorders, decrease insulin resistance, and ameliorate the antioxidative ability.

Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors vs. Dipeptidyl Peptidase-4 (DPP4) Inhibitors for New-Onset Dementia: A Propensity Score-Matched Population-Based Study With Competing Risk Analysis

Introduction: The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2I) and dipeptidyl peptidase-4 inhibitors (DPP4I) on new-onset cognitive dysfunction in type 2 diabetes mellitus remain unknown. This study aimed to evaluate the effects of the two novel antidiabetic agents on cognitive dysfunction by comparing the rates of dementia between SGLT2I and DPP4I users.

Methods: This was a population-based cohort study of type 2 diabetes mellitus patients treated with SGLT2I and DPP4I between January 1, 2015 and December 31, 2019 in Hong Kong. Exclusion criteria were <1-month exposure or exposure to both medication classes, or prior diagnosis of dementia or major neurological/psychiatric diseases. Primary outcomes were new-onset dementia, Alzheimer's, and Parkinson's. Secondary outcomes were all-cause, cardiovascular, and cerebrovascular mortality.

Results: A total of 13,276 SGLT2I and 36,544 DPP4I users (total n = 51,460; median age: 66.3 years old [interquartile range (IQR): 58–76], 55.65% men) were studied (follow-up: 472 [120–792] days). After 1:2 matching (SGLT2I: n = 13,283; DPP4I: n = 26,545), SGLT2I users had lower incidences of dementia (0.19 vs. 0.78%, p < 0.0001), Alzheimer's (0.01 vs. 0.1%, p = 0.0047), Parkinson's disease (0.02 vs. 0.14%, p = 0.0006), all-cause (5.48 vs. 12.69%, p < 0.0001), cerebrovascular (0.88 vs. 3.88%, p < 0.0001), and cardiovascular mortality (0.49 vs. 3.75%, p < 0.0001). Cox regression showed that SGLT2I use was associated with lower risks of dementia (hazard ratio [HR]: 0.41, 95% confidence interval [CI]: [0.27–0.61], P < 0.0001), Parkinson's (HR:0.28, 95% CI: [0.09–0.91], P = 0.0349), all-cause (HR:0.84, 95% CI: [0.77–0.91], P < 0.0001), cardiovascular (HR:0.64, 95% CI: [0.49–0.85], P = 0.0017), and cerebrovascular (HR:0.36, 95% CI: [0.3–0.43], P < 0.0001) mortality.

Conclusions: The use of SGLT2I is associated with lower risks of dementia, Parkinson's disease, and cerebrovascular mortality compared with DPP4I use after 1:2 ratio propensity score matching.

Role of DPP-4 and SGLT2 Inhibitors Connected to Alzheimer Disease in Type 2 Diabetes Mellitus

Alzheimer's disease (AD) is characterized by memory loss and cognitive decline. Additionally, abnormal extracellular amyloid plaques accumulation and nerve damage caused by intracellular neurofibrillary tangles, and tau protein are characteristic of AD. Furthermore, AD is associated with oxidative stress, impaired mitochondrial structure and function, denormalization, and inflammatory responses. Recently, besides the amyloid β hypothesis, another hypothesis linking AD to systemic diseases has been put forth by multiple studies as a probable cause for AD. Particularly, type 2 diabetes mellitus (T2DM) and its features, including hyperinsulinemia, and chronic hyperglycemia with an inflammatory response, have been shown to be closely related to AD through insulin resistance. The brain cannot synthesize or store glucose, but it does require glucose, and the use of glucose in the brain is higher than that in any other organ in the mammalian body. One of the therapeutic drugs for T2DM, dipeptidyl peptidase-4 (DPP-4) inhibitor, suppresses the degradation of incretins, glucagon-like peptides and glucose-dependent insulinotropic peptide. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, recently used in T2DM treatment, have a unique mechanism of action via inhibition of renal glucose reabsorption, and which is different from the mechanisms of previously used medications. This manuscript reviews the pathophysiological relationship between the two diseases, AD and T2DM, and the pharmacological effects of therapeutic T2DM drugs, especially DPP-4 inhibitors, and SGLT2 inhibitors.

