Brief report: lack of replication of an association between anti-citrullinated fibrinogen and subclinical atherosclerosis in patients with rheumatoid arthritis

Cardiovascular Risk in Rheumatoid Arthritis and Mechanistic Links: From Pathophysiology to Treatment

Rheumatoid arthritis (RA) is an autoimmune inflammatory arthritis. Inflammation, however, can spread beyond the joints to involve other organs. During the past few years, it has been well recognized that RA associates with increased risk for cardiovascular (CV) disease (CVD) compared with the general population. This seems to be due not only to the increased occurrence in RA of classical CVD risk factors and comorbidities like smoking, obesity, hypertension, diabetes, metabolic syndrome, and others but also to the inflammatory burden that RA itself carries. This is not unexpected given the strong links between inflammation and atherosclerosis and CVD. It has been shown that inflammatory cytokines which are present in abundance in RA play a significant role in every step of plaque formation and rupture. Most of the therapeutic regimes used in RA treatment seem to offer significant benefits to that end. However, more studies are needed to clarify the effect of these drugs on various parameters, including the lipid profile. Of note, although pharmacological intervention significantly helps reduce the inflammatory burden and therefore the CVD risk, control of the so-called classical risk factors is equally important. Herein, we review the current evidence for the underlying pathogenic mechanisms linking inflammation with CVD in the context of RA and reflect on the possible impact of treatments used in RA.

Immunotherapy for the rheumatoid arthritis-associated coronary artery disease: promise and future

Objective:

To review the latest progress on the pathogenic mechanism and management of rheumatoid arthritis (RA)-associated coronary artery disease (CAD), and propose advice on future management optimization as well as prospects for research and development of new therapeutic regimen.

Data sources:

This study was based on data obtained from PubMed up to May 2019 using various search terms and their combinations, including coronary artery disease, myocardial ischemia, cardiovascular diseases, RA, rheumatic diseases, treatment, therapy, strategies, immunotherapy, inflammation, and anti-inflammation.

Study selection:

All retrieved literature was scrutinized, most relevant articles about the pathogenic mechanism and clinical management, especially anti-inflammatory therapy of RA-associated CAD were reviewed.

Results:

RA is an immune-mediated chronic inflammatory disease which has a great social disease burden. In addition to typical arthritic manifestations, RA also affects extra-articular tissues and organs, within which the involvement of the cardiovascular system, especially incorporating CAD, is the leading cause of death for patients with RA. Recently, numerous basic and clinical studies have been carried out on the mechanism of CAD development and progression under the inflammatory cascade of RA. The effect of traditional RA drugs on CAD risk management has been gradually clarified, and more emerging biologic agents are being explored and studied, which have also achieved satisfactory outcomes. Furthermore, with the success of the CANTOS clinical trial, novel anti-inflammatory therapy for the prevention of cardiovascular disease is believed to have a broad prospect.

Conclusions:

RA is an independent risk factor for CAD, which mainly results from the underlying inflammatory cascade; therefore, anti-inflammatory therapy, especially the emerging novel biologic drugs, is important for CAD management in patients with RA and may also be a promising approach among the general population.

Association between biologic disease modifying anti-rheumatic drugs and incident hypertension in patients with rheumatoid arthritis: Results from prospective nationwide KOBIO Registry

There has been some debate between biologic disease modifying anti-rheumatic drugs (bDMARDs) treatment and hypertension (HTN) in rheumatoid arthritis (RA). The aim of this study was to determine the effect of bDMARDs on the development of HTN in patients with RA.A total of 996 patients eligible for analysis were recruited from the Korean College of Rheumatology Biologics & Targeted Therapy (KOBIO) registry from 2012 to 2018. The bDMARDs were tumor necrosis factor (TNF) inhibitors, abatacept, and tocilizumab. The cDMARDs included methotrexate, hydroxychloroquine, and leflunomide. The incidence rate and 95% confidence interval of HTN were estimated using the Kaplan-Meier method. Hazard ratio (HR) of risk factors associated with hypertension was assessed by cox proportional hazard model analysis.Among the 996 patients, 62 patients (6.2%) were newly diagnosed with HTN. There were differences in incidence rate of HTN among conventional DMARDs (cDMARDs), TNF inhibitors, tocilizumab, and abatacept during the follow-up period (P = .015). Kaplan-Meier analysis showed that there was a significant difference in incident HTN only between cDMARDs and tocilizumab (P = .001). Systolic blood pressure and positive rheumatoid factor were associated with development of HTN (HR = 1.049, P = .016 and HR = 1.386, P = .010, respectively). Cox proportional hazard model analysis showed no difference in the development of HTN between bDMARDs and cDMARDs in RA.This study showed that bDMARDs treatment might not increase risk of incident HTN in patients with RA, compared to cDMARDs.

