The association of cigarette smoking with disease outcome in patients with early inflammatory polyarthritis

Obesity and the Development of Arthritis Among Adults in the United States Using NHANES Data

Background

The alarming increase in the prevalence of obesity and arthritis in America in recent times is concerning both in terms of the deleterious health effects on the individuals and economic cost. The wear and tear on the musculoskeletal and the inflammatory effects of obesity may be the reasons for the rise in arthritis among individuals with obesity.

Objective

To investigate the association between obesity and the development of arthritis among adults in the United States.

Design

A total of 17 016 participants were included from the 2012 to 2018 National Health and Nutrition Examination Survey (NHANES). Most of the participants were aged 30 years and above (79.7%). The racial distribution included 64.0% Non-Hispanic whites, 15.3% Hispanics, 11.4% Non-Hispanics blacks, and 9.4% from all other races.

Methods

Obesity was defined as a body mass index (BMI) > 30 kg/m², and the outcome variable of interest, arthritis status, was self-reported. Survey weighted logistic regression was performed to calculate the odds ratio (OR) and 95% confidence interval controlling for potential confounding factors.

Result

Nearly 40% of all participants were individuals with obesity, and 27.5% reported having some form of arthritis. The risk of developing arthritis was higher in individuals with obesity (OR: 1.55, 95% CI: 1.35-1.80), women (OR: 1.94, 95%CI: 1.66-2.28), and individuals 30 years or older (OR: 10.81, 95% CI: 6.36-18.37) with non-Hispanic whites being the most affected race. The C-reactive protein (CRP) and white blood cell count (WBC) levels were higher in all individuals with obesity even though there was no statistical difference between individuals with obesity with and without arthritis.

Conclusions

Obesity substantially heightens the risk of developing arthritis due to the mechanical stress on weight-bearing joints and subsequent chronic-low level inflammation contributing to disease progression.

Smoking, but not use of complementary and alternative medicine predicts residual functional disability in patients with inflammatory arthritis on biologic disease-modifying anti-rheumatic drugs: Results from the Singapore National Biologics Register

AIMS

To describe inflammatory arthritis (IA) patients initiating biologic disease-modifying anti-rheumatic drugs (bDMARDs) who use complementary and alternative medicine (CAM), and determine the impact of CAM on predicting modified Health Assessment Questionnaire (mHAQ) at 6 months.

METHODS

This was a prospective inception cohort study of patients ≥21 years old initiating a bDMARD for IA after July 2016. Data were obtained via questionnaires and abstraction from medical records. Baseline characteristics between ever-CAM and CAM non-users were compared. CAM as a predictor of mHAQ ≥1 at 6 months after bDMARD initiation was analyzed using multivariate logistic regression, adjusting for other baseline characteristics.

RESULTS

We recruited 299 patients (36.2% male, mean age 49.0 years). There were 45.8% who had rheumatoid arthritis, 54.2% had a spondyloarthropathy, median disease duration of 1.1 years and median mHAQ of 0.4. Compared to CAM non-users, ever-CAM users had a lower mean body mass index, were less likely to speak English, and more likely to smoke and drink alcohol. There was no association of CAM use with high mHAQ and no interaction with smoking. Smoking (odds ratio [OR] 938.9; 95% CI 3.20-275 884.1), baseline mHAQ (OR 252.2; 95% CI 5.34-11 899.2) and Charlson's Comorbidity Index score ≥4 (OR 237.4; 95% CI 1.22-46 184.4) independently predicted high mHAQ at 6 months.

CONCLUSIONS

CAM use was not associated with high mHAQ at 6 months. Smoking was an independent predictor of residual functional disability at 6 months, even after adjusting for age, comorbidity and baseline mHAQ. Greater emphasis on smoking cessation may improve long-term functional outcomes in IA patients on bDMARDs.

Does smoking affect level of seropositivity in RA? A post-HOC global and inter-country analysis of COMORA cohort

To study the association of smoking status and the level of seropositivity in RA patients from COMORA Cohort. A post hoc analysis of COMORA database included 3439 RA patients was performed. Current smokers or recently quitted (< 3 years) were initially compared to those who never smoked or stopped > 3 years (Group I vs. II) regarding their seropositivity status (high positive, low positive and negative) for Rheumatoid Factor (RF) or Anti-citrullinated antibodies (ACPA). A further comparison was made between current smokers (Group III) and never smoked patients (Group IV). Analysis was also done on the individual country level for the 17 countries included in the COMORA study. Out of 3439 RA patients, 705 (20.5%) were smokers (group I), and 2734 (79.5%) were non-smokers (group II). Significantly more patients in group I, 442 (62.7%), had high levels of seropositivity than those in group II, 1556 (56.9%), [P = 0.006, OR 1.27 (95% CI, 1.07-1.5)]. More current smoker patients (group III-286 out of 456 "62.7%") had high levels of seropositivity than never smoked patients (group IV-1236 out of 2191 "56.4%"), with significant difference [P = 0.013, OR 1.3 (95% CI, 1.06-1.6)]. In 11 countries, higher proportions of patients with high level of seropositivity in group I was found, with statistical significance in four countries. Smoking was associated with higher level of seropositivity in patients with RA in this post hoc analysis, both on a global level and in certain individual countries. As smoking is a modifiable risk factor, studying the effects of quitting smoking on level of seropositivity and other disease parameters is warranted.

Anti-cyclic citrullinated peptide antibody predicts the development of rheumatoid arthritis in patients with undifferentiated arthritis

BACKGROUND

Clinical outcomes of undifferentiated arthritis (UA) are diverse, and only 40% of patients with UA develop rheumatoid arthritis (RA) after 3 years. Discovering predictive markers at disease onset for further intervention is critical. Therefore, our objective was to analyze the clinical outcomes of UA and ascertain the predictors for RA development.

METHODS

We performed a prospective, multi-center study from January 2013 to October 2016 among Chinese patients diagnosed with UA in 22 tertiary-care hospitals. Clinical and serological parameters were obtained at recruitment. Follow-up was undertaken in all patients every 12 weeks for 2 years. Predictive factors of disease progression were identified using multivariate Cox proportional hazards regression.

RESULTS

A total of 234 patients were recruited in this study, and 17 (7.3%) patients failed to follow up during the study. Among the 217 patients who completed the study, 83 (38.2%) patients went into remission. UA patients who developed RA had a higher rheumatoid factor (RF)-positivity (42.9% vs. 16.8%, χ = 8.228, P = 0.008), anti-cyclic citrullinated peptide (CCP) antibody-positivity (66.7% vs. 10.7%, χ = 43.897, P < 0.001), and double-positivity rate of RF and anti-CCP antibody (38.1% vs. 4.1%, χ = 32.131, P < 0.001) than those who did not. Anti-CCP antibody but not RF was an independent predictor for RA development (hazard ratio 18.017, 95% confidence interval: 5.803-55.938; P < 0.001).

CONCLUSION

As an independent predictor of RA, anti-CCP antibody should be tested at disease onset in all patients with UA.

