Incident ischaemic stroke and Type 2 diabetes: trends in incidence and case fatality in Scotland 2004-2013

Incidence of stroke, subsequent clinical outcomes and health care resource utilization in people with type 2 diabetes: a real-world database study in France: "INSIST" study

BACKGROUND

People with type 2 diabetes (T2D) are at elevated risk of cardiovascular disease (CVD) including stroke, yet existing real-world evidence (RWE) on the clinical and economic burden of stroke in this population is limited. The aim of this cohort study was to evaluate the clinical and economic burden of stroke among people with T2D in France.

METHODS

We conducted a retrospective RWE study using data from the nationally representative subset of the French Système National des Données de Santé (SNDS) database. We assessed the incidence of stroke requiring hospitalization between 2012 and 2018 among T2D patients. Subsequent clinical outcomes including CVD, stroke recurrence, and mortality were estimated overall and according to stroke subtype (ischemic versus hemorrhagic). We also examined the treatment patterns for glucose-lowering agents and CVD agents, health care resource utilization and medical costs.

RESULTS

Among 45,331 people with T2D without baseline history of stroke, 2090 (4.6%) had an incident stroke requiring hospitalization. The incidence of ischemic stroke per 1000 person-years was 4.9-times higher than hemorrhagic stroke (6.80 [95% confidence interval (CI) 6.47-7.15] versus 1.38 [1.24-1.54]). During a median follow-up of 2.4 years (interquartile range 0.6; 4.4) from date of index stroke, the rate of CVD, stroke recurrence and mortality per 1000 person-years was higher among hemorrhagic stroke patients than ischemic stroke patients (CVD 130.9 [107.7-159.0] versus 126.4 [117.2-136.4]; stroke recurrence: 86.7 [66.4-113.4] versus 66.5 [59.2-74.6]; mortality 291.5 [259.1-327.9] versus 144.1 [134.3-154.6]). These differences were not statistically significant, except for mortality (adjusted hazard ratio 1.95 [95% CI 1.66-2.92]). The proportion of patients prescribed glucagon-like peptide-1 receptor agonists increased from 4.2% at baseline to 6.6% during follow-up. The proportion of patients prescribed antihypertensives and statins only increased slightly following incident stroke (antihypertensives: 70.9% pre-stroke versus 76.7% post-stroke; statins: 24.1% pre-stroke versus 30.0% post-stroke). Overall, 68.8% of patients had a subsequent hospitalization. Median total medical costs were €12,199 (6846; 22,378).

CONCLUSIONS

The high burden of stroke among people with T2D, along with the low proportion of patients receiving recommended treatments as per clinical guidelines, necessitates a strengthened and multidisciplinary approach to the CVD prevention and management in people with T2D.

Trends in incidence of ischaemic stroke in people with and without diabetes in Ireland 2005-2015

AIMS

We aim to describe the epidemiology of ischaemic stroke and in-hospital mortality associated with stroke among men and women with and without diabetes from 2005 to 2015.

METHODS

Secondary data analysis of national hospital discharge data from the Hospital Inpatient Enquiry database. Stroke incidence and in-hospital mortality rates in people with and without diabetes were calculated. Poisson regression models were used to estimate the incidence rate ratio (IRR) and assess trends over time.

RESULTS

The age-adjusted incidence of stroke was twice as high in people with diabetes compared to those without diabetes (men IRR 2.0 [95% CI 1.95-2.06] and women IRR 2.2 [95% CI 2.12-2.27]). The incidence of ischaemic stroke decreased by an average 1.7% per year in men with diabetes and 3.3% per year in women with diabetes. In people without diabetes, the average annual reduction was smaller (0.2% per year in men and 1% per year in women). In-hospital mortality associated with admission with ischaemic stroke was approximately twice as high in those with diabetes compared to those without diabetes among men [IRR 1.81 (1.67-1.97)] and women [IRR 2 (95% CI 1.84-2.18)].

CONCLUSION

Despite decreases in incidence of ischaemic stroke and associated in-hospital mortality, there remains a twofold increased risk of ischaemic stroke and mortality in people with diabetes. Therefore, priority must be given to management of risk factors for ischaemic stroke in people with diabetes as well as continued development of targeted stroke prevention strategies.