What role does rheumatoid arthritis disease activity have in cardiovascular risk?

Rheumatoid arthritis (RA) is associated with a 1.3 to 3-fold increase in mortality, being the major cause of death from cardiovascular complications (40%-50%). Therefore, the initial approach should include cardiovascular risk (CVR) assessment using algorithms adapted for this population. Although, SCOREM is an important advance, there are data indicating that subclinical atherosclerosis may be underdiagnosed.

OBJECTIVE

To estimate the strength of association between carotid ultrasound and SCOREM in this population, as well as the implication of disease activity.

METHODOLOGY

Cross-sectional, observational, analytical study performed at the General Hospital of Ciudad Real, Spain, between June 2013 and May 2014. The evaluation of CVR was performed and, according to SCOREM, the population was divided into low and high (medium, high and very high) risk. We studied the presence of subclinical atherosclerosis in low-risk patients.

RESULTS

Of the total of 119 RA patients, 73.1% had traditional risk factors. Thirty-eight patients were excluded because of a previous cardiovascular event, diabetes mellitus and/or nephropathy. Atheromatous plaque was observed in 14.63% of the low-risk population. The factor with the strongest association to the presence of subclinical atherosclerosis was a moderate or high activity of RA measured by the simplified disease activity index with an odds ratio of 4.95 (95% CI: 1.53-16.01).

CONCLUSIONS

Although there was an acceptable correlation between the presence of subclinical atherosclerosis and SCOREM, there was a considerable proportion of atheromatous plaques in low-risk patients. Disease activity was the risk factor most closely associated with increased CVR.

Association Between Anti-Citrullinated Fibrinogen Antibodies and Coronary Artery Disease in Rheumatoid Arthritis

OBJECTIVE

Antibodies against citrullinated fibrinogen (anti-Cit-fibrinogen) have been implicated in rheumatoid arthritis (RA) and associated with cardiovascular risk in RA. The objective of this study was to examine the association between anti-Cit-fibrinogens and coronary artery disease (CAD) outcomes.

METHODS

We performed the study in an RA cohort based in a large academic institution linked with electronic medical record data containing information on CAD outcomes from medical record review. Using a published bead-based assay method, we measured 10 types of anti-Cit-fibrinogens. We applied a score test to determine the association between the anti-Cit-fibrinogens as a group with CAD outcomes. Principal components analysis (PCA) was performed to assess whether the anti-Cit-fibrinogens clustered into groups. Each group was then additionally tested for association with CAD. Sensitivity analyses were also performed using a published International Classification of Disease, Ninth Revision code group for ischemic heart disease (IHD) as the outcome.

RESULTS

We studied 1,006 RA subjects (mean ± SD age 61.0 ± 13.0 years; 72.2% anti-cyclic citrullinated peptide positive). As a group, anti-Cit-fibrinogen was associated with CAD (P = 1.1 × 10^-4 ). From the PCA analysis, we observed 3 main groups, of which only 1 group, containing 7 of the 10 anti-Cit-fibrinogens, was significantly associated with CAD outcomes (P = 0.015). In the sensitivity analysis, all anti-Cit-fibrinogens as a group remained significantly associated with IHD (P = 2.9 × 10^-4 ).

CONCLUSION

Anti-Cit-fibrinogen antibodies as a group were associated with CAD outcomes in our RA cohort, with the strongest signal for association arising from a subset of the autoantibodies.

