Heterogeneity between men and women in the influence of the HLA-DRB1 shared epitope on the clinical expression of rheumatoid arthritis

Presence of Autoantibodies in Males and Females With Rheumatoid Arthritis: A Systematic Review and Metaanalysis

OBJECTIVE

Rheumatoid arthritis (RA) is more common in females, and although the cause of RA is unknown, it is characterized by the production of autoantibodies. The aims of this study were to determine whether RA-associated autoantibodies are more often found in females than males and to identify factors that influence the relationship between sex and seropositivity.

METHODS

Databases were searched and studies of RA (N ≥ 100) were included if they reported proportion of seropositive patients with RA by sex. Metaanalyses and metaregression were conducted using the random-effects model. Covariates regressed were smoking, age, BMI, Health Assessment Questionnaire-Disability Index (HAQ-DI), and the Disease Activity Score in 28 joints (DAS28).

RESULTS

Eighty-four studies with a total of 141,381 subjects with rheumatoid factor (RF) seropositivity and 95,749 subjects with anticitrullinated protein antibody (ACPA) seropositivity met inclusion criteria. The mean age of participants ranged from 37 to 68 years and the proportion of female subjects ranged from 9% to 92%. Results indicated that females were less likely than males to be seropositive: odds ratio (OR) 0.84 [95% CI 0.77-0.91] for RF and OR 0.88 [95% CI 0.81-0.95] for ACPA. BMI, smoking, mean age, DAS28, and HAQ-DI did not affect the relationship between sex and seropositivity.

CONCLUSION

Although studies report that females have higher RA disease activity than males and that seropositivity predicts worse outcomes, females were less likely to be seropositive than males.

Current Understanding of an Emerging Role of HLA-DRB1 Gene in Rheumatoid Arthritis-From Research to Clinical Practice

Rheumatoid arthritis (RA) is an autoimmune disease with an unclear pathogenic mechanism. However, it has been proven that the key underlying risk factor is a genetic predisposition. Association studies of the HLA-DRB1 gene clearly indicate its importance in RA morbidity. This review presents the current state of knowledge on the impact of HLA-DRB1 gene, functioning both as a component of the patient’s genome and as an environmental risk factor. The impact of known HLA-DRB1 risk variants on the specific structure of the polymorphic HLA-DR molecule, and epitope binding affinity, is presented. The issues of the potential influence of HLA-DRB1 on the occurrence of non-articular disease manifestations and response to treatment are also discussed. A deeper understanding of the role of the HLA-DRB1 gene is essential to explore the complex nature of RA, which is a result of multiple contributing factors, including genetic, epigenetic and environmental factors. It also creates new opportunities to develop modern and personalized forms of therapy.

Elevated matrix metalloproteinase-3 level may affect hearing function in patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease. Sensorineural and conductive hearing loss have been reported in RA, but the results of most studies are not in agreement. The pathogenesis of the hearing loss is not clearly understood. The presence of sensorineural hearing loss was related to matrix metalloproteinase-3 (MMP-3). The aim of this study was to assess hearing loss in RA patients and to examine the correlation between plasma MMP-3 levels and hearing loss in such patients.

METHODS

This is a cross-sectional and analytic research. Subjects consisted of 21 RA patients with hearing loss as a study group and 21 RA patients without hearing loss as controls. All patients were evaluated by pure tone audiometry and tympanometry. The amounts of plasma MMP-3 were determined using enzyme-linked immunosorbent assay. Pearson Chi-square test was used to determine the correlation of gender, age, disease duration, erythrocyte sedimentation rate, and platelet count of both groups. Independent t-test was used to assess equality of mean values at 250 to 8000 Hz hearing thresholds, pure tone mean values, air-bone gaps, and MMP-3 plasma levels of both groups.

