Medical and cost burden of atherosclerosis among patients treated in routine clinical practice

Emerging applications of single-cell profiling in precision medicine of atherosclerosis

Atherosclerosis is a chronic, progressive, inflammatory disease that occurs in the arterial wall. Despite recent advancements in treatment aimed at improving efficacy and prolonging survival, atherosclerosis remains largely incurable. In this review, we discuss emerging single-cell sequencing techniques and their novel insights into atherosclerosis. We provide examples of single-cell profiling studies that reveal phenotypic characteristics of atherosclerosis plaques, blood, liver, and the intestinal tract. Additionally, we highlight the potential clinical applications of single-cell analysis and propose that combining this approach with other techniques can facilitate early diagnosis and treatment, leading to more accurate medical interventions.

Participation of Krüppel-like Factors in Atherogenesis

Atherosclerosis is an important problem in modern medicine, the keys to understanding many aspects of which are still not available to clinicians. Atherosclerosis develops as a result of a complex chain of events in which many cells of the vascular wall and peripheral blood flow are involved. Endothelial cells, which line the vascular wall in a monolayer, play an important role in vascular biology. A growing body of evidence strengthens the understanding of the multifaceted functions of endothelial cells, which not only organize the barrier between blood flow and tissues but also act as regulators of hemodynamics and play an important role in regulating the function of other cells in the vascular wall. Krüppel-like factors (KLFs) perform several biological functions in various cells of the vascular wall. The large family of KLFs in humans includes 18 members, among which KLF2 and KLF4 are at the crossroads between endothelial cell mechanobiology and immunometabolism, which play important roles in both the normal vascular wall and atherosclerosis.

Linking In Vitro Models of Endothelial Dysfunction with Cell Senescence

Endothelial cell dysfunction is the principal cause of several cardiovascular diseases that are increasing in prevalence, healthcare costs, and mortality. Developing a standardized, representative in vitro model of endothelial cell dysfunction is fundamental to a greater understanding of the pathophysiology, and to aiding the development of novel pharmacological therapies. We subjected human umbilical vein endothelial cells (HUVECs) to different periods of nutrient deprivation or increasing doses of H2O2 to represent starvation or elevated oxidative stress, respectively, to investigate changes in cellular function. Both in vitro cellular models of endothelial cell dysfunction-associated senescence developed in this study, starvation and oxidative stress, were validated by markers of cellular senescence (increase in β-galactosidase activity, and changes in senescence gene markers SIRT1 and P21) and endothelial dysfunction as denoted by reductions in angiogenic and migratory capabilities. HUVECs showed a significant H2O2 concentration-dependent reduction in cell viability (p < 0.0001), and a significant increase in oxidative stress (p < 0.0001). Furthermore, HUVECs subjected to 96 h of starvation, or exposed to concentrations of H2O2 of 400 to 1000 μM resulted in impaired angiogenic and migratory potentials. These models will enable improved physiological studies of endothelial cell dysfunction, and the rapid testing of cellular efficacy and toxicity of future novel therapeutic compounds.

Impaired macrophage trafficking and increased helper T-cell recruitment with loss of cadherin-11 in atherosclerotic immune response

Inflammation caused by infiltrating macrophages and T cells promotes plaque growth in atherosclerosis. Cadherin-11 (CDH11) is a cell-cell adhesion protein implicated in several fibrotic and inflammatory diseases. Much of the research on CDH11 concerns its role in fibroblasts, although its expression in immune cells has been noted as well. The objective of this study was to assess the effect of CDH11 on the atherosclerotic immune response. In vivo studies of atherosclerosis indicated an increase in Cdh11 in plaque tissue. However, global loss of Cdh11 resulted in increased atherosclerosis and inflammation. It also altered the immune response in circulating leukocytes, decreasing myeloid cell populations and increasing T-cell populations, suggesting possible impaired myeloid migration. Bone marrow transplants from Cdh11-deficient mice resulted in similar immune cell profiles. In vitro examination of Cdh11-/- macrophages revealed reduced migration, despite upregulation of a number of genes related to locomotion. Flow cytometry revealed an increase in CD3+ and CD4+ helper T-cell populations in the blood of both the global Cdh11 loss and the bone marrow transplant animals, possibly resulting from increased expression by Cdh11-/- macrophages of major histocompatibility complex class II molecule genes, which bind to CD4+ T cells for coordinated activation. CDH11 fundamentally alters the immune response in atherosclerosis, resulting in part from impaired macrophage migration and altered macrophage-induced T-cell activation.NEW & NOTEWORTHY Cadherin-11 is well known to contribute to inflammatory and fibrotic disease. Here, we examined its role in atherosclerosis progression, which is predominantly an inflammatory process. We found that while cadherin-11 is associated with plaque progression, global loss of cadherin-11 exacerbated the disease phenotype. Moreover, loss of cadherin-11 in bone marrow-derived immune cells resulted in impaired macrophage migration and an unexplained increase in circulating helper T cells, presumably due to altered macrophage function without cadherin-11.

