The prevalence of coronary artery calcium among diabetic individuals without known coronary artery disease

Rosiglitazone improves insulin resistance but does not improve exercise capacity in individuals with impaired glucose tolerance: A randomized clinical study

Dysmetabolic states, such as type 2 diabetes (T2D), characterized by insulin resistance (IR), are associated with fatty liver, increased cardiovascular disease (CVD) risk, and decreased functional exercise capacity (FEC). Rosiglitazone (RO) improves exercise capacity and IR in T2D. However, the effects of RO on FEC and other markers of CVD risk in prediabetes are unknown. We hypothesized that insulin sensitization with RO would improve exercise capacity and markers of CVD risk in participants with impaired glucose tolerance (IGT). Exercise performance (peak oxygen consumption and oxygen uptake kinetics), IR (homeostasis model assessment of IR and quantitative insulin sensitivity check index), and surrogate cardiovascular endpoints (coronary artery calcium (CAC) volume and density and C-reactive protein (CRP)) were measured in participants with IGT after 12 and 18 months of RO or placebo (PL). RO did not significantly improve exercise capacity. Glycemic measures and IR were significantly lower in people on RO compared to PL at 18 months. CAC volume progression was not different between PL and RO groups. RO did not improve exercise capacity during an 18-month intervention despite improved IR and glycemia in people with IGT. Future studies should explore why effects on FEC with RO occur in T2D but not IGT. Understanding these questions may help in targeting therapeutic approaches in T2D and IGT.

Screening for Coronary Artery Disease in Patients with Diabetes

PURPOSE OF REVIEW

The study aims to describe methods for detecting subclinical coronary artery disease (CAD) and their potential implications in asymptomatic patients with diabetes.

RECENT FINDINGS

Imaging tools can assess non-invasively the presence and severity of CAD, based on myocardial ischemia, coronary artery calcium score, and coronary computed tomography coronary angiography. Subclinical CAD is common in the general population ageing 50 to 64 years with any coronary atherosclerosis present in 42.1% and obstructive CAD in 5.2%. In patients with diabetes, an even higher prevalence has been noted. The presence of myocardial ischemia, obstructive CAD, and the extent of coronary atherosclerosis provide powerful risk stratification regarding the risk of cardiovascular events. However, randomized trials evaluating systematic screening in the general population or patients with diabetes have demonstrated only moderate impact on management and no significant impact on patient outcomes. Despite providing improved risk stratification, systematic screening of CAD is not recommended in patients with diabetes.

Coronary Artery Calcium and Cognitive Decline in the Diabetes Prevention Program Outcomes Study

Background Our aim was to investigate the association of coronary artery calcium (CAC) with cognitive function in adults with impaired glucose tolerance or type 2 diabetes. Methods and Results The Diabetes Prevention Program was a randomized controlled trial comparing an intensive lifestyle intervention, metformin, or placebo for prevention of type 2 diabetes among patients with prediabetes. After 3 years, intensive lifestyle intervention and placebo were stopped, the metformin arm was unmasked, and participants continued in the DPPOS (Diabetes Prevention Program Outcomes Study). Approximately 14 years after randomization (Y14), CAC (Agatston score) was assessed with computed tomography, and cognitive performance was assessed with the Spanish English Verbal Learning Test (SEVLT) and Digit Symbol Substitution Test. SEVLT and Digit Symbol Substitution Test were reassessed 5 years later (Y19) along with the Modified Mini-Mental State Exam. We examined cross-sectional and longitudinal associations between CAC and cognition among 1931 participants using linear and logistic regression. In unadjusted analyses, compared with no calcification, CAC score >300 was associated with decreased performance on all cognitive tests at Y14 in both sexes. Additionally, CAC >300 was associated with a greater 5-year decline in SEVLT Immediate Recall in both sexes and SEVLT Delayed Recall in women. After adjustment for demographic, genetic, metabolic, vascular, and behavioral covariates, CAC score >300 remained associated with greater decline in only SEVLT Delayed Recall in women. Conclusions In women with prediabetes or diabetes, CAC >300, compared with no calcification, was independently associated with greater decline in verbal memory. Registration information clinicaltrials.gov. Identifier: NCT00038727.

Can HDL cholesterol be replaced by paraoxonase 1 activity in the prediction of severe coronary artery disease in patients with type 2 diabetes?

BACKGROUND AND AIMS

Novel biomarkers are required to improve cardiovascular disease prediction in patients with type 2 diabetes (T2D) as a high-risk population. This study was conducted to examine whether coronary artery disease (CAD) risk assessment can be improved by substituting high-density lipoprotein (HDL)-bound paraoxonase 1 (PON1) activity for HDL cholesterol (HDL-C) concentration in patients with T2D.

METHODS AND RESULTS

In this study, we studied 139 patients with T2D (mean age 64.12 ± 8.17 years) who underwent coronary angiographic examination. The initial rate of substrate hydrolysis was spectrophotometrically assayed in kinetic mode for measuring PON1 activity. Receiver operating characteristic (ROC) graphs are created by plotting true positivity versus false positivity. In patients with HbA_1c ≥ 7%, PON1 (AUC = 0.7, p = 0.029) and nonHDL-C/PON1 (AUC = 0.75, p = 0.013) were significantly more capable of differentiating patients with CAD from those without CAD compared to HDL-C and nonHDL-C/HDL-C. Also, the predictive power of PON1 (AUC = 0.64, p = 0.029) and nonHDL-C/PON1 (AUC = 0.71, p = 0.004) were significantly higher in comparison with HDL-C and nonHDL-C/HDL-C for CAD characterization in patients aged ≥50 years. Moreover, PON1 and nonHDL-C/PON1 are associated with the incidence of CAD with an AUC of 0.7 (p = 0.026) and AUC of 0.64 (p = 0.087), respectively, among subjects with low HDL-C.

CONCLUSION

PON1 and the ratio of nonHDL-C/PON1 significantly improve the prediction of severe CAD in T2D patients and in patients with HbA_1c ≥ 7%, age ≥50 years, or low HDL-C. PON1 activity and lipid ratios using this enzyme may be valuable as substitutes of HDL-C for increasing clinical efficacies in cardiovascular risk assessment.

Impaired intracellular calcium homeostasis enhances protein O-GlcNAcylation and promotes vascular calcification and stiffness in diabetes

Vascular calcification is accelerated in patients with diabetes mellitus and increases risk of cardiovascular events and mortality. Vascular smooth muscle cells (VSMC) play a key role in regulating vascular tone and contribute significantly to the development of diabetic vasculopathy. In this study, the function of stromal interaction molecule 1 (STIM1), an important regulator for intracellular calcium homeostasis, in diabetic vascular calcification was investigated, and the underlying molecular mechanisms were uncovered. A SMC-specific STIM1 deletion mouse model (STIM1Δ/Δ) was generated by breeding the STIM1 floxed mice (STIM1f/f) with SM22α-Cre transgenic mice. Using aortic arteries from the STIM1Δ/Δ mice and their STIM1f/f littermates, we found that SMC-specific STIM1 deletion induced calcification of aortic arteries cultured in osteogenic media ex vivo. Furthermore, STIM1 deficiency promoted osteogenic differentiation and calcification of VSMC from the STIM1Δ/Δ mice. In the low-dose streptozotocin (STZ)-induced mouse model of diabetes, SMC-specific STIM1 deletion markedly enhanced STZ-induced vascular calcification and stiffness in the STIM1Δ/Δ mice. The diabetic mice with SMC-specific STIM1 ablation also exhibited increased aortic expression of the key osteogenic transcription factor, Runx2, and protein O-GlcNAcylation, an important post-translational modulation that we have reported to promote vascular calcification and stiffness in diabetes. Consistently, elevation of O-GlcNAcylation was demonstrated in aortic arteries and VSMC from the STIM1Δ/Δ mice. Inhibition of O-GlcNAcylation with a pharmacological inhibitor abolished STIM1 deficiency-induced VSMC calcification, supporting a critical role of O-GlcNAcylation in mediating STIM1 deficiency-induced VSMC calcification. Mechanistically, we identified that STIM1 deficiency resulted in impaired calcium homeostasis, which activated calcium signaling and increased endoplasmic reticulum (ER) stress in VSMC, while inhibition of ER stress attenuated STIM1-induced elevation of protein O-GlcNAcylation. In conclusion, the study has demonstrated a causative role of SMC-expressed STIM1 in regulating vascular calcification and stiffness in diabetes. We have further identified a novel mechanisms underlying STIM1 deficiency-induced impairment of calcium homeostasis and ER stress in upregulation of protein O-GlcNAcylation in VSMC, which promotes VSMC osteogenic differentiation and calcification in diabetes.

