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Objectives: In rheumatology, there is a clinical need to identify patients at high risk (>50%) of not responding to the first-line therapy methotrexate (MTX) due to lack of disease control or discontinuation due to adverse events (AEs). Despite this need, previous prediction models in this context are at high risk of bias and ignore AEs. Our objectives were to (i) develop a multinomial model for outcomes of low disease activity and discontinuing due to AEs 6 months after starting MTX, (ii) update prognosis 3-month following treatment initiation, and (iii) externally validate these models., Study Design and Setting: A multinomial model for low disease activity (submodel 1) and discontinuing due to AEs (submodel 2) was developed using data from the UK Rheumatoid Arthritis Medication Study, updated using landmarking analysis, internally validated using bootstrapping, and externally validated in the Norwegian Disease-Modifying Antirheumatic Drug register. Performance was assessed using calibration (calibration-slope and calibration-in-the-large), and discrimination (concordance-statistic and polytomous discriminatory index)., Results: The internally validated model showed good calibration in the development setting with a calibration-slope of 1.01 (0.87, 1.14) (submodel 1) and 0.83 (0.30, 1.34) (submodel 2), and moderate discrimination with a c-statistic of 0.72 (0.69, 0.74) and 0.53 (0.48, 0.59), respectively. Predictive performance decreased after external validation (calibration-slope 0.78 (0.64, 0.93) (submodel 1) and 0.86 (0.34, 1.38) (submodel 2)), which may be due to differences in disease-specific characteristics and outcome prevalence., Conclusion: We addressed previously identified methodological limitations of prediction models for outcomes of MTX therapy. The multinomial approach predicted outcomes of disease activity more accurately than AEs, which should be addressed in future work to aid implementation into clinical practice., Competing Interests: Declaration of competing interest KLH has received speaker honoraria from AbbVie and grant income from BMS and Pfizer. TKK has received fees for speaking from Janssen, Sandoz, Grünenthal, and UCB; fees for consulting from AbbVie, Galapagos, Janssen, Pfizer, and Sandoz; research funding to Diakonhjemmet Hospital from AbbVie, BMS, Novartis, Pfizer, and UCB., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objectives: To understand the relationships between deprivation and obesity with self-reported disability and disease activity in people with RA, and to determine whether BMI mediates the relationship between area-level deprivation and these outcomes., Methods: Data came from the Rheumatoid Arthritis Medication Study (RAMS), a 1-year multicentre prospective observational cohort of people with RA recruited from rheumatology centres across England commencing MTX for the first time. A total of 1529 and 1626 people were included who had a baseline and at least one follow-up measurement at 6 or 12 months of HAQ-Disability Index (HAQ-DI) and DAS in 28 joints (DAS28), respectively. Linear mixed models estimated the associations of deprivation and obesity with repeated measures HAQ-DI and DAS28. Causal mediation analyses estimated the mediating effect of BMI on the relationship between deprivation and RA outcomes., Results: Higher deprivation and obesity were associated with higher disability [adjusted regression coefficients highest vs lowest deprivation fifths 0.32 (95% CI 0.19, 0.45); obesity vs no obesity 0.13 (95% CI 0.06, 0.20)] and higher disease activity [adjusted regression coefficients highest vs lowest deprivation fifths 0.34 (95% CI 0.11, 0.58); obesity vs no obesity 0.17 (95% CI 0.04, 0.31)]. BMI mediated part of the association between higher deprivation and self-reported disability (14.24%) and DAS (17.26%)., Conclusions: People with RA living in deprived areas have a higher burden of disease, which is partly mediated through obesity. Weight-loss strategies in RA could be better targeted towards those living in deprived areas., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objective: We undertook this study to estimate changes in cell-specific DNA methylation (DNAm) associated with methotrexate (MTX) response using whole blood samples collected from rheumatoid arthritis (RA) patients before and after initiation of MTX treatment., Methods: Patients included in this study were from the Rheumatoid Arthritis Medication Study (n = 66) and the University of California San Francisco Rheumatoid Arthritis study (n = 11). All patients met the American College of Rheumatology RA classification criteria. Blood samples were collected at baseline and following treatment. Disease Activity Scores in 28 joints using the C-reactive protein level were collected at baseline and after 3-6 months of treatment with MTX. Methylation profiles were generated using the Illumina Infinium HumanMethylation450 and MethylationEPIC v1.0 BeadChip arrays using DNA from whole blood. MTX response was defined using the EULAR response criteria (responders showed good/moderate response; nonresponders showed no response). Differentially methylated positions were identified using the Limma software package and Tensor Composition Analysis, which is a method for identifying cell-specific differential DNAm at the CpG level from tissue-level ("bulk") data. Differentially methylated regions were identified using Comb-p software., Results: We found evidence of differential global methylation between treatment response groups. Further, we found patterns of cell-specific differential global methylation associated with MTX response. After correction for multiple testing, 1 differentially methylated position was associated with differential DNAm between responders and nonresponders at baseline in CD4+ T cells, CD8+ T cells, and natural killer cells. Thirty-nine cell-specific differentially methylated regions associated with MTX treatment response were identified. There were no significant findings in analyses of whole blood samples., Conclusion: We identified cell-specific changes in DNAm that were associated with MTX treatment response in RA patients. Future studies of DNAm and MTX treatment response should include measurements of DNAm from sorted cells., (© 2023 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Hepatotoxicity is a serious adverse drug reaction related to methotrexate (MTX). However, the cause of drug-induced liver injury (DILI) is still unclear and unpredictable. Genetic risk factors may predispose for MTX-DILI. Therefore, we conducted a nested case-control genome-wide association study to explore genetic risk factors associated with MTX-DILI. Seven international groups contributed blood samples and data of patients with rheumatoid arthritis who used MTX. MTX-DILI was defined as an alanine aminotransferase (ALT) level of at least three times the upper limit of normal (ULN), to increase contrast controls ALT levels did not raise above two times the ULN. Per study site, control subjects and patients with MTX-DILI (ratio 3:1) were matched for age, gender, and duration of MTX use. Patients were genotyped using Illumina GSA MD-24v1-0 and data were imputed using the 1000 Genomes reference panel. Single-nucleotide polymorphisms (SNPs) were analyzed using an additive genetic model, corrected for sex, country, and age. A P-value of ≤ 5 × 10 -8 was considered significant, whereas a  P-value of ≤ 5 × 10 -6 was considered suggestive. A total of 108 MTX-DILI cases and 311 controls were included for association analysis. None of the SNPs were significantly associated with MTX-DILI. However, we found seven suggestive genetic variants associated with MTX-DILI (P-values 7.43 × 10 -8 to 4.86 × 10 -6 ). Of those, five SNPs were in the intronic protein-coding regions of FTCDNL1, BCOR, FGF14, RBMS3, and PFDN4/DOK5. Investigation of candidates SPATA9 (rs72783407), PLCG2 (rs60427389), RAVER2 (rs72675408), JAK1 (rs72675451), PTPN2 (rs2476601), MTHFR C677T (rs1801133), and into the HLA region did not show significant findings. No genetic variants associated with MTX-DILI were found, whereas suggestive SNPs need further investigation., (© 2023 The Authors. Clinical Pharmacology & Therapeutics published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Objectives: To identify groups of people with RA with different disability trajectories over 10 years, despite comparable levels of inflammation., Methods: Data for this analysis came from three European prospective cohort studies of people with RA [Norfolk Arthritis Register (NOAR), Early RA Network (ERAN), Étude et Suivi des Polyarthrites Indifférenciées Récentes (ESPOIR)]. Participants were assessed regularly over 8 (ERAN) to 10 (NOAR/ESPOIR) years. Inclusion criteria were: recruited after 1 January 2000, <24 months baseline symptom duration, and disability (HAQ) and inflammation [two-component DAS28 (DAS28-2C)] recorded at baseline and at one other follow-up. People in each cohort also completed patient-reported outcome measures at each assessment (pain, fatigue, depressive symptoms). Group-based trajectory models were used to identify distinct groups of people with similar HAQ and DAS28-2C trajectories over follow-up., Results: This analysis included 2500 people with RA (NOAR: 1000, ESPOIR: 766, ERAN: 734). ESPOIR included more women and the participants were younger [mean (standard deviation) age: NOAR: 57.1 (14.6), ESPOIR: 47.6 (12.5), ERAN: 56.8 (13.8); women: NOAR: 63.9%, ESPOIR: 76.9%, ERAN: 69.1%). Within each cohort, two pairs of trajectories following the hypothesized pattern (comparable DAS28-2Cs but different HAQs) were identified. Higher pain, fatigue and depressive symptoms were associated with increased odds of being in the high HAQ trajectories., Conclusion: Excess disability is persistent in RA. Controlling inflammation may not be sufficient to alleviate disability in all people with RA, and effective pain, fatigue and mood management may be needed in some groups to improve long-term function., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Background: No reliable biomarkers to predict response to TNF inhibitors (TNFi) in RA patients currently exist. The aims of this study were to replicate changes in gene co-expression modules that were previously reported in response to TNFi therapy in RA; to test if changes in module expression are specific to TNFi therapy; and to determine whether module expression transitions towards a disease-free state in responding patients., Method: Published transcriptomic data from the whole blood of disease-free controls (n = 10) and RA patients, treated with the TNFi adalimumab (n = 70) or methotrexate (n = 85), were studied. Treatment response was assessed using the EULAR response criteria following 3 or 6 months of treatment. Change in transcript expression between pre- and post-treatment was recorded for previously defined modules. Linear mixed models tested whether modular expression after treatment transitioned towards a disease-free state., Results: For 25 of the 27 modules, change in expression between pre- and post-treatment in the adalimumab cohort replicated published findings. Of these 25 modules, six transitioned towards a disease-free state by 3 months (P < 0.05), irrespective of clinical response. One module (M3.2), related to inflammation and TNF biology, significantly correlated with response to adalimumab. Similar patterns of modular expression, with reduced magnitude, were observed in the methotrexate cohort., Conclusion: This study provides independent validation of changes in module expression in response to therapy in RA. However, these effects are not specific to TNFi. Further studies are required to determine whether specific modules could assist molecular classification of therapeutic response., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objectives: To estimate prevalence rates and identify baseline predictors of adverse events (AEs) over the first year of treatment in patients with RA starting MTX., Methods: Data came from the UK Rheumatoid Arthritis Medication Study (RAMS), a prospective cohort of patients with RA starting MTX. This analysis included patients aged ≥18 years with physician diagnosed RA and symptom duration ≤2 years, who were commencing MTX for the first time. AEs were recorded by interviewing patients at 6- and 12-month follow-up visits. The period prevalence rates of AEs are reported for 0-6 months, 6-12 months and 0-12 months of follow-up. The associations between baseline characteristics and AEs were assessed using multivariable logistic regression., Results: A total of 1069 patients were included in the analysis. Overall, 77.5% experienced at least one AE. The most commonly reported AEs were: gastrointestinal (42.0%), neurological (28.6%), mucocutaneous (26.0%), pulmonary (20.9%), elevated alanine transaminase (18.0%) and haematological AEs (5.6%). Factors associated with increased odds of AEs were: women vs men (gastrointestinal, mucocutaneous, neurological) and alcohol consumption (nausea, alopecia, mucocutaneous). Older age, higher estimated glomerular filtration rate and alcohol consumption were associated with less reporting of haematological AEs., Conclusions: AEs were common among patients over the first year of MTX, although most were not serious. Knowledge of the rates and factors associated with AE occurrence are valuable when communicating risks prior to commencing MTX. This can help patients make informed decisions whether to start MTX, potentially increasing adherence to treatment., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Background: In the management of rheumatoid arthritis (RA), there is a clinical need to identify which patients are at high-risk of not responding to methotrexate (MTX), or experiencing adverse events (AEs), to enable earlier alternative treatments. Many clinical prediction models (CPMs) have previously been developed, but a summary of such models and their methodological quality is lacking. This systematic review aimed to (i) identify and summarize previously published CPMs of MTX outcomes in biologic-naïve RA patients, and (ii) critically appraise their methodological properties., Methods: Medline and Embase were searched to identify studies developing or validating CPMs of MTX outcomes in RA patients. The risk of bias (ROB) was assessed using PROBAST (prediction model risk of bias assessment tool). A fixed effects meta-analysis summarised discrimination for models with multiple external validations., Results: The systematic review identified 20 CPMs across 13 studies, and 4 validation studies. Three outcome types were used: a state of disease activity (n = 14, 70%); EULAR response criteria (n = 4, 20%); or discontinuation due to AEs (n = 2, 10%). Only one model accounted for potential competing risks, and nine (45%) were internally validated. Eight (40%) models used multiple imputation for missing data, others were often limited to complete case analysis. There was overall high ROB. The meta-analysis summarised c-statistics for two models with multiple external validations was 0.77 (95% CI: 0.69, 0.84) and 0.68 (0.64, 0.71)., Conclusion: This review highlights several methodological shortcomings that should be addressed in future model development to increase potential for implementation into practice., Competing Interests: Declaration of Competing Interest KLH has received speaker honoraria from Abbvie and grant income from BMS and Pfizer. The remaining authors have no conflicts of interest to declare., (Copyright © 2022. Published by Elsevier Inc.)