RESULTS

This study found sensorineural (76.2%), conductive (14.3%), and mixed (9.5%) hearing loss. The most common degree of hearing loss was mild (66.7%). There was an increased incidence of As-type tympanogram in the study group (28.6%) and control group (47.6%). There were significant differences between both groups in mean hearing thresholds (p < 0.001), mean of air conduction thresholds at 1000 to 8000 Hz (p < 0.05), and mean of bone conduction thresholds in all frequencies (p < 0.05). The significant difference of mean MMP-3 levels was also found between the groups (p < 0.001).

CONCLUSION

Hearing loss is a common finding in RA. MMP-3 plasma contributed to degrade the incudomalleolar and incudostapedial joints and could damage the inner ear hair cells due to oxidative process in RA.

Increased risk of rheumatoid arthritis among mothers with children who carry DRB1 risk-associated alleles

OBJECTIVE

To investigate whether a child's genotype affects a mother's risk of rheumatoid arthritis (RA) beyond the risk associated with her genotype and to test whether exposure to fetal alleles inherited from the father increases risk of RA among mothers without risk alleles.

METHODS

A case-control study was conducted among 1165 mothers (170 cases/995 controls) and their respective 1482 children. We tested the association between having any child with alleles encoding amino acids (AAs) associated with RA including the 'shared epitope' (SE) and DERAA AA sequences at positions 70-74; AA valine, lysine and alanine at positions 11, 71 and 74 of HLA-DRB1; aspartic acid at position 9 of HLA-B and phenylalanine at position 9 of DPB1. We used logistic regression models to estimate OR and 95% CI for each group of alleles, adjusting for maternal genotype and number of live births.

RESULTS

We found increased risk of RA among mothers who had any child with SE (OR 3.0; 95% CI 2.0 to 4.6); DERAA (OR 1.7; 95% CI 1.1 to 2.6); or valine (OR 2.3; 95% CI 1.6 to 3.5), lysine (OR 2.3; 95% CI 1.5 to 3.4) and alanine (OR 2.8; 95% CI 1.2 to 6.4) at DRB1 positions 11, 71 and 74, respectively. Among non-carrier mothers, increased risk of RA was associated with having children who carried DERAA (OR 1.7; 95% CI 1.0 to 2.7) and alleles encoding lysine at DRB1 position 71 (OR 2.3; 95% CI 1.5 to 4.8).

CONCLUSION

Findings support the hypothesis that a child's genotype can contribute independently to risk of RA among mothers.

Evaluation of X Chromosome Inactivation with Respect to HLA Genetic Susceptibility in Rheumatoid Arthritis and Systemic Sclerosis

Background

Autoimmune diseases, including rheumatoid arthritis (RA) and systemic sclerosis (SSc) are characterized by a strong genetic susceptibility from the Human Leucocyte Antigen (HLA) locus. Additionally, disorders of epigenetic processes, in particular non-random X chromosome inactivation (XCI), have been reported in many female-predominant autoimmune diseases. Here we test the hypothesis that women with RA or SSc who are strongly genetically predisposed are less susceptible to XCI bias.

Methods

Using methylation sensitive genotyping of the androgen receptor (AR) gene, XCI profiles were performed in peripheral blood mononuclear cells from 161 women with RA, 96 women with SSc and 100 healthy women. HLA-DRB1 and DQB1 were genotyped. Presence of specific autoantibodies was documented for patients. XCI skewing was defined as having a ratio ≥ 80:20 of cells inactivating the same X chromosome.

Results

110 women with RA, 68 women with SSc, and 69 controls were informative for the AR polymorphism. Among them 40.9% of RA patients and 36.8% of SSc patients had skewed XCI compared to 17.4% of healthy women (P = 0.002 and 0.018, respectively). Presence of RA-susceptibility alleles coding for the “shared epitope” correlated with higher skewing among RA patients (P = 0.002) and such correlation was not observed in other women, healthy or with SSc. Presence of SSc-susceptibility alleles did not correlate with XCI patterns among SSc patients.