Assessing prognosis and prediction of treatment response in early rheumatoid arthritis: systematic reviews

BACKGROUND

Rheumatoid arthritis (RA) is a chronic, debilitating disease associated with reduced quality of life and substantial costs. It is unclear which tests and assessment tools allow the best assessment of prognosis in people with early RA and whether or not variables predict the response of patients to different drug treatments.

OBJECTIVE

To systematically review evidence on the use of selected tests and assessment tools in patients with early RA (1) in the evaluation of a prognosis (review 1) and (2) as predictive markers of treatment response (review 2).

DATA SOURCES

Electronic databases (e.g. MEDLINE, EMBASE, The Cochrane Library, Web of Science Conference Proceedings; searched to September 2016), registers, key websites, hand-searching of reference lists of included studies and key systematic reviews and contact with experts.

STUDY SELECTION

Review 1 - primary studies on the development, external validation and impact of clinical prediction models for selected outcomes in adult early RA patients. Review 2 - primary studies on the interaction between selected baseline covariates and treatment (conventional and biological disease-modifying antirheumatic drugs) on salient outcomes in adult early RA patients.

RESULTS

Review 1 - 22 model development studies and one combined model development/external validation study reporting 39 clinical prediction models were included. Five external validation studies evaluating eight clinical prediction models for radiographic joint damage were also included. c-statistics from internal validation ranged from 0.63 to 0.87 for radiographic progression (different definitions, six studies) and 0.78 to 0.82 for the Health Assessment Questionnaire (HAQ). Predictive performance in external validations varied considerably. Three models [(1) Active controlled Study of Patients receiving Infliximab for the treatment of Rheumatoid arthritis of Early onset (ASPIRE) C-reactive protein (ASPIRE CRP), (2) ASPIRE erythrocyte sedimentation rate (ASPIRE ESR) and (3) Behandelings Strategie (BeSt)] were externally validated using the same outcome definition in more than one population. Results of the random-effects meta-analysis suggested substantial uncertainty in the expected predictive performance of models in a new sample of patients. Review 2 - 12 studies were identified. Covariates examined included anti-citrullinated protein/peptide anti-body (ACPA) status, smoking status, erosions, rheumatoid factor status, C-reactive protein level, erythrocyte sedimentation rate, swollen joint count (SJC), body mass index and vascularity of synovium on power Doppler ultrasound (PDUS). Outcomes examined included erosions/radiographic progression, disease activity, physical function and Disease Activity Score-28 remission. There was statistical evidence to suggest that ACPA status, SJC and PDUS status at baseline may be treatment effect modifiers, but not necessarily that they are prognostic of response for all treatments. Most of the results were subject to considerable uncertainty and were not statistically significant.

LIMITATIONS

The meta-analysis in review 1 was limited by the availability of only a small number of external validation studies. Studies rarely investigated the interaction between predictors and treatment.

SUGGESTED RESEARCH PRIORITIES

Collaborative research (including the use of individual participant data) is needed to further develop and externally validate the clinical prediction models. The clinical prediction models should be validated with respect to individual treatments. Future assessments of treatment by covariate interactions should follow good statistical practice.

CONCLUSIONS

Review 1 - uncertainty remains over the optimal prediction model(s) for use in clinical practice. Review 2 - in general, there was insufficient evidence that the effect of treatment depended on baseline characteristics.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016042402.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Smoking Is Associated with Higher Disease Activity in Rheumatoid Arthritis: A Longitudinal Study Controlling for Time-varying Covariates

OBJECTIVE

Prior studies around the relationship between smoking and rheumatoid arthritis (RA) disease activity have reported inconsistent findings, which may be ascribed to heterogeneous study designs or biases in statistical analyses. We examined the association between smoking and RA outcomes using statistical methods that account for time-varying confounding and loss to followup.

METHODS

We included 282 individuals with an RA diagnosis using electronic health record data collected at a public hospital between 2013 and 2017. Current smoking status and disease activity were assessed at each visit; covariates included sex, race/ethnicity, age, obesity, and medication use. We used longitudinal targeted maximum likelihood estimation to estimate the causal effect of smoking on disease activity measures at 27 months, and compared results to conventional longitudinal methods.

RESULTS

Smoking was associated with an increase of 0.64 units in the patient global score compared to nonsmoking (p = 0.01), and with 2.58 more swollen joints (p < 0.001). While smoking was associated with a higher clinical disease activity score (2.11), the difference was not statistically significant (p = 0.22). We found no association between smoking and physician global score, or C-reactive protein levels, and an inverse association between smoking and tender joint count (p = 0.05). Analyses using conventional methods showed a null relationship for all outcomes.

CONCLUSION

Smoking is associated with higher levels of disease activity in RA. Causal methods may be useful for investigations of additional exposures on longitudinal outcome measures in rheumatologic disease.

Smoking and response to rituximab in rheumatoid arthritis: results from an international European collaboration

OBJECTIVES

To investigate whether smoking habits predict response to rituximab (RTX) in rheumatoid arthritis (RA).

METHOD

We included patients from the CERERRA international cohort receiving the first treatment cycle with available smoking status (n = 2481, smokers n = 528, non-current smokers n = 1953) and at least one follow-up visit. Outcome measures were change in Disease Activity Score based on 28-joint count (ΔDAS28) and European League Against Rheumatism (EULAR) good response at 6 months, with non-current smokers as the referent group.

RESULTS

Compared with non-smokers at baseline, smokers were more often rheumatoid factor (RF)/anti-citrullinated protein antibody (ACPA) positive and males, had shorter disease duration, lower DAS28 and Health Assessment Questionnaire (HAQ) score, a higher number of prior biological disease-modifying anti-rheumatic drugs, and were more likely to receive concomitant conventional synthetic disease-modifying anti-rheumatic drug (csDMARDs). Disease activity had decreased less in smokers at 6 months (ΔDAS28 = 1.5 vs 1.7, p = 0.006), although the difference was no longer significant after correction for baseline DAS28 (p = 0.41). EULAR good response rates did not differ between smokers and non-smokers overall or stratified by RF/ACPA status, although smokers had lower good response rates among seronegative patients (ACPA-negative: 6% vs 14%, RF-negative: 11% vs 18%). Smoking did not predict good response [odds ratio (OR) = 1.04, 95% confidence interval (CI) = 0.76-1.41], while ACPA, DAS28, HAQ, and concomitant csDMARDs were significant predictors for good response. However, when stratified by country, smokers were less likely to achieve good response in Sweden (unadjusted OR = 0.24, 95% CI = 0.07-0.89), and a trend was seen in the Czech Republic (OR = 0.45, 95% CI = 0.16-1.02).

CONCLUSION

In this large, observational, multinational RA cohort, smokers starting RTX differed from non-smokers by having shorter disease duration and lower disease activity, but more previous treatments. The overall results do not support smoking as an important predictor for response to RTX in patients with RA.