Objectives: To describe how many people with RA reduce their baseline physical activity level over the first year of MTX treatment, and which factors predict this., Methods: Data came from the Rheumatoid Arthritis Medication Study (RAMS), a prospective cohort of people with early RA starting MTX. Participants reported demographics and completed questionnaires at baseline, and 6 and 12 months, including reporting the number of days per week they performed ≥20 min of physical activity, coded as none, low (1-3 days) or high (4-7 days). The physical activity levels of participants over 12 months are described. Predictors of stopping physical activity were assessed using multivariable logistic regression., Results: In total, 1468 participants were included [median (interquartile range) age 60 (50, 69) years; 957 (65.2%) women]. At baseline, the physical activity levels of the people with RA were: none = 408 (27.8%), low = 518 (35.3%) and high = 542 (36.9%). Eighty percent of participants maintained some physical activity or began physical activity between assessments (baseline to 6 months = 79.3%, 6 months to 12 months = 80.7%). In total, 24.1% of participants reduced physical activity and 11.3% of participants stopped performing physical activity between baseline and 6 months (6 months to 12 months: 22.6% and 10.2%, respectively). Baseline smoking, higher disability and greater socioeconomic deprivation were associated with stopping physical activity., Conclusion: Many people with early RA were not performing physical activity when starting MTX, or stopped performing physical activity over the first year of treatment. These people may require interventions to stay active. These interventions need to be mindful of socioeconomic barriers to physical activity participation., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objectives: This systematic review aims to summarize rates of adverse events (AEs) in patients with RA or inflammatory arthritis starting MTX as monotherapy or in combination with other csDMARDs, and to identify reported predictors of AEs., Methods: Three databases were searched for studies reporting AEs in MTX-naïve patients with RA. Randomized controlled trials (RCTs) and observational cohort studies were included. Prevalence rates of AEs were pooled using random effects meta-analysis, stratified by study design., Results: Forty-six articles (34 RCTs and 12 observational studies) were identified. The pooled prevalence of total AEs was 80.1% in RCTs (95% CI: 73.5, 85.9), compared with 23.1% in observational studies (95% CI: 12.3, 36.0). The pooled prevalence of serious AEs was 9.5% in RCTs (95% CI: 7.4, 11.7), and 2.1% in observational studies (95% CI: 1.0, 3.4). MTX discontinuation due to AEs was higher in observational studies (15.5%, 95% CI: 9.6, 22.3) compared with RCTs (6.7%, 95% CI: 4.7, 8.9). Gastrointestinal events were the most commonly reported AEs (pooled prevalence: 32.7%, 95% CI: 18.5, 48.7). Five studies examined predictors of AEs. RF status, BMI and HAQ score were associated with MTX discontinuation due to AEs; ACPA negativity, smoking and elevated creatinine were associated with increased risk of elevated liver enzymes., Conclusion: The review provides an up-to-date overview of the prevalence of AEs associated with MTX in patients with RA. The findings should be communicated to patients to help them make informed choices prior to commencing MTX., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: To describe the illness perceptions of patients with RA over the first year of MTX treatment, and the association between illness perceptions and outcomes., Methods: Data came from the Rheumatoid Arthritis Medication Study (RAMS), a UK multicentre cohort study of RA patients starting MTX for the first time. Patients were assessed at baseline, and at 6 and 12 months. Patients completed the Brief Illness Perception Questionnaire (B-IPQ) at each assessment, as well as other patient-reported outcomes (PROs). The inflammation score (2-component DAS28) was calculated. Subgroups of patients with similar trajectories across the eight (B-IPQ) items were identified using a latent class growth model. Predictors of group membership were identified using multinomial logistic regression. Associations between subgroups and PROs over follow-up were assessed using linear mixed models., Results: Three subgroups were identified in the analysis population (N = 1087): Positive illness perceptions (N = 322), Negative illness perceptions (N = 534) and Improvers (N = 231) who switched from negative to positive illness perceptions over follow-up. Baseline disability was associated with group membership [Positive vs Negative: relative risk ratio (RRR) 0.37, 95% CI: 0.25, 0.54; Improvers vs Negative: RRR 0.60, 95% CI: 0.43, 0.83], as were other PROs (pain, fatigue, anxiety, depression). The Negative group had worse disability, pain and fatigue over follow-up compared with the other groups, controlling for inflammation., Conclusion: Negative illness perceptions are associated with poor PROs over time. The Improvers subgroup illustrated that illness perceptions can change in RA. Illness perceptions represent a potential therapeutic target that should be assessed using randomized trials., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objectives: Work is an important health outcome. This study aimed to identify predictors of work loss, absenteeism and presenteeism over 1 year in RA patients commencing treatment with MTX or biologics., Methods: Patients aged 18-65 years in full/part-time employment from two UK prospective cohorts were included: MTX-starters = Rheumatoid Arthritis Medication Study; and biologic-starters = Biologics in Rheumatoid Arthritis Genetics and Genomics Study Syndicate. Presenteeism and absenteeism were assessed using the RA-specific Work Productivity Survey at baseline, and 6 and 12 months. Potential predictors including baseline age, gender, clinical measures (e.g. disability, pain, fatigue), psychological distress, occupation and EULAR response from baseline to 6 months were investigated., Results: A total of 51/463 MTX-starters and 30/260 biologic-starters left work over 12 months. Higher baseline psychological distress in MTX-starters [odds ratio (OR) 1.1 (95% CI: 1.0, 1.1)] and higher disability in biologic-starters [OR 3.5 (95% CI: 1.4, 8.6)] predicted work loss. Some 16.1% of patients reported sick-leave, which was predicted by disability [OR (95% CI): MTX-starters: 1.5 (0.9, 2.3); biologic-starters: 2.4 (1.1, 5.2)]. Median presenteeism scores were very low (minimal interference) in both cohorts. Higher fatigue for MTX starters [incidence rate ratio 1.2 (95% CI: 1.0, 1.4)] and higher disability in biologic-starters (incidence rate ratio 1.4 (95% CI: 1.1, 1.7)] predicted presenteeism. Good EULAR response was associated with lower absenteeism and presenteeism in both cohorts., Conclusion: Patients with RA still face significant limitations regarding their ability to work. Disability and EULAR response were the main predictors of work outcomes, emphasizing the need to control the disease and the importance of function in enabling work participation., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objectives: To describe outcomes of patients with early RA in a patient acceptable symptom state (PASS) at treatment initiation and to identify clusters of symptoms associated with poor outcomes., Methods: Data came from the Rheumatoid Arthritis Medication Study, a UK multicentre cohort study of RA patients starting MTX. The HAQ, DAS28 and other patient-reported outcome measures (PROMs) were collected at baseline, and at 6 and 12 months. Patients answering yes to the question 'Is your current condition satisfactory, when you take your general functioning and your current pain into consideration?' were defined as PASS; patients answering no were defined as N-PASS. Symptom clusters in the baseline PASS group were identified using K-medians cluster analysis. Outcomes of baseline PASS vs N-PASS patients and each cluster are compared using random effects models., Results: Of 1127 patients, 572 (50.8%) reported being in PASS at baseline. Over one year, baseline PASS patients had lower DAS28 (mean difference = -0.71, 95% CI -0.83, -0.59) and HAQ scores (mean difference = -0.48, 95% CI -0.56, -0.41) compared with N-PASS patients. Within the baseline PASS group, we identified six symptom clusters. Clusters characterized by high disease activity and high PROMs, or moderate disease activity and high PROMs, had the worst outcomes compared with the other clusters., Conclusion: Despite reporting their condition as 'satisfactory', early RA patients with high PROM scores are less likely to respond to therapy. This group may require increased vigilance to optimize outcomes., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Seropositivity for anti-citrullinated peptide antibodies (ACPA) in patients with rheumatoid arthritis (RA), a chronic autoimmune arthritis, is associated with worse long-term disease outcomes. ACPA is ubiquitously tested in RA patients, but other autoantibodies exist (in both citrullinated and non-citrullinated form) which may provide additional information on RA subtypes and/or treatment response. We used a multiplex bead-based assay of 376 autoantibodies to test associations between these autoantibodies and treatment response in RA patients. Clusters of patients with similar autoantibody expression were defined and cluster membership was associated with treatment response. Thirty-four autoantibodies were differentially expressed in RA patients compared with healthy controls; citrullinated vimentin was associated with treatment response. A selection of citrullinated autoantibodies was found to be associated with treatment response in a subanalysis of ACPA-negative RA patients. Finer ACPA specificities in ACPA-negative RA patients may be predictive of treatment response and could represent a rich vein of future study.

