Radiographic changes around the glenoid component in primary reverse shoulder arthroplasty at mid-term follow-up.

BACKGROUND: Some local events after reverse shoulder arthroplasty (RSA) occur without the patient experiencing symptoms and yet may be detected on diagnostic imaging, thereby serving as indicators of future complications that may require revision. Most of these events involve the glenoid component, but radiographic studies evaluating this component are scarce, especially medium- and long-term studies. This study aimed to analyze the radiographic changes around the glenoid component and determine the risk factors associated with the presence of these radiographic changes. MATERIALS AND METHODS: A retrospective review of 105 primary Grammont-style RSAs implanted between 2003 and 2014 was conducted. Radiographic outcomes were evaluated in patients with ≥5 years of radiographic follow-up. Standardized digital radiographs obtained immediately postoperatively and at a minimum follow-up time of 5 years were analyzed to determine (1) glenoid component position (inclination and height) and (2) minor radiographic changes (Sirveaux grade 1 or 2 scapular notching; nondisplaced acromial fracture; radiolucent lines around 1 or 2 screws; Brooker grade 1a, 1b, or 2 heterotopic calcifications; or single screw rupture), as well as major radiographic changes (Sirveaux grade 3 or 4 scapular notching; radiolucent lines around ≥3 screws or central peg; Brooker grade 1c or 3 heterotopic calcifications; prosthetic dislocation; loosening or migration; or disassembly). RESULTS: Major radiologic changes were identified in 14.3% of the cases. Bivariate analysis showed that more changes were associated with the arthroplasties implanted in the first years of the study (odds ratio [OR] = 0.81, P = .012). This time-related variable was also associated with inclination (OR = 0.88, P = .045) and height (OR = 0.75, P = .001), improving in arthroplasties implanted in the last years of the study. Multivariate analysis revealed an increased risk of severe scapular notching mainly associated with superior tilt (OR = 2.52, P = .036) and a high (OR = 2.68, P = .019) or excessively high (OR = 7.55, P = .013) position and an increased risk of loosening signs associated with superior tilt (OR = 8.92, P = 9.1 × 10-6). CONCLUSIONS: The percentage of radiologic changes of the glenoid component in RSA is considerable, despite the detection of a decrease in their presence among the arthroplasties implanted outside the initial period. Superior tilt and an excessively high position appear to be associated with a severe degree of scapular notching development and increased risk of radiographic loosening signs. Knowledge of the factors associated with major radiologic changes in the medium-term follow-up will help to optimize the primary surgical technique for each patient and indication, improving implant survival in primary RSA surgery.

Risk factors for hospital admissions related to COVID-19 in patients with autoimmune inflammatory rheumatic diseases.

OBJECTIVES: To describe patients with autoimmune inflammatory rheumatic diseases (AIRD) who had COVID-19 disease; to compare patients who required hospital admission with those who did not and assess risk factors for hospital admission related to COVID-19. METHODS: An observational longitudinal study was conducted during the pandemic peak of severe acute respiratory syndrome coronavirus 2 (1 March 2020 to 24 April). All patients attended at the rheumatology outpatient clinic of a tertiary hospital in Madrid, Spain with a medical diagnosis of AIRD and with symptomatic COVID-19 were included. The main outcome was hospital admission related to COVID-19. The covariates were sociodemographic, clinical and treatments. We ran a multivariable logistic regression model to assess risk factors for the hospital admission. RESULTS: The study population included 123 patients with AIRD and COVID-19. Of these, 54 patients required hospital admission related to COVID-19. The mean age on admission was 69.7 (15.7) years, and the median time from onset of symptoms to hospital admission was 5 (3-10) days. The median length of stay was 9 (6-14) days. A total of 12 patients died (22%) during admission. Compared with outpatients, the factors independently associated with hospital admission were older age (OR: 1.08; p=0.00) and autoimmune systemic condition (vs chronic inflammatory arthritis) (OR: 3.55; p=0.01). No statistically significant findings for exposure to disease-modifying antirheumatic drugs were found in the final model. CONCLUSION: Our results suggest that age and having a systemic autoimmune condition increased the risk of hospital admission, whereas disease-modifying antirheumatic drugs were not associated with hospital admission.