The impact of smoking on disease activity, disability, and radiographic damage in rheumatoid arthritis: is cigarette protective?

The ojective of this study is to assess the effect of tobacco smoking on disease activity, functional ability, and joint damage in a cohort of patients with early onset rheumatoid arthritis (EORA). 129 EORA patients attending the Rheumatology Unit of the School of Medicine of the "Universidad Nacional de Colombia" and the "Clínica de Artritis y Rehabilitación" in Bogota, Colombia, were enrolled in a prospective observational cohort study with 3-year follow-up. Clinical, biological, immunogenetics, and radiographic data were analyzed. Active disease was defined as DAS28 > 2.6. Smoking status was assessed by self-report as "never smokers" and "ever smokers". Patient groups with different smoking status were compared for RA measures. Status as "never smokers" and "ever smokers" was reported by 81.3 and 18.7%. Ever smokers had less risk of disability (HAQ-DI ≥ 0.5) at 36 month (Ever smokers vs. Never smokers OR for HAQ ≥ 0.5 0.25, 95% CI 0.06-0.97, p = 0.04). When former smokers were excluded in analysis, we found that current smoking was also associated with less disability and less risk of active disease. The percentage of erosive disease, radiographic progression, and SvdH score were similar in all smoking categories. In Colombian patients with EORA, smoking was associated with less disease activity and disability. Radiographic joint damage progressed at an equivalent rate in smokers and non-smokers. These data suggest a more benign, or at least not deleterious clinical course in smokers with RA.

Relationship Between Smoking and Structural Damage, Autoimmune Antibodies, and Disability in Rheumatoid Arthritis Patients

Objectives

This study aims to investigate the relationship between smoking and structural damage, autoimmune antibodies, and disability in rheumatoid arthritis (RA) patients.

Patients and methods

This cross-sectional study included 165 RA patients (36 males, 129 females; mean age 52.4±12.8 years; range 21 to 82 years). Disease duration, age at disease onset, smoking habits, rheumatoid factor (RF), and anti-cyclic citrullinated peptide levels were recorded. Morning stiffness, pain with visual analog scale, Health Assessment Questionnaire Scores And Disease Activity Score 28 were calculated. Patients' standard hand radiographs were evaluated.

Results

Patients were divided into three groups according to their smoking habits. Ninety-nine patients (60%) were never smokers, 45 patients (27.3%) were long-term smokers and 21 patients (12.7%) were new smokers. Three groups were compared for disease activity. Disease activity score 28 scores were 3.2±1.2, 3.2±1.3, and 3.2±1.4, respectively (p>0.05). The erosion score (2.6±5.8, 7.1±10.9, and 11.1±19.2, respectively) and joint space narrowing score (9.9±7.3, 18.6±14.9, and 17.3±12.3, respectively) according to modified Sharp method were significantly lower in never smokers group than other groups (p<0.05). RF titrations were 55.2±58.9, 60.5±63.1, and 84.9±71.5, respectively, and levels of long-term smokers group were significantly higher than the other groups (p<0.05). Joint space narrowing score was 16.2±11.9 and 6.4±10.4 in RF (+) and RF (-) patients, respectively (p<0.05). There was no significant relationship between anti-cyclic citrullinated peptide levels and others parameters.

Conclusion

Although smoking is known as a poor prognostic factor in RA, there was no correlation between disease activity and smoking in our study. However, less radiographic damage was found in never smokers. Smoking does not appear to correlate with RA disease activity but it may be effective in the long-term joint damage.

Plausible Roles for RAGE in Conditions Exacerbated by Direct and Indirect (Secondhand) Smoke Exposure

Approximately 1 billion people smoke worldwide, and the burden placed on society by primary and secondhand smokers is expected to increase. Smoking is the leading risk factor for myriad health complications stemming from diverse pathogenic programs. First- and second-hand cigarette smoke contains thousands of constituents, including several carcinogens and cytotoxic chemicals that orchestrate chronic inflammatory responses and destructive remodeling events. In the current review, we outline details related to compromised pulmonary and systemic conditions related to smoke exposure. Specifically, data are discussed relative to impaired lung physiology, cancer mechanisms, maternal-fetal complications, cardiometabolic, and joint disorders in the context of smoke exposure exacerbations. As a general unifying mechanism, the receptor for advanced glycation end-products (RAGE) and its signaling axis is increasingly considered central to smoke-related pathogenesis. RAGE is a multi-ligand cell surface receptor whose expression increases following cigarette smoke exposure. RAGE signaling participates in the underpinning of inflammatory mechanisms mediated by requisite cytokines, chemokines, and remodeling enzymes. Understanding the biological contributions of RAGE during cigarette smoke-induced inflammation may provide critically important insight into the pathology of lung disease and systemic complications that combine during the demise of those exposed.

Increased inflammation and disease activity among current cigarette smokers with rheumatoid arthritis: a cross-sectional analysis of US veterans

OBJECTIVES

Cigarette smoking is a major risk factor for RA and has been associated with increased disease severity and lower rates of disease remission. We hypothesized that inflammation and disease activity would be associated with smoking status and this would be related to levels of ACPA.

METHODS

RA patients from the Veterans Affairs RA registry were studied (n = 1466): 76.9% anti-CCP2 positive, 89% male, median age 63 years (interquartile range 57-72), median disease duration 8.45 years (interquartile range 2.8-18). Baseline serum samples were evaluated for levels of anti-CCP2, RF, 19 distinct ACPAs and 17 cytokines. Smoking status at baseline was recorded as current, former or never. The association of smoking status with cytokines, autoantibodies and disease activity (DAS28) was evaluated.

RESULTS

Among anti-CCP-positive RA patients, RA-associated cytokines (false-discovery rates q < 0.1%) and DAS28 (P < 0.01) were higher in current smokers compared with former or never smokers. DAS28 and cytokine levels were similar between former and never smokers. In contrast, ACPA concentrations were higher among both current and former smokers compared with never smokers, and levels of ACPA were not associated with DAS28 or cytokine levels.

CONCLUSION

Among anti-CCP2-positive RA patients, current smoking status is associated with elevations in pro-inflammatory cytokines and increased RA disease activity. Similar levels of inflammation and disease activity among former and never smokers suggests that the detrimental effects of smoking could be ameliorated through tobacco cessation. The effect of tobacco cessation on RA disease activity should be evaluated prospectively.

The Autoimmune Ecology

Autoimmune diseases (ADs) represent a heterogeneous group of disorders that affect specific target organs or multiple organ systems. These conditions share common immunopathogenic mechanisms (i.e., the autoimmune tautology), which explain the clinical similarities they have among them as well as their familial clustering (i.e., coaggregation). As part of the autoimmune tautology, the influence of environmental exposure on the risk of developing ADs is paramount (i.e., the autoimmune ecology). In fact, environment, more than genetics, shapes immune system. Autoimmune ecology is akin to exposome, that is all the exposures - internal and external - across the lifespan, interacting with hereditary factors (both genetics and epigenetics) to favor or protect against autoimmunity and its outcomes. Herein, we provide an overview of the autoimmune ecology, focusing on the immune response to environmental agents in general, and microbiota, cigarette smoking, alcohol and coffee consumption, socioeconomic status (SES), gender and sex hormones, vitamin D, organic solvents, and vaccines in particular. Inclusion of the autoimmune ecology in disease etiology and health will improve the way personalized medicine is currently conceived and applied.