Incidence of Stroke in People With Diabetes Compared to Those Without Diabetes: A Systematic Review

BACKGROUND

One of the goals of the St. Vincent Declaration was to reduce serious complications of diabetes, including strokes. However, it remains uncertain whether this goal has been achieved.

STUDY AIM

To evaluate the incidence of stroke in the diabetic population and its differences regarding sex, ethnicity, age, and region, to compare the incidence rate in people with and without diabetes, and to investigate time trends.

MATERIALS AND METHODS

A systematic review was conducted according to the guidelines for meta-analysis of observational studies in epidemiology (the MOOSE group) and the PRISMA group guidelines.

RESULTS

Nineteen of the 6.470 studies retrieved were included in the analysis. The incidence of stroke in the population with diabetes ranged from 238 per 100,000 person-years in Germany in 2014 to 1191 during the 1990s in the United Kingdom. The relative risk comparing people with diabetes to those without diabetes varied between 1.0 and 2.84 for total stroke, 1.0 and 3.7 for ischemic stroke, and 0.68 and 1.6 for hemorrhagic stroke. Differences between fatal and non-fatal stroke were significant, depending on the time period and the population. We found decreasing time trends in people with diabetes and stable incidence rates of stroke over time in people without diabetes.

CONCLUSION

The considerable differences between results can partly be explained by differences in study designs, statistical methods, definitions of stroke, and methods used to identify patients with diabetes. The lack of evidence arising from these differences ought to be rectified by new studies.

Sex differences in pressure and flow waveform physiology across the life course

Cardiovascular disease (CVD) has long been deemed a disease of old men. However, in 2019 CVD accounted for 35% of all deaths in women and, therefore, remains the leading cause of death in both men and women. There is increasing evidence to show that risk factors, pathophysiology and health outcomes related to CVD differ in women compared with men, yet CVD in women remains understudied, underdiagnosed and undertreated. Differences exist between the sexes in relation to the structure of the heart and vasculature, which translate into differences in blood pressure and flow waveform physiology. These physiological differences between women and men may represent an important explanatory factor contributing to the sex disparity in CVD presentation and outcomes but remain understudied. In this review we aim to describe sex differences in arterial pressure and flow waveform physiology and explore how they may contribute to differences in CVD in women compared to men. Given that unfavourable alterations in the cardiovascular structure and function can start as early as in utero, we report sex differences in waveform physiology across the entire life course.

Calibrating a network meta-analysis of diabetes trials of sodium glucose cotransporter 2 inhibitors, glucagon-like peptide-1 receptor analogues and dipeptidyl peptidase-4 inhibitors to a representative routine population: a systematic review protocol

INTRODUCTION

Participants in randomised controlled trials (trials) are generally younger and healthier than many individuals encountered in clinical practice. Consequently, the applicability of trial findings is often uncertain. To address this, results from trials can be calibrated to more representative data sources. In a network meta-analysis, using a novel approach which allows the inclusion of trials whether or not individual-level participant data (IPD) is available, we will calibrate trials for three drug classes (sodium glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP1) receptor analogues and dipeptidyl peptidase-4 (DPP4) inhibitors) to the Scottish diabetes register.

METHODS AND ANALYSIS

Medline and EMBASE databases, the US clinical trials registry (clinicaltrials.gov) and the Chinese Clinical Trial Registry (chictr.org.cn) will be searched from 1 January 2002. Two independent reviewers will apply eligibility criteria to identify trials for inclusion. Included trials will be phase 3 or 4 trials of SGLT2 inhibitors, GLP1 receptor analogues or DPP4 inhibitors, with placebo or active comparators, in participants with type 2 diabetes, with at least one of glycaemic control, change in body weight or major adverse cardiovascular event as outcomes. Unregistered trials will be excluded.We have identified a target population from the population-based Scottish diabetes register. The chosen cohort comprises people in Scotland with type 2 diabetes who either (1) require further treatment due to poor glycaemic control where any of the three drug classes may be suitable, or (2) who have adequate glycaemic control but are already on one of the three drug classes of interest or insulin.