Visual acuity loss and development of ocular complications in white dot syndromes: a longitudinal analysis of 3 centers.

PURPOSE: To compare the clinical prognosis among selected white dot syndromes (WDS) (birdshot chorioretinopathy (BRC), multifocal choroiditis, serpiginous choroidopathy (SC), and others) and to identify risk factors of poor visual prognosis. METHODS: Retrospective longitudinal cohort study including 84 patients (143 affected eyes) diagnosed with WDS between 1982 and July 2017, followed up until loss of follow-up or December 2017, and recruited from three Uveitis Clinics (Madrid Community, Spain). Our main outcome measures were temporary or permanent moderate (corrected visual acuity in the Snellen scale < 20/50) or severe (< 20/200) vision losses, and development of new ocular complications. Incidence rates (IR) of the main outcome measures were estimated per 100 eye-years. Bivariate and multivariate Cox robust regression models analyzed the association of demographic- and clinical-related variables with vision loss. RESULTS: SC exhibited the greatest IR of vision loss, even in the multivariate models. Previous events of vision loss, presence of choroidal neovascularization, and cataracts exhibited worse visual prognosis. Monotherapy with immunosuppressive drugs but not combine therapy was also associated with higher IR of visual loss. Regarding new ocular complications, BRC showed the highest IR of epiretinal membrane and macular edema. CONCLUSIONS: SC presents the worst visual prognosis. Some ocular manifestations can identify patients with WDS at risk of a worse clinical evolution.

Validation of a Quality of Life Instrument in Spanish Patients With Rheumatic Diseases: The Rosser Classification System.

OBJECTIVE: The aim of this study was to assess the reliability and validity of the Spanish version of the Rosser classification system for disease states in patients with musculoskeletal disorders. METHODS: Our study was based on a questionnaire validation design. Patients were attended at an outpatient rheumatology clinic at Hospital Clínico San Carlos, Madrid, Spain. The Rosser classification system was completed by the physician from the research team (PMQ) and by the patient (HMQ). Criterion standards: The EuroQol-5D for the HMQ and the physician global estimate (DOCGL) for the PMQ. Internal consistency reliability was assessed using Cronbach α. Test-retest reliability and interobserver reliability were analyzed using the intraclass correlation coefficient. The criterion validity between HMQ and EuroQol-5D and between PMQ and DOCGL was assessed using the Spearman correlation coefficient. RESULTS: The full analysis was based on 4 samples of patients (104 to 266 patients), most of whom were middle-aged women. For HMQ, Cronbach α was 0.70. Test-retest reproducibility was 0.7. With respect to criterion validity, significant correlations in the expected direction were observed. For PMQ, Cronbach α was 0.70, indicating excellent intraobserver and interobserver reliability. With respect to criterion validity, strong correlations were observed between the PMQ and the DOCGL. CONCLUSIONS: The Rosser classification system showed satisfactory reliability and suitable criterion validity for patients with musculoskeletal disorders. The instrument seems to be suitable for clinical decision making and research.

Are rheumatologists adhering to the concepts window of opportunity and treat-to-target? Earlier and more intense disease-modifying anti-rheumatic drug treatment over time in patients with early arthritis in the PEARL study.

OBJECTIVES: To analyse changes over time in the treatment with disease modifying anti-rheumatic drugs and biological therapies prescribed to patients from an early arthritis register and whether these changes had an impact on their outcome. METHODS: This was a longitudinal retrospective 2-year study based on data collected in the PEARL study. The population was clustered in three groups depending on year of symptoms onset (2000-2004, 2005-2009, 2010-2014). Intensity of disease-modifying anti-rheumatic drug treatment was calculated and the percentage of patients receiving biological therapy during the first 2-year follow-up was collected. Disease activity and remission at the end of follow-up, as well as radiological progression were the outcomes analysed. Multivariable analyses were fitted to determine which variables including the three period times were associated with the outcomes. RESULTS: A significant increase in treatment intensity was observed in patients with undifferentiated arthritis, getting closer to that prescribed to patients fulfilling the 1987 RA criteria at the last period studied (2010-2014). This finding was associated with a significantly higher percentage of patients in remission and lower progression of the erosion component of the Sharp van der Heijde score. CONCLUSIONS: During the last 15 years, the treatment of patients with early arthritis in our hospital has been progressively increased and it has been associated with significantly better outcomes.