Increased cardiovascular risk in rheumatoid arthritis: mechanisms and implications

Rheumatoid arthritis is a systemic autoimmune disease characterized by excess morbidity and mortality from cardiovascular disease. Mechanisms linking rheumatoid arthritis and cardiovascular disease include shared inflammatory mediators, post-translational modifications of peptides/proteins and subsequent immune responses, alterations in the composition and function of lipoproteins, increased oxidative stress, and endothelial dysfunction. Despite a growing understanding of these mechanisms and their complex interplay with conventional cardiovascular risk factors, optimal approaches of risk stratification, prevention, and treatment in the context of rheumatoid arthritis remain unknown. A multifaceted approach to reduce the burden posed by cardiovascular disease requires optimal management of traditional risk factors in addition to those intrinsic to rheumatoid arthritis such as increased disease activity. Treatments for rheumatoid arthritis seem to exert differential effects on cardiovascular risk as well as the mechanisms linking these conditions. More research is needed to establish whether preferential rheumatoid arthritis therapies exist in terms of prevention of cardiovascular disease. Ultimately, understanding the unique mechanisms for cardiovascular disease in rheumatoid arthritis will aid in risk stratification and the identification of novel targets for meaningful reduction of cardiovascular risk in this patient population.

Anti-High-Density Lipoprotein Antibodies and Antioxidant Dysfunction in Immune-Driven Diseases

Introduction

Impaired high-density lipoprotein (HDL) levels and antioxidant functionality of HDL, mainly attributed to a decreased paraoxonase-1 (PON1) functionality, have been described in autoimmune conditions. In this setting, a role for humoral response in cardiovascular disease is emerging. This study evaluates the role of immunoglobulin G (IgG) antibodies against HDL and disease-related autoantibodies on HDL dysfunction in immune-driven diseases.

Methods

Serum IgG anti-HDL antibodies, PON1 activity, and total antioxidant capacity (TAC) were quantified in 381 patients with different immune-driven diseases [18 mixed connective tissue disease (MCTD), 35 primary Sjögren syndrome (pSS), 38 systemic sclerosis (SSc), 33 ANCA-associated vasculitis (AAV), 60 diabetes mellitus 1, 29 autoimmune B12 deficiency/pernicious anemia, 29 primary biliary cirrhosis, 46 IBD/Crohn, 54 IBD/UC, and 39 celiac disease (CD)] and 138 healthy controls.

Results

IgG anti-HDL antibodies were increased in MCTD, pSS, AAV, and inflammatory bowel disease (IBD) [Crohn and ulcerative colitis (UC)], even after correcting for total IgG levels, but not in organ-specific autoimmune diseases. Anti-HDL antibodies were negatively associated with PON1 activity in MCTD (r = −0.767, p < 0.001) and AAV (r = −0.478, p = 0.005), whereas both anti-HDL and anti-neutrophil cytoplasm antibod levels were related to an impaired PON1 activity and TAC in IBD/UC. In SSc, anti-centromere antibodies correlated PON1 activity. anti-Saccharomyces cerevisiae antibodies levels were negatively associated with PON1 activity (r = −0.257, p = 0.012) and PON1/TAC ratio (r = −0.261, p = 0.009) in IBD/Crohn. HDL dysfunction in CD was only related to anti-transglutaminase levels.

Conclusion

IgG anti-HDL antibodies and HDL dysfunction are common hallmarks of systemic autoimmunity. Anti-HDL and disease-related autoantibodies account for the HDL antioxidant dysfunction in immune-driven conditions, mainly in systemic autoimmune disorders.

Phenome-Wide Association Study of Autoantibodies to Citrullinated and Noncitrullinated Epitopes in Rheumatoid Arthritis

OBJECTIVE

Patients with rheumatoid arthritis (RA) develop autoantibodies against a spectrum of antigens, but the clinical significance of these autoantibodies is unclear. Using a phenome-wide association study (PheWAS) approach, we examined the association between autoantibodies and clinical subphenotypes of RA.

METHODS

This study was conducted in a cohort of RA patients identified from the electronic medical records (EMRs) of 2 tertiary care centers. Using a published multiplex bead assay, we measured 36 autoantibodies targeting epitopes implicated in RA. We extracted all International Classification of Diseases, Ninth Revision (ICD-9) codes for each subject and grouped them into disease categories (PheWAS codes), using a published method. We tested for the association of each autoantibody (grouped by the targeted protein) with PheWAS codes. To determine significant associations (at a false discovery rate [FDR] of ≤0.1), we reviewed the medical records of 50 patients with each PheWAS code to determine positive predictive values (PPVs).