ETHICS AND DISSEMINATION

Ethical approval for IPD use was obtained from the University of Glasgow MVLS College Ethics Committee (Project: 200160070). The Scottish diabetes register has approval from the Scottish A Research Ethics Committee (11/AL/0225) and operates with Public Benefit and Privacy Panel for Health and Social Care approval (1617-0147).

PROSPERO REGISTRATION NUMBER

CRD42020184174.

Twenty-Year Temporal Trends in Risk of Ischemic Stroke in Incident Type 2 Diabetes: A Danish Population-Based Cohort Study

OBJECTIVE

We examined temporal trends in risk of first-time ischemic stroke in patients with incident type 2 diabetes mellitus (T2DM) and no prior atherosclerotic cardiovascular disease (ASCVD).

RESEARCH DESIGN AND METHODS

Using nationwide health registries, we identified all patients with incident T2DM without a prior hospital diagnosis of ASCVD from 1996 to 2015 in Denmark. Patients were assigned to 5-year periods based on the date of T2DM diagnosis and were followed for 5 years. Each patient was matched by sex and age with up to three individuals from the general population. Temporal trends in ischemic stroke were examined using Cox regression to compute hazard ratios (HRs). Temporal use of prophylactic cardiovascular medications was also assessed.

RESULTS

The study comprised 288,825 patients with incident T2DM and 782,232 general population individuals. From 1996-2000 to 2011-2015, the 5-year risk of first-time ischemic stroke was approximately halved in the T2DM cohort (5.2% vs. 2.7%; sex- and age-adjusted HR 0.52 [95% CI 0.49-0.55]). Patients diagnosed in 2011-2015 had increased risk of ischemic stroke compared with individuals in the general population; however, the risk difference narrowed over time (5.2% vs. 2.9% in 1996-1999 [difference 2.3%]; 2.7% vs. 2.0% in 2011-2015 [difference 0.7%]). Use of prophylactic cardiovascular medications increased markedly during the overall study period, especially use of statins (from 5% to 50%) and multiple antihypertensive drugs (from 18% to 33%).

CONCLUSIONS

From 1996 to 2015, the 5-year risk of first-time ischemic stroke was approximately halved in patients with incident T2DM and no prior ASCVD, coinciding with markedly increased use of prophylactic cardiovascular medications.

The cost of prevalent and incident cardiovascular disease in people with type 2 diabetes in Scotland: data from the Scottish Care Information-Diabetes Collaboration

AIM

To compare costs for three groups of people with type 2 diabetes, those at high risk of future cardiovascular disease, those without cardiovascular disease and those with established cardiovascular disease, and to also compare costs incurred by people with type 2 diabetes with an incident cardiovascular disease event with those who remain incident event-free over a 3-year period.

METHODS

Data about people with type 2 diabetes in Scotland were obtained from the Scottish Care Information Diabetes registry. Data linkage was used to retrieve information on healthcare utilization, care home use and deaths. Productivity effects were estimated for those of non-pensionable age. We estimated costs over 12 months (prevalent cardiovascular disease) and 3 years from incident cardiovascular disease event.

RESULTS

Mean annual cost per person with established cardiovascular disease was £6900, £3300 for a person at high risk of future cardiovascular disease, and £2500 for a person without cardiovascular disease and not at high risk. In year 1, the cost of an incident cardiovascular disease event was £16 700 compared with £2100 for people without an incident event. Over 2 years, the cumulative costs were £21 500 and £4200, and by year 3, £25 000 and £5900, respectively.

CONCLUSIONS

Cardiovascular disease in people with type 2 diabetes places a significant financial burden on healthcare and the wider economy. Our results emphasize the financial consequences of cardiovascular disease prevention strategies.

Diabetes in ischaemic stroke in a regional Australian hospital - uncharted territory

BACKGROUND

Stroke and diabetes (DM) are significant interrelated healthcare issues but there is a dearth of data on the prevalence of DM among Australia's regional stroke population.

AIMS

We aimed to determine the prevalence of DM in stroke patients at a large regional centre, including sub-analyses on stroke subtypes, glycaemic control and renal function in ischaemic stroke (IS).