Comparative Cost-Effectiveness of Clinic, Home, or Ambulatory Blood Pressure Measurement for Hypertension Diagnosis in US Adults

Previous cost-effectiveness models found ambulatory blood pressure monitoring (ABPM) to be a favorable strategy to diagnose hypertension; however, they mostly focused on older adults with a positive clinic blood pressure (BP) screen. We evaluated the cost-effectiveness of 3 methods of BP measurement for hypertension diagnosis in primary care settings among 14 age- and sex-stratified hypothetical cohorts (adults ≥21 years of age), accounting for the possibility of both false-positive (white-coat hypertension) and false-negative (masked hypertension) clinic measurements. We compared quality-adjusted life-years and lifetime costs ($US 2017 from the US healthcare perspective) associated with clinic BP measurement, home BP monitoring, and ABPM under 2 scenarios: positive and negative initial screen. Model parameters were obtained from published literature, publicly available data sources, and expert input. In the screen-positive scenario, ABPM was the dominant strategy among all age and sex groups. Compared with clinic BP measurement, ABPM was associated with cost-savings ranging from $77 (women 80 years of age) to $5013 (women 21 years of age). In the screen-negative scenario, ABPM was the dominant strategy in all men and women <80 years of age with cost-savings ranging from $128 (women 70 years of age) to $2794 (women 21 years of age). Sensitivity analyses showed that results were sensitive to test specificity and antihypertensive medication costs. ABPM is recommended as the diagnostic strategy of choice for most adults in primary care settings regardless of initial screening results.

The Transcriptomic Toolbox: Resources for Interpreting Large Gene Expression Data within a Precision Medicine Context for Metabolic Disease Atherosclerosis

As one of the most widespread metabolic diseases, atherosclerosis affects nearly everyone as they age; arteries gradually narrow from plaque accumulation over time reducing oxygenated blood flow to central and periphery causing heart disease, stroke, kidney problems, and even pulmonary disease. Personalized medicine promises to bring treatments based on individual genome sequencing that precisely target the molecular pathways underlying atherosclerosis and its symptoms, but to date only a few genotypes have been identified. A promising alternative to this genetic approach is the identification of pathways altered in atherosclerosis by transcriptome analysis of atherosclerotic tissues to target specific aspects of disease. Transcriptomics is a potentially useful tool for both diagnostics and discovery science, exposing novel cellular and molecular mechanisms in clinical and translational models, and depending on experimental design to identify and test novel therapeutics. The cost and time required for transcriptome analysis has been greatly reduced by the development of next generation sequencing. The goal of this resource article is to provide background and a guide to appropriate technologies and downstream analyses in transcriptomics experiments generating ever-increasing amounts of gene expression data.

Estimating the economic burden of cardiovascular events in patients receiving lipid-modifying therapy in the UK

OBJECTIVES

To characterise the costs to the UK National Health Service of cardiovascular (CV) events among individuals receiving lipid-modifying therapy.

DESIGN

Retrospective cohort study using Clinical Practice Research Datalink records from 2006 to 2012 to identify individuals with their first and second CV-related hospitalisations (first event and second event cohorts). Within-person differences were used to estimate CV-related outcomes.

SETTING

Patients in the UK who had their first CV event between January 2006 and March 2012.

PARTICIPANTS

Patients ≥18 years who had a CV event and received at least 2 lipid-modifying therapy prescriptions within 180 days beforehand.

PRIMARY AND SECONDARY OUTCOME MEASURES

Direct medical costs (2014 £) were estimated in 3 periods: baseline (pre-event), acute (6 months afterwards) and long-term (subsequent 30 months). Primary outcomes included incremental costs, resource usage and total costs per period.

RESULTS

There were 24 093 patients in the first event cohort of whom 5274 were included in the second event cohort. The mean incremental acute CV event costs for the first event and second event cohorts were: coronary artery bypass graft/percutaneous transluminal coronary angioplasty (CABG/PTCA) £5635 and £5823, myocardial infarction £4275 and £4301, ischaemic stroke £3512 and £4572, heart failure £2444 and £3461, unstable angina £2179 and £2489 and transient ischaemic attack £1537 and £1814. The mean incremental long-term costs were: heart failure £848 and £2829, myocardial infarction £922 and £1385, ischaemic stroke £973 and £682, transient ischaemic attack £705 and £1692, unstable angina £328 and £677, and CABG/PTCA £-368 and £599. Hospitalisation accounted for 95% of acute and 61% of long-term incremental costs. Higher comorbidity was associated with higher long-term costs.