Vagus nerve stimulation: a new bioelectronics approach to treat rheumatoid arthritis?

There has been a marked improvement in the treatment of rheumatoid arthritis (RA), but most patients do not achieve disease remission. Therefore, there is still a need for new treatments. By screening an adenoviral short hairpin RNA library, we discovered that knockdown of the nicotinic acetylcholine receptor type 7 (α7nAChR) in RA fibroblast-like synoviocytes results in an increased production of mediators of inflammation and degradation. The α7nAChR is intimately involved in the cholinergic anti-inflammatory pathway (CAP). This led us to study the effects of α7nAChR activation in an animal model of RA, and we could show that this resulted in reduced arthritis activity. Accordingly, stimulation of the CAP by vagus nerve stimulation improved experimental arthritis. Conversely, we found aggravation of arthritis activity after unilateral cervical vagotomy as well as in α7nAChR-knockout mice. Together, these data provided the basis for exploration of vagus nerve stimulation in RA patients as a novel anti-inflammatory approach.

Rheumatoid nodule in the lower lip of a patient with rheumatoid arthritis: a novel case report and review of literature

PURPOSE

Rheumatoid nodules are a well-characterized common extra-articular manifestation of rheumatoid arthritis. However, the occurrence of a rheumatoid nodule in the oral mucosa is extremely rare.

PATIENTS AND METHODS

We present the case of a rheumatoid nodule in the lower lip, which rarely presents with variations in the clinical manifestation, that occurred in a 48-year-old female patient with rheumatoid arthritis. The nodule was totally excised under the clinical diagnosis of either a fibroma or salivary gland lesion.

RESULTS

On histopathologic examination, within the deep mucosa, a necrobiotic nodule surrounded by elongated histiocytic cells with a focal palisaded arrangement. The lesion was diagnosed postoperatively as a rheumatoid nodule from the histopathologic and clinical findings.

CONCLUSIONS

Few studies have been performed of oral rheumatoid lesions; however, a review of the published data showed that this is the first case of a rheumatoid nodule in the lower lip of a patient with rheumatoid arthritis.

Current smoking status is a strong predictor of radiographic progression in early rheumatoid arthritis: results from the SWEFOT trial

Objectives

To study clinical predictors for radiographic progression after 1 year in an early rheumatoid arthritis (RA) trial.

Methods

In the SWEFOT trial population, disease modifying antirheumatic drug (DMARD) naïve RA patients started methotrexate; 3-month responders (DAS28 <3.2) continued (n=147), while non-responders were randomised to addition of sulfasalazine+hydroxychloroquine (n=130) or infliximab (n=128). X-rays were scored by the Sharp-van der Hejde score (SHS) method and radiographic progression was defined as a ≥5 increase after 1 year. Potential baseline predictors of radiographic progression were tested using multivariable logistic regression, adjusted for potential confounders.

Results

79 of 311 patients with available radiographs at baseline and follow-up had radiographic progression. The following baseline parameters were independent predictors of radiographic progression at 1 year: baseline erosions (adjusted OR=2.29, 95% CI 1.24 to 4.24), erythrocyte sedimentation rate (adjusted OR per tertile increase=1.72, 95% CI 1.12 to 2.65) and C-reactive protein (adjusted OR per tertile increase=1.52, 95% CI 1.03 to 2.26). Current smoking was an independent predictor of radiographic progression (adjusted OR=2.17, 95% CI 1.06 to 4.45). These results remained after further adjustment for treatment strategy. Three-dimensional matrix including current smoking status, erosions and C-reactive protein tertiles showed a 12–63% risk gradient from patients carrying none compared with all predictors. Rheumatoid factor (RF)/anti-cyclic citrullinated peptide (anti-CCP) positivity did not significantly predict radiographic progression using SHS increase ≥5 as cut-off. In a secondary exploratory analysis using cut-off >1, both RF and anti-CCP positivity were significant predictors in the unadjusted, but not the adjusted analyses. The other parameters also remained significant using this lower cut-off.

Conclusions

In addition to previously described predictors, we identified smoking as a strong independent risk factor for radiographic progression in early RA.

Trial registration number

NCT00764725.

Selection bias in rheumatic disease research

The identification of modifiable risk factors for the development of rheumatic conditions and their sequelae is crucial for reducing the substantial worldwide burden of these diseases. However, the validity of such research can be threatened by sources of bias, including confounding, measurement and selection biases. In this Review, we discuss potentially major issues of selection bias--a type of bias frequently overshadowed by other bias and feasibility issues, despite being equally or more problematic--in key areas of rheumatic disease research. We present index event bias (a type of selection bias) as one of the potentially unifying reasons behind some unexpected findings, such as the 'risk factor paradox'--a phenomenon exemplified by the discrepant effects of certain risk factors on the development versus the progression of osteoarthritis (OA) or rheumatoid arthritis (RA). We also discuss potential selection biases owing to differential loss to follow-up in RA and OA research, as well as those due to the depletion of susceptibles (prevalent user bias) and immortal time bias. The lesson remains that selection bias can be ubiquitous and, therefore, has the potential to lead the field astray. Thus, we conclude with suggestions to help investigators avoid such issues and limit the impact on future rheumatology research.

[Interluekin-1: from regulation of cell proliferation to chronic inflammatory diseases]

  Interleukin 1 (IL-1) was initially defined as a factor which is produced by macrophages and exhibits proliferative activity on thymocytes and fibroblasts, B cell activation and endogenous pyrogen activity. Now IL-1 is known to exhibit pleiotropic activities on various cell types and play important roles in the regulation of immune, nervous and endocrine systems, progression of tumor cells, hematopoietic cell proliferation/differentiation and especially in inflammatory diseases. In 1985 I found that IL-1 exhibits cytocidal activity against human melanoma cells. Since then I have been engaged in the research of various aspects of IL-1. This review summarizes current knowledge of IL-1, including our research and beneficial effect of IL-1 blocking on inflammatory diseases.