Objective: Potential targets for treat-to-target strategies in juvenile idiopathic arthritis are minimal disease activity (MDA) and clinically inactive disease (CID). We undertook this study to compare short- and long-term outcomes following achievement of MDA and CID on the 10-joint clinical Juvenile Arthritis Disease Activity Score (cJADAS10) and following achievement of CID on Wallace et al's preliminary criteria., Methods: Children recruited to the Childhood Arthritis Prospective Study, a UK multicenter inception cohort, were selected if they were recruited prior to January 2011 and diagnosed as having oligoarthritis or rheumatoid factor-negative or -positive polyarthritis. One year following diagnosis, children were assessed for MDA on the cJADAS10 and for CID on both Wallace et al's preliminary criteria and the cJADAS10. Associations were tested between those disease states and functional ability, absence of joints with limited range of motion, psychosocial health, and pain at 1 year and annually to 5 years., Results: Of 832 children, 70% were female and the majority had oligoarthritis (68%). At 1 year, 21% had achieved CID according to both definitions, 7% according to Wallace et al's preliminary criteria alone, and 16% according to the cJADAS10 alone; 56% had not achieved CID. Only 10% of children in the entire cohort achieved MDA without also achieving CID. Achieving either early CID state was associated with a greater absence of joints with limited range of motion. However, only CID according to the cJADAS10 was associated with improved functional ability and psychosocial health. Achieving CID was superior to achieving MDA in terms of short- and long-term pain and the absence of joints with limited range of motion., Conclusion: CID on the cJADAS10 may be preferable as a treatment target to CID on Wallace et al's preliminary criteria in terms of both feasibility of application and long-term outcomes., (© 2018 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of American College of Rheumatology.)