Plasma phosphate and all-cause mortality in individuals with and without type 2 diabetes: the Dutch population-based lifelines cohort study

Introduction

Individuals with type 2 diabetes have a substantially elevated cardiovascular risk. A higher plasma phosphate level promotes vascular calcification, which may adversely affect outcomes in individuals with type 2 diabetes. We hypothesized that the association between plasma phosphate and all-cause mortality is stronger in individuals with type 2 diabetes, compared to those without diabetes.

Methods

We analysed the association between plasma phosphate and all-cause mortality in the Dutch population-based Lifelines cohort and in subgroups with and without type 2 diabetes, using multivariable Cox regression adjusted for potential confounders. Effect modification was tested using multiplicative interaction terms.

Results

We included 57,170 individuals with 9.4 [8.8–10.4] years follow-up. Individuals within the highest phosphate tertile (range 1.00–1.83 mmol/L) were at higher risk of all-cause mortality (fully adjusted HR 1.18 [95% CI 1.02–1.36], p = 0.02), compared with the intermediate tertile (range 0.85–0.99 mmol/L). We found significant effect modification by baseline type 2 diabetes status (p-interaction = 0.003). Within the type 2 diabetes subgroup (N = 1790), individuals within the highest plasma phosphate tertile had an increased mortality risk (HR 1.73 [95% CI 1.10–2.72], p = 0.02 vs intermediate tertile). In individuals without diabetes at baseline (N = 55,380), phosphate was not associated with mortality (HR 1.12 [95% CI 0.96–1.31], p = 0.14). Results were similar after excluding individuals with eGFR < 60 mL/min/1.73 m².

Discussion

High-normal plasma phosphate levels were associated with all-cause mortality in individuals with type 2 diabetes. The association was weaker and non-significant in those without diabetes. Measurement of phosphate levels should be considered in type 2 diabetes; whether lowering phosphate levels can improve health outcomes in diabetes requires further study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01499-4.

The metabolic signature of cardiovascular disease and arterial calcification in patients with chronic kidney disease

BACKGROUND AND AIMS

The relationship between chronic kidney disease (CKD) and cardiovascular events is well-established. Clinically recognised risk factors of cardiovascular disease cannot fully explain this association. The objective of the present cross-sectional study was to investigate associations between serum metabolites and prevalent cardiovascular disease, as well as subclinical cardiovascular disease measured as coronary artery calcium score (CACS) in patients with CKD.

METHODS

More than 200 preselected metabolites were quantified using nuclear magnetic resonance spectroscopy in 725 patients and 174 controls from the Copenhagen CKD Cohort. CACS was determined by computed tomography.

RESULTS

Mean age of patients was 57.8 years, and 444 (61.3%) were men. Most of patients had hypercholesterolemia, and 133 (18.3%) had type 2 diabetes. Overall, 85 metabolites were significantly associated with prevalent cardiovascular disease in a model adjusted for eGFR, age, and sex, as well as Bonferroni correction for multiple testing (p < 0.001). After further adjusting for diabetes, BMI, smoking, and cholesterol-lowering medication, the significance was lost for all but six metabolites (concentration of ApoA-1, cholesterol in total HDL and HDL2, total lipids and phospholipids in large HDL particles, and the ratio of phospholipids to total lipids in smaller VLDL particles). Of the 85 metabolites associated with prevalent cardiovascular disease, 71 were also associated with CACS in a similar pattern. Yet, in the model adjusted for all seven cardiovascular risk factors, only serum glucose levels and the ratio of triglycerides to total lipids in larger LDL particles remained significant.

CONCLUSIONS

In patients with CKD, associations with prevalent cardiovascular disease were mainly found for HDL-related metabolites, while CACS was associated with glucose levels and increased triglycerides to total lipids ratio in LDL particles.

Evolution of Coronary Calcium Screening for Assessment of Atherosclerotic Cardiovascular Disease Risk and Role in Preventive Cardiology

PURPOSE OF REVIEW

Coronary artery calcium (CAC) is an important measure of subclinical atherosclerosis and strongly predicts atherosclerotic cardiovascular disease (ASCVD) outcomes. The purpose of this review is to discuss the key studies that have helped to establish its role as an important screening tool and its place in preventive cardiology.

RECENT FINDINGS

Epidemiologic studies document a strong relation of age, race/ethnicity, and risk factors with the prevalence and extent of CAC. Large-scale registry and prospective investigations show CAC to be the strongest subclinical disease predictor of ASCVD outcomes, with higher CAC scores associated with successively higher risks and those with a CAC score of 0 having a long-term "warranty" against having events. Moreover, CAC is associated with greater initiation of preventive health behaviors and therapy. Current US guidelines utilize CAC to inform the treatment decision for statin therapy. Further study is underway to document whether CAC screening will ultimately improve clinical outcomes. CAC is well established as the most important subclinical cardiovascular disease measure for prediction of future ASCVD outcomes and can be used for informing the treatment decision for preventive therapies.

18F-Sodium Fluoride Positron Emission Tomography Activity Predicts the Development of New Coronary Artery Calcifications

OBJECTIVE

The coronary calcium score (CCS) predicts cardiovascular disease risk in individuals with diabetes, and rate of progression of CCS is an additional and incremental marker of risk. ¹⁸F-sodium fluoride positron emission tomography (¹⁸F-NaF PET) detects early and active calcifications within the vasculature. We aimed to ascertain the relationship between ¹⁸F-NaF PET activity and CCS progression in patients with diabetes. Approach and Results: We identified individuals between 50 and 80 years with diabetes and no history of clinical coronary artery disease. Those with a CCS ≥10 were invited to undergo ¹⁸F-NaF PET scanning and then repeat CCS >2 years later. ¹⁸F-NaF PET and CCS analysis were performed on a per-coronary and a per-patient level. We compared the proportion of CCS progressors in ¹⁸F-NaF PET-positive versus ¹⁸F-NaF PET-negative coronary arteries. Forty-one participants with 163 coronary arteries underwent follow-up CCS 2.8±0.5 years later. ¹⁸F-NaF PET-positive coronary arteries (n=52) were more likely to be CCS progressors, compared with negative coronary arteries (n=111; 86.5% versus 52.3%, P<0.001). Adjusting for baseline CCS, ¹⁸F-NaF PET-positive disease was an independent predictor of subsequent CCS progression (odds ratio, 2.92 [95% CI, 1.32-6.45], P=0.008). All subjects (100%, 15/15) with ≥2 ¹⁸F-NaF-positive coronary arteries progressed in CCS.