Severe adverse drug reactions to biological disease-modifying anti-rheumatic drugs in elderly patients with rheumatoid arthritis in clinical practice.

OBJECTIVES: Biological DMARDs are widely used in the treatment of rheumatoid arthritis (RA) but their relationship with adverse drug reaction (ADR) is important. RA is now known to increase in incidence and prevalence with age. Our objective was to assess the incidence of severe ADR in the long term, compare safety between the different bDMARDs and identify other possible risk factors for severe ADR in elderly RA patients. METHODS: A 14-year retrospective longitudinal study was performed. RA patients followed in an out-patient clinic starting bDMARDs after the age of 65 were included. PRIMARY OUTCOME: discontinuation due to a severe ADR related to bDMARDs (etanercept, infliximab, adalimumab, rituximab, golimumab, certolizumab, abatacept and tocilizumab). Covariables: sociodemographic, clinical and therapy. Incidence rates of discontinuation were estimated using survival techniques and comparison between bDMARDs discontinuation rates and other associated factors were run by Cox regression models. RESULTS: We analysed 286 courses of bDMARDs therapy in 146 elderly patients (604 patient-years). 78% were women, with a mean age at diagnosis of 66.5±7 years, and a median time to the start of the first bDMARDs of 6±4 years. The incidence of discontinuation due to severe ADR estimated was 10.2% patient-years, with a median survival of around 7 years. The most frequent cause was infections. Etanercept had the lowest risk of severe ADR compared to other bDMARDs. CONCLUSIONS: Our study reflects the 'real world' experience in elderly RA patients on bDMARDs, with non-selected patients for a 14-year follow-up.

Treatment with methotrexate and risk of relapses in patients with giant cell arteritis in clinical practice.

OBJECTIVES: To assess the incidence and the risk of relapses in giant cell arteritis (GCA) patients treated with and without methotrexate (MTX) in clinical practice. Other associated factors were also investigated. METHODS: An inception cohort of GCA was assembled in the out-patient clinic at Hospital Clínico San Carlos, including patients from the date of diagnosis (Jan-1991 until Sept-2013), and followed-up until lost of follow up or Sept-2014. MAIN OUTCOME: relapse defined as recurrence of symptoms or signs of GCA with high ESR and the need to increase glucocorticoids at least 10mg over the previous dose. The independent variable was exposure to MTX over time. Covariables: Sociodemographic, clinical, and treatment. Incidence rates of relapses (IR) per 100 patient-year with their 95% confidence intervals [CI] were estimated using survival techniques. MTX influence on relapses was analysed by Cox models. RESULTS: 168 patients were included (675 patient-year). 31% of patients had relapses (IR of 12 [9.6-14.9]), and the median number of relapses was 1[1-2]. 65% of the patients were on MTX, (mean dose: 10mg). In the bivariate analysis, the risk of relapses in patients with and without MTX did not achieve statistical signification (p=0.1). After adjusting in the multivariate analysis, exposure to MTX had 72% less risk of relapse compared to those without MTX (p<0.05). Other variables included in the final model were: visual alterations and malaise at clinical presentation of GCA. CONCLUSIONS: The use of MTX seems to decrease the risk of recurrences. We also found other factors influencing on relapses.

Disease Remission in Children and Adolescents with Intermediate Uveitis: A Survival Analysis.