Cigarette smoke condensate extracts induce IL-1-beta production from rheumatoid arthritis patient-derived synoviocytes, but not osteoarthritis patient-derived synoviocytes, through aryl hydrocarbon receptor-dependent NF-kappa-B activation and novel NF-kappa-B sites

Cigarette smoking is a major established environmental risk factor for rheumatoid arthritis (RA), and synoviocyte-derived proinflammatory cytokines are implicated in the pathogenesis of RA. We have reported that aryl hydrocarbon or cigarette smoke condensate (CSC) is able to upregulate the production of proinflammatory cytokines from an RA patient-derived synovial fibroblast cell line MH7A. In this study, we compared the effect of CSC on induction of interleukin-1β (IL-1β) from RA or osteoarthritis (OA) patient-derived synovial fibroblasts, and studied the mechanism of the effect of CSC. CSC induced IL-1β mRNA from RA patient-derived synoviocytes and MH7A, but not from OA patient-derived synoviocytes. CSC induced the mRNA and both precursor and mature forms of IL-1β, and caspase-1 activity in MH7A. The mechanism of CSC-induced IL-1β mRNA expression was investigated in MH7A. Reporter gene analyses and promoter pull-down assay indicated that 3 novel NF-κB sites at -3771 to -3762 bp, -3105 to -3096 bp, and -2787 to -2778 bp in the promoter region of the IL-1β gene, especially the far distal NF-κB site and NF-κB activation, are critical for the gene activation by CSC. CSC-induced NF-κB activation, IL-1β promoter activity, IL-1β mRNA upregulation, and CYP1A1 mRNA induction were all inhibited by an aryl hydrocarbon receptor (AhR) antagonist α-naphthoflavone. These results indicate that CSC induced IL-1β production from RA patient-derived synoviocytes, but not OA patient-derived synoviocytes, through AhR-dependent NF-κB activation and novel NF-κB sites.

What Have We Learned about the Pathogenesis of Rheumatoid Arthritis from TNF-Targeted Therapy?

Studies of cytokine regulation in rheumatoid arthritis led to the development of TNFα inhibitors which are now used for a number of indications, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, psoriatic arthritis, and ankylosing spondylitis. The widespread use of biologics in the clinic offers unique opportunities for probing disease pathogenesis and this paper provides an overview of rheumatoid arthritis, with a particular emphasis on the impact of anti-TNFα therapy on pathogenetic mechanisms. An overview is also provided on the most commonly used animal models that mimic RA, including adjuvant-induced arthritis, collagen-induced arthritis, TNFα-transgenic mice, and the K/BxN and SKG models. These models have led to significant discoveries relating to the importance of pro-inflammatory cytokines in the pathogenesis of rheumatoid arthritis, resulting from disregulation of the normally finely tuned balance of pro- and anti-inflammatory cytokine signalling. In addition, experimental evidence is discussed suggesting how genetic and environmental factors can contribute to disease susceptibility. The role of effector and regulatory T cells is discussed in the light of the relatively disappointing therapeutic effects of T cell modifying agents such as anti-CD4 antibody and cyclosporin. It is concluded that comprehensive analyses of mechanisms of action of biologics and other drugs entering the clinic will be essential to optimise therapy, with the ultimate aim of providing a cure.

Dendritic cells provide a potential link between smoking and inflammation in rheumatoid arthritis

Introduction

Smoking increases the risk of developing rheumatoid arthritis (RA) and affects the severity of established RA. Smoking can impact on Th17 lymphocyte differentiation and function through activation of the aryl hydrocarbon receptor (AHR), a process with implications for the pathogenic mechanisms in RA that involve the cytokine, interleukin (IL)-17A. The objective of this study was to establish any effect of smoking on the inflammatory tissue lesions of rheumatoid arthritis via the AHR and IL-17A.

Methods

Twenty synovial and eighteen subcutaneous nodule tissue samples from 31 patients with RA were studied. Patient smoking status at the time of tissue collection was established. Expression of AHR, CYP1A1, AHRR, IL6, IL17A, IL17F, IL22, IL23, IL23R, IFNG, TBX21, IDO1 and FOXP3 genes were assessed in tissues and cultured cells using real-time PCR. Two-colour immunofluorescence was used to co-localise AHR and CYP1A1 protein in synovial tissues. The response of monocytes and monocyte-derived dendritic cells (mo-DCs) to the AHR agonist, benzo(a)pyrene (BaP) was compared in vitro.

Results

AHR gene expression was demonstrated in rheumatoid synovial tissues and nodules with significantly greater expression in synovia. Expression was not influenced by smoking in either tissue. Evidence of AHR activation, indicated by CYP1A1 and AHRR gene expression, was found only in synovia from patients who smoked. However, IL17A gene expression was lower in synovia from smokers. TBX21 and FOXP3 expression was not affected by smoking. Within the synovial tissues of smokers the principal cell type with evidence of AHR activation was a subset of synovial DCs. This observation was consistent with the sensitivity of human mo-DCs to BaP stimulation demonstrated in vitro. Exposure to BaP affected mo-DC function as demonstrated by decreased IL6 expression induced by PolyI:C, without affecting indoleamine 2,3 dioxygenase (IDO)1 expression.

Conclusion

Our findings show that one effect of smoking on inflamed rheumatoid synovial tissue involves activation of the AHR pathway. A subset of synovial DCs is important in the response to cigarette smoke. The potential for smoking to affect DC behaviour in joint tissues has relevance to both early and late phases of RA pathogenesis and warrants further investigation.

Tobacco and other environmental risk factors in rheumatoid arthritis

Many environmental factors have been associated with an increased risk of developing Rheumatoid Arthritis (RA), but so far smoking is the only environmental risk factor that has been extensively studied and widely accepted. Smoking is associated with an increased risk of developing seropositive RA (RF and/or ACPA). Recent studies show that tobacco smoking can influence disease phenotype, with the development of more aggressive disease and greater joint damage; but other studies show contradictory results. Recent data suggests that response to antirheumatic therapy in RA is worse in smokers. In this article we review different environmental factors that have been associated with an increased risk of developing RA, with a special interest in tobacco smoking.

Factors associated with severe skin infections in patients treated with biologic therapies for inflammatory rheumatic diseases

BACKGROUND

The incidence of severe infections is increased under biologic therapies and the skin is the second localization.

OBJECTIVE

To appraise the factors associated with severe skin infections (SSI) in patients under biologic therapies for inflammatory rheumatic diseases (IRD).

METHODS

We performed a case-control (ratio 1:3) study nested in a prospective cohort of patients with IRD. SSI was defined as requiring hospitalization or intravenous anti-infectious therapy. We defined two imbedded periods: period A was the time window between the first biologic therapy and the SSI; period B was the last 3 or 12 months (for tumor necrosis factor blockers or rituximab, respectively) before the SSI.

RESULTS

Among 4,361 patients with IRD, 29 had a SSI under biologic therapy. In multivariate analyses, SSI were significantly associated with smoking, baseline C-reactive protein and gammaglobulinemia, non-steroidal anti-inflammatory drugs before biologic therapy, cumulative dose of steroids, concomitant steroids during period A, number of different biologic therapies during period A, treatment with infliximab during period A, period B or as first biologic therapy and treatment at high dose during period B.

CONCLUSION

In patients under biologic therapies for IRD, the risk of SSI is associated with several factors including tobacco, treatment with infliximab or high dose range.

Smoking, smoking cessation, and disease activity in a large cohort of patients with rheumatoid arthritis

OBJECTIVE

While cigarette smoking is the best-studied environmental factor contributing to rheumatoid arthritis (RA), no study to date has examined the influence of smoking cessation on disease activity. We examined this relationship in an observational cohort of patients with RA in the United States.