CONCLUSIONS

In subjects with diabetes, ¹⁸F-NaF PET positivity at baseline, independently predicted the progression of calcifications within the coronary arteries 2.8 years later. These findings suggest ¹⁸F-NaF PET may be a promising technique for earlier identification of patients at higher risk of cardiovascular events.

Sex Differences in Coronary Artery Calcium and Mortality From Coronary Heart Disease, Cardiovascular Disease, and All Causes in Adults With Diabetes: The Coronary Calcium Consortium

OBJECTIVE

While diabetes has been previously noted to be a stronger risk factor for cardiovascular disease (CVD) in women compared with men, whether this is still the case is not clear. Coronary artery calcium (CAC) predicts coronary heart disease (CHD) and CVD in people with diabetes; however, its sex-specific impact is less defined. We compared the relation of CAC in women versus men with diabetes for total, CVD, and CHD mortality.

RESEARCH DESIGN AND METHODS

We studied adults with diabetes from a large registry of patients with CAC scanning with mortality follow-up over 11.5 years. Cox regression examined the relation of CAC with mortality end points.

RESULTS

Among 4,503 adults with diabetes (32.5% women) aged 21-93 years, 61.2% of women and 80.4% of men had CAC >0. Total, CVD, and CHD mortality rates were directly related to CAC; women had higher total and CVD death rates than men when CAC >100. Age- and risk factor-adjusted hazard ratios (HRs) per log unit CAC were higher among women versus men for total mortality (1.28 vs. 1.18) (interaction P = 0.01) and CVD mortality (1.47 vs. 1.27) (interaction P = 0.04) but were similar for CHD mortality (1.48 and 1.48). For CVD mortality, HRs with CAC scores of 101-400 and >400 were 3.67 and 6.27, respectively, for women and 1.63 and 3.48, respectively, for men (interaction P = 0.04). For total mortality, HRs were 2.56 and 4.05 for women, respectively, and 1.88 and 2.66 for men, respectively (interaction P = 0.01).

CONCLUSIONS

CAC predicts CHD, CVD, and all-cause mortality in patients with diabetes; however, greater CAC predicts CVD and total mortality more strongly in women.

Coronary artery calcification, carotid intima-media thickness and cardiac dysfunction in young adults with type 2 diabetes mellitus

AIMS

Cardiovascular diseases (CVD) are the major causes of mortality in patients with type 2 diabetes mellitus (T2DM). There is paucity of information on prevalence of subclinical atherosclerosis and cardiac dysfunction in young adults with T2DM. This study aimed to assess the prevalence of subclinical atherosclerosis and cardiac dysfunction in young adults with T2DM, asymptomatic for CVD.

METHODS

Sixty-two patients with T2DM, age between 30 and 50 years were evaluated for coronary artery calcium (CAC) score, carotid intima-media thickness (CIMT) and flow-mediated dilatation (FMD) at the brachial artery. All were subjected to 2D-color Doppler echocardiography, electrocardiography and testing for serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hsCRP). The results were compared with those in 60 age, sex and BMI-matched healthy controls.

RESULTS

Prevalence of a positive CAC score was comparable among subjects with and without T2DM (14.5% vs 11.7%). Patients with T2DM had a significantly higher CIMT (0.54 ± 0.15 vs 0.49 ± 0.10 mm, p = 0.01), left ventricular (LV) mass (170 ± 36 vs 147 ± 23 g, p < 0.001), heart rate (83 ± 13 vs 74 ± 11, p < 0.001) and QTc interval (402 ± 20 vs 382 ± 21 ms, p < 0.001) compared to controls. FMD was lower in patients with T2DM compared to controls (9.1 ± 4.4% vs 10.7 ± 3.9%, p = 0.04). There was a higher prevalence of LV hypertrophy (37% vs 7%, p < 0.001) and diastolic dysfunction (7% vs 0) in patients with T2DM compared to controls. None of the participants had systolic dysfunction. Hypertension (42 vs 7%, p < 0.001) and metabolic syndrome (76 vs 35%, p < 0.001) were more prevalent in the patient group. In the multivariate analysis, age was the lone predictor of CIMT and FMD; while T2DM and male gender were the independent predictors of LV mass.

CONCLUSIONS

Young adults with T2DM, asymptomatic for CVD had a higher prevalence of CVD risk factors, LV hypertrophy and diastolic dysfunction. A higher CIMT and LV mass, and a lower FMD were noted in patients with T2DM. CAC score was comparable between the groups and thus may not be a useful tool for assessment of subclinical atherosclerosis in this cohort, where CIMT and FMD may be more appropriate.

Subclinical macroangiopathic target organ damage in type 1 diabetes mellitus patients

PURPOSE

We have summarized key studies regarding the assessment of subclinical macroangiopathic target organ damage (TOD) in type 1 diabetes mellitus (T1DM).

RESULTS

Although chronic complications resulting from hyperglycemia, in particular macroangiopathies, are still the first cause of death in T1DM, there has been growing recognition of the role of hypoglycemia in cardiovascular morbidity and mortality. Subclinical TOD diagnosis ensures early implementation of the complex management aiming at either partial reversal of these complications or at least its downturn. To better identify patients with early TODs, several non-invasive diagnostic techniques are employed, including the ultrasonographic assessment of the intima-media thickness (IMT), computed tomography (CT) for coronary artery calcium (CAC) scores, and pulse wave velocity (PWV) measurement for arterial stiffness evaluation. Various studies reported that T1DM patients present an increased IMT. An increasing IMT fairly correlates with the cardiovascular (CV) events risk even after the adjustment to age, diabetes duration, quality of glucose control as well as the presence of hypertension, and chronic complications. Another, well established marker of the organ damage - CAC score is recommended by ACC/AHA guidelines to assess the overall CV risk in T1DM. Also, the arterial stiffness evaluation with PWV may further improve CV risk prediction, which has been reported in multiple studies including the Framingham Heart Study.

CONCLUSIONS

There is shortage of data from prospective studies which could confirm the benefits of early treatment initiation based on the presence of the subclinical organ damage in T1DM. Most evidence comes from T2DM trials, where effective preventive measures were identified i.e.: smoking cessation, reasonable blood glucose control, efficacious hypertension treatment, and dyslipidemia management, as well as renoprotection. There is still a field for further research to see if routine assessment of asymptomatic vascular damage and early implementation of aggressive treatment would reduce mortality excess from CVD in T1DM.

Metabolic Stress and Cardiovascular Disease in Diabetes Mellitus: The Role of Protein O-GlcNAc Modification

Mammalian cells metabolize glucose primarily for energy production, biomass synthesis, and posttranslational glycosylation; and maintaining glucose metabolic homeostasis is essential for normal physiology of cells. Impaired glucose homeostasis leads to hyperglycemia, a hallmark of diabetes mellitus. Chronically increased glucose in diabetes mellitus promotes pathological changes accompanied by impaired cellular function and tissue damage, which facilitates the development of cardiovascular complications, the major cause of morbidity and mortality of patients with diabetes mellitus. Emerging roles of glucose metabolism via the hexosamine biosynthesis pathway (HBP) and increased protein modification via O-linked β-N-acetylglucosamine (O-GlcNAcylation) have been demonstrated in diabetes mellitus and implicated in the development of diabetic cardiovascular complications. This review will discuss the biological outcomes of the glucose metabolism via the hexosamine biogenesis pathway and protein O-GlcNAcylation in regulating cellular homeostasis, and highlight the regulations and contributions of elevated O-GlcNAcylation to the pathogenesis of diabetic cardiovascular disease.