Conclusion

Data demonstrate XCI skewing in both RA and SSc compared to healthy women. Unexpectedly, skewed XCI occurs more often in women with RA carrying the shared epitope, which usually reflects severe disease. This reinforces the view that loss of mosaicism in peripheral blood may be a consequence of chronic autoimmunity.

Mortality in Rheumatoid Arthritis (RA): factors associated with recording RA on death certificates

BACKGROUND

Death certificates can be used to assess disease prevalence and incidence; however, rheumatoid arthritis (RA) often remains unreported in death certificates. We sought to determine to what extent RA is underreported and what demographic and clinical characteristics could predict mention of RA in the death certificate.

METHODS

We recruited 1328 patients with RA from private, public and military rheumatology practices and followed them prospectively for yearly evaluations. A rheumatologist assessed clinical characteristics of RA and comorbidities at each evaluation. Deaths were identified through family members, other physicians, obituaries and public death databases. All were confirmed with state-issued death certificates. Patients with and without RA in death certificate were compared using bivariate and multivariate analyses.

RESULTS

By December 2013, 326 deaths had occurred. We received and reviewed death certificates for all confirmed deaths, of which 58 (17.7 %) mentioned RA on the death certificate. Bivariate analysis revealed that younger age, a greater number of deformities, higher Sharp score and lower socioeconomic status were each associated with recording RA. Multivariable analyses revealed that comorbidity [OR (95 % CI) = 0.84 (0.73, 0.97); P = 0.022] was inversely associated with listing RA on the death certificate, while the number of deformities [OR (95 % CI) = 1.04 (1.00, 1.07); P = 0.033] and a certified physician's signature on the death certificate [OR (95 % CI) = 4.79 (1.35, 16.9); P = 0.015] increased likelihood of reporting RA.

CONCLUSION

In this cohort, RA was not listed in over 80 % of death certificates. Younger patients with fewer comorbidities and more joint deformities were more likely to have RA reported.

DISCUSSION

RA is often not included in death certificates. The findings of this study suggest that older patients may have a greater number of comorbidities, thus decreasing the likelihood that RA be included when completing the death certificate.

Association of socioeconomic status with treatment delays, disease activity, joint damage, and disability in rheumatoid arthritis

OBJECTIVE

To examine the association of socioeconomic status (SES) and delays in disease-modifying antirheumatic drug (DMARD) treatment with clinical measures in rheumatoid arthritis (RA) patients.

METHODS

RA patients were recruited from rheumatology practices. We assessed SES based on education, occupation, and income, and divided patients into tertiles. The time from RA symptom onset to DMARD initiation (DMARD lag) was determined by self-report of the 2 dates, and distance to the rheumatologist (Distance) was obtained from Google Maps. We examined disease activity, determined by the Disease Activity Score in 28 joints using the erythrocyte sedimentation rate (DAS28-ESR); joint damage, determined from hand radiographs by Sharp scores; and physical disability, determined by the modified Health Assessment Questionnaire (M-HAQ). We used linear regression models to examine the relationship between clinical measures and SES, Distance, and DMARD lag.

RESULTS

We recruited 1,209 RA patients, 1,159 of whom had received DMARD treatment. Mean ± SD DMARD lag was 6.9 ± 9.0 years. On average, patients with lower SES waited 8.5 ± 10.2 years after onset of RA symptoms to begin DMARD treatment, compared to those in the middle and upper SES tertiles who waited 6.1 ± 7.9 years (P = 0.002) and 6.1 ± 8.6 years (P = 0.009), respectively. Each year of delayed treatment was associated with a DAS28-ESR increase of 0.02 (P ≤ 0.001), a Sharp score increase of 1.33 (P ≤ 0.001), and an M-HAQ score increase of 0.01 (P ≤ 0.001).

CONCLUSION

Low SES was associated with delay in DMARD initiation, and both were independently associated with worse clinical measures in RA. Strategies to reduce treatment delay in low-SES RA patients are needed.