METHODS

We conducted a retrospective analysis of all patients (n = 323) with IS or transient ischaemic attack (TIA) admitted to Ballarat Base Hospital from January 2015 to December 2016. Demographic data, cardiovascular risk factors, aetiology/territory of IS, pre-morbid DM status, indicators of glycaemic control and renal impairment were recorded.

RESULTS

DM was present in 28.5% of IS and TIA patients including 4% being newly diagnosed. Among diabetic IS patients, 45.3% had poor glycaemic control (HbA1c ≥7.0%) while 16% had moderate to severe renal impairment (eGFR of <30). The majority of IS were partial anterior circulation stroke (53.4%) and cardioembolism was the commonest mechanism (43.5%). We found no significant association between DM and a specific stroke location or mechanism.

CONCLUSION

Almost a third of IS/TIA patients had DM with a significant proportion showing poor glycaemic control. The DM prevalence in our cohort was comparable to reported rates from other developed countries. While we found no association between DM and a particular stroke type or mechanism, it is likely a reflection of our cohort size. Our study demonstrated that DM, as a significant risk factor in IS, warrants early detection and better management strategies. This article is protected by copyright. All rights reserved.

Exosomes derived from bone marrow mesenchymal stem cells harvested from type two diabetes rats promotes neurorestorative effects after stroke in type two diabetes rats

BACKGROUND AND PURPOSE

Diabetes elevates the risk of stroke, promotes inflammation, and exacerbates vascular and white matter damage post stroke, thereby hindering long term functional recovery. Here, we investigated the neurorestorative effects and the underlying therapeutic mechanisms of treatment of stroke in type 2 diabetic rats (T2DM) using exosomes harvested from bone marrow stromal cells obtained from T2DM rats (T2DM-MSC-Exo).

METHODS

T2DM was induced in adult male Wistar rats using a combination of high fat diet and Streptozotocin. Rats were subjected to transient 2 h middle cerebral artery occlusion (MCAo) and 3 days later randomized to one of the following treatment groups: 1) phosphate-buffered-saline (PBS, i.v), 2) T2DM-MSC-Exo, (3 × 10¹¹, i.v), 3) T2DM-MSC-Exo with miR-9 over expression (miR9+/+-T2DM-MSC-Exo, 3 × 10¹¹, i.v) or 4) MSC-Exo derived from normoglycemic rats (Nor-MSC-Exo) (3 × 10¹¹, i.v). T2DM sham control group is included as reference. Rats were sacrificed 28 days after MCAo.

RESULTS

T2DM-MSC-Exo treatment does not alter blood glucose, lipid levels, or lesion volume, but significantly improves neurological function and attenuates post-stroke weight loss compared to PBS treated as well as Nor-MSC-Exo treated T2DM-stroke rats. Compared to PBS treatment, T2DM-MSC-Exo treatment of T2DM-stroke rats significantly 1) increases tight junction protein ZO-1 and improves blood brain barrier (BBB) integrity; 2) promotes white matter remodeling indicated by increased axon and myelin density, and increases oligodendrocytes and oligodendrocyte progenitor cell numbers in the ischemic border zone as well as increases primary cortical neuronal axonal outgrowth; 3) decreases activated microglia, M1 macrophages, and inflammatory factors MMP-9 (matrix mettaloproteinase-9) and MCP-1 (monocyte chemoattractant protein-1) expression in the ischemic brain; and 4) decreases miR-9 expression in serum, and increases miR-9 target ABCA1 (ATP-binding cassette transporter 1) and IGFR1 (Insulin-like growth factor 1 receptor) expression in the brain. MiR9+/+-T2DM-MSC-Exo treatment significantly increases serum miR-9 expression compared to PBS treated and T2DM-MSC-Exo treated T2DM stroke rats. Treatment of T2DM stroke with miR9+/+-T2DM-MSC-Exo fails to improve functional outcome and attenuates T2DM-MSC-Exo treatment induced white matter remodeling and anti-inflammatory effects in T2DM stroke rats.

CONCLUSIONS

T2DM-MSC-Exo treatment for stroke in T2DM rats promotes neurorestorative effects and improves functional outcome. Down regulation of miR-9 expression and increasing its target ABCA1 pathway may contribute partially to T2DM-MSC-Exo treatment induced white matter remodeling and anti-inflammatory responses.

