Sex difference in the incidence of microvascular complications in patients with type 2 diabetes mellitus: a prospective cohort study

Sex differences in risk of incident microvascular and macrovascular complications: a population-based data-linkage study among 25 713 people with diabetes

BACKGROUND

The global prevalence of diabetes is similar in men and women; however, there is conflicting evidence regarding sex differences in diabetes-related complications. The aim of this study was to investigate sex differences in incident microvascular and macrovascular complications among adults with diabetes.

METHODS

This prospective cohort study linked data from the 45 and Up Study, Australia, to administrative health records. The study sample included 25 713 individuals (57% men), aged ≥45 years, with diabetes at baseline. Incident cardiovascular disease (CVD), eye, lower limb, and kidney complications were determined using hospitalisation data and claims for medical services. Multivariable Cox proportional hazards models were used to assess the association between sex and incident complications.

RESULTS

Age-adjusted incidence rates per 1000 person years for CVD, eye, lower limb, and kidney complications were 37, 52, 21, and 32, respectively. Men had a greater risk of CVD (adjusted hazard ratio (aHR) 1.51, 95% CI 1.43 to 1.59), lower limb (aHR 1.47, 95% CI 1.38 to 1.57), and kidney complications (aHR 1.55, 95% CI 1.47 to 1.64) than women, and a greater risk of diabetic retinopathy (aHR 1.14, 95% CI 1.03 to 1.26). Over 10 years, 44%, 57%, 25%, and 35% of men experienced a CVD, eye, lower limb, or kidney complication, respectively, compared with 31%, 61%, 18%, and 25% of women. Diabetes duration (<10 years vs ≥10 years) had no substantial effect on sex differences in complications.

CONCLUSIONS

Men with diabetes are at greater risk of complications, irrespective of diabetes duration. High rates of complications in both sexes highlight the importance of targeted complication screening and prevention strategies from diagnosis.

Sex differences in diabetes‑induced hepatic and renal damage

Diabetes mellitus (DM) is a disease that affects millions of individuals worldwide and is characterized by abnormal glucose metabolism that can induce severe damage to numerous organs throughout the body. Sex differences have been demonstrated in a number of factors associated with diabetes and its complications, such as diabetic kidney disease and diabetic liver disease. To investigate the sex differences in DM further, the changes in the weight, food and water intake, and blood sugar of mice were recorded for 8 weeks in the present study. Hematoxylin and eosin staining, Masson's trichrome staining and transmission electron microscopy were used to observe the pathological changes of liver and kidney tissues. There is no significant difference in the water intake and blood glucose concentration between db/db female and male mice was observed. However, sex differences in liver and kidney damage including glomerular injury and hepatic fibrosis were found. In conclusion, the present study characterized the features of liver and kidney damage in db/db mice and indicated that sex differences should be taken into account in experiments using female and male experimental animals. Furthermore, sex differences should be taken into account in the selection of drug interventions in experiments and in clinical drug therapy.

Biology and Clinical Use of Glucagon-Like Peptide-1 Receptor Agonists in Vascular Protection

Glucagon-like peptide-1 receptor agonists (GLP1RA) are incretin agents initially designed for the treatment of type 2 diabetes mellitus but because of pleiotropic actions are now used to reduce cardiovascular disease in people with type 2 diabetes mellitus and in some instances as approved treatments for obesity. In this review we highlight the biology and pharmacology of GLP1RA. We review the evidence for clinical benefit on major adverse cardiovascular outcomes in addition to modulation of cardiometabolic risk factors including reductions in weight, blood pressure, improvement in lipid profiles, and effects on kidney function. Guidance is provided on indications and potential adverse effects to consider. Finally, we describe the evolving landscape of GLP1RA and including novel glucagon-like peptide-1-based dual/polyagonist therapies that are being evaluated for weight loss, type 2 diabetes mellitus, and cardiorenal benefit.

Association of Male Sex and Microvascular Alterations on Optical Coherence Tomography Angiography in Diabetes

Purpose

Epidemiologically, men have a higher incidence, severity, and progression of diabetic retinopathy (DR) than women. We investigated microvascular differences between men and women with diabetes on optical coherence tomography angiography (OCTA).