METHODS

Patients enrolled in the Consortium of Rheumatology Researchers of North America registry (CORRONA) were stratified into never, former, and current smokers at enrollment. Current smokers were further stratified into continued and ceased smoking groups during their followup in the registry. The primary outcome was change in Clinical Disease Activity Index (CDAI) at last visit in a multivariate, random-effects regression model accounting for multiple timepoints.

RESULTS

At last visit, there was no significant change in CDAI between ceased smokers and continued smokers (coefficient -0.00091, SE 0.0033, p = 0.7834). The study did confirm prior cross-sectional studies that current smokers have worse disease activity than former or never smokers.

CONCLUSION

In the short term, smoking cessation did not appear to influence change in disease activity over time.

Patients with early rheumatoid arthritis who smoke are less likely to respond to treatment with methotrexate and tumor necrosis factor inhibitors: observations from the Epidemiological Investigation of Rheumatoid Arthritis and the Swedish Rheumatology Register cohorts

OBJECTIVE

To determine whether cigarette smoking influences the response to treatment in patients with early rheumatoid arthritis (RA).

METHODS

We retrieved clinical information about patients entering the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) early RA cohort from 1996 to 2006 (n=1,998) who were also in the Swedish Rheumatology Register (until 2007). Overall, 1,430 of the 1,621 registered patients were followed up from the time of inclusion in the EIRA cohort. Of these, 873 started methotrexate (MTX) monotherapy at inclusion, and 535 later started treatment with a tumor necrosis factor (TNF) inhibitor as the first biologic agent. The primary outcome was a good response according to the European League Against Rheumatism criteria at the 3-month visit. The influence of cigarette smoking (current or past) on the response to therapy was evaluated by logistic regression, with never smokers as the referent group.

RESULTS

Compared with never smokers, current smokers were less likely to achieve a good response at 3 months following the start of MTX (27% versus 36%; P=0.05) and at 3 months following the start of TNF inhibitors (29% versus 43%; P=0.03). In multivariate analyses in which clinical, serologic, and genetic factors were considered, the inverse associations between current smoking and good response remained (adjusted odds ratio [OR] for MTX response 0.60 [95% CI 0.39-0.94]; adjusted OR for TNF inhibitor response 0.52 [95% CI 0.29-0.96]). The lower likelihood of a good response remained at later followup visits. Evaluating remission or joint counts yielded similar findings. Past smoking did not affect the chance of response to MTX or TNF inhibitors. Evaluating the overall cohort, which reflects all treatments used, current smoking was similarly associated with a lower chance of a good response (adjusted ORs for the 3-month, 6-month, 1-year, and 5-year visits 0.61, 0.65, 0.78, 0.66, and 0.61, respectively).

CONCLUSION

Among patients with early RA, current cigarette smokers are less likely to respond to MTX and TNF inhibitors.

Etiological role of cigarette smoking in rheumatoid arthritis: Nasal exposure to cigarette smoke condensate extracts augments the development of collagen-induced arthritis in mice

Cigarette smoking is a major environmental risk factor for rheumatoid arthritis (RA). However, the experimental bases supporting the etiological role of cigarette smoking in RA have not been fully provided. We have reported that cigarette smoke condensate (CSC), by means of subcutaneous injection into DBA/1J mice with collagen and complete Freund's adjuvant or intraperitoneal injection one day before immunization, augmented the development of arthritis in the mouse model of collagen type II-induced arthritis (CIA). However, these experimental procedures may not be appropriate for cigarette smoking. In this study, we nasally exposed mice to mainstream CSC and found that CSC augmented the induction and development of arthritis and antibody level against collagen. Histological examination confirmed the augmenting effect of CSC. These findings provide experimental bases supporting the etiological role of cigarette smoking in RA.

Cigarette smoke condensate extracts augment collagen-induced arthritis in mice

Although cigarette smoking is a solid environmental risk factor for rheumatoid arthritis (RA) as revealed by epidemiological studies, the scientific basis has not been provided. Proinflammatory cytokines produced by synoviocytes are implicated in the pathogenesis of RA. As cigarette smoke condensate (CSC) is able to up-regulate the production of proinflammatory cytokines from human fibroblast-like synoviocytes, we studied the effect of CSC on induction of arthritis in the mouse model of collagen type II-induced arthritis (CIA). When mainstream CSC or sidestream CSC was administered into DBA/1J mice at the time of immunization with collagen and complete Freund adjuvant, CSC dose-dependently augmented the induction and clinical development of arthritis at both young and older mice. Peritoneal injected mainstream CSC one day before immunization also exhibited the augmenting effect, suggesting the systemic effect of CSC. These results support the etiological role of cigarette smoking in RA.

Determinants of red blood cell methotrexate polyglutamate concentrations in rheumatoid arthritis patients receiving long-term methotrexate treatment

OBJECTIVE

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug (DMARD) in the management of rheumatoid arthritis (RA). MTX is transported into cells, where additional glutamate moieties are added and it is retained as MTX polyglutamates (MTXGlu [referred to as a group as MTXGlun]). There is large interpatient variability in MTXGlun concentrations. This study was undertaken to determine nongenetic factors that influence red blood cell (RBC) MTXGlun concentrations in patients receiving long-term stable low-dose oral MTX.

METHODS

One hundred ninety-two patients receiving long-term oral MTX for the treatment of RA were recruited. Trough MTXGlun concentrations were measured by high-performance liquid chromatography. Univariate analysis was performed to determine variables influencing MTXGlun concentrations. Backward stepwise multivariate regression analysis was done to determine variables that affect individual MTXGlun concentrations; variables with P values of <0.1 in the univariate analysis for any MTXGlun were included.

RESULTS

Univariate analysis revealed that increased age, lower estimated glomerular filtration rate (GFR), higher MTX dosage, longer duration of MTX treatment, and use of prednisone were associated with significantly higher MTXGlun concentrations. Smokers had significantly lower concentrations of MTXGlu3, MTXGlu3-5, and MTXGlu1-5. Sex, rheumatoid factor and anti-cyclic citrullinated peptide status, RBC folate level, and body mass index had no significant effect on MTXGlun levels. Concomitant use of other DMARDs was associated with lower MTXGlu2 levels, and treatment with nonsteroidal antiinflammatory drugs was associated with lower MTXGlu3 and MTXGlu1-5 concentrations. Multivariate regression analysis revealed that age, MTX dosage, and estimated GFR were the major determinants of MTXGlun concentrations.

CONCLUSION

Large interpatient variability in MTXGlun concentrations can be explained, at least in part, by a combination of factors, particularly age, MTX dosage, and renal function. There are complex interactions between smoking, RBC folate levels, and concentrations of MTXGlun.