Prevalence, incidence and mortality of type 1 and type 2 diabetes in Denmark 1996-2016

INTRODUCTION

The objective of this study was to give an overview of prevalence, incidence and mortality of type 1 (T1D) and type 2 diabetes (T2D) in Denmark, and their temporal trends.

RESEARCH DESIGN AND METHODS

We constructed a diabetes register from existing population-based healthcare registers, including a classification of patients as T1D or T2D, with coverage from 1996 to 2016. Using complete population records for Denmark, we derived prevalence, incidence, mortality and standardized mortality ratio (SMR).

RESULTS

The overall prevalence of diabetes at 2016 was 0.5% for T1D and 4.4% for T2D, with annual increases since 1996 of 0.5% for T1D and 5.5% for T2D. Incidence rates of T1D decreased by 3.5% per year, with increase for persons under 25 years of age and a decrease for older persons. T2D incidence increased 2.5% per year until 2011, decreased until 2014 and increased after that, similar in all ages. The annual decrease in mortality was 0.3% for T1D and 2.9% for T2D. The mortality rate ratio between T1D and T2D was 1.9 for men and 1.6 for women. SMR decreased annually 2% for T1D and 0.5% for T2D.

CONCLUSIONS

Incidence and prevalence of diabetes is increasing, but mortality among patients with diabetes in Denmark is decreasing faster than the mortality among persons without diabetes. T1D carries a 70% higher mortality than T2D.

Determinants of Case Fatality After Hospitalization for Stroke in France 2010 to 2015

Background and Purpose- The aims of this study were to (1) describe early and late case fatality rates after stroke in France, (2) evaluate whether their determinants differed, and (3) analyze time trends between 2010 and 2015. Methods- Data were extracted from the Système National des données de santé database. Patients hospitalized for stroke each year from 2010 to 2015, aged ≥18 years, and affiliated to the general insurance scheme were selected. Cox regressions were used to separately analyze determinants of 30-day and 31- to 365-day case fatality rates for each stroke type (ischemic, intracerebral hemorrhage, and subarachnoid hemorrhage). Results- In 2015, of the 73 124 persons hospitalized for stroke, 26.8% died in the following year, with the majority of deaths occurring within the first 30 days (56.9%). Nonadmission to a stroke unit, older age, and having comorbidities were all associated with a poorer 30-day and 31- to 365-day prognosis. Female sex was associated with a lower 31- to 365-day case fatality rate for all patients with stroke. Living in an area with a high deprivation index was associated with both higher 30-day and 31- to 365-day case fatality rates for all stroke types. Between 2010 and 2015, significant decreases in both 30-day and 31- to 365-day case fatality rates for ischemic patients were observed. Conclusions- Case fatality rates after stroke remained high in 2015 in France, despite major improvements in stroke care and organization. Improvement in stroke awareness and preparedness, particularly in the most deprived areas, together with better follow-up after the acute phase are urgently needed.

Incidence of Type 2 Diabetes in People With a History of Hospitalization for Major Mental Illness in Scotland, 2001-2015: A Retrospective Cohort Study

OBJECTIVE

To determine the incidence of type 2 diabetes in people with a history of hospitalization for major mental illness versus no mental illness in Scotland by time period and sociodemographics.

RESEARCH DESIGN AND METHODS

We used national Scottish population-based records to create cohorts with a hospital record of schizophrenia, bipolar disorder, or depression or no mental illness and to ascertain diabetes incidence. We used quasi-Poisson regression models including age, sex, time period, and area-based deprivation to estimate incidence and relative risks (RRs) of diabetes by mental illness status. Estimates are illustrated for people aged 60 years and in the middle deprivation quintile in 2015.

RESULTS

We identified 254,136 diabetes cases during 2001-2015. Diabetes incidence in 2015 was 1.5- to 2.5-fold higher in people with versus without a major mental disorder, with the gap having slightly increased over time. RRs of diabetes incidence were greater among women than men for schizophrenia (RR 2.40 [95% CI 2.01, 2.85] and 1.63 [1.38, 1.94]), respectively) and depression (RR 2.10 [1.86, 2.36] and 1.62 [1.43, 1.82]) but similar for bipolar disorder (RR 1.65 [1.35, 2.02] and 1.50 [1.22, 1.84]). Absolute and relative differences in diabetes incidence associated with mental illness increased with increasing deprivation.