Methods

Three × 3 mm OCTA macula scans of non-diabetic and patients with diabetes were obtained. Vascular parameters included parafoveal vessel density (VD), vessel length density (VLD), and flow index (FI) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) as well as foveal avascular zone (FAZ) area and perimeter. Multivariable linear regression was used for statistical analysis.

Results

There were 1809 patients with diabetes and 217 non-diabetic participants that were included in this study. Diabetic individuals included those with no DR (n = 1356), mild non-proliferative DR (NPDR; n = 286), moderate NPDR (n = 126), and severe NPDR/proliferative DR (PDR; n = 41). Male sex was significantly associated with smaller FAZ area/perimeter and lower DCP VLD in both non-diabetic subjects and patients with diabetes. Male sex in the diabetic group was additionally associated with lower SCP VD/VLD and DCP VD. Addition of an interaction between male sex and diabetes status in the interaction analysis showed that being male and diabetic conferred increased reduction in DCP VD and VLD compared to sex-based changes in non-diabetics. Larger FAZ perimeter, lower SCP VD/VLD, and lower DCP VLD were associated with poorer visual acuity in diabetics.

Conclusions

On OCTA, male patients with diabetes may have more severe microvascular disease especially in the DCP compared to women.

Translational Evidence

Sex-based alterations in diabetic microvascular disease has the potential to influence future basic and clinical studies as well as the implementation of OCTA disease markers.

Evidence of Neurovascular Water Exchange and Endothelial Vascular Dysfunction in Schizophrenia: An Exploratory Study

BACKGROUND AND HYPOTHESIS

Mounting evidence supports cerebrovascular contributions to schizophrenia spectrum disorder (SSD) but with unknown mechanisms. The blood-brain barrier (BBB) is at the nexus of neural-vascular exchanges, tasked with regulating cerebral homeostasis. BBB abnormalities in SSD, if any, are likely more subtle compared to typical neurological insults and imaging measures that assess large molecule BBB leakage in major neurological events may not be sensitive enough to directly examine BBB abnormalities in SSD.

STUDY DESIGN

We tested the hypothesis that neurovascular water exchange (Kw) measured by non-invasive diffusion-prepared arterial spin label MRI (n = 27 healthy controls [HC], n = 32 SSD) is impaired in SSD and associated with clinical symptoms. Peripheral vascular endothelial health was examined by brachial artery flow-mediated dilation (n = 44 HC, n = 37 SSD) to examine whether centrally measured Kw is related to endothelial functions.

STUDY RESULTS

Whole-brain average Kw was significantly reduced in SSD (P = .007). Exploratory analyses demonstrated neurovascular water exchange reductions in the right parietal lobe, including the supramarginal gyrus (P = .002) and postcentral gyrus (P = .008). Reduced right superior corona radiata (P = .001) and right angular gyrus Kw (P = .006) was associated with negative symptoms. Peripheral endothelial function was also significantly reduced in SSD (P = .0001). Kw in 94% of brain regions in HC positively associated with peripheral endothelial function, which was not observed in SSD, where the correlation was inversed in 52% of brain regions.

CONCLUSIONS

This study provides initial evidence of neurovascular water exchange abnormalities, which appeared clinically associated, especially with negative symptoms, in schizophrenia.

Sexual dimorphism in mitochondrial dysfunction and diabetes mellitus: evidence from a population-based cohort study

BACKGROUND

Pathophysiological mechanisms underlying sex-based differences in diabetes remain poorly understood. Mitochondrial metabolite methylmalonic acid (MMA) accumulation reflects mitochondrial dysfunction which is involved in sex-specific pathophysiological responses biologically. We aimed to investigate the sex-specific associations between mortality risk and MMA in adults with the presence or absence of type 2 diabetes.

METHODS

This cohort study included 24,164 adults (12,123 females and 12,041 males) from the NHANES study during 1999-2014. Both sexes were separately categorized as those with no diabetes, prediabetes, undiagnosed diabetes, and diagnosed diabetes. Circulating MMA level was measured at baseline by mass-spectrometric detection. Mortality status was ascertained from baseline until December 31, 2015.