Risk factors for the development of rheumatoid arthritis

There is increasing interest in attempting to understand what the risk factors are that lead to the development of rheumatoid arthritis (RA). Twin studies have proved a genetic role but also quantified the non-genetic risk. There is thus scope for identifying environmental predictors that might offer a strategy to prevent the disease. Changes in the female hormonal environment such as in pregnancy, breastfeeding and the use of the oral contraceptive (OC) pill appear to have a role. Of the traditional lifestyle exposures, cigarette smoking has been associated with a consistently increased risk that might also apply to the passive inhalation of smoke. Occupation probably has a minor influence, although exposure to silica dust is of aetiological importance. Recent studies have highlighted a role for diet, with suggestions that diets high in caffeine, low in antioxidants and high in red meat may contribute to an increased risk. The most plausible environmental exposure is infection and although several decades of study have produced few definitive candidate organisms, Epstein-Barr virus (EBV) remains an interesting target.

Where to for tobacco regulation: time for new approaches?

From a public health perspective, tobacco remains the number one drug problem facing most countries, even countries such as Australia, which has made considerable headway in reducing tobacco use and associated harm. Clearly more needs to be done, but is it the case that more of the same will be sufficient? In this Harm Reduction Digest based in part on a presentation at the 'International Research Symposium Preventing Substance Use, Risky Use and Harm: What is Evidence-Based Policy?' held in Fremantle, Western Australia in February 2003, the author proposes a new regulatory framework through which to further reduce tobacco-related harm. The paper challenges whether the current profit motive is an appropriate driver of the tobacco industry and suggests a new model of tobacco regulation.

What epidemiology has told us about risk factors and aetiopathogenesis in rheumatic diseases

This article will review how epidemiological studies have advanced our knowledge of both genetic and environmental risk factors for rheumatic diseases over the past decade. The major rheumatic diseases, including rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, systemic lupus erythematosus, scleroderma, osteoarthritis, gout, and fibromyalgia, and chronic widespread pain, will be covered. Advances discussed will include how a number of large prospective studies have improved our knowledge of risk factors, including diet, obesity, hormones, and smoking. The change from small-scale association studies to genome-wide association studies using gene chips to reveal new genetic risk factors will also be reviewed.

Relationship Between Pack-year History of Smoking and Response to Tumor Necrosis Factor Antagonists in Patients with Rheumatoid Arthritis

Objective.

To determine whether there is a quantitative relationship between smoking history and response to therapy with tumor necrosis factor (TNF) antagonists.

Methods.

A history of cigarette smoking was obtained from a questionnaire completed by each patient starting therapy with TNF antagonists since 2002 (n = 154). A core set of demographic and clinical variables was recorded at baseline and at 3 and 12 months. The extent of smoking was quantified in pack-years (py), with 1 py equivalent to 20 cigarettes per day for 1 year. The association between smoking intensity and response was assessed using contingency tables and logistic regression analysis. Response to therapy was defined according to the European League Against Rheumatism improvement criteria.

Results.

There was an increasing trend of no response at 3 and 12 months with increasing py history [p (trend) = 0.008 and 0.003, respectively]. The change in Disease Activity Score (DAS)28 over the first 3 months was inversely associated with the number of py (r = −0.28, p = 0.002). The association of py history with response failure was independent of age, sex, disease duration, baseline disease activity score (DAS28), Health Assessment Questionnaire (HAQ) score, IgM rheumatoid factor, and smoking at baseline. The most significant effect was seen in patients treated with infliximab.

Conclusion.

RA patients with a history of smoking were more likely to show a poor response to TNF antagonists. Response failure was associated with the intensity of previous smoking, irrespective of smoking status at initiation of anti-TNF therapy.

Does smoking reduce infliximab's effectiveness against Crohn's disease?

Crohn's disease (CD) is an idiopathic inflammatory bowel disease and has no known cure. CD symptoms are treated using an array of medicines, including biological agents such as infliximab. However, infliximab therapy is expensive; therefore, identifying variables that can help predict response to infliximab is worthwhile. The present article reviews the impact of tobacco smoking on the efficacy of infliximab in CD. Earlier studies have speculated that smoking has a negative effect on the response to infliximab in CD, but the current literature is largely unable to identify a significant relationship between the two. Although smoking is known to have a negative effect on the course of CD, as well as other organ systems, presently, a CD patient's smoking status should not influence treatment decisions regarding infliximab therapy.

Smoking and inflammatory diseases

Smoking has an impact on the development and outcome of rheumatoid arthritis (RA) and lupus. In RA, smoking is associated with the development of the anti-cyclic citrullinated peptide (CCP2)-positive subset. This risk is increased in heavy smokers carrying at least one copy of the HLA DRB1 shared epitope (SE) alleles. Whereas this interaction between smoking and SE relevant in northern Europe, discrepant results have been observed in other geographic locations, suggesting the involvement of other environmental stimuli and/or gene polymorphisms. There is no interaction between tobacco exposure and PTPN22 1858T for the development of anti-CCP-positive or anti-CCP-negative RA. A strong association exists between smoking and the occurrence of extra-articular manifestations (subcutaneous nodules and cardiovascular events), but smoking has no influence on radiographic outcome. In lupus, tobacco exposure has an impact on the production of anti-double-stranded Desoxyribonuclic (dsDNA) and possibly on the development of the disease, as well as on disease activity/severity. In both diseases, smoking might interfere with drug efficacy.

Cigarette smoking, disease severity and autoantibody expression in African Americans with recent-onset rheumatoid arthritis

OBJECTIVE

To examine the association of smoking with clinical and serological features in African Americans with recent-onset rheumatoid arthritis (RA) and to explore whether this association is dependent on the presence of the HLA-DRB1 shared epitope (SE).

METHODS

In African Americans with recent-onset RA (n = 300), we examined the association of cigarette smoking (current versus past versus never and pack-years of exposure) with anti-cyclic citrullinated peptide antibody, rheumatoid factor (RF) (IgM and IgA), rheumatoid nodules and baseline radiographic erosions using logistic and cumulative logistic regression (adjusting for SE status). We also examined for evidence of interaction between smoking status and SE for all outcomes.

RESULTS

Although there was no association with RF-IgA seropositivity, current smokers were approximately twice as likely as never smokers to have higher IgA-RF concentrations (based on tertiles; OR = 1.74; 95% CI 1.05 to 2.88) and nodules (OR = 2.43; 95% CI 1.13 to 5.22). These associations were most pronounced in those with more than 20 pack-years of exposure. There was no association of smoking status or cumulative tobacco exposure with anti-cyclic citrullinated peptide antibody, IgM-RF or radiographic erosions. There was also no evidence of a biological or statistical SE-smoking interaction for any of the outcomes examined.

CONCLUSIONS

This is the first study to systematically examine the association of cigarette smoking with RA-related features in African Americans. Cigarette smoking is associated with both subcutaneous nodules and higher serum concentrations of IgA-RF in African Americans with RA, associations that may have important implications for long-term outcomes in this population.