CONCLUSIONS

Revascularisation and myocardial infarction were associated with the highest incremental costs following a CV event. On the basis of real-world data, the economic burden of CV events in the UK is substantial, particularly among those with greater comorbidity burden.

Healthcare costs associated with cardiovascular events in patients with hyperlipidemia or prior cardiovascular events: estimates from Swedish population-based register data

OBJECTIVES

To estimate healthcare costs of new cardiovascular (CV) events (myocardial infarction, unstable angina, revascularization, ischemic stroke, transient ischemic attack, heart failure) in patients with hyperlipidemia or prior CV events.

METHODS

A retrospective population-based cohort study was conducted using Swedish national registers and electronic medical records. Patients with hyperlipidemia or prior CV events were stratified into three cohorts based on CV risk level: history of major cardiovascular disease (CVD), coronary heart disease (CHD) risk-equivalent, and low/unknown risk. Propensity score matching was applied to compare patients with new events to patients without new events for estimation of incremental costs of any event and by event type.

RESULTS

A CV event resulted in increased costs over 3 years of follow-up, with the majority of costs occurring in the 1st year following the event. The mean incremental cost of patients with a history of major CVD (n = 6881) was €8588 during the 1st year following the event. This was similar to that of CHD risk-equivalent patients (n = 3226; €6663) and patients at low/unknown risk (n = 2497; €8346). Ischemic stroke resulted in the highest 1st-year cost for patients with a history of major CVD and CHD risk-equivalent patients (€10,194 and €9823, respectively); transient ischemic attack in the lowest (€3917 and €4140). Incremental costs remained elevated in all cohorts during all three follow-up years, with costs being highest in the major CVD history cohort.

CONCLUSIONS

Healthcare costs of CV events are substantial and vary considerably by event type. Incremental costs remain elevated for several years after an event.

Clinical and economic burden associated with cardiovascular events among patients with hyperlipidemia: a retrospective cohort study

BACKGROUND

Annual direct costs for cardiovascular (CV) diseases in the United States are approximately $195.6 billion, with many high-risk patients remaining at risk for major cardiovascular events (CVE). This study evaluated the direct clinical and economic burden associated with new CVE up to 3 years post-event among patients with hyperlipidemia.

METHODS

Hyperlipidemic patients with a primary inpatient claim for new CVE (myocardial infarction, unstable angina, ischemic stroke, transient ischemic attack, coronary artery bypass graft, percutaneous coronary intervention and heart failure) were identified using IMS LifeLink PharMetrics Plus data from January 1, 2006 through June 30, 2012. Patients were stratified by CV risk into history of CVE, modified coronary heart disease risk equivalent, moderate- and low-risk cohorts. Of the eligible patients, propensity score matched 243,640 patients with or without new CVE were included to compare healthcare resource utilization and direct costs ranging from the acute (1-month) phase through 3 years post-CVE date (follow-up period).

RESULTS

Myocardial infarction was the most common CVE in all the risk cohorts. During the acute phase, among patients with new CVE, the average incremental inpatient length of stay and incremental costs ranged from 4.4-6.2 days and $25,666-$30,321, respectively. Acute-phase incremental costs accounted for 61-75% of first-year costs, but incremental costs also remained high during years 2 and 3 post-CVE.

CONCLUSIONS

Among hyperlipidemic patients with new CVE, healthcare utilization and costs incurred were significantly higher than for those without CVE during the acute phase, and remained higher up to 3 years post-event, across all risk cohorts.

Assessing the intersection of cardiovascular disease, venous thromboembolism, and polycystic ovary syndrome

INTRODUCTION

No study has examined how the relationship between polycystic ovary syndrome (PCOS) and atherosclerotic cardiovascular diseases (aCVD), of ischemic stroke (ISCH), acute myocardial infarction (AMI), and peripheral vascular disease (PAD), differ in the presence of venous thromboembolism (VTE).

MATERIALS AND METHODS

We performed a cross-sectional analysis using Truven Health Analytics MarketScan® Commercial databases from 2004-2011. The association between women aged 18-64 years with and without PCOS, and aCVD was assessed using VTE-stratified multivariable logistic regression models.

RESULTS

Overall, women with PCOS were more likely to have aCVD, (aOR, 1.27; 95% CI, 1.10-1.46) especially ISCH (aOR, 1.56; 95% CI, 1.30-1.88), than women without PCOS. When stratified by VTE status, women with PCOS and a VTE diagnosis had a decreased odds of having any aCVD (aOR 0.67; 95% CI, 0.46-0.98), and VTE diagnosis more often preceded the occurrence of ISCH and AMI among women with PCOS compared with women without PCOS.