Imaging to Stratify Coronary Artery Disease Risk in Asymptomatic Patients with Diabetes

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in patients with diabetes mellitus. Patients with diabetes have a higher prevalence of CAD and a larger magnitude of ischemia, and they are more likely to have silent myocardial ischemia and myocardial infarction. However, recent large cohort studies demonstrate that diabetic patients are not a homogenous group with similar high risk for cardiac events. In fact, more than 30% of asymptomatic diabetic patients do not have evidence of coronary atherosclerosis and have a very low annual cardiac event rate. Accordingly, there has been a recent paradigm shift as to whether the detection of subclinical coronary atherosclerosis through imaging can best guide therapeutic decision making. This review discusses the role of various cardiac imaging techniques for stratifying cardiovascular risk and optimizing therapy in asymptomatic diabetic patients.

Diabetes, subclinical atherosclerosis and multiple cardiovascular risk factors in hard-to-reach asymptomatic patients

AIM

To examine the association of cardiovascular disease risk factors with and their cumulative effect on coronary artery calcium in hard-to-reach asymptomatic patients with diabetes.

METHODS

A total of 2563 community-dwelling asymptomatic subjects from Central Appalachia participated in coronary artery calcium screening at a heart centre. Binary variable was used to indicate that coronary artery calcium was either present or absent. Independent variables consisted of demographic and modifiable risk factors and medical conditions. Descriptive statistics and multinomial logistic regression analyses were conducted.

RESULTS

In total, 55.8% and 13.7% of study participants had subclinical atherosclerosis (coronary artery calcium ⩾1) and diabetes, respectively. The presence of coronary artery calcium was higher in subjects with diabetes (68.5%) than those without (53.8%). Compared to subjects without diabetes with coronary artery calcium = 0, obesity, hypertension, hypercholesterolaemia and smoking increased the odds of the presence of coronary artery calcium (coronary artery calcium score ⩾1) regardless of diabetes status; however, with larger odds ratios in subjects with diabetes. Compared to subjects without diabetes with coronary artery calcium score = 0, having 3, 4 and ⩾5 risk factors increased the odds of presence of coronary artery calcium in subjects with diabetes by 14.06 (confidence interval = 3.26-62.69), 32.30 (confidence interval = 7.41-140.82) and 47.12 (confidence interval = 10.35-214.66) times, respectively.

CONCLUSION

There is a need for awareness about subclinical atherosclerosis in patients with diabetes and more research about coronary artery calcium in subpopulations of patients.

Associations of coronary artery calcified plaque density with mortality in type 2 diabetes: the Diabetes Heart Study

BACKGROUND

Coronary artery calcified plaque (CAC) is strongly predictive of cardiovascular disease (CVD) events and mortality, both in general populations and individuals with type 2 diabetes at high risk for CVD. CAC is typically reported as an Agatston score, which is weighted for increased plaque density. However, the role of CAC density in CVD risk prediction, independently and with CAC volume, remains unclear.

METHODS

We examined the role of CAC density in individuals with type 2 diabetes from the family-based Diabetes Heart Study and the African American-Diabetes Heart Study. CAC density was calculated as mass divided by volume, and associations with incident all-cause and CVD mortality [median follow-up 10.2 years European Americans (n = 902, n = 286 deceased), 5.2 years African Americans (n = 552, n = 93 deceased)] were examined using Cox proportional hazards models, independently and in models adjusted for CAC volume.

RESULTS

In European Americans, CAC density, like Agatston score and volume, was consistently associated with increased risk of all-cause and CVD mortality (p ≤ 0.002) in models adjusted for age, sex, statin use, total cholesterol, HDL, systolic blood pressure, high blood pressure medication use, and current smoking. However, these associations were no longer significant when models were additionally adjusted for CAC volume. CAC density was not significantly associated with mortality, either alone or adjusted for CAC volume, in African Americans.

CONCLUSIONS

CAC density is not associated with mortality independent from CAC volume in European Americans and African Americans with type 2 diabetes.

Influence of diabetes mellitus duration on the efficacy of ischemic preconditioning in a Zucker diabetic fatty rat model

Augmented mortality and morbidity following an acute myocardial infarction in patients with diabetes mellitus Type 2 (T2DM) may be caused by increased sensitivity to ischemia reperfusion (IR) injury or altered activation of endogenous cardioprotective pathways modified by T2DM per se or ischemic preconditioning (IPC). We aimed to investigate, whether the duration of T2DM influences sensitivity against IR injury and the efficacy of IPC, and how myocardial glucose oxidation rate was involved. Male Zucker diabetic fatty rats (homozygote (fa/fa)) at ages 6-(prediabetic), 12- (onset diabetes) and 24-weeks of age (late diabetes) and their age-matched non-diabetic controls (heterozygote (fa/+) were subjected to IR injury in the Langendorff model and randomised to IPC stimulus or control. T2DM rats were endogenously protected at onset of diabetes, as infarct size was lower in 12-weeks T2DM animals than in 6- (35±2% vs 53±4%; P = 0.006) and 24-weeks animals (35±2% vs 72±4%; P<0.0001). IPC reduced infarct size in all groups irrespective of the presence of T2DM and its duration (32±3%; 20±2%; 36±4% respectively; (ANOVA P<0.0001). Compared to prediabetic rats, myocardial glucose oxidation rates were reduced during stabilisation and early reperfusion at onset of T2DM, but these animals retained the ability to increase oxidation rate in late reperfusion. Late diabetic rats had low glucose oxidation rates throughout stabilisation and reperfusion. Despite inherent differences in sensitivity to IR injury, the cardioprotective effect of IPC was preserved in our animal model of pre-, early and late stage T2DM and associated with adaptations to myocardial glucose oxidation capacity.

Genome-wide association study of coronary artery calcified atherosclerotic plaque in African Americans with type 2 diabetes

Background

Coronary artery calcified atherosclerotic plaque (CAC) predicts cardiovascular disease (CVD). Despite exposure to more severe conventional CVD risk factors, African Americans (AAs) are less likely to develop CAC, and when they do, have markedly lower levels than European Americans. Genetic factors likely contribute to the observed ethnic differences. To identify genes associated with CAC in AAs with type 2 diabetes (T2D), a genome-wide association study (GWAS) was performed using the Illumina 5 M chip in 691 African American-Diabetes Heart Study participants (AA-DHS), with replication in 205 Jackson Heart Study (JHS) participants with T2D. Genetic association tests were performed on the genotyped and 1000 Genomes-imputed markers separately for each study, and combined in a meta-analysis.

Results

Single nucleotide polymorphisms (SNPs), rs11353135 (2q22.1), rs16879003 (6p22.3), rs5014012, rs58071836 and rs10244825 (all on chromosome 7), rs10918777 (9q31.2), rs13331874 (16p13.3) and rs4459623 (18q12.1) were associated with presence and/or quantity of CAC in the AA-DHS and JHS, with meta-analysis p-values ≤8.0 × 10⁻⁷. The strongest result in AA-DHS alone was rs6491315 in the 13q32.1 region (parameter estimate (SE) = −1.14 (0.20); p-value = 9.1 × 10⁻⁹). This GWAS peak replicated a previously reported AA-DHS CAC admixture signal (rs7492028, LOD score 2.8).

Conclusions

Genetic association between SNPs on chromosomes 2, 6, 7, 9, 16 and 18 and CAC were detected in AAs with T2D from AA-DHS and replicated in the JHS. These data support a role for genetic variation on these chromosomes as contributors to CAC in AAs with T2D, as well as to variation in CAC between populations of African and European ancestry.

Electronic supplementary material

The online version of this article (10.1186/s12863-017-0572-9) contains supplementary material, which is available to authorized users.