Cigarette smoke condensate upregulates the gene and protein expression of proinflammatory cytokines in human fibroblast-like synoviocyte line

Rheumatoid arthritis (RA) is characterized by proliferation of synoviocytes that produce proinflammatory cytokines, which are implicated in the pathogenesis of RA. When human fibroblast-like synoviocytes line MH7A was treated with cigarette smoke condensate (CSC), either mainstream or sidestream, expression levels of interleukin (IL)-1alpha, IL-1beta, IL-6, IL-8, and CYP1A1 mRNA were upregulated in both time- and dose-dependent manners. The upregulatory effects of CSC on these cytokines were not significantly inhibited by alpha-naphthoflavone, an aryl hydrocarbon receptor (AhR) antagonist, suggesting that the effects of CSC were independent of AhR. Cycloheximide treatment indicated that the augmenting effect of CSC on IL-1alpha, IL-1beta and IL-8, but not IL-6 and CYP1A1, mRNA expression requires de novo protein synthesis. CSC also induced cytokines at protein levels and further augmented the effects of tumor necrosis factor alpha on induction of these cytokines at both mRNA and protein levels. These results support the epidemiological studies indicating a strong association between heavy cigarette smoking and pathogenesis of RA.

Pathogenesis and therapy of rheumatoid arthritis

Rheumatoid arthritis is a chronic disabling disease affecting at least 1% of the population on a worldwide basis. Research aimed at understanding the pathogenesis of this disease led to the identification of TNFalpha as a major pro-inflammatory cytokine expressed in the inflamed joints of patients with rheumatoid arthritis. Subsequently, in vitro studies provided evidence to suggest that TNFalpha played an important role in driving the expression of additional pro-inflammatory cytokines, such as IL-1, GM-CSF, IL-6, and IL-8, in synovial cell cultures. Another important finding that confirmed the pathological significance of TNFalpha was that mice genetically engineered to overexpress TNFalpha spontaneously developed arthritis. Subsequently, the therapeutic effect TNFalpha blockade was tested in animal models prior to clinical trials in human patients, which provided unequivocal verification of the validity of TNFalpha as a therapeutic target. Anti-TNFalpha therapy is now accepted as a fully-validated treatment modality for rheumatoid arthritis.

Cigarette smoking and radiographic progression in rheumatoid arthritis

BACKGROUND

Smoking is a well-established environmental risk factor for the development of rheumatoid arthritis (RA). However, it remains unclear whether smoking influences RA disease progression and whether smokers have more radiographic damage progression than non-smokers over time.

OBJECTIVE

To compare the rates of radiographic damage progression in current smokers and non-smokers in a large prospective RA cohort.

METHODS

The SCQM-RA is a population-based registry monitoring disease activity, radiographic damage and symptoms at regular intervals. All patients in the SCQM-RA database with sequential plain radiographs were included. Joint erosions were assessed in 38 hand and foot joints with a validated scoring method. The rate of erosion progression was analysed using multivariate longitudinal regression models and adjusted for potential confounders.

RESULTS

2004 RA patients with a mean of 3.6 sequential radiographs and 3.1 years of follow-up were included. The 545 (27%) current smokers smoked on average 16 cigarettes per day and had a mean past smoking exposure of 20.6 pack-years. Radiographic joint damage progressed at a similar rate in current smokers and non-smokers (p = 0.26). However, smoking intensity was associated with a significant inverse dose-response; heavy smokers (>1 pack-day) progressed significantly less than non-smokers or moderate smokers (p<0.001).

CONCLUSION

Radiographic joint damage progressed at an equivalent rate in smokers and non-smokers. Furthermore, a significant trend was observed for reduced radiographic progression and generally more favourable functional scores among heavy smokers, suggesting that cigarette smoke does not accelerate RA disease progression.

Risk and predictors of infection leading to hospitalisation in a large primary-care-derived cohort of patients with inflammatory polyarthritis

BACKGROUND

The increased mortality observed in patients with rheumatoid arthritis is partly due to an increased occurrence of serious infections. A retrospective study from the Mayo Clinic found that infection risk is increased in rheumatoid arthritis. In particular, serious infection was associated with severe disease and use of corticosteroids. Robust estimates are required from prospective studies of incident cases.

OBJECTIVE

To examine the risk of infection leading to hospitalisation and potential factors associated with this risk in an unselected population of patients with inflammatory polyarthritis.

DESIGN

A prospective cohort study comparing infection incidence in new-onset patients with inflammatory polyarthritis with local population experience.

PATIENTS AND METHODS

2108 patients with inflammatory polyarthritis from a community-based register were studied and followed up annually (median 9.2 years). The rate of hospitalisations for serious infection was compared with the rate of hospitalisations in the regional population. The contribution of potential predictors was assessed by undertaking a within-cohort analysis.

RESULTS

Overall, the incidence of infection was more than two and a half times that of the general population (varying by site). History of smoking, corticosteroid use and rheumatoid factor were found to be significantly independent predictors of infection-related hospitalisation. Patients with inflammatory polyarthritis with all three factors were more than seven times as likely to be hospitalised compared with the rest of the cohort.

DISCUSSION

These findings provide background data on the risk of infection associated with rheumatoid arthritis, and are of particular interest given the current awareness of the risk of infection associated with anti-tumour necrosis factoralpha treatments.

Association of HLA-C3 and smoking with vasculitis in patients with rheumatoid arthritis

OBJECTIVE

To compare HLA-C genotypes and smoking habits in patients with vasculitis or other severe extraarticular manifestations of rheumatoid arthritis (ExRA) with those in RA patients without extraarticular disease.

METHODS

Patients were recruited from a large research database of patients with RA at the Mayo Clinic, from 2 Swedish cohorts of prevalent RA cases, and from a regional Swedish early RA cohort. Patients with severe ExRA (n = 159) and control patients with RA but no history of ExRA (non-ExRA controls) (n = 178) were matched for duration of RA and for clinical center. Data on smoking at RA onset, rheumatoid factor (RF) status, and antinuclear antibodies (ANAs) were extracted from the medical records. Polymerase chain reaction-based HLA-C genotyping was performed using a sequence-specific primer kit.

RESULTS

The distribution of HLA-C alleles was significantly different between patients with RA-associated vasculitis and non-ExRA controls (P = 0.014). This was mainly due to a positive association of the HLA-C3 allele with vasculitis (allele frequency 0.411 in vasculitis patients versus 0.199 in non-ExRA controls; P < 0.001) and a decreased frequency of HLA-C7 (0.122 and 0.243, respectively; P = 0.018). The association between HLA-C3 and vasculitis was not due to linkage disequilibrium with HLA-DRB1. Smoking (P = 0.001), RF positivity (P < 0.0001), and presence of ANAs (P < 0.0001) were all associated with ExRA. HLA-C3 and smoking were both significant predictors of vasculitis in a multivariate model.

CONCLUSION

Vasculitis in RA is associated with HLA-C3. Smoking is an independent predictor of vasculitis and other types of severe ExRA. Our results suggest that these variables are among the genetic and environmental factors that contribute significantly to the pathomechanisms of systemic RA.