Improvements in life expectancy in adult type 2 diabetes patients in the last six decades

Update on the pathogenesis and treatment of skeletal fragility in type 2 diabetes mellitus

Fracture risk is increased in patients with type 2 diabetes mellitus (T2DM). In addition, these patients sustain fractures despite having higher levels of areal bone mineral density, as measured by dual-energy X-ray absorptiometry, than individuals without T2DM. Thus, additional factors such as alterations in bone quality could have important roles in mediating skeletal fragility in patients with T2DM. Although the pathogenesis of increased fracture risk in T2DM is multifactorial, impairments in bone material properties and increases in cortical porosity have emerged as two key skeletal abnormalities that contribute to skeletal fragility in patients with T2DM. In addition, indices of bone formation are uniformly reduced in patients with T2DM, with evidence from mouse studies published over the past few years linking this abnormality to accelerated skeletal ageing, specifically cellular senescence. In this Review, we highlight the latest advances in our understanding of the mechanisms of skeletal fragility in patients with T2DM and suggest potential novel therapeutic approaches to address this problem.

Metabolic syndrome exacerbates amyloid pathology in a comorbid Alzheimer's mouse model

Alzheimer's disease (AD) often coexists with other aging-associated diseases including obesity, diabetes, hypertension, and cardiovascular diseases. The early stage of these comorbidities is known as metabolic syndrome (MetS) which is highly prevalent in mid-life. An important cause of MetS is the deficiency of SIRT3, a mitochondrial deacetylase which enhances the functions of critical mitochondrial proteins, including metabolic enzymes, by deacetylation. Deletion of Sirt3 gene has been reported to result in the acceleration of MetS. In a recently published study, we demonstrated in the brain of Sirt3^-/- mice, downregulation of metabolic enzymes, insulin resistance and elevation of inflammatory markers including microglial proliferation. These findings suggested a novel pathway that could link SIRT3 deficiency to neuroinflammation, an important cause of Alzheimer's pathogenesis. Therefore, we hypothesized that MetS and amyloid pathology may interact through converging pathways of insulin resistance and neuroinflammation in comorbid AD. To investigate these interactions, we crossed Sirt3^-/- mice with APP/PS1 mice and successfully generated APP/PS1/Sirt3^-/- mice with amyloid pathology and MetS. In these comorbid AD mice, we observed exacerbation of insulin resistance, glucose intolerance, amyloid plaque deposition, markers of neuroinflammation, including elevated expression of IL-1β, TNF-α and Cox-2 at 8 months of age. There was also increased microglial proliferation and activation. Our observations suggest a novel mechanism by which MetS may interact with amyloid pathology during the cellular phase of AD. Therapeutic targeting of SIRT3 in AD with comorbidities may produce beneficial effects.

Effect of type 2 diabetes medications on fracture risk

Type 2 diabetes, one of the most frequent chronic diseases, has an important effect on bone metabolism, with most studies reporting an increased prevalence of fractures in these patients despite an apparently increased bone mineral density. Most probable explanation is an alteration of bone structure/quality with increased fragility but the different diabetes medications influence the risk of fracture. While metformin and incretin-based therapies are safe, thiazolidinediones and canagliflozin (sodium-glucose cotransporter-2 inhibitor) negatively impact bone metabolism and should be avoided in subjects at increased risk of fractures. Insulin and sulphonylureas are generally safe but can increase the risk of hypoglycemia and falls with subsequent traumatic fractures. Their combination should be avoided, especially in elderly subjects.

Rates and Causes of Death among Adult Diabetes Patients in Romania

Aims: To study the age and sex-dependent mortality rates and causes of death in a large Romanian diabetes cohort as compared with the general population. Methods: All adult patients aged 20-64 years, receiving a free diabetes prescription in a major urban area during 2001-2008 were included and followed-up for death until December 31, 2011. Crude mortality rates and standardized mortality rate ratios (SMR) against general population (data from the National Institute of Statistics) were calculated. Years lost due to diabetes were computed assuming the general population mortality rates for ages below 20 and above 64 years. Results: During the 11 years study period, 49,328 diabetes patients (mean age at baseline 53.0 ± 8.8 years) contributed 297,370 person-years and 5,053 deaths. All cause mortality rates (per 1000 person years) increased with age and was 3.4 in 20-24 years age group and 25.7 in 60-64 year age group, while the corresponding SMR decreased from 6.0 to 1.5. Diabetes patients aged 20-24 years had a life expectancy of 48.6 years, which was 6.6 years less compared with the corresponding general population (55.2 years). The gap was 7.0 years in women and 5.8 years in men. Diabetes patients aged 20-24 years lost 196 minutes of life daily due to diabetes in women and 182 minutes in men. Conclusions: Mortality rates increased, while mortality rate ratios against general population decreased with age. Men had higher mortality rates, but women had higher mortality rate ratios in the gender analysis.