Assessing Cardiovascular Risk and Testing in Type 2 Diabetes

PURPOSE OF REVIEW

Type 2 diabetes confers approximately twofold-increased risk for cardiovascular disease. Early risk stratification of these patients may help reduce cardiovascular events. This review discusses the state of the art of risk factors, biomarkers, and subclinical disease parameters potentially useful in cardiovascular risk assessment in type 2 diabetes.

RECENT FINDINGS

Scientific progress in the past decade has identified a spectrum of risk in diabetic individuals rather than categorizing diabetes as a coronary heart disease equivalent as previously done. Recent data on emerging biomarkers and diagnostic imaging, along with traditional risk factors, provide evidence to help inform individualized cardiovascular risk assessment. Comprehensive assessment of traditional risk factors, biomarkers, complications of diabetes, and subclinical atherosclerosis may help classify diabetic individuals as low, intermediate, or high risk for determining the intensity of lifestyle modification and pharmacotherapy. Further research may lead to a comprehensive pathway for cardiovascular disease risk assessment in diabetic patients.

Presence, Characteristics, and Volumes of Coronary Plaque Determined by Computed Tomography Angiography in Young Type 2 Diabetes Mellitus

Prevention and management of coronary artery disease (CAD) is of great concern in patients with diabetes mellitus. Although the impact of coronary atherosclerosis is described well for subjects older than 40 years, the prevalence and types of coronary atherosclerosis in young patients are not well known. The aim of this study was to evaluate the prevalence, extent, severity, and volumes of coronary plaque in type 2 diabetes mellitus (T2DM) population younger than of 40 years. This prospective study enrolled 181 subjects (25-40 year old) undergoing coronary computed tomography angiography, with 86 T2DM and 95 nondiabetic age/gender-matched subjects. Coronary artery calcium (CAC), plaque assessment including total segment stenosis (sum of individual segmental stenosis), total plaque scores (sum of semiquantitative segmental plaque burden), segment involvement scores (number of segments with plaque) were evaluated. In addition, we quantitatively measured plaque volumes in total, fibrous, fibrous fatty, dense calcified, and low-attenuation plaque using novel plaque software. Compared with nondiabetic patients, the prevalence of CAD, calcified, and noncalcified plaques was higher in patients with T2DM (19% vs 58%; p <0.001). In patients with a zero CAC, T2DM had a higher prevalence (46%) of noncalcified plaque (p <0.0001). In multivariate linear regression models after adjusting for traditional cardiovascular risk factors, increased total segmental stenosis, total plaque scores, and segment involvement scores were associated with T2DM. Regarding quantitative plaque assessment, all volumes in noncalcified plaque type were approximately threefold higher in patients with T2DM. In conclusion, young patients with T2DM are susceptible to premature CAD with more calcified and noncalcified plaques. Early prevention program using computed tomography angiography might be helpful in identifying young diabetic patients with subclinical atherosclerosis.

Coronary atherosclerosis in indigenous South American Tsimane: a cross-sectional cohort study

BACKGROUND

Conventional coronary artery disease risk factors might potentially explain at least 90% of the attributable risk of coronary artery disease. To better understand the association between the pre-industrial lifestyle and low prevalence of coronary artery disease risk factors, we examined the Tsimane, a Bolivian population living a subsistence lifestyle of hunting, gathering, fishing, and farming with few cardiovascular risk factors, but high infectious inflammatory burden.

METHODS

We did a cross-sectional cohort study including all individuals who self-identified as Tsimane and who were aged 40 years or older. Coronary atherosclerosis was assessed by coronary artery calcium (CAC) scoring done with non-contrast CT in Tsimane adults. We assessed the difference between the Tsimane and 6814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA). CAC scores higher than 100 were considered representative of significant atherosclerotic disease. Tsimane blood lipid and inflammatory biomarkers were obtained at the time of scanning, and in some patients, longitudinally.

FINDINGS

Between July 2, 2014, and Sept 10, 2015, 705 individuals, who had data available for analysis, were included in this study. 596 (85%) of 705 Tsimane had no CAC, 89 (13%) had CAC scores of 1-100, and 20 (3%) had CAC scores higher than 100. For individuals older than age 75 years, 31 (65%) Tsimane presented with a CAC score of 0, and only four (8%) had CAC scores of 100 or more, a five-fold lower prevalence than industrialised populations (p≤0·0001 for all age categories of MESA). Mean LDL and HDL cholesterol concentrations were 2·35 mmol/L (91 mg/dL) and 1·0 mmol/L (39·5 mg/dL), respectively; obesity, hypertension, high blood sugar, and regular cigarette smoking were rare. High-sensitivity C-reactive protein was elevated beyond the clinical cutoff of 3·0 mg/dL in 360 (51%) Tsimane participants.

INTERPRETATION

Despite a high infectious inflammatory burden, the Tsimane, a forager-horticulturalist population of the Bolivian Amazon with few coronary artery disease risk factors, have the lowest reported levels of coronary artery disease of any population recorded to date. These findings suggest that coronary atherosclerosis can be avoided in most people by achieving a lifetime with very low LDL, low blood pressure, low glucose, normal body-mass index, no smoking, and plenty of physical activity. The relative contributions of each are still to be determined.

FUNDING

National Institute on Aging, National Institutes of Health; St Luke's Hospital of Kansas City; and Paleocardiology Foundation.

Cardiovascular risk assessment in patients with diabetes

Although patients with diabetes have 2 to 4 times increased risk of cardiovascular morbidity and mortality than individuals without diabetes, recent studies indicate that a significant part of patients are in a lower cardiovascular risk category. Men younger than 35 years, women younger than 45 years, patients with diabetes duration of less than 10 years without other risk factors have a much lower risk than patients who have traditional cardiovascular risk factors, and subclinical or established coronary artery disease (CAD). These patients are not risk equivalent as stated in previous studies. On the contrary, when in the presence of traditional risk factors or evidence of subclinical coronary disease (e.g. high coronary calcium score), the coronary risk is much increased and patients may be classified at a higher-risk category. Recent guidelines do not anymore consider diabetes as a CAD risk equivalent and recommend cardiovascular risk stratification for primary prevention. Stratification of diabetic patients improves accuracy in prediction of subclinical CAD, silent ischemia and future cardiovascular events. Stratification also discriminates higher from lower risk patients who may need intensive statin or aspirin prevention, while avoiding overtreatment in lower risk cases. It may also allow the clinician to decide whether to intensify risk reduction actions through specific newer drugs for glucose control such as SGLT-2 inhibitors or GLP-1 agonists, which recently have shown additional cardiovascular protector effect. This review addresses the assessment of cardiovascular disease risk using traditional and non-traditional cardiovascular risk factors. It also reviews the use of risk calculators and new reclassification tools, focusing on the detection of subclinical atherosclerosis as well as silent ischemia in the asymptomatic patients with diabetes.

Clinical Update: Cardiovascular Disease in Diabetes Mellitus: Atherosclerotic Cardiovascular Disease and Heart Failure in Type 2 Diabetes Mellitus - Mechanisms, Management, and Clinical Considerations

Cardiovascular disease remains the principal cause of death and disability among patients with diabetes mellitus. Diabetes mellitus exacerbates mechanisms underlying atherosclerosis and heart failure. Unfortunately, these mechanisms are not adequately modulated by therapeutic strategies focusing solely on optimal glycemic control with currently available drugs or approaches. In the setting of multifactorial risk reduction with statins and other lipid-lowering agents, antihypertensive therapies, and antihyperglycemic treatment strategies, cardiovascular complication rates are falling, yet remain higher for patients with diabetes mellitus than for those without. This review considers the mechanisms, history, controversies, new pharmacological agents, and recent evidence for current guidelines for cardiovascular management in the patient with diabetes mellitus to support evidence-based care in the patient with diabetes mellitus and heart disease outside of the acute care setting.