RESULTS

During a median follow-up of 11.1 years, 3375 deaths were documented. Males had a particularly higher mortality than females in adults with diagnosed diabetes compared to differences in those with no diabetes, prediabetes and undiagnosed diabetes (sex differences in mortality rate per 1000 person-years across diabetic status: 0.62, 1.44, 5.78, and 9.77, p < 0.001). Notably, the sex-specific difference in associations between MMA and mortality was significant only in adults with diagnosed diabetes (p for interaction = 0.028), not in adults with no diabetes and prediabetes. Adjusted HRs (95%CIs) per doubling of MMA for all-cause mortality were 1.19 (1.04-1.37) in females with diagnosed diabetes versus 1.58 (1.36-1.86) in male counterparts. In addition, MMA levels had an insignificant or weak correlation with sex hormone profiles at baseline, regardless of diabetes status and sex.

CONCLUSIONS

Sex difference in mortality risk was especially significant in diagnosed type 2 diabetes. Increasing equivalent exposure to mitochondrial metabolite MMA was associated with a greater excess risk of future mortality in males with diabetes than in females.

Sex differences in neurology: a scoping review

OBJECTIVE

Historically, neurology research has demonstrated a sex bias with mainly male subjects included in clinical trials as well as lack of reporting of data by sex. In recent years, emphasis has been placed on increased participation of female participants and explicit declaration/evaluation of sex differences in clinical research.We aimed to review the available literature examining sex differences across four subspecialty areas in neurology (demyelination, headache, stroke, epilepsy) and whether sex and gender terms have been used appropriately.

DESIGN

This scoping review was performed by searching Ovid MEDLINE, Cochrane Central Registry of Controlled Trials, EMBASE, Ovid Emcare and APA PsycINFO databases from 2014 to 2020. Four independent pairs of reviewers screened titles, abstracts and full texts. Studies whose primary objective was to assess sex or gender differences among adults with one of four neurological conditions were included. We report the scope, content and trends of previous studies that have evaluated sex differences in neurology.

RESULTS

The search retrieved 22 745 articles. Five hundred and eighty-five studies met the inclusion criteria in the review. The majority of studies were observational, often examining similar concepts designed for a different country or regional population, with rare randomised controlled trials designed specifically to assess sex differences in neurology. There was heterogeneity observed in areas of sex-specific focus between the four subspecialty areas. Thirty-six per cent (n=212) of articles used the terms sex and gender interchangeably or incorrectly.

CONCLUSIONS

Sex and gender are important biological and social determinants of health. However, the more explicit recognition of these factors in clinical literature has not been adequately translated to significant change in neuroscience research regarding sex differences. This study illustrates the ongoing need for more urgent informed action to recognise and act on sex differences in scientific discovery and correct the use of sex and gender terminology.

TRIAL REGISTRATION

The protocol for this scoping review was registered with Open Science Framework.

Sex differences in risk factors for end-stage kidney disease and death in type 2 diabetes: A retrospective cohort study

BACKGROUND

This study investigated the sex differences in the risk of end-stage kidney disease (ESKD) and mortality, as well as the effect modification of sex on associated factors in patients with type 2 diabetes.

METHODS

This multicenter observational cohort study included 4328 patients with type 2 diabetes. Hazard ratios (HRs) with 95% confidence intervals (CIs) of sex for ESKD and death were estimated using Cox proportional regression with adjustment for baseline covariates. For assessing risk modification, HRs and incidence rates for ESKD and death were compared between sexes across patient characteristics using Cox proportional and Poisson regression models.

RESULTS

During a median follow-up of 7 years, 276 patients (70% men) developed ESKD, and 241 patients (68% men) died. Men had higher risks of ESKD (HR 1.34; 95% CI 1.02-1.75; p = .034) and death (HR 1.64; 95% CI 1.24-2.16; p = .001) versus women after adjusting for multiple covariates. Among patients with microalbuminuria, men had a substantially higher risk of ESKD versus women, compared to those with normo- and macroalbuminuria (p for interaction .04). Incidence rates were also increased in men versus women with albuminuria of around 300 mg/g. No differences were detected in the association of sex and death across baseline patient subgroups.

CONCLUSIONS

In type 2 diabetes, men had an increased risk of ESKD and death versus women. Moderately increased albuminuria was strongly associated with sex difference in developing ESKD.