Background: Methotrexate (MTX) remains the disease-modifying anti-rheumatic drug of first choice in rheumatoid arthritis (RA) but response varies. Predicting non-response to MTX could enable earlier access to alternative or additional medications and control of disease progression. We aimed to identify baseline predictors of non-response to MTX and combine these into a prediction algorithm., Methods: This study included patients recruited to the Rheumatoid Arthritis Medication Study (RAMS), a UK multi-centre prospective observational study of patients with RA or undifferentiated polyarthritis, commencing MTX for the first time. Non-response to MTX at 6 months was defined as "no response" using the European League Against Rheumatism (EULAR) response criteria, discontinuation of MTX due to inefficacy or starting biologic therapy. The association of baseline demographic, clinical and psychosocial predictors with non-response was assessed using logistic regression. Predictive performance was assessed using the area under the receiver operating characteristic curve (AUC) and calibration plots., Results: Of 1050 patients, 449 (43%) were classified as non-responders. Independent multivariable predictors of MTX non-response (OR (95% CI)) were rheumatoid factor (RF) negativity (0.62 (0.45, 0.86) for RF positivity versus negativity), higher Health Assessment Questionnaire score (1.64 (1.25, 2.15)), higher tender joint count (1.06 (1.02, 1.10)), lower Disease Activity score in 28 joints (0.29 (0.23, 0.39)) and higher Hospital Anxiety and Depression Scale anxiety score (1.07 (1.03, 1.12)). The optimism-corrected AUC was 0.74., Conclusions: This is the first model for MTX non-response to be developed in a large contemporary study of patients commencing MTX in which demographic, clinical and psychosocial predictors were considered. Patient anxiety was a predictor of non-response and could be addressed at treatment commencement.