Recent diabetes-related mortality trends in Romania

AIMS

As there are no published articles on country-level diabetes-related mortality in Romania, we aimed to investigate this aspect for the 1998-2015 period.

METHODS

Anonymized demographic and diabetes-related mortality data (underlying or first secondary cause of death) were retrospectively obtained from the National Institute of Statistics/Eurostat microdata. Age-standardized mortality rates (ASMR) and their annual percentage change (APC) were analysed.

RESULTS

During 1998-2015, 4,567,899 persons died in Romania, among whom, diabetes was responsible for 168,854 cases. The ASMR for diabetes was 39.34 per 100,000 person-years (p-y) (95% CI 39.32-39.35). There was an increase in ASMR from 27.10 per 100,000 p-y (95% CI 27.01-27.19) in women and 30.88 per 100,000 p-y (95% CI 30.77-30.99) in men in 1998 to 35.42 per 100,000 p-y (95% CI 35.34-35.51) in women and 48.41 per 100,000 p-y (95% CI 48.29-48.52) in men, in 2015. The mean APC in women was 3.8% per year (95% CI 3.5-4.0, p < 0.001) during 1998-2010 and - 1.9% per year (95% CI - 2.7 to - 1.1, p < 0.001) during 2010-2015. The mean APC in men was 5.3% per year (95% CI 5.0-5.5, p < 0.001) during 1998-2010 and - 1.5% per year (95% CI - 2.2 to - 0.8, p < 0.001) during 2010-2015. Diabetes-related mortality rates increased with age, with men experiencing higher mortality rates than women for most age groups and calendar years.

CONCLUSIONS

Diabetes-related mortality rates increased significantly in Romania during 1998-2010, followed by a steady decline during 2010-2015.

The Role of Hyperglycemia, Insulin Resistance, and Blood Pressure in Diabetes-Associated Differences in Cognitive Performance-The Maastricht Study

OBJECTIVE

To study to what extent differences in cognitive performance between individuals with different glucose metabolism status are potentially attributable to hyperglycemia, insulin resistance, and blood pressure-related variables.

RESEARCH DESIGN AND METHODS

We used cross-sectional data from 2,531 participants from the Maastricht Study (mean age ± SD, 60 ± 8 years; 52% men; n = 666 with type 2 diabetes), all of whom completed a neuropsychological test battery. Hyperglycemia was assessed by a composite index of fasting glucose, postload glucose, glycated hemoglobin (HbA_1c), and tissue advanced glycation end products; insulin resistance by the HOMA of insulin resistance index; and blood pressure-related variables included 24-h ambulatory pressures, their weighted SDs, and the use of antihypertensive medication. Linear regression analyses were used to estimate mediating effects.

RESULTS

After adjustment for age, sex, and education, individuals with type 2 diabetes, compared with those with normal glucose metabolism, performed worse in all cognitive domains (mean differences in composite z scores for memory -0.087, processing speed -0.196, executive function and attention -0.182; P values <0.032), whereas individuals with prediabetes did not. Diabetes-associated differences in processing speed and executive function and attention were largely explained by hyperglycemia (mediating effect 79.6% [bootstrapped 95% CI 36.6; 123.4] and 50.3% [0.6; 101.2], respectively) and, for processing speed, to a lesser extent by blood pressure-related variables (17.7% [5.6; 30.1]), but not by insulin resistance. None of the factors explained the differences in memory function.

CONCLUSIONS

Our cross-sectional data suggest that early glycemic and blood pressure control, perhaps even in the prediabetic stage, may be promising therapeutic targets for the prevention of diabetes-associated decrements in cognitive performance.

PATIENTS TREATED WITH INSULIN AND SULPHONYLUREA ARE AT INCREASED MORTALITY RISK AS COMPARED WITH THOSE TREATED WITH INSULIN PLUS METFORMIN

AIMS

To investigate the effect of sulphonylurea (SU) treatment on all-cause and cardiovascular mortality as compared with metformin (MET), when used in combination with insulin (INS) in type 2 diabetes.

METHODS

All type 2 diabetes patients aged ≥40 years were included at their first prescription of INS+MET or INS+SU, during 2001-2008. They were considered at risk until death or December 31st, 2011. Mortality rates were calculated per 1000 person-years. Crude and adjusted rate ratios (RR) were calculated using time dependent analysis with INS+MET as reference.

RESULTS

There were 7122 patients (60.8% women) included in the analysis, with a mean age at baseline of 62.0±9.9 years. During the 11 years of study, patients on INS+MET contributed 13620 person-years and 330 deaths (mortality rate 24, CI95% 22-27), while those on INS+SU contributed 8720 person-years and 393 deaths (mortality rate 45, CI95% 41-50). Adjusted all-cause mortality RR were: SU 1.6 (CI95% 1.21-2.11, p<0.001), glimepiride 1.18 (CI95% 0.73-1.91, p=0.51), gliclazide 1.78 (CI95% 1.07-2.95, p=0.024), glibenclamide 1.66 (CI95% 0.71-3.88, p=0.23), glipizide 1.24 (CI95% 0.68-2.27, p=0.49), and gliquidonum 2.32 (CI95% 1.54-3.50, p=0.001).