CONCLUSIONS

Disparities in diabetes incidence between people with and without major mental illness appear to be widening. Major mental illness has a greater effect on diabetes risk in women and people living in more deprived areas, which has implications for intervention strategies to reduce diabetes risk in this vulnerable population.

Incidence of Hospitalization for Heart Failure and Case-Fatality Among 3.25 Million People With and Without Diabetes Mellitus

Supplemental Digital Content is available in the text.

Background:

Recent clinical trials of new glucose-lowering treatments have drawn attention to the importance of hospitalization for heart failure as a complication of diabetes mellitus. However, the epidemiology is not well described, particularly for type 1 diabetes mellitus. We examined the incidence and case-fatality of heart failure hospitalizations in the entire population aged ≥30 years resident in Scotland during 2004 to 2013.

Methods:

Date and type of diabetes mellitus diagnosis were linked to heart failure hospitalizations and deaths using the national Scottish registers. Incidence rates and case-fatality were estimated in regression models (quasi-Poisson and logistic regression respectively). All estimates are adjusted for age, sex, socioeconomic status, and calendar-year.

Results:

Over the 10-year period of the study, among 3.25 million people there were 91, 429, 22 959, and 1313 incident heart failure events among those without diabetes mellitus, with type 2, and type 1 diabetes mellitus, respectively. The crude incidence rates of heart failure hospitalization were therefore 2.4, 12.4, and 5.6 per 1000 person-years for these 3 groups. Heart failure hospitalization incidence was higher in people with diabetes mellitus, regardless of type, than in people without. Relative differences were smallest for older men, in whom the difference was nonetheless large (men aged 80, rate ratio 1.78; 95% CI, 1.45–2.19). Rates declined similarly, by 0.2% per calendar-year, in people with type 2 diabetes mellitus and without diabetes mellitus. Rates fell faster, however, in those with type 1 diabetes mellitus (2.2% per calendar-year, rate ratio for type 1/calendar-year interaction 0.978; 95% CI, 0.959–0.998).

Thirty-day case-fatality was similar among people with type 2 diabetes mellitus and without diabetes mellitus, but was higher in type 1 diabetes mellitus for men (odds ratio, 0.96; 95% CI, 0.95–0.96) and women (odds ratio, 0.98; 95% CI, 0.97–0.98). Case-fatality declined over time for all groups (3.3% per calendar-year, odds ratio per calendar-year 0.967; 95% CI, 0.961–0.973).

Conclusions:

Despite falling incidence, particularly in type 1 diabetes mellitus, heart failure remains ≈2-fold higher than in people without diabetes mellitus, with higher case-fatality in those with type 1 diabetes mellitus. These findings support the view that heart failure is an under-recognized and important complication in diabetes mellitus, particularly for type 1 disease.

Cardiovascular disease prevalence and risk factor prevalence in Type 2 diabetes: a contemporary analysis

AIMS

To describe the prevalence of major cardiovascular disease (CVD) and risk factor control in a contemporary population with Type 2 diabetes.

METHODS

We used data from the national registry in Scotland, Scottish Care Information-Diabetes, linked to hospital admissions. Using descriptive statistics and logistic regression we described associations of risk factors with CVD. CVD was defined based on diagnostic codes in primary or secondary care data for ischaemic heart disease, cerebrovascular disease peripheral arterial disease, heart failure, cardiac arrhythmia, hypertensive heart disease and revascularization procedures.

RESULTS

Among 248 400 people with Type 2 diabetes with a median age of 67.5 years (IQR 58.2, 76.1) and median diabetes duration of 7.8 years (3.8, 13.0), 32% had prior CVD (35% of men, 29% of women). Median HbA_1c overall was 55 mmol/mol (7.2%), median SBP was 132 mmHg, median total cholesterol was 4.1 mmol/l and mean BMI was 32 kg/m² _. Overall two-thirds (65% of men, 68% of women) have two or more of the following CVD risk factor thresholds: HbA_1c ≥ 53 mmol/mol (7%), SBP > 130 mmHg or DBP > 80 mmHg, total cholesterol ≥ 5 mmol/l or BMI ≥ 30 kg/m² , or were currently smoking. Overall 84% were taking anti-hypertensives and 75% a statin. Use of metformin was common at 58%, but other diabetes drugs that reduce CVD were rarely used.