Smoking and diabetes: sex and gender aspects and their impact on vascular diseases

Smoking and diabetes mellitus (DM) have been identified as two major cardiovascular risk factors for many years. In the field of cardiovascular diseases, considering sex differences, or gender differences, or both has become an essential element in moving toward equitable and quality healthcare. We reviewed the impact of sex or gender on the link between smoking and DM. The risk of type 2 DM (T2DM) due to smoking has been established in both sexes at the same level. As is the case in the general population, the prevalence of smoking in those with DM is higher in men than in women, although the decrease in smoking observed in recent years is more pronounced in men than in women. Regarding chronic DM complications, smoking is an independent risk factor for all-cause mortality, as well as macrovascular and microvascular complications, in both sexes. Nevertheless, in T2DM, the burden of smoking appears to be greater in women than in men for coronary heart disease morbidity, women having a 50% higher risk of fatal coronary event. Women are more dependent to nicotine, cumulate psychosocial barriers to quitting smoking, and are more likely to gain weight, which might make it more difficult for them to quit smoking. Smoking cessation advice and treatments should take into account gender differences to improve the success and long-term maintenance of abstinence in people with and without DM. This might include interventions that address emotions and stress in women or designed to reach specific populations of men.

Smoking and diabetes interplay: A comprehensive review and joint statement

Evidence shows that smoking increases the risk of pre-diabetes and diabetes in the general population. Among persons with diabetes, smoking has been found to increase the risk of all-cause mortality and aggravate chronic diabetic complications and glycemic control. The current paper, which is a joint position statement by the French-Speaking Society on Tobacco (Société Francophone de Tabacologie) and the French-Speaking Society of Diabetes (Société Francophone du Diabète), summarizes the data available on the association between smoking and diabetes and on the impact of smoking and smoking cessation among individuals with type 1, type 2, and gestational diabetes mellitus. It also provides evidence-based information about the pharmacological and behavioral strategies for smoking cessation in these patients.

Assessment of variation in long-term outcomes of integrated care initiatives in Dutch health care

Introduction

The care for many patients with diabetes mellitus type 2 in the Netherlands, is contracted by a local care group. The healthcare providers, who collectively shape a care group, provide protocolled diabetes care. Differences exist between care groups in terms of their organizational and financial arrangements. These differences may result in variation in outcomes. The aim of this study is to assess whether variation in healthcare costs, diabetes complications and related hospital admissions on the level of care groups exist.

Methods

A quantitative cohort study was conducted. Patients who used diabetes medication (more than 180 days of defined daily doses per year) for the first time between the years 2014 and 2019 were included. Data were extracted from health insurance claims between 2014 and 2019. Generalized linear mixed models were used to analyse patient variation in healthcare costs (two and six years follow-up), diabetes-related complications and hospital admission days. Intraclass correlation coefficients were calculated to estimate the amount of variation that was attributable to the care groups.

Results

A large variation in outcome variables was observed between patients and a small variation between care groups. The intraclass correlation coefficient for long-term costs was 0.4%; for short-term costs between 0.1% and 0.3%; for complications 1% and for hospital days 4%.

Discussion

A large variation between patients with diabetes mellitus type 2 exists in terms of their healthcare costs and complications. In our study, care groups accounted minimally for this variation. A generalized linear mixed model in combination with year cohorts is a tool to study variations in the long-term outcomes of integrated care initiatives.

Microvascular Dysfunction in Skeletal Muscle Precedes Myocardial Vascular Changes in Diabetic Cardiomyopathy: Sex-Dependent Differences

Aim

To uncover sex-related microvascular abnormalities that underlie the early presentation of reduced perfusion in leg skeletal muscle in a type II rat model of diabetic cardiomyopathy.

Methods and Results

Diabetes was induced using a non-obese, diet-based, low-dose streptozotocin model in adult female (18 diabetic, 9 control) and male rats (29 diabetic, 11 control). Time-course monitoring over 12 months following diabetes induction was performed using echocardiography, treadmill exercise, photoacoustic imaging, flow-mediated dilation (FMD), histopathology, and immunohistochemistry. Diabetic rats maintained normal weights. Hypertension appeared late in both diabetic males (7 months) and females (10 months), while only diabetic males had elevated cholesterol (7 months). On echocardiography, all diabetic animals maintained normal ejection fraction and exhibited diastolic dysfunction, mild systolic dysfunction, and a slightly enlarged left ventricle. Exercise tolerance declined progressively and early in males (4 months), later in females (8 months); FMD showed lower baseline femoral arterial flow but unchanged reactivity in both sexes (5 months); and photoacoustic imaging showed lower tissue oxygen saturation in the legs of diabetic males (4 months) and diabetic females (10 months). Myocardial perfusion was normal in both sexes. Histopathology at the final timepoint of Month 10 (males) and Month 12 (females) revealed that myocardial microvasculature was normal in both vessel density and structure, thus explaining normal perfusion on imaging. However, leg muscle microvasculature exhibited perivascular smooth muscle thickening around small arterioles in diabetic females and around large arterioles in diabetic males, explaining the depressed readings on photoacoustic and FMD. Histology also confirmed the absence of commonly reported HFpEF markers, including microvessel rarefaction, myocardial fibrosis, and left ventricular hypertrophy.