RESULTS

We studied 1,006 RA patients; the mean ± SD age of the patients was 61.0 ± 12.9 years, and 79.0% were female. A total of 3,568 unique ICD-9 codes were grouped into 625 PheWAS codes; the 206 PheWAS codes with a prevalence of ≥3% were studied. Using the PheWAS method, we identified 24 significant associations of autoantibodies to epitopes at an FDR of ≤0.1. The associations that were strongest and had the highest PPV for the PheWAS code were autoantibodies against fibronectin and obesity (P = 6.1 × 10^-4 , PPV 100%), and that between fibrinogen and pneumonopathy (P = 2.7 × 10^-4 , PPV 96%). Pneumonopathy codes included diagnoses for cryptogenic organizing pneumonia and obliterative bronchiolitis.

CONCLUSION

We demonstrated application of a bioinformatics method, the PheWAS, to screen for the clinical significance of RA-related autoantibodies. Using the PheWAS approach, we identified potentially significant links between variations in the levels of autoantibodies and comorbidities of interest in RA.

Association of Anti-Citrullinated Peptide Antibodies With Coronary Artery Calcification in Rheumatoid Arthritis

OBJECTIVE

Citrullinated proteins have been found within atherosclerotic plaque. However, studies evaluating the association between anti-citrullinated protein antibodies (ACPAs) and imaging measures of atherosclerosis in patients with rheumatoid arthritis (RA) have been limited to seroreactive citrullinated fibrinogen or citrullinated vimentin and have rendered contradictory results. Therefore, our objective was to evaluate this association using an extended panel of ACPAs in a larger sample of RA patients without clinical cardiovascular disease (CVD).

METHODS

ACPAs were identified using a custom Bio-Plex bead assay in 270 patients from 2 independent RA cohorts without clinical CVD, with the first one consisting of 195 patients and the other of 75 patients. Coronary artery calcium (CAC) was assessed by computed tomography as a measure of coronary artery disease.

RESULTS

High levels of anti-citrullinated histone H2B antibodies were strongly associated with higher CAC scores, compared with lower antibody levels (P = 0.001); this remained significant after adjustment for traditional CV and RA-specific risk factors (P = 0.03). No association between levels of ACPAs and CAC progression at 3 years was seen (P = 0.09); however, the number of progressors was small (n = 92).

CONCLUSION

Higher levels of ACPAs targeting Cit-histone H2B were associated with higher CAC scores when compared to lower antibody levels, suggesting a potential role for histone citrullination seroreactivity in atherosclerosis.

Anti-carbamylated protein autoantibodies associated with mortality in Spanish rheumatoid arthritis patients

Patients with rheumatoid arthritis (RA) have an increased mortality rate that is associated with the presence of RA-specific autoantibodies in many studies. However, the relative role of rheumatoid factor (RF), anti-CCP antibodies and the most recently established RA-autoantibodies, directed against carbamylated proteins (anti-CarP antibodies), is unclear. Here, we have assessed the role of these three antibodies in 331 patients with established RA recruited from 2001 to 2009 and followed until November 2015. During this time, 124 patients died (37.5%). This death rate corresponds to a mortality rate 1.53 (95% CI 1.26 to 1.80) folds the observed in the reference population. We used for analysis of all-cause mortality the Cox proportional hazard regression model with adjustment for age, sex and smoking. It showed a trend for association with increased mortality of each of the three RA autoantibodies in antibody-specific analysis (hazards ratio (HR) from 1.37 to 1.79), but only the HR of the anti-CarP antibodies was significant (HR = 1.79, 95% CI 1.23 to 2.61, p = 0.002). In addition, the multivariate analysis that included all autoantibodies showed a marked decrease in the HR of RF and of anti-CCP antibodies, whereas the HR of anti-CarP remained significant. This increase was specific of respiratory system causes of death (HR = 3.19, 95% CI 1.52 to 6.69, p = 0.002). Therefore, our results suggest a specific relation of anti-CarP antibodies with the increased mortality in RA, and drive attention to their possible connection with respiratory diseases.