Effects of covariates and interactions on a genome-wide association analysis of rheumatoid arthritis

While genetic and environmental factors and their interactions influence susceptibility to rheumatoid arthritis (RA), causative genetic variants have not been identified. The purpose of the present study was to assess the effects of covariates and genotype x sex interactions on the genome-wide association analysis (GWAA) of RA using Genetic Analysis Workshop 16 Problem 1 data and a logistic regression approach as implemented in PLINK. After accounting for the effects of population stratification, effects of covariates and genotype x sex interactions on the GWAA of RA were assessed by conducting association and interaction analyses. We found significant allelic associations, covariate, and genotype x sex interaction effects on RA. Several top single-nucleotide polymorphisms (SNPs) (~22 SNPs) showed significant associations with strong p-values (p < 1 x 10-4 - p < 1 x 10-24). Only three SNPs on chromosomes 4, 13, and 20 were significant after Bonferroni correction, and none of these three SNPs showed significant genotype x sex interactions. Of the 30 top SNPs with significant (p < 1 x 10-4 - p < 1 x 10-6) interactions, ~23 SNPs showed additive interactions and ~5 SNPs showed only dominance interactions. Those SNPs showing significant associations in the regular logistic regression failed to show significant interactions. In contrast, the SNPs that showed significant interactions failed to show significant associations in models that did not incorporate interactions. It is important to consider interactions of genotype x sex in addition to associations in a GWAA of RA. Furthermore, the association between SNPs and RA susceptibility varies significantly between men and women.

Rheumatoid arthritis: a review of the cutaneous manifestations

Rheumatoid arthritis is a chronic inflammatory arthritis with significant extra-articular manifestations. Of note are unique cutaneous manifestations that the dermatologist may encounter. This article will make the dermatologist more cognizant of these skin findings in patients with this systemic inflammatory disorder. It examines rheumatoid arthritis, focusing on the general nonspecific and disease-specific rheumatoid arthritic skin changes. Classic rheumatoid nodules, accelerated rheumatoid nodulosis, rheumatoid nodulosis, rheumatoid vasculitis, Felty syndrome, pyoderma gangrenosum, interstitial granulomatosus dermatitis with arthritis, palisaded neutrophilic and granulomatosis dermatitis, rheumatoid neutrophilic dermatitis, juvenile rheumatoid arthritis, and adult-onset Still disease are reviewed. Understanding the cutaneous expressions of rheumatoid arthritis may lead to early diagnosis, prompt treatment, and lower morbidity and mortality for the affected persons. Learning objective At the completion of this learning activity, participants should be able to describe rheumatoid arthritis in terms of its epidemiology, etiology, pathogenesis, and general and specific cutaneous manifestations.

A model of impairment and functional limitation in rheumatoid arthritis

Background

We have previously proposed a theoretical model for studying physical disability and other outcomes in rheumatoid arthritis (RA). The purpose of this paper is to test a model of impairment and functional limitation in (RA), using empirical data from a sample of RA patients. We based the model on the disablement process framework.

Methods

We posited two distinct types of impairment in RA: 1) Joint inflammation, measured by the tender, painful and swollen joint counts; and 2) Joint deformity, measured by the deformed joint count. We hypothesized direct paths from the two impairments to functional limitation, measured by the shirt-button speed, grip strength and walking velocity. We used structural equation modeling to test the hypothetical relationships, using empirical data from a sample of RA patients recruited from six rheumatology clinics.

Results

The RA sample was comprised of 779 RA patients. In the structural equation model, the joint inflammation impairment displayed a strong significant path toward the measured variables of joint pain, tenderness and swelling (standardized regression coefficients 0.758, 0.872 and 0.512, P ≤ 0.001 for each). The joint deformity impairment likewise displayed significant paths toward the measured upper limb, lower limb, and other deformed joint counts (standardized regression coefficients 0.849, 0.785, 0.308, P ≤ 0.001 for each). Both the joint inflammation and joint deformity impairments displayed strong direct paths toward functional limitation (standardized regression coefficients of -0.576 and -0.564, respectively, P ≤ 0.001 for each), and explained 65% of its variance. Model fit to data was fair to good, as evidenced by a comparative fit index of 0.975, and the root mean square error of approximation = 0.058.