CONCLUSIONS

When combined with insulin as dual therapy, patients treated with SU were at increased mortality risk as compared with insulin + MET.

Influenza Virus and Glycemic Variability in Diabetes: A Killer Combination?

Following the 2009 H1N1 influenza virus pandemic, numerous studies identified the striking link between diabetes mellitus and influenza disease severity. Typically, influenza virus is a self-limiting infection but in individuals who have a pre-existing chronic illness, such as diabetes mellitus, severe influenza can develop. Here, we discuss the latest clinical and experimental evidence for the role of diabetes in predisposing the host to severe influenza. We explore the possible mechanisms that underlie this synergy and highlight the, as yet, unexplored role that blood glucose oscillations may play in disease development. Diabetes is one of the world’s fastest growing chronic diseases and influenza virus represents a constant and pervasive threat to human health. It is therefore imperative that we understand how diabetes increases influenza severity in order to mitigate the burden of future influenza epidemics and pandemics.

Clinical characteristics of Chinese patients with duration of type 2 diabetes >40 years

BACKGROUND

Although type 2 diabetes mellitus (T2DM) shortens life expectancy by 10-12 years, some patients survive extremely long durations of diabetes. The clinical characteristics of Chinese patients with >40 years T2DM remain unknown. Thus, the aim of the present study was to document the clinical profile of patients with T2DM for ≥40 years.

METHODS

The present study evaluated 157 survivors with >40 years T2DM from a total of 582 773 patients with T2DM enrolled in a Chinese national survey of HbA1c. Two matched case-control studies were performed on long T2DM survivors (cases) separately matched according to: (1) survey day, sex, and survey hospital; and (2) age, sex, and survey hospital. Conditional logistic regression analysis was performed to obtain odds ratios (ORs) for long survival.

RESULTS

Patients with a long duration of T2DM had a mean (± SD) age of 75 ± 10 years. Their T2DM had been diagnosed at a mean age of 32 years and the median duration of diabetes was 41 years. In both case-control studies, long-duration T2DM was associated with an increased risk of hyperglycemia (OR 6.31; 95% confidence interval [CI] 1.89-21.09) and coronary heart disease (CHD; OR 2.18 95% CI 1.01-4.70). However, long-duration T2DM was not associated with a higher likelihood of abnormal lipids, diabetic nephropathy (DN), or stroke compared with patients with a shorter duration of T2DM.

CONCLUSIONS

The present study suggests that Chinese patients with long-term T2DM also had increased risks of hyperglycemia and non-fatal CHD. Further studies are needed to investigate whether survival of these patients was associated with non-increased risk of DN.

Common neurodegenerative pathways in obesity, diabetes, and Alzheimer's disease

Cognitive decline in chronic diabetic patients is a less investigated topic. Diabetes and obesity are among the modifiable risk factors for Alzheimer's disease (AD), the most common form of dementia. Studies have identified several overlapping neurodegenerative mechanisms, including oxidative stress, mitochondrial dysfunction, and inflammation that are observed in these disorders. Advanced glycation end products generated by chronic hyperglycemia and their receptor RAGE provide critical links between diabetes and AD. Peripheral inflammation observed in obesity leads to insulin resistance and type 2 diabetes. Although the brain is an immune-privileged organ, cross-talks between peripheral and central inflammation have been reported. Damage to the blood brain barrier (BBB) as seen with aging can lead to infiltration of immune cells into the brain, leading to the exacerbation of central inflammation. Neuroinflammation, which has emerged as an important cause of cognitive dysfunction, could provide a central mechanism for aging-associated ailments. To further add to these injuries, adult neurogenesis that provides neuronal plasticity is also impaired in the diabetic brain. This review discusses these molecular mechanisms that link obesity, diabetes and AD. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Cardiovascular Mortality in Type 2 Diabetes Patients with Incident Exposure to Insulin Glargine