Methotrexate (MTX) monotherapy is a common first treatment for rheumatoid arthritis (RA), but many patients do not respond adequately. In order to identify genetic predictors of response, we have combined data from two consortia to carry out a genome-wide study of response to MTX in 1424 early RA patients of European ancestry. Clinical endpoints were change from baseline to 6 months after starting treatment in swollen 28-joint count, tender 28-joint count, C-reactive protein and the overall 3-component disease activity score (DAS28). No single nucleotide polymorphism (SNP) reached genome-wide statistical significance for any outcome measure. The strongest evidence for association was with rs168201 in NRG3 (p = 10 -7 for change in DAS28). Some support was also seen for association with ZMIZ1, previously highlighted in a study of response to MTX in juvenile idiopathic arthritis. Follow-up in two smaller cohorts of 429 and 177 RA patients did not support these findings, although these cohorts were more heterogeneous.

Background: Oral methotrexate (MTX) is the first-line therapy for patients with rheumatoid arthritis (RA). However, approximately one quarter of patients discontinue MTX within 12 months. MTX failure, defined as MTX cessation or the addition of another anti-rheumatic drug, is usually due adverse event(s) and/or inefficacy. The aims of this study were to evaluate the rate and predictors of oral MTX failure., Methods: Subjects were recruited from the Norfolk Arthritis Register (NOAR), a primary care-based inception cohort of patients with early inflammatory polyarthritis (IP). Subjects were eligible if they commenced MTX as their first DMARD and were recruited between 2000 and 2008. Patient-reported reasons for MTX failure were recorded and categorised as adverse event, inefficacy or other. The addition of a second DMARD during the study period was categorised as failure due to inefficacy. Cox proportional hazards regression models were used to assess potential predictors of MTX failure, accounting for competing risks., Results: A total of 431 patients were eligible. The probability of patients remaining on MTX at 2 years was 82%. Competing risk analysis revealed that earlier MTX failure due to inefficacy was associated with rheumatoid factor (RF) positivity, younger age at symptom onset and higher baseline disease activity (DAS-28). MTX cessation due to an adverse event was less likely in the RF-positive cohort., Conclusions: RF-positive inflammatory polyarthritis patients who are younger with higher baseline disease activity have an increased risk of MTX failure due to inefficacy. Such patients may require combination therapy as a first-line treatment.

Background: Patients with rheumatoid arthritis (RA) who take methotrexate (MTX) are advised to limit their alcohol intake due to potential combined hepatotoxicity. However, data are limited to support this. The aim of this study was to quantify the risk of developing abnormal liver blood tests at different levels of alcohol consumption, using routinely collected data from primary care., Methods: Patients with RA in the Clinical Practice Research Datalink starting MTX between 1987 and 2016 were included. Hepatotoxicity was defined as transaminitis: alanine transaminase or aspartate aminotransferase more than three times the upper limit of normal. Crude rates of transaminitis were calculated per 1000 person-years, categorised by weekly alcohol consumption in units. Cox proportional hazard models tested the association between alcohol consumption and transaminitis univariately, then age and gender adjusted., Results: 11 839 patients were included, with 530 episodes of transaminitis occurring in 47 090 person-years follow-up. Increased weekly alcohol consumption as a continuous variable was associated with increased risk of transaminitis, adjusted HR (95% CI) per unit consumed 1.01 (1.00 to 1.02); consuming between 15 and 21 units was associated with a possible increased risk of hepatotoxicity, while drinking >21 units per week significantly increased rates of transaminitis, adjusted HR (95% CI) 1.85 (1.17 to 2.93)., Conclusions: Weekly alcohol consumption of <14 units per week does not appear to be associated with an increased risk of transaminitis., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Objective: To describe the outcome in patients with rheumatoid arthritis (RA) over 20 years from symptom onset, and to assess the association between early treatment (with disease-modifying antirheumatic drugs/steroids) and mortality and disability during follow-up., Methods: Patients recruited to the Norfolk Arthritis Register (NOAR) between 1990 and 1994 who met the 2010 American College of Rheumatology/European League Against Rheumatism RA criteria at baseline were included in this analysis. Demographic and clinical variables were collected at baseline and at years 1-3, 5, 7, 10, 15, and 20. Disease activity (swollen joint count [SJC]/tender joint count [TJC]), disability (Health Assessment Questionnaire disability index [HAQ DI]), and mortality over 20 years were determined. Associations between treatment group (early treatment [ET], treatment ≤6 months after symptom onset; late treatment [LT], treatment >6 months after symptom onset; never treatment [NT], no treatment) and mortality and disability were assessed using weighted pooled logistic regression and weighted multilevel mixed-effects linear regression, respectively. Inverse weights were used to account for confounding by indication and censoring., Results: This study included 602 patients with RA (median age 56 years [interquartile range 44-68 years]; 65.9% women). The median SJCs and TJCs were low during the follow-up period (1-3 swollen joints and 3-6 tender joints). The median HAQ DI score increased after year 1 but remained at low/moderate levels (median 1.25 after year 10). The risk of mortality was reduced in the ET and LT groups compared with that in the NT group. The ET group and the NT group had comparable HAQ DI scores during the follow-up period (β = 0.03, 95% confidence interval [95% CI] -0.06, 0.12), while the HAQ DI score was increased in the LT group (for LT versus NT, β = 0.10 [95% CI 0.02, 0.17])., Conclusion: The results of this study indicate the importance of early treatment with regard to the long-term outcomes in patients with RA., (© 2017 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of American College of Rheumatology.)