Conclusion

Exercise intolerance manifesting early in the progression of diabetic cardiomyopathy can be attributed to decreased perfusion to the leg skeletal muscle due to perivascular smooth muscle thickening around small arterioles in females and large arterioles in males. This microvascular abnormality was absent in the myocardium, where perfusion levels remained normal throughout the study. We conclude that although skeletal muscle microvascular dysfunction of the vasculature presents at different levels depending on sex, it consistently presents early in both sexes prior to overt cardiac changes such as rarefaction, fibrosis, or hypertrophy.

Regional cutaneous vasodilator responses to rapid and gradual local heating in young adults

PURPOSE

To examine the extent of regional variations in cutaneous vasodilatation during rapid and gradual local thermal hyperaemia (LTH) in young adults.

METHODS

In thirty young adults (21 ± 3 years, 15 females), cutaneous vascular conductance, normalized to maximum local skin heating at 44 °C (%CVC_max), was assessed at the upper chest, abdomen, dorsal arm, dorsal forearm, thigh, and medial calf during rapid (33-42 °C at 1 °C·20 s^-1) and gradual (33-42 °C at 1 °C·5 min^-1) LTH on separate days. For both protocols, local temperatures were held at 42 °C for up to 35 min, followed by 20-30 min at 44 °C. During rapid LTH, between-region responses were evaluated at baseline, the initial vasodilator peak, and 42 °C plateau. During gradual LTH, responses were assessed at baseline and the 42 °C plateau.

RESULTS

There were significant main effects of body region on %CVC_max for the initial peak and plateau during rapid LTH and for the plateau during gradual LTH (all P < 0.001) Conversely, main effects of sex and the sex by region interaction were not significant (all P > 0.05). The magnitudes of between-region differences varied across the body (~1-17% range). The greatest effects were observed for the abdomen, wherein responses were consistently lower compared to other regions. Further, responses were consistent between males and females across all body regions and heating phases.

CONCLUSION

Regional variations in the cutaneous vasodilator response to local heating are evident for rapid and gradual LTH in young adults, with the largest effects observed for the abdomen, albeit regional differences were similar between sexes.

Sex-Based Analysis of Potential Inflammation-Related Protein Biomarkers in the Aqueous Humor of Patients With Diabetes Mellitus

Purpose

To investigate whether men have higher inflammatory protein biomarker concentrations in their aqueous humor (AH) compared with women in groups of patients with varying levels of diabetic disease.

Methods

This cross-sectional study included AH specimens from 59 adult patients comprised of three groups: no diabetes mellitus (DM), DM without diabetic retinopathy (DR), and DM with proliferative diabetic retinopathy (PDR). Protein biomarker concentration values were quantified using a commercial proximity extension assay-based technique.

Results

Intersex comparisons of concentration values for each protein biomarker revealed no discoveries in patients with no DM or with PDR. In contrast, 24 discoveries were detected in patients with DM without DR. The mean concentration value for all 24 protein biomarkers was higher in men compared with women. Of these 24 proteins, 12 demonstrated a significant association with sex on multivariate linear regression analysis. The β coefficient results demonstrated a positive association between male sex and concentration value for all 12 of these proteins.

Conclusions

Higher AH concentration levels of several potential biomarkers, including chemokines, proteases, proteins involved in programmed cell death, and a T-cell surface protein, were detected in men with DM with no DR. These findings suggest that men may have a more inflammatory disease phenotype compared with women in this group of patients.

Translational Relevance

The findings of this study help explain differences in epidemiologic patterns of diabetic retinopathy development between men and women.