The Association Between Second-Line Oral Antihyperglycemic Medication on Types of Dementia in Type 2 Diabetes: A Nationwide Real-World Longitudinal Study

BACKGROUND

There are few reports that evaluated the association between various types of dementia and dual oral therapy with antihyperglycemic medication.

OBJECTIVE

The goal of this study was to investigate the association between treatment of dual antihyperglycemic medication and dementia subclass in type 2 diabetes mellitus using the Korean National Health Insurance System.

METHODS

This study included 701,193 individuals with diabetes prescribed dual oral therapy between 2009 and 2012 from the Korean National Health Insurance Service Database, which were tracked until 2017. All-cause, Alzheimer's (AD) and vascular dementia (VaD) were investigated by dual oral therapy. Adjustments were made for age, sex, income, diabetes duration, hypertension, dyslipidemia, smoking, drinking, exercise, body mass index, glucose level, and estimated glomerular filtration rate.

RESULTS

Dual therapy with metformin (Met) + dipeptidyl peptidase-4 inhibitor (DPP-4i), Met + thiazolidinedione (TZD), and sulfonylurea (SU) + thiazolidinediones (TZD) were significantly associated with all-cause dementia (HR = 0.904, 0.804, and 0.962, respectively) and VaD (HR = 0.865, 0.725, and 0.911, respectively), compared with Met + SU. Met + DPP-4i and Met + TZD were associated with significantly lower risk of AD (HR = 0.922 and 0.812), compared with Met + SU. Dual therapy with TZD was associated with a significantly lower risk of all-cause dementia, AD, and VaD than nonusers of TZD (HR = 0.918, 0.925 and 0.859, respectively).

CONCLUSION

Adding TZD or DPP-4i instead of SU as second-line anti-diabetic treatment may be considered for delaying or preventing dementia. Also, TZD users relative to TZD non-users on dual oral therapy were significantly associated with lower risk of various types of dementia.

The effects of dipeptidyl peptidase-4 inhibitors and glucagon-like peptide 1 receptor agonists on cognitive functions in adults with type 2 diabetes mellitus: a systematic review and meta-analysis

AIMS

The effects of dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors/DPP-4I) and glucagon-like peptide 1 receptor agonists (GLP-1 RA) on cognition in patients with type 2 diabetes mellitus (T2DM) remain controversial. We aimed to explore this clinical issue through a systematic review and meta-analysis.

METHODS

PubMed, EMBASE and the Cochrane Library were searched, and data were expressed as mean difference (MD) or hazard ratio (HR)/odds ratio (OR) with a 95% confidence interval (CI). Heterogeneity was assessed using the Chi-squared test and the I² statistic. The study was registered with PROSPERO (ID: CRD42019138777).

RESULTS

Eleven studies (n = 304,258 T2DM patients) were included in our review. In the DPP-4I group, six studies were enrolled to estimate ΔMini-Mental State Examination (MMSE) scores from baseline to the final evaluations after DPP-4I treatment, which showed no statistical difference (MD 0.20; 95% CI - 0.75 to 1.15, p = 0.68). ΔMMSE scores in the DPP-4I group and the other antidiabetic groups were compared, revealing no statistical difference (MD 0.57; 95% CI - 0.05 to 1.19, p = 0.07). Two cohort studies were pooled to determine the HRs for dementia, showing a lower risk of dementia after DPP-4I treatment (HR 0.52; 95% CI 0.29-0.93, p = 0.03). In the GLP-1 analogs group, two studies were included, one of which revealed a downward trend in the risk of dementia after GLP-1 analog treatment, while the other revealed no significant difference after incretins treatment.

CONCLUSIONS

Currently there is not enough irrefutable evidence to support the hypothesis of positive effects of incretins on cognition. Further clinical studies need to be performed.

Association between the Use of Dipeptidyl Peptidase 4 Inhibitors and the Risk of Dementia among Patients with Type 2 Diabetes in Taiwan

STUDY OBJECTIVES

Diabetes mellitus per se and its related therapy have been frequently associated with an increased risk of developing dementia. However, studies that explored the risk of dementia from the use of the novel oral antidiabetic medication dipeptidyl peptidase 4 inhibitor (DPP-4i) have been limited, especially in Asian populations. The present study aimed to determine the effect of DPP-4i on the subsequent risk of dementia among patients with type 2 diabetes (T2D) in Taiwan.