Background: We implemented a novel method for providing contextual adverse event rates for a randomised controlled trial (RCT) programme through coordinated analyses of five RA registries, focusing here on cardiovascular disease (CVD) and mortality., Methods: Each participating registry (Consortium of Rheumatology Researchers of North America (CORRONA) (USA), Swedish Rheumatology Quality of Care Register (SRR) (Sweden), Norfolk Arthritis Register (NOAR) (UK), CORRONA International (East Europe, Latin America, India) and Institute of Rheumatology, Rheumatoid Arthritis (IORRA) (Japan)) defined a main cohort from January 2000 onwards. To address comparability and potential bias, we harmonised event definitions and defined several subcohorts for sensitivity analyses based on disease activity, treatment, calendar time, duration of follow-up and RCT exclusions. Rates were standardised for age, sex and, in one sensitivity analysis, also HAQ., Results: The combined registry cohorts included 57 251 patients with RA (234 089 person-years)-24.5% men, mean (SD) baseline age 58.2 (13.8) and RA duration 8.2 (11.7) years. Standardised registry mortality rates (per 100 person-years) varied from 0.42 (CORRONA) to 0.80 (NOAR), with 0.60 for RCT patients. Myocardial infarction and major adverse cardiovascular events (MACE) rates ranged from 0.09 and 0.31 (IORRA) to 0.39 and 0.77 (SRR), with RCT rates intermediate (0.18 and 0.42), respectively. Additional subcohort analyses showed small and mostly consistent changes across registries, retaining reasonable consistency in rates across the Western registries. Additional standardisation for HAQ returned higher mortality and MACE registry rates., Conclusions: This coordinated approach to contextualising RA RCT safety data demonstrated reasonable differences and consistency in rates for mortality and CVD across registries, and comparable RCT rates, and may serve as a model method to supplement clinical trial analyses for drug development programmes., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objectives: Early remission is the current treatment strategy for patients with inflammatory polyarthritis (IP) and RA. Our objective was to identify baseline factors associated with achieving remission: sustained (SR), intermittent (IR) or never (NR) over a 5-year period in patients with early IP., Methods: Clinical and demographic data of patients with IP recruited to the Norfolk Arthritis Register (NOAR) were obtained at baseline and years 1, 2, 3 and 5. Remission was defined as no tender or swollen joints (out of 51). Patients were classified as NR or PR, respectively, if they were in remission at: no assessment or ⩾3 consecutive assessments after baseline, and IR otherwise. Ordinal regression and a random effects model, respectively, were used to examine the association between baseline factors, remission group and HAQ scores over time., Results: A total of 868 patients (66% female) were included. Of these, 54%, 34% and 12% achieved NR, IR and SR, respectively. In multivariate analysis, female sex (odds ratio, OR 0.47, 95% CI: 0.35, 0.63), higher tender joint count (OR = 0.94, 95% CI: 0.93, 0.96), higher HAQ (OR = 0.59, 95% CI: 0.48, 0.74), being obese (OR = 0.70, 95% CI: 0.50, 0.99), hypertensive (OR = 0.67, 95% CI: 0.50, 0.90) or depressed (OR = 0.74, 95% CI: 0.55, 1.00) at baseline were independent predictors of being in a lower remission group. IR and SR were associated with lower HAQ scores over time and lower DAS28 at year 5., Conclusion: Women with higher tender joint count and disability at baseline, depression, obesity and hypertension were less likely to achieve remission. This information could help when stratifying patients for more aggressive therapy., (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Purpose: Observational studies can provide context for adverse events observed in clinical trials, especially for infrequent events or long-term risks. We developed methods to improve safety contextualization for a rheumatoid arthritis drug development program through coordinated analyses of multiple registries., Methods: We identified and characterized differences and similarities across five registries (Swedish Rheumatology Quality of Care Register, Consortium of Rheumatology Researchers of North America [CORRONA], Norfolk Arthritis Register, Institute of Rheumatology Rheumatoid Arthritis, and the new CORRONA International), harmonized outcome definitions, and investigated whether restricted subcohorts improved comparability with trial populations. To address confounding, we identified risk predictors for outcomes of interest (mortality, cardiovascular disease, infection, and malignancy). We used patient-level analyses at each registry and central analysis of standardized group-level data., Results: Despite data differences, the coordinated approach enabled consistent variable definitions for key baseline characteristics and outcomes. Selection of restricted subcohorts (e.g., using active joint count criteria) improved baseline comparability with trial patients for some rheumatoid arthritis disease activity measures, but less for other characteristics (e.g., age and comorbidity); however, such selection decreased sample size considerably. For most outcomes, age was the most important risk predictor, emphasizing the importance of age/sex standardization to address confounding. The prospective approach enabled use of recent relevant data; the distributed analysis safeguarded confidentiality of registry data., Conclusions: Compared with reliance on published data alone, a forward-looking coordinated approach across multiple observational data sources can improve comparability and consistency and better support sensitivity analyses and data interpretation, in contextualizing safety data from clinical trials. This approach may have utility to support safety assessments across diverse diseases and drug development programs and satisfy future regulatory requirements., (Copyright © 2015 John Wiley & Sons, Ltd.)

Objectives: To explore the change in direct medical costs associated with inflammatory polyarthritis (IP) 10 to 15 years after its onset., Methods: Patients from the Norfolk Arthritis Register who had previously participated in a health economic study in 1999 were traced 10 years later and invited to participate in a further prospective questionnaire-based study. The study was designed to identify direct medical costs and changes in health status over a 6-month period using previously validated questionnaires as the primary source of data., Results: A representative sample of 101 patients with IP from the 1999 cohort provided complete data over the 6-month period. The mean disease duration was 14 years (SD 2.1, median 13.6, interquartile range 12.6-15.4). The mean direct medical cost per patient over the 6-month period was £1496 for IP (inflated for 2013 prices). This compared with £582 (95% CI £355-£964) inflated to 2013 prices per patient with IP 10 years earlier in their disease. The increased cost was largely associated with the use of biologics in the rheumatoid arthritis subgroup of patients (51% of total costs incurred). Other direct cost components included primary care costs (11%), hospital outpatient (19%), day care (12%), and inpatient stay (4%)., Conclusion: The direct healthcare costs associated with IP have more than doubled with increasing disease duration, largely as a result of the use of biologics. The results showed a shift in the direct health costs from inpatient to outpatient service use.