CONCLUSIONS

There continues to be a high prevalence of CVD among people with Type 2 diabetes and a high level of unmet need for risk factor control. This implies substantial scope for reducing the excess risk of CVD in diabetes through improved management of known risk factors.

Cardiovascular disease in diabetes type 2: current concepts

Type 2 diabetes is a major and accelerating public health challenge. Between 1980 and 2014, a period of just 35 years, the number of adults with diabetes globally is estimated to have increased from 108 to 422 million, due not only to sharply rising obesity rates, but also to increasing population size, longer life expectancy, and rising prevalence of diabetes worldwide. Overall, worldwide age-standardized adult diabetes prevalence doubled from 4.3% to 9.0% in men and from 5.0% to 7.9% in women. The largest increases in diabetes type 2 have been demonstrated in low- and middle-income countries, whilst rises in high-income countries have been less marked, or even flat. Diabetes type 2 rates in low- and middle-income countries now in many instances surpass those in high-income countries, in response to changes in lifestyle. One factor of particular concern are the large relative increases in type 2 diabetes amongst young individuals observed in many countries, their higher overall risk factor burden, long exposure to hyperglycaemia and greater risk of complications over the life course. Type 2 diabetes is increasingly found to be a heterogeneous condition, where risk of cardiovascular disease that traditionally has been estimated at 2-4 times that of the nondiabetic population varies substantially with diabetes phenotype and accordingly diabetes does not confer the same increase in relative or absolute risk in all people. New research shows that excess risk varies substantially with type of outcome, age, glycaemic control, the presence of renal complications and other factors. Heart failure, previously less recognized that other cardiovascular conditions, is increasingly coming into focus, because of strong links with poor glycaemic control and obesity. The knowledge about risk of cardiovascular disease in diabetes is almost entirely derived from high-income countries, whereas there is comparatively very little data from low- and middle income countries, where the majority of persons with type 2 diabetes live, and where management in many cases is far from optimal. The reductions in cardiovascular disease incidence and mortality now observed in high-income countries are encouraging, because this reinforces the fact that improvement is possible and that a near-normal, or even normal life-expectancy can be achieved in subtypes of type 2 diabetes.

Multivariate analysis of genomics data to identify potential pleiotropic genes for type 2 diabetes, obesity and dyslipidemia using Meta-CCA and gene-based approach

Previous studies have demonstrated the genetic correlations between type 2 diabetes, obesity and dyslipidemia, and indicated that many genes have pleiotropic effects on them. However, these pleiotropic genes have not been well-defined. It is essential to identify pleiotropic genes using systematic approaches because systematically analyzing correlated traits is an effective way to enhance their statistical power. To identify potential pleiotropic genes for these three disorders, we performed a systematic analysis by incorporating GWAS (genome-wide associated study) datasets of six correlated traits related to type 2 diabetes, obesity and dyslipidemia using Meta-CCA (meta-analysis using canonical correlation analysis). Meta-CCA is an emerging method to systematically identify potential pleiotropic genes using GWAS summary statistics of multiple correlated traits. 2,720 genes were identified as significant genes after multiple testing (Bonferroni corrected p value < 0.05). Further, to refine the identified genes, we tested their relationship to the six correlated traits using VEGAS-2 (versatile gene-based association study-2). Only the genes significantly associated (Bonferroni corrected p value < 0.05) with more than one trait were kept. Finally, 25 genes (including two confirmed pleiotropic genes and eleven novel pleiotropic genes) were identified as potential pleiotropic genes. They were enriched in 5 pathways including the statin pathway and the PPAR (peroxisome proliferator-activated receptor) Alpha pathway. In summary, our study identified potential pleiotropic genes and pathways of type 2 diabetes, obesity and dyslipidemia, which may shed light on the common biological etiology and pathogenesis of these three disorders and provide promising insights for new therapies.