CONCLUSIONS

Overall, women with PCOS were more likely to have aCVD, with stroke being the most prevalent manifestation. Although VTE often occurred before any aCVD, it appeared to have an inverse association with the development of ISCH, AMI, and PAD among women with PCOS, suggesting that aggressively treating VTE or aCVD early may limit the chances of developing the other thrombogenic condition among women with PCOS.

Burden of First and Recurrent Cardiovascular Events Among Patients With Hyperlipidemia

BACKGROUND

Acute cardiovascular (CV) events have been evaluated in patients with specific comorbidities but have not focused on patients with hyperlipidemia or on the their long-term costs.

OBJECTIVES

To evaluate incidence of CV events, costs, and resource utilization among patients with hyperlipidemia and baseline risk of CV disease (CVD).

METHODS

Patients (age 18 to 64 years) diagnosed with hyperlipidemia or using lipid-modifying medications were identified from administrative claims. Patients were categorized into 3 cohorts based on pre-index clinical characteristics-secondary prevention (SP; history of CV event, n = 15 613); high risk (HR; CVD, n = 47 600); and primary prevention (PP; no CV event history or CVD, n = 60 637)-and followed up to 2 years after the CV event.

RESULTS

During follow-up, ≥1 new CV event occurred in 43.0% of the SP cohort, 33.9% of HR, and 20.9% of PP; and ≥3 new events occurred in 19.8% of the SP cohort, 12.9% of HR, and 5.5% of PP. Incremental total costs were $19 320 for SP, $20 003 for HR, and $17 650 for PP. Compared with patients with only 1 CV event, the mean 2-year cost was 30% higher in patients with 2 CV events and 48% higher in patients with 3 CV events. Only 50% of HR patients (with or without CV events) received statins.

CONCLUSIONS

Patients with recurrent CV events had higher total health care costs during 24-month follow-up for each type of CV event. Total health care costs among patients with a CV event were higher for the initial as well as subsequent events. Statins and lipid-modifying medications were significantly underutilized in all cohorts, despite the presence of CVD.

Management of sacroiliac joint disruption and degenerative sacroiliitis with nonoperative care is medical resource-intensive and costly in a United States commercial payer population

Introduction

Low back pain is common and originates in the sacroiliac (SI) joint in 15%–30% of cases. Traditional SI joint disruption/degenerative sacroiliitis treatments include nonoperative care or open SI joint fusion. To evaluate the usefulness of newly developed minimally-invasive technologies, the costs of traditional treatments must be better understood. We assessed the costs of nonoperative care for SI joint disruption to commercial payers in the United States (US).

Methods

A retrospective study of claim-level medical resource use and associated costs used the MarketScan® Commercial Claims and Encounters as well as Medicare Supplemental Databases of Truven Healthcare. Patients with a primary ICD-9-CM diagnosis code for SI joint disruption (720.2, 724.6, 739.4, 846.9, or 847.3), an initial date of diagnosis from January 1, 2005 to December 31, 2007 (index date), and continuous enrollment for ≥1 year before and 3 years after the index date were included. Claims attributable to SI joint disruption with a primary or secondary ICD-9-CM diagnosis code of 71x.xx, 72x.xx, 73x.xx, or 84x.xx were identified; the 3-year medical resource use-associated reimbursement and outpatient pain medication costs (measured in 2011 US dollars) were tabulated across practice settings. A subgroup analysis was performed among patients with lumbar spinal fusion.

Results

The mean 3-year direct, attributable medical costs were $16,196 (standard deviation [SD] $28,592) per privately-insured patient (N=78,533). Among patients with lumbar spinal fusion (N=434), attributable 3-year mean costs were $91,720 (SD $75,502) per patient compared to $15,776 (SD $27,542) per patient among patients without lumbar spinal fusion (N=78,099). Overall, inpatient hospitalizations (19.4%), hospital outpatient visits and procedures (14.0%), and outpatient pain medications (9.6%) accounted for the largest proportion of costs. The estimated 3-year insurance payments attributable to SI joint disruption were $1.6 billion per 100,000 commercial payer beneficiaries.

Conclusion

The economic burden of SI joint disruption among privately-insured patients in the US is substantial, highlighting the need for more cost-effective therapies.

OSA and atherosclerosis

Untreated obstructive sleep apnea (OSA) is increasingly recognized as a risk factor contributing to cardiovascular morbidity and mortality. Research in recent decades has uncovered many components of the complex pathological events leading to the atherosclerotic vascular diseases in OSA, which involve heightened oxidative stress as a result of intermittent hypoxia, vascular inflammation, activation of platelet and coagulation cascades, endothelial dysfunction and ultimately the formation of atherosclerotic plagues. The close association of OSA and conventional cardiovascular risk factors including hypertension, diabetes mellitus, dyslipidemia and obesity adds to the adverse cardiovascular sequelae. Further studies are required to clarify further on the pathophysiological processes, and the effect size of OSA therapy, and other potential preventive strategies.