Biologic therapies have revolutionized treatment outcomes for patients with inflammatory arthritis. However, there remains a concern regarding their safety during conception, pregnancy and breastfeeding. Data on the safety of these treatments are largely limited to uncontrolled case reports. Collective evidence from many hundreds of pregnancies in inflammatory arthritis and IBD have suggested that exposure to anti-TNF therapies at the time of conception or during the first trimester does not result in an increased risk of adverse pregnancy and fetal outcomes. Monoclonal antibodies, and to a lesser extent recombinant fusion proteins, do cross the placenta during the second and third trimester and are functional in the fetus, as evidence by lymphopaenia reported at birth in children exposed to rituximab in utero. In addition, live vaccines should be avoided in children with in utero exposure to biologics for at least the first 6 months of life. The longer-term effects of in utero exposure remain unknown. Studies suggest that many of these drugs do enter breast milk in small amounts, but the extent to which they are absorbed by the infant is less clear. Limited reports have not suggested adverse pregnancy outcomes in women whose partners were exposed to anti-TNF therapies or rituximab at the time of conception. Data on other biologic therapies, including anakinra, abatacept and tocilizumab, in both men and women remain extremely limited., (© The Author 2013. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

With the establishment of the new American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) 2010 criteria for rheumatoid arthritis (RA) to diagnose patients earlier and with the introduction of early and aggressive treatment, the current aim is remission resulting in less functional disability, halting of radiographic damage, less pain, less fatigue and no loss of employment. These outcomes can be related to the World Health Organization International Classification of Functioning, Disability and Health (the WHO ICF framework). This framework includes the component body functions, body structures, activities and participation related to the disease. These components are related to each other in a bidirectional way and can be influenced by contextual factors including environmental and personal factors. This framework can be used to describe trends in RA outcomes and the impact of contextual factors on these outcomes. Despite aggressive treatment strategies, patients with RA still experience loss of function, pain and fatigue, and a relatively high proportion of patients have to take sick leave or become work disabled within the first few years of the disease. There is evidence that more stringent definitions of remission lead to greater improvement of outcomes and that the aim should be sustained remission and not just remission. There is, however, a need for a better understanding of the relation between contextual factors and activity and participation outcomes to better guide therapy decisions by rheumatologists and provide information to patients, families and policymakers about the impact of RA on their lives and to the society. The overall aim of this overview is to highlight the important contextual factors and consequences that relate to outcomes typically measured in RA studies and to demonstrate the additional benefits that can be achieved with remission and sustained remission., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Treatment strategies for tight control of early rheumatoid arthritis (RA) are highly effective but can be improved., Objective: To investigate whether adding prednisone, 10 mg/d, at the start of a methotrexate (MTX)-based treatment strategy for tight control in early RA increases its effectiveness., Design: A 2-year, prospective, randomized, placebo-controlled, double-blind, multicenter trial (CAMERA-II [Computer Assisted Management in Early Rheumatoid Arthritis trial-II]). (International Standard Randomised Controlled Trial Number: ISRCTN 70365169), Setting: 7 hospitals in the Netherlands., Patients: 236 patients with early RA (duration <1 year)., Intervention: Patients were randomly assigned to an MTX-based, tight control strategy starting with either MTX and prednisone or MTX and placebo. Methotrexate treatment was tailored to the individual patient at monthly visits on the basis of predefined response criteria aiming for remission., Measurements: The primary outcome was radiographic erosive joint damage after 2 years. Secondary outcomes included response criteria, remission, and the need to add cyclosporine or a biologic agent to the treatment., Results: Erosive joint damage after 2 years was limited and less in the group receiving MTX and prednisone (n = 117) than in the group receiving MTX and placebo (n = 119). The MTX and prednisone strategy was also more effective in reducing disease activity and physical disability, achieving sustained remission, and avoiding the addition of cyclosporine or biologic treatment. Adverse events were similar in both groups, but some occurred less in the MTX and prednisone group., Limitation: A tight control strategy for RA implies monthly visits to an outpatient clinic, which is not always feasible., Conclusion: Inclusion of low-dose prednisone in an MTX-based treatment strategy for tight control in early RA improves patient outcomes., Primary Funding Source: Catharijne Foundation.

There are secular trends in improvement in disease activity and X-ray damage at baseline and cross-sectionally in prevalent cases of rheumatoid arthritis (RA) in recent years. These changes should translate into improved physical function and mortality, but evidence for this is lacking, perhaps because the mean age at RA diagnosis and of prevalent cases is increasing, mainly as a consequence of demographic changes. This trend is accompanied by an increasing prevalence of co-morbidities, in particular cardiovascular and respiratory disease. The higher prevalence of smoking, diabetes and physical inactivity in RA cases contributes to the burden of co-morbidity. Predictors of poorer treatment response and thus a worse prognosis include female gender, being a smoker, autoantibody positivity, high baseline disease activity and co-morbidities such as depression. There is a need for better understanding of predictors of treatment response to guide the right choice of therapy and thus improve outcome further., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objectives: To identify baseline disease-related predictors in patients with early inflammatory polyarthritis (IP) for starting subsequent biological therapy and to determine if patients who failed their first non-biological disease-modifying antirheumatic drug (DMARD) within 6 months were more likely to need biological therapy., Methods: Patients with early IP recruited between 1990 and 1994 (cohort 1) and between 2000 and 2004 (cohort 2) in the Norfolk Arthritis Register were included in this study. The association between possible predictors with the start of biological therapy was assessed using Cox proportional hazards regression models., Results: 32/407 (7.9%) patients in cohort 1 and 45/416 (10.8%) patients in cohort 2 received biological therapy during follow-up. In both cohorts, anti-citrullinated protein antibody (ACPA) positivity (cohort 1, HR 7.62, 95% CI 2.46 to 23.58; cohort 2, HR 4.68, 95% CI 2.23 to 9.78) was the strongest predictor for starting biological therapy. In cohort 2, younger patients (HR 0.97, 95% CI 0.95 to 0.99) and patients who failed their first non-biological DMARD within 6 months due to inefficacy were also more likely to receive biological therapy (HR 2.35, 95% CI 1.05 to 5.27)., Conclusion: Patients with early IP who are ACPA positive, are younger or who fail their first non-biological DMARD due to inefficacy within 6 months are more likely to need biological therapy.