METHODS

This study utilized data from the Longitudinal Health Insurance Database between 2008 and 2015. We enrolled 2903 patients aged ≥50 years, who were on DPP-4i for a diagnosis of T2D and had no dementia. A total of 11,612 subjects were included and compared with a propensity score-matched control group who did not use DPP-4i (non-DPP-4i group). Survival analysis was performed to estimate and compare the risk of dementia-including Alzheimer's disease, vascular dementia, and other dementia types-between the two groups. Results: Both groups had a mean age of 68 years, had a preponderance of women (61.8%), and were followed up for a mean duration of 7 years. The risk of all-cause dementia was significantly lower in the DPP-4i group than in the non-DPP-4i group (hazard ratio (HR) 0.798; 95% confidence interval (CI) 0.681-0.883; p < 0.001), with a class effect. This trend was particularly observed for vascular dementia (HR 0.575; 95% CI 0.404-0.681; p < 0.001), but not in Alzheimer's disease (HR 0.891; 95% CI 0.712-1.265; p = 0.297). The Kaplan-Meier analysis showed that the preventive effect on dementia was positively correlated with the cumulative dose of DPP-4i. Conclusions: DPP-4i decreased the risk of dementia with a class effect, especially vascular dementia, but not in Alzheimer's disease. Our results provide important information on the drug choice when managing patients with T2D in clinical practice.

Diabetes Therapies for Dementia

PURPOSE OF REVIEW

Type 2 diabetes (T2D) is a well-established risk factor for the development of dementia. Dementia and T2D share some underlying pathophysiology that has led to interest in the potential to repurpose drugs used in the management of T2D to benefit brain health. This review describes the scientific data available on the use of T2D medications for the risk reduction or management of dementia, in people with and without T2D.

RECENT FINDINGS

Results from basic laboratory research support the potential for commonly-used medications for T2D, including those with direct glucose-lowering properties, to have a beneficial effect on brain health. However, human studies have been mostly observational in nature and report conflicting results. Preliminary data suggest that intranasal insulin, metformin, and GLP-1 agonists show promise for dementia, but confirmatory evidence for their benefit in dementia is still lacking. Current evidence does not support the repurposing of T2D medications for dementia risk reduction or management. Research in the field of T2D and dementia is active, and further data are required before definitive conclusions can be drawn.

Dipeptidyl Peptidase-4 Inhibitors for the Potential Treatment of Brain Disorders; A Mini-Review With Special Focus on Linagliptin and Stroke

Cerebral stroke is a leading cause of death and persistent disability of elderly in the world. Although stroke prevention by targeting several risk factors such as diabetes and hypertension has decreased the stroke incidence, the total number of strokes is increasing due to the population aging and new preventive therapies are needed. Moreover, post-stroke acute pharmacological strategies aimed to reduce stroke-induced brain injury have failed in clinical trials despite being effective in animal models. Finally, approximately 30% of surviving stroke patients do not recover from stroke and remain permanently dependent on supportive care in activities of daily living. Therefore, strategies to improve stroke recovery in the post-acute phase are highly needed. Linagliptin is a dipeptidyl peptidase-4 inhibitor which is clinically approved to reduce hyperglycemia in type 2 diabetes. The regulation of glycemia by dipeptidyl peptidase-4 inhibition is mainly achieved by preventing endogenous glucagon-like peptide-1 (GLP-1) degradation. Interestingly, linagliptin has also shown glycaemia-independent beneficial effects in animal models of stroke, Parkinson's disease and Alzheimer's disease. In some case the preclinical data have been supported with some clinical data. Although potentially very interesting for the development of new strategies against stroke and neurodegenerative disorders, the mode of action of linagliptin in the brain is still largely unknown and seems to occur in a GLP-1R-independent manner. The purpose of this mini-review is to summarize and discuss the recent experimental and clinical work regarding the effects of linagliptin in the central nervous system, with special emphasis on acute neuroprotection, stroke prevention and post-stroke recovery. We also highlight the main questions in this research field that need to be addressed in clinical perspective.