Conclusion

This evidence supports the occurrence of two distinct impairments in RA, joint inflammation and joint deformity, that together, contribute strongly to functional limitations in this disease. These findings may have implications for investigators aiming to measure outcome in RA.

Effect of glucocorticoids on the arteries in rheumatoid arthritis

OBJECTIVE

Glucocorticoids are suspected to cause atherosclerosis. Because of the possibility that their antiinflammatory effect may be antiatherogenic, this study investigated the effect of glucocorticoids on the arteries of patients with rheumatoid arthritis (RA).

METHODS

We assessed the arteries of 647 patients with RA. Central atherosclerosis was measured using high-resolution carotid ultrasound for the presence of plaque and for the extent of carotid artery intima-media thickness (CaIMT). Peripheral atherosclerosis was assessed using the systolic pressures of the dorsal pedal, posterior tibial, and brachial arteries to obtain the ankle-brachial index (ABI). Cumulative glucocorticoid dose was determined using pharmacy records, supplemented by self-report. Cardiovascular (CV) risk factors and RA clinical manifestations were ascertained using clinical and laboratory methods.

RESULTS

Among the RA patients studied, 427 (66%) had received glucocorticoids. Of those who had never received glucocorticoids, 100 (47%) of 215 had carotid plaque and 17 (8%) of 219 had > or =1 incompressible lower-limb artery (ABI >1.3). Among patients in the highest tertile of lifetime glucocorticoid exposure (>16.24 gm prednisone), the frequency of carotid plaque increased to 85 (62%) of 138 (P = 0.006) and that of lower-limb arterial incompressibility increased to 24 (17%) of 140 (P = 0.008), with differences remaining significant after adjustment for age at onset, disease duration, sex, CV risk factors, and RA clinical manifestations (tender, swollen, and deformed joint counts, subcutaneous nodules, rheumatoid factor seropositivity, and erythrocyte sedimentation rate). The CaIMT also displayed an increase with higher glucocorticoid exposure, but the differences did not reach significance. Lower-limb artery obstruction (ABI < or =0.9) was not associated with glucocorticoid exposure.

CONCLUSION

In this RA sample, glucocorticoid exposure was associated with carotid plaque and arterial incompressibility, independent of CV risk factors and RA clinical manifestations. This supports a role for glucocorticoids in the CV complications that occur in RA.

Increased susceptibility to rheumatoid arthritis in Koreans heterozygous for HLA-DRB1*0405 and *0901

OBJECTIVE

To investigate the association of susceptibility and protective HLA-DRB1 alleles with rheumatoid arthritis (RA) and its clinical markers in an Asian population.

METHODS

All RA patients (n = 574) and control subjects (n = 392) were Korean. HLA-DRB1 typing and further subtyping of all alleles was performed by polymerase chain reaction, sequence-specific oligonucleotide probe hybridization, and direct DNA sequencing analysis. We used a relative predispositional effects (RPEs) method and a false discovery rate correction method for multiple comparisons.