Objective: The British Society for Rheumatology Biologics Register (BSRBR) has collected data on adverse events including pregnancies in patients with rheumatoid arthritis treated with anti-tumour necrosis factor (anti-TNF) therapy. The purpose of this report is to summarise the pregnancy outcomes in women treated with anti-TNF in the BSRBR., Methods: Patients were categorised according to anti-TNF exposure as follows: (1) exposure to anti-TNF and to methotrexate (MTX) and/or leflunomide (LEF) at conception (n=21 pregnancies); (2) exposure to anti-TNF at conception (n=50); (3) exposure to anti-TNF prior to conception (n=59); (4) no exposure to anti-TNF (control group; n=10)., Results: Eighty-eight live births in a total of 130 pregnancies were reported in patients who received anti-TNF before or during pregnancy. The rate of spontaneous abortion was highest among patients exposed to anti-TNF at the time of conception (with MTX/LEF 33% and without MTX/LEF 24%). This compared with 17% spontaneous abortions in those with prior exposure to anti-TNF and 10% spontaneous abortions in the control group. Ten terminations were performed., Conclusion: Although the results to date have been promising, no firm conclusions can be drawn about the safety of anti-TNF during pregnancy and, without further evidence, guidelines which suggest these drugs should be avoided at the time of conception cannot yet be changed.

Objective: To describe working status in patients with RA, AS and PsA treated with anti-TNF therapy registered with the British Society for Rheumatology Biologics Register., Methods: Patients with RA (n = 3291), AS (n = 229) and PsA (n = 254) treated with anti-TNF therapy were included in this study. In addition, biologic-naive patients with RA (n = 379) were included. At baseline and 3 years after registration, all patients reported their working status. Baseline characteristics between working and work-disabled patients were compared. Logistic regression analysis was applied to identify factors associated with new work disability in patients with RA., Results: At baseline, work disability rates were already high: 49% for RA, 39% for PsA, 41% for AS and 36% for biologic-naive patients. Work-disabled patients had a higher HAQ score and worse disease activity than working patients. Working patients with a high HAQ score [odds ratio (OR) 2.79; 95% CI 1.89, 4.12] and a manual job (OR 2.31; 95% CI 1.52, 3.52) at baseline were more likely to become work disabled at follow-up, while those patients in remission 6 months after commencing anti-TNF therapy were less likely to become work disabled. However, use of anti-TNF therapy did not prevent patients with RA from becoming work disabled (OR for RA control patients vs RA anti-TNF patients 0.80; 95% CI 0.36, 1.81, adjusted for baseline variables)., Conclusion: A high percentage of patients with RA, AS and PsA were already work disabled at the start of anti-TNF therapy. There is less future work disability in working patients with RA who responded to anti-TNF therapy.

Objectives: Many criteria for clinically inactive disease (CID) and minimal disease activity (MDA) have been proposed for juvenile idiopathic arthritis (JIA). It is not known to what degree each of these criteria overlap within a single patient cohort. This study aimed to compare the frequency of MDA and CID across different criteria in a cohort of children with JIA at 1 year following presentation.Methods: The Childhood Arthritis Prospective Study recruits children at initial presentation to paediatric or adolescent rheumatology in seven UK centres. Children recruited between October 2001 and December 2013 were included. The proportions of children with CID and MDA at 1 year were calculated using four investigator-defined and eight published composite criteria. Missing data were accounted for using multiple imputation under different assumptions.Results: In a cohort of 1415 children and adolescents, 67% patients had no active joints at 1 year. Between 48% and 61% achieved MDA and between 25% and 38% achieved CID using published criteria. Overlap between criteria varied. Of 922 patients in MDA by either the original composite criteria, Juvenile Arthritis Disease Activity Score (JADAS) or clinical JADAS cut-offs, 68% were classified as in MDA by all 3 criteria. Similarly, 44% of 633 children with CID defined by either Wallace's preliminary criteria or the JADAS cut-off were in CID according to both criteria.Conclusions: In a large JIA prospective inception cohort, a majority of patients have evidence of persistent disease activity after 1 year. Published criteria to capture MDA and CID do not always identify the same groups of patients. This has significant implications when defining and applying treat-to-target strategies. [ABSTRACT FROM AUTHOR]

Objective: Comparisons of data from different registries can be helpful in understanding variations in many aspects of rheumatoid arthritis (RA). The study aim was to assess and improve the comparability of demographic, clinical, and comorbidity data from 5 international RA registries.Methods: Using predefined definitions, 2 subsets of patients (main cohort and subcohort) from 5 international observational registries (Consortium of Rheumatology Researchers of North America Registry [CORRONA], the Swedish Rheumatology Quality of Care Register [SRR], the Norfolk Arthritis Register [NOAR], the Institute of Rheumatology Rheumatoid Arthritis cohort [IORRA], and CORRONA International) were evaluated and compared. Patients ages >18 years with RA, and present in or recruited to the registry from January 1, 2000, were included in the main cohort. Patients from the main cohort with positive rheumatoid factor and/or erosive RA who had received ≥1 synthetic disease-modifying antirheumatic drug (DMARD), and switched to or added another DMARD, were included in the subcohort at time of treatment switch.Results: Age and sex distributions were fairly similar across the registries. The percentage of patients with a high Disease Activity Score in 28 joints score varied between main cohorts (17.5% IORRA, 18.9% CORRONA, 24.7% NOAR, 27.7% CORRONA International, and 36.8% SRR), with IORRA, CORRONA, and CORRONA International including more prevalent cases of RA; the differences were smaller for the subcohort. Prevalence of comorbidities varied across registries (e.g., coronary artery disease ranged from 1.5% in IORRA to 7.9% in SRR), partly due to the way comorbidity data were captured and general cultural differences; the pattern was similar for the subcohorts.Conclusion: Despite different inclusion criteria for the individual RA registries, it is possible to improve the comparability and interpretability of differences across RA registries by applying well-defined cohort definitions. [ABSTRACT FROM AUTHOR]