The study investigated the impact of insulin glargine exposure on cardiovascular mortality in type 2 diabetes patients with incident insulin initiation. All consecutive diabetes patients aged >40 years were screened at their first diabetes outpatient visit between 01/01/2001 and 12/31/2008 (n = 79869). Exclusion criteria restricted the cohort to 4990 incident insulin users, aged 40-79 years, who were followed up for death until 12/31/2011. Baseline was defined 6 months after insulin initiation. Adjusted time-dependent competing risk regression analysis was performed. Mean baseline age was 62 ± 9 years, with mean follow-up of 4.7 ± 1.9 years. During 23179 person-years of exposure time, there were 887 deaths (521 cardiovascular). Glargine cumulative time exposure significantly lowered overall cardiovascular, subhazard ratio (SHR) 0.963 (CI 95% 0.944-0.981, p < 0.001), and myocardial infarction mortality, SHR 0.945 (CI 95% 0.899-0.994, p = 0.028), but not stroke mortality. Glargine cumulative dose exposure (10,000 IU increments) significantly lowered cardiovascular mortality, SHR 0.977 (CI 95% 0.960-0.993, p = 0.006), but not for myocardial infarction and stroke. Both cumulative dose and time exposure to insulin glargine were associated with lower cardiovascular mortality. The effect was mostly driven by myocardial infarction end point, supporting the concept of macrovascular benefit for basal analogue insulin use in type 2 diabetes.

Cancer specific mortality in insulin-treated type 2 diabetes patients

Aims

To test the hypothesis that cumulative exposure to insulin and long-acting insulin analogs might be associated with cancer mortality in diabetes patients.

Methods

All consecutive diabetes patients aged over 40 years, residing in a major urban area were screened at their first diabetes outpatient visit between 01/01/2001-12/31/2008 (n = 79869). Exclusion criteria were insulin treatment at screening, no insulin treatment until 12/31/2008, less than 6 months of glucose-lowering treatment alone before insulin initiation, insulin prescription before glargine became available, age <40/≥80 years at first insulin prescription, and <6 months of insulin exposure. A total 4990 subjects were followed-up for death based on death certificate, until 12/31/2011. Adjusted time-dependent competing risk regression analysis, with daily updates of treatment modalities was performed. Results are expressed for every 10,000 IU of cumulative dose or one year of cumulative time exposure to insulin.

Results

Mean baseline age was 62±9 years, and follow-up 4.7±1.9 years. Glargine cumulative dose was associated with lower cancer mortality risk (subhazard ratio, SHR: 0.94 (95%CI 0.89–0.99, p = 0.033)). Cumulative exposure limited to that attained one year prior to death revealed lower SHRs for cumulative time (0.94 (95%CI 0.89–0.99, p = 0.018)) and cumulative dose of glargine (0.92 (95%CI 0.86–0.98, p = 0.014)). Glargine cumulative time and cumulative dose were significant predictors for lower pancreatic and breast cancer mortality, but not for deaths from lung, colorectal, female genital, liver, and urinary tract cancer. No increased hazards were found for any other subtypes of insulins.

Conclusions

The cumulative dose exposure to insulin glargine was associated with a lower risk of cancer mortality in general, and of breast and pancreatic cancer in particular. This effect remained even after additional “fixed” cohort or propensity score analyses.

Epidemiology of diabetes and diabetes complications in the elderly: an emerging public health burden

Diabetes in the elderly is a growing public health burden. Persons with diabetes are living longer and are vulnerable to the traditional microvascular and macrovascular complications of diabetes but also at increased risk for geriatric syndromes. Peripheral vascular disease, heart disease, and stroke all have a high prevalence among older adults with diabetes. Traditional microvascular complications such as retinopathy, nephropathy, and neuropathy also frequently occur. Unique to this older population is the effect of diabetes on functional status. Older adults with diabetes are also more likely to experience geriatric syndromes such as falls, dementia, depression, and incontinence. Further studies are needed to better characterize those elderly individuals who may be at the highest risk of adverse complications from diabetes.

The dynamics of life expectancy over the last six decades in elderly people with diabetes

AIM

To investigate the historical changes in survival with diabetes in elderly people with diabetes.

RESEARCH DESIGN AND METHODS

We analyzed 6504 deaths (44.5% males) registered in a large urban population, aged ≥65 years, and deceased between 1943 and 2009. We split the analysis into three time periods according to year of death: 1943-1965, 1966-1988 and 1989-2009. The parallel changes in the corresponding general population were available.

RESULTS

The mean age at diabetes onset was 70.8 ± 4.7 years, with mean disease duration at death 7.5 ± 5 years, and mean age at death 78.3 ± 5.9 years. The mean survival loss due to diabetes (expected minus observed survival) was 4.5 ± 5.1 years (4.9 ± 5.1 years for females versus 4.1 ± 5.2 years for males, p<0.001). The mean disease duration at death was 6.4 ± 5.7 years in the period 1943-1965, followed by a significant (p=0.019) rise to 7 ± 5 years in 1966-1988, and 8.3 ± 4.9 years (p<0.001) in 1989-2009. There was a significant increase in coronary heart disease and stroke, and a significant decrease in infections and end-stage renal disease as causes of death.

CONCLUSIONS

We found a significant increase in age at onset and survival with diabetes leading to a significant increase in age at death. Females had a higher survival loss due to diabetes compared with males.