RESULTS

The DRB1*0405 and *0901 alleles showed the most significant associations with RA (P = 7.83 x 10(-24), odds ratio [OR] 4.40 [95% confidence interval (95% CI) 3.24-5.99], and P = 3.76 x 10(-9), OR 2.47 [95% CI 1.82-3.36], respectively). The RPEs test showed that the DRB1*0401 and *0410 alleles conferred susceptibility and that the DRB1*0701, *0802, *1301, *1302, *1403, and *1405 alleles showed significant protective effects. Susceptibility and protective alleles both showed a pattern consistent with additive genetic effects, and each influenced RA independently of the other. The compound heterozygote DRB1*0405/*0901 was associated with the highest risk of RA (corrected P = 1.81 x 10(-11), OR 58.2 [95% CI 7.95-425.70]). The mean age at disease onset was approximately 4 years earlier or was 3 years earlier, respectively, in patients with at least 1 copy of the DRB1*0405 or the DRB1*0901 allele. Radiographic changes (stages II-IV) were more frequent in patients with at least 1 copy of DRB1*0405 (P = 0.032, 92.6% versus 84.3%, OR 2.33 [95% CI 1.24-4.39]).

CONCLUSION

The DRB1*0405/*0901 heterozygote has the strongest association with RA, suggesting that this heterozygote enhances the susceptibility to RA in Koreans.

Lower limb arterial incompressibility and obstruction in rheumatoid arthritis

BACKGROUND

Despite increased cardiovascular morbidity and mortality in rheumatoid arthritis, the peripheral arteries remain understudied.

OBJECTIVE

To examine the lower limb arteries in age and sex matched, non-smoking subjects with and without rheumatoid arthritis.

METHODS

The ankle-brachial index (ABI) was measured at the posterior tibial and dorsal pedal arteries. Arteries were classified as obstructed with ABI < or =0.9, normal with ABI >0.9 but < or =1.3, and incompressible with ABI >1.3. Multinomial logistic regression was used to estimate differences in ABI between patients and controls, adjusting for cardiovascular risk factors, rheumatoid arthritis manifestations, inflammation markers, and glucocorticoid dose.

RESULTS

234 patients with rheumatoid arthritis and 102 controls were studied. Among the rheumatoid patients, 66 of 931 arteries (7%) were incompressible and 30 (3%) were obstructed. Among the controls, three of 408 arteries (0.7%) were incompressible (p = 0.002) and four (1%) were obstructed (p = 0.06). At the person level, one or more abnormal arteries occurred among 45 rheumatoid patients (19%), v five controls (5%, p = 0.001). The greater frequency of arterial incompressibility and obstruction in rheumatoid arthritis was independent of age, sex, and cardiovascular risk factors. Adjustment for inflammation markers, joint damage, rheumatoid factor, and glucocorticoid use reduced rheumatoid arthritis v control differences. Most arterial impairments occurred in rheumatoid patients with 20 or more deformed joints. This subgroup had more incompressible (15%, p< or =0.001) and obstructed arteries (6%, p = 0.005) than the controls, independent of covariates.

CONCLUSIONS

Peripheral arterial incompressibility and obstruction are increased in rheumatoid arthritis. Their propensity for patients with advanced joint damage suggests shared pathogenic mechanisms.

Latent variable approach to the measurement of physical disability in rheumatoid arthritis

OBJECTIVE

To measure physical disability in rheumatoid arthritis (RA) using a latent variable derived from a generic and a disease-specific self-reported disability instrument and an observer-assessed functional status scale.

METHODS

Consecutive patients with RA completed the modified Health Assessment Questionnaire (M-HAQ) and the Short Form 36 (SF-36) physical function scale. An observer assigned a Steinbrocker functional classification. We used principal component factor analysis to extract a latent variable from the 3 scales. We used the Bayesian Information Criterion to compare how well the new latent variable and the 3 primary scales fit the criterion standards of current work status; vital status at 6 years; grip strength; walking velocity; the timed-button test; pain; and joint tenderness, swelling, and deformity.

RESULTS

Complete data were available for 776 RA patients. The extracted latent variable explained 75% of the variance in the 3 primary scales. On a scale of 0-100, higher scores representing less disability, its mean +/- SD was 56.4 +/- 22.5. Correlation between the latent variable and the M-HAQ was -0.87; between the latent variable and SF-36 physical function scale was 0.89, and between the latent variable and Steinbrocker class was -0.85. Multivariate models that included the latent variable had superior fit than did models containing the primary scales for the criteria of current working; death by 6 years; pain; joint tenderness, swelling, or deformity; grip strength; walking velocity; and timed button test.