Coronary Atherosclerotic Plaque Detected by Computed Tomographic Angiography in Subjects with Diabetes Compared to Those without Diabetes

OBJECTIVES

Little data are available regarding coronary plaque composition and semi-quantitative scores in individuals with diabetes; the extent to which diabetes may affect the presence and extent of Coronary Artery Calcium (CAC) needs more evaluation. Considering that this information may be of great value in formulating preventive interventions in this population, we compared these findings in individuals with diabetes to those without.

METHODS

Multi-Detector Computed Tomographic (MDCT) images of 861 consecutive patients with diabetes who were referred to Los Angeles Biomedical Research Institute from January 2000 to September 2012, were evaluated using a 15-coronary segment model. All 861 patients underwent calcium scoring and from these; 389 had coronary CT angiography (CTA). CAC score was compared to 861 age, sex and ethnicity matched controls without diabetes after adjustment for Body Mass Index (BMI), family history of coronary artery disease, hyperlipidemia, hypertension and smoking. Segment Involvement Score (SIS; the total number of segments with any plaque), Segment Stenosis Score (SSS; the sum of maximal stenosis score per segment), Total Plaque Score (TPS; the sum of the plaque amount per segment) and plaque compositionwere compared to 389 age, sex and ethnicity matched controls without diabetes after adjustment for BMI, family history of coronary artery disease, hyperlipidemia, hypertension and smoking.

RESULTS

Diabetes was positively correlated to the presence and extent of CAC (P<0.0001 for both). SIS, SSS and TPS were significantly higher in those with diabetes (P<0.0001). Number of mixed and calcified plaques were significantly higher in those with diabetes (P = 0.018 and P<0.001 respectively) but there was no significant difference in the number of non-calcified plaques between the two groups (P = 0.398).

CONCLUSIONS

Patients with diabetes have higher CAC and semi-quantitative coronary plaque scores compared to the age, gender and ethnicity matched controls without diabetes after adjustment for cardiovascular risk factors. Since mixed plaque is associated with worse long-term clinical outcomes, these findings support more aggressive preventive measures in this population.

Prognostic value of calcium score and coronary flow velocity reserve in asymptomatic diabetic patients

BACKGROUND

The risk stratification of patients with diabetes mellitus (DM) is a major objective for the clinicians, and it can be achieved by coronary flow velocity reserve (CFVR) or with coronary artery calcium score (CS). CS evaluates underlying coronary atherosclerotic plaque burden and CFVR estimates both presence of coronary artery stenosis and microvascular function. Consequently, CFVR may provide unique risk information beyond the extent of coronary atherosclerosis.

AIM

Our aim is to assess joint prognostic value of CFVR and CS in asymptomatic DM patients.

MATERIALS AND METHODS

We prospectively included 200 asymptomatic patients (45,5 % male, mean age 57,35 ± 11,25), out of which, there were 101 asymptomatic patients with DM and 99 asymptomatic patients without DM, but with one or more conventionally risk factors for coronary artery disease. We analyzed clinical, biochemical, metabolic, inflammatory parameters, CS by Agatston method, transthoracic Doppler echocardiography CFVR of left anterior descending artery and echocardiographic parameters.

RESULTS

Total CS and CS LAD were significantly higher, while mean CFVR was lower in diabetics compared to the nondiabetics. During 1 year follow-up, 24 patients experienced cardio-vascular events (one cardiovascular death, two strokes, three myocardial infarctions, nine new onsets of unstable angina and nine myocardial revascularizations): 19 patients with DM and five non DM patients, (p = 0,003). Overall event free survival was significantly higher in non DM group, compared to the DM group (94,9 % vs. 81,2 %, p = 0,002 respectively), while the patients with CS ≥200 and CFVR <2 had the worst outcome during 1 year follow up in the whole study population as well as in the DM group. At multivariable analysis CFVR on LAD (HR 12.918, 95 % CI 3.865-43.177, p < 0.001) and total CS (HR 13.393, 95 % CI 1.675-107.119, p = 0.014) were independent prognostic predictors of adverse events in DM group of patients.

CONCLUSION

Both CS and CFVR provide independent and complementary prognostic information in asymptomatic DM patients. When two parameters are analyzed together, the risk stratification ability improves, even when DM patients are analyzed together with non DM patients. As a result, DM patients with CS ≥200 and CFVR <2 had the worst outcome. Consequently, the use of two tests identified subset of patients who can derive the most benefit from the intensive prevention measures.

Update on Prevention of Cardiovascular Disease in Adults With Type 2 Diabetes Mellitus in Light of Recent Evidence: A Scientific Statement From the American Heart Association and the American Diabetes Association

Cardiovascular disease risk factor control as primary prevention in patients with type 2 diabetes mellitus has changed substantially in the past few years. The purpose of this scientific statement is to review the current literature and key clinical trials pertaining to blood pressure and blood glucose control, cholesterol management, aspirin therapy, and lifestyle modification. We present a synthesis of the recent literature, new guidelines, and clinical targets, including screening for kidney and subclinical cardiovascular disease for the contemporary management of patients with type 2 diabetes mellitus.

Update on Prevention of Cardiovascular Disease in Adults With Type 2 Diabetes Mellitus in Light of Recent Evidence: A Scientific Statement From the American Heart Association and the American Diabetes Association

Cardiovascular disease risk factor control as primary prevention in patients with type 2 diabetes mellitus has changed substantially in the past few years. The purpose of this scientific statement is to review the current literature and key clinical trials pertaining to blood pressure and blood glucose control, cholesterol management, aspirin therapy, and lifestyle modification. We present a synthesis of the recent literature, new guidelines, and clinical targets, including screening for kidney and subclinical cardiovascular disease for the contemporary management of patients with type 2 diabetes mellitus.

Glucose stimulates chondrocyte differentiation of vascular smooth muscle cells and calcification: A possible role for IL-1β

Vascular calcification is a hallmark of type 2 diabetes. Glucose stimulates calcification in culture of vascular smooth muscle cells (VSMCs) but the underlying mechanisms remain obscure. We observed that high glucose levels stimulated mouse and human VSMC trans-differentiation into chondrocytes, with increased levels of Sox9, type II collagen, glycosaminoglycan and Runx2 expression, and increased alkaline phosphatase activity and mineralization. These effects were associated with increased expression of IL-1β, which stimulated alkaline phosphatase and calcification, suggesting that glucose induces chondrocyte differentiation of VSMCs, possibly through IL-1β activation.

Analysis of a cardiovascular disease genetic risk score in the Diabetes Heart Study

AIMS

It remains unclear whether the high cardiovascular disease (CVD) burden in people with type 2 diabetes (T2D) is associated with genetic variants that contribute to CVD in general populations. Recent studies have examined genetic risk scores of single-nucleotide polymorphisms (SNPs) identified by genome-wide association studies for their cumulative contribution to CVD-related traits. Most analyses combined SNPs associated with a single phenotypic class, e.g., lipids. In the present analysis, we examined a more comprehensive risk score comprised of SNPs associated with a broad range of CVD risk phenotypes.

METHODS

The composite risk score was analyzed for potential associations with subclinical CVD, self-reported CVD events, and mortality in 983 T2D-affected individuals of European descent from 466 Diabetes Heart Study (DHS) families. Genetic association was examined using marginal models with generalized estimating equations for subclinical CVD and prior CVD events and Cox proportional hazards models with sandwich-based variance estimation for mortality; analyses were adjusted for age and sex.