PURPOSE: To report the incidence rate (IR) of remission in pediatric noninfectious intermediate uveitis (IU). METHODS: Longitudinal retrospective cohort study, including 19 patients (32 eyes) between 1985 and 2014, followed-up until loss or January 2016. Remission was defined following the Standardization of Uveitis Nomenclature workshop criteria, prolonged remission as a remission spanning 12 months and until the end of follow-up, and relapse as recurrence of inflammatory activity in an eye in remission. RESULTS: Median follow-up time was 6.3 years. IRs (95% confidence interval) for remission, relapse, and prolonged remission were 18.6 (13.1-26.5), 32.3 (20.6-50.7), and 6.7 (3.8-11.9) episodes per 100 eye-years, respectively. 48% of eyes relapsed in the first year following remission. 25 and 50% of eyes achieved prolonged remission after 5 and 10 years of follow-up, respectively. CONCLUSIONS: Inflammatory relapses may be frequent in noninfectious IU affecting children and adolescents, appearing early after remission. Also, prolonged remission seems infrequent, being achieved late during follow-up.

A combined large-scale meta-analysis identifies COG6 as a novel shared risk locus for rheumatoid arthritis and systemic lupus erythematosus.

OBJECTIVES: During the last years, genome-wide association studies (GWASs) have identified a number of common genetic risk factors for rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). However, the genetic overlap between these two immune-mediated diseases has not been thoroughly examined so far. The aim of the present study was to identify additional risk loci shared between RA and SLE. METHODS: We performed a large-scale meta-analysis of GWAS data from RA (3911 cases and 4083 controls) and SLE (2237 cases and 6315 controls). The top-associated polymorphisms in the discovery phase were selected for replication in additional datasets comprising 13 641 RA cases and 31 921 controls and 1957 patients with SLE and 4588 controls. RESULTS: The rs9603612 genetic variant, located nearby the COG6 gene, an established susceptibility locus for RA, reached genome-wide significance in the combined analysis including both discovery and replication sets (p value=2.95E-13). In silico expression quantitative trait locus analysis revealed that the associated polymorphism acts as a regulatory variant influencing COG6 expression. Moreover, protein-protein interaction and gene ontology enrichment analyses suggested the existence of overlap with specific biological processes, specially the type I interferon signalling pathway. Finally, genetic correlation and polygenic risk score analyses showed cross-phenotype associations between RA and SLE. CONCLUSIONS: In conclusion, we have identified a new risk locus shared between RA and SLE through a meta-analysis including GWAS datasets of both diseases. This study represents the first comprehensive large-scale analysis on the genetic overlap between these two complex disorders.

Long-term continuation of methotrexate therapy in giant cell arteritis patients in clinical practice.

OBJECTIVES: To assess the long-term continuation of methotrexate (MTX) in a cohort of patients with giant cell arteritis (GCA) in daily clinical practice. Factors associated with its discontinuation rate were also investigated. METHODS: A longitudinal study from 1991-2014, was performed. GCA patients with MTX and followed-up in a rheumatology outpatient clinic of Madrid during the study period were included. PRIMARY OUTCOME: discontinuation of MTX due to: adverse drug reactions (ADR moderate and severe); inefficacy; sustained clinical response; patient decision. Covariables: sociodemographic, clinical and therapy. Incidence rates (IR) of MTX discontinuation per 100 patient-years with their 95% confidence interval (CI) were estimated using survival techniques. Factors associated to specific discontinuation causes were analysed using Cox models. RESULTS: We included 108 patients (244 patient-years). The IR was 37.2 [30.3-45.7]. The IR due to ADR, severe ADR, sustained clinical response and inefficacy was 20.8 [15.8-27.4]; 5.7 [3.3-9.6]; 8.2 [5.3-12.7] and 2.8 [1.3-6.0], respectively. Regarding multivariate analysis, younger patients, baseline cardiovascular disease, taking more glucocorticoids and lower initial doses of MTX were associated to a higher discontinuation rate due to inefficacy. Factors influencing the suspension due to ADRs were: older age, baseline. Chronic obstructive pulmonary disease, higher baseline erythrocyte sedimentation