CONCLUSION

A latent variable derived from the M-HAQ, the SF-36 physical function scale, and the Steinbrocker functional class provides a parsimonious scale to measure physical disability in RA. The fit of the latent variable to comparison standards is equivalent or superior to that of the primary scales.

Measurement of global functional performance in patients with rheumatoid arthritis using rheumatology function tests

Outcome assessment in patients with rheumatoid arthritis (RA) includes measurement of physical function. We derived a scale to quantify global physical function in RA, using three performance-based rheumatology function tests (RFTs). We measured grip strength, walking velocity, and shirt button speed in consecutive RA patients attending scheduled appointments at six rheumatology clinics, repeating these measurements after a median interval of 1 year. We extracted the underlying latent variable using principal component factor analysis. We used the Bayesian information criterion to assess the global physical function scale's cross-sectional fit to criterion standards. The criteria were joint tenderness, swelling, and deformity, pain, physical disability, current work status, and vital status at 6 years after study enrolment. We computed Guyatt's responsiveness statistic for improvement according to the American College of Rheumatology (ACR) definition. Baseline functional performance data were available for 777 patients, and follow-up data were available for 681. Mean ± standard deviation for each RFT at baseline were: grip strength, 14 ± 10 kg; walking velocity, 194 ± 82 ft/min; and shirt button speed, 7.1 ± 3.8 buttons/min. Grip strength and walking velocity departed significantly from normality. The three RFTs loaded strongly on a single factor that explained ≥70% of their combined variance. We rescaled the factor to vary from 0 to 100. Its mean ± standard deviation was 41 ± 20, with a normal distribution. The new global scale had a stronger fit than the primary RFT to most of the criterion standards. It correlated more strongly with physical disability at follow-up and was more responsive to improvement defined according to the ACR20 and ACR50 definitions. We conclude that a performance-based physical function scale extracted from three RFTs has acceptable distributional and measurement properties and is responsive to clinically meaningful change. It provides a parsimonious scale to measure global physical function in RA.

Association between carotid atherosclerosis and markers of inflammation in rheumatoid arthritis patients and healthy subjects

OBJECTIVE

To examine the relationship between markers of systemic inflammation and carotid atherosclerosis in patients with rheumatoid arthritis (RA) and healthy controls.

METHODS

Carotid artery intima-media thickness (IMT) and carotid plaque were measured using high-resolution B-mode ultrasound in 204 patients with RA, ages 40-85, and 102 age- and sex-matched healthy persons. No subject in either group had ever smoked cigarettes. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were used to measure systemic inflammation. The relationship of the carotid artery IMT and carotid plaque to inflammation markers was examined, adjusting for age, sex, RA versus control status, and the cardiovascular (CV) risk factors hypercholesterolemia, systolic blood pressure, diabetes mellitus, and body mass index (BMI).

RESULTS

A significant linear trend for increased carotid artery IMT was associated with increasing ESR and CRP categories (r = 0.16, P = 0.004 for ESR, and r = 0.13, P = 0.02 for CRP). These trends did not differ among RA cases and controls, and were independent of age, sex, and CV risk factors. The difference in carotid artery IMT between the lowest and highest categories of ESR was 0.221 mm (95% confidence interval [95% CI] 0.767-1.020, P = 0.02). The difference between extreme CRP categories was 0.275 mm (95% CI 0.039-0.509, P = 0.02). Both remained significant after CV risk factor adjustment. Carotid plaque displayed a similar relationship to markers of inflammation.

CONCLUSION

Increased carotid artery IMT and the presence of carotid plaque are associated with markers of systemic inflammation in patients with RA and in healthy subjects. This observation is consistent with hypotheses that assign a role to systemic inflammation in atherosclerosis, and may have implications regarding RA and other chronic inflammatory diseases.