RESULTS

An increase in genetic risk score was significantly associated with higher levels of coronary artery calcified plaque (p = 1.23 × 10(-4)); however, no significant associations with self-reported myocardial infarction and CVD events and all-cause and CVD mortality were observed.

CONCLUSIONS

These results suggest that a genetic risk score of SNPs associated with CVD events and risk factors does not significantly account for CVD risk in the DHS, highlighting the limitations of applying current genetic markers for CVD in individuals with diabetes.

Association between hemoglobin A1c variability and subclinical coronary atherosclerosis in subjects with type 2 diabetes

AIMS

We examined the association between hemoglobin A1c (HbA1c) variability and subclinical coronary atherosclerosis in subjects with type 2 diabetes.

METHODS

We used the multidetector coronary computed tomography data collected from subjects with type 2 diabetes who did not have a history of cardiovascular disease or angina symptoms. HbA1c measurements preceding the date of cardiac imaging were retrospectively collected, and intraindividual SD (HbA1c-SD), CV and adjusted SD of HbA1c measurements were calculated. Subclinical coronary atherosclerosis was defined as calcium score >400 without any cardiac symptoms.

RESULTS

A total of 595 subjects were categorized according to the median value of each HbA1c variability indicators. The prevalence of subclinical coronary atherosclerosis was higher in higher HbA1c variability group compared with lower HbA1c variability group. Multivariable logistic regression analysis showed that higher HbA1c-SD and -CV were associated with the presence of subclinical coronary atherosclerosis, independent of mean HbA1c level in subjects with diabetes duration ≤10 years (OR [95% CI]; HbA1c-SD, 2.894 [1.105-7.584]; HbA1c-CV, 2.540 [1.022-6.316]).

CONCLUSIONS

Long-term stabilization of blood glucose level might be important in preventing subclinical coronary atherosclerosis in subjects with earlier period of type 2 diabetes.

Relationships between Cognitive Performance, Neuroimaging and Vascular Disease: The DHS-MIND Study

BACKGROUND

Type 2 diabetes mellitus increases the risk of cognitive decline and dementia, and elevated burdens of vascular disease are hypothesized to contribute to this risk. These relationships were examined in the Diabetes Heart Study-MIND using a battery of cognitive tests, neuroimaging measures and subclinical cardiovascular disease (CVD) burden assessed by coronary artery calcified (CAC) plaque. We hypothesized that CAC would attenuate the association between neuroimaging measures and cognition performance.

METHODS

Associations were examined using marginal models in this family-based cohort of 572 European Americans from 263 families. All models were adjusted for age, gender, education, type 2 diabetes and hypertension, with some neuroimaging measures additionally adjusted for intracranial volume.

RESULTS

Higher total brain volume was associated with better performance on the Digit Symbol Substitution Task and Semantic Fluency (both p ≤ 7.0 × 10(-4)). Higher gray matter volume was associated with better performance on the Modified Mini-Mental State Examination and Semantic Fluency (both p ≤ 9.0 × 10(-4)). Adjusting for CAC caused minimal changes to the results.

CONCLUSIONS

Relationships exist between neuroimaging measures and cognitive performance in a type 2 diabetes-enriched European American cohort. Associations were minimally attenuated after adjusting for subclinical CVD. Additional work is needed to understand how subclinical CVD burden interacts with other factors and impacts relationships between neuroimaging and cognitive testing measures.

Inflammation: a culprit for vascular calcification in atherosclerosis and diabetes

It is today acknowledged that aging is associated with a low-grade chronic inflammatory status, and that inflammation exacerbates age-related diseases such as osteoporosis, Alzheimer's disease, atherosclerosis and type 2 diabetes mellitus (T2DM). Vascular calcification is a complication that also occurs during aging, in particular in association with atherosclerosis and T2DM. Recent studies provided compelling evidence that vascular calcification is associated with inflammatory status and is enhanced by inflammatory cytokines. In the present review, we propose on one hand to highlight the most important and recent findings on the cellular and molecular mechanisms of vascular inflammation in atherosclerosis and T2DM. On the other hand, we will present the effects of inflammatory mediators on the trans-differentiation of vascular smooth muscle cell and on the deposition of crystals. Since vascular calcification significantly impacts morbidity and mortality in affected individuals, a better understanding of its induction and development will pave the way to develop new therapeutic strategies.

Predictors of all-cause and cardiovascular disease mortality in type 2 diabetes: Diabetes Heart Study

BACKGROUND

Many studies evaluated the best predictors for cardiovascular disease (CVD) events in individuals with type 2 diabetes (T2D), but few studies examined the factors most strongly associated with mortality in T2D. The Diabetes Heart Study (DHS), an intensively phenotyped family-based cohort enriched for T2D, provided an opportunity to address this question.

METHODS

Associations with mortality were examined in 1022 European Americans affected by T2D from 476 DHS families. All-cause mortality was 31.2 % over an average 9.6 years of follow-up. Cox proportional hazards models with sandwich-based variance estimation were used to evaluate associations between all-cause and CVD mortality and 24 demographic and clinical factors, including coronary artery calcified plaque (CAC), carotid artery intima-media thickness, medications, body mass index, waist hip ratio, lipids, blood pressure, kidney function, QT interval, educational attainment, and glycemic control. Nominally significant factors (p < 0.25) from univariate analyses were included in model selection (backward elimination, forward selection, and stepwise selection). Age and sex were included in all models.

RESULTS

The all-cause mortality model selected from the full DHS sample included age, sex, CAC, urine albumin: creatinine ratio (UACR), insulin use, current smoking, and educational attainment. The CVD mortality model selected from the full sample included age, sex, CAC, UACR, triglycerides, and history of CVD events. Beyond age, the most significant associations for both mortality models were CAC (2.03 × 10(-4) ≤ p ≤ 0.001) and UACR (1.99 × 10(-8) ≤ p ≤ 2.23 × 10(-8)). To confirm the validity of the main predictors identified with model selection using the full sample, a two-fold cross-validation approach was used, and similar results were observed.

CONCLUSIONS

This analysis highlights important demographic and clinical factors, notably CAC and albuminuria, which predict mortality in the general population of patients with T2D.

Prediction of mortality using a multi-bed vascular calcification score in the Diabetes Heart Study

Background

Vascular calcified plaque, a measure of subclinical cardiovascular disease (CVD), is unlikely to be limited to a single vascular bed in patients with multiple risk factors. Consideration of vascular calcified plaque as a global phenomenon may allow for a more accurate assessment of the CVD burden. The aim of this study was to examine the utility of a combined vascular calcified plaque score in the prediction of mortality.

Methods

Vascular calcified plaque scores from the coronary, carotid, and abdominal aortic vascular beds and a derived multi-bed score were examined for associations with all-cause and CVD-mortality in 699 European-American type 2 diabetes (T2D) affected individuals from the Diabetes Heart Study. The ability of calcified plaque to improve prediction beyond Framingham risk factors was assessed.

Results

Over 8.4 ± 2.3 years (mean ± standard deviation) of follow-up, 156 (22.3%) participants were deceased, 74 (10.6%) from CVD causes. All calcified plaque scores were significantly associated with all-cause (HR: 1.4-1.8; p < 1x10⁻⁵) and CVD-mortality (HR: 1.5-1.9; p < 1×10⁻⁴) following adjustment for Framingham risk factors. Associations were strongest for coronary calcified plaque. Improvement in prediction of outcome beyond Framingham risk factors was greatest using coronary calcified plaque for all-cause mortality (AUC: 0.720 to 0.757, p = 0.004) and the multi-bed score for CVD mortality (AUC: 0.731 to 0.767, p = 0.008).

Conclusions

Although coronary calcified plaque and the multi-bed score were the strongest predictors of all-cause mortality and CVD-mortality respectively in this T2D-affected sample, carotid and abdominal aortic calcified plaque scores also significantly improved prediction of outcome beyond traditional risk factors and should not be discounted as risk stratification tools.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-014-0160-5) contains supplementary material, which is available to authorized users.

Cross-sectional analysis of calcium intake for associations with vascular calcification and mortality in individuals with type 2 diabetes from the Diabetes Heart Study

BACKGROUND

The use of calcium supplements to prevent declines in bone mineral density and fractures is widespread in the United States, and thus reports of elevated cardiovascular disease (CVD) risk in users of calcium supplements are a major public health concern. Any elevation in CVD risk with calcium supplement use would be of particular concern in individuals with type 2 diabetes (T2D) because of increased risks of CVD and fractures observed in this population.

OBJECTIVE

In this study, we examined associations between calcium intake from diet and supplements and measures of subclinical CVD (calcified plaque in the coronary artery, carotid artery, and abdominal aorta) and mortality in individuals affected by T2D.

DESIGN

We performed a cross-sectional analysis in individuals affected by T2D from the family-based Diabetes Heart Study (n = 720).

RESULTS

We observed no significant associations of calcium from diet or supplements with any of our measures of calcified plaque, and no greater mortality risk was observed with increased calcium intake. Instead, calcium supplement use was modestly associated with reduced all-cause mortality in women (HR: 0.62; 95% CI: 0.42, 0.92; P = 0.017).

CONCLUSION

Our results do not support a substantial association between calcium intake from diet or supplements and CVD risk in individuals with T2D.

Contributors to mortality in high-risk diabetic patients in the Diabetes Heart Study

OBJECTIVE

Not all individuals with type 2 diabetes and high coronary artery calcified plaque (CAC) experience the same risk for adverse outcomes. This study examined a subset of high-risk individuals based on CAC >1,000 mg (using a total mass score) and evaluated whether differences in a range of modifiable cardiovascular disease (CVD) risk factors provided further insights into risk for mortality.

RESEARCH DESIGN AND METHODS

We assessed contributors to all-cause mortality among 371 European American individuals with type 2 diabetes and CAC >1,000 from the Diabetes Heart Study (DHS) after 8.2 ± 3.0 years (mean ± SD) of follow-up. Differences in known CVD risk factors, including modifiable CVD risk factors, were compared between living (n = 218) and deceased (n = 153) participants. Cox proportional hazards regression models were used to quantify risk for all-cause mortality.

RESULTS

Deceased participants had a longer duration of type 2 diabetes (P = 0.02) and reduced use of cholesterol-lowering medications (P = 0.004). Adjusted analyses revealed that vascular calcified plaque scores were associated with increased risk for mortality (hazard ratio 1.31-1.63; 3.89 × 10(-5) < P < 0.03). Higher HbA1c, lipids, and C-reactive protein and reduced kidney function also were associated with a 1.1- to 1.5-fold increased risk for mortality (3.45 × 10(-6) < P < 0.03) after adjusting for confounding factors.

CONCLUSIONS

Even in this high-risk group, vascular calcification and known CVD risk factors provide useful information for ongoing assessment. The use of cholesterol-lowering medication seemed to be protective for mortality.

Altered coronary artery calcium scores before bariatric surgery

Introduction

Obesity is an important cause of cardiovascular disease, especially coronary artery disease. Severely obese patients are particularly prone to this risk. The coronary artery calcium (CAC) score is a strong predictor of coronary heart disease and provides incremental information beyond traditional risk factors. We sought to determine the prevalence of abnormally high CAC scores in the preoperative setting among patients undergoing bariatric surgery and to establish risk predictors for higher scores.

Methods

We performed an observational study of 202 patients free of known coronary artery disease who were referred for bariatric surgery. In each patient, the presence of CAC was detected with computed tomography, and coronary risk variables were either measured or determined via questionnaire.

Results

CAC was found in 14.4% of the overall population (26% of male and 10.5% of female patients). Participants with altered CAC scores were older (mean age, 46.8 years). The variables positively associated with an altered CAC score were older age, male sex, type 2 diabetes, hypertension, and hypercholesterolemia. Multivariate-adjusted analysis showed that age (OR, 1.11; 95% CI, 1.06–1.17; p = 0.001), male sex (OR, 4.17; 95% CI, 1.52–11.47; p = 0.006), and hypercholesterolemia (OR, 6.21; 95% CI, 1.81–21.29; p = 0.004) were most closely related to the presence of CAC.

Conclusion

Obese patients in the preoperative bariatric surgery setting have a high prevalence of abnormal CAC scores. Traditional risk factors play a important role in this scenario.

Hemoglobin A1C in non-diabetic patients: an independent predictor of coronary artery disease and its severity

AIMS

To determine the association between glycated hemoglobin (HbA1c) and angiographically proven coronary artery disease (CAD) and its severity in nondiabetic individuals.

METHODS

We enrolled 299 consecutive individuals undergoing coronary angiography for suspected ischemia. Patients were included if they had no history of prior revascularization or diabetes mellitus and had fasting blood glucose<126mg/dl (7.0mmol/l) and HbA1c<6.5% (47mmol/mol). The severity of the CAD was also evaluated using the Gensini score. Serum HbA1c (NGSP certified Method), highly sensitive C-reactive protein (hsCRP), lipid profile, insulin and APO lipoprotein A1 and B100 levels were measured.

RESULTS

Mean age was 58.8±10.4 year; 60.9% men. One hundred forty seven patients had significant CAD (≥50% stenosis in any major vessel). With increasing HbA1c levels, there was a significant increase in the prevalence of CAD and number of vessels involved. In multivariate analysis, HbA1c emerged as an independent predictor of significant CAD (OR: 2.8, 95% CI: 1.3-6.2, p=0.009). Adjusted ORs for the occurrence of CAD were highest in subjects with both hsCRP and HbA1c in the upper 2 quartiles (OR: 4.183; 95% CI: 1.883-9.290, p<0.0001). There was a significant association between Gensini score and increasing HbA1c tertiles (p=0.038). The ideal cut-off value of HbA1c for prediction of the occurrence of CAD was 5.6% 38mmol/mol) (sensitivity: 60.5%, specificity: 52%).

CONCLUSIONS

In non-diabetic subjects, HbA1c could be utilized for risk stratification of CAD and its severity, independent of traditional cardiovascular risk factors, insulin resistance and inflammatory markers.

The influence of subclinical cardiovascular disease and related risk factors on cognition in type 2 diabetes mellitus: The DHS-Mind study

We hypothesized that measures of coronary artery calcified plaque (CAC) collected at baseline from the Diabetes Heart Study (DHS) would explain associations between cognition and diabetes collected at follow-up approximately 7 years later. The DHS is a sibling study of cardiovascular disease (CVD) in a cohort with a high prevalence of type 2 diabetes (~80%). Associations between baseline CAC and cognitive performance were tested using generalized estimating equations and mixed effects models to adjust for familial relationships. Diabetes status was associated (p<0.05) with poorer performance on tests of verbal memory, processing speed, and semantic fluency adjusting for age, sex, education, and hypertension status. As hypothesized, including CAC in the statistical model attenuated this association. Additionally, CAC and fasting glucose predicted performance in tasks not associated with diabetes status in this study (Stroop Task, Phonemic Fluency). These results confirm work attributing the heterogeneity of cognitive outcomes in type 2 diabetes to subclinical risk factors that combine to affect different aspects of brain function. Importantly, these results imply that risk factor intervention should begin before comorbidities, particularly CVD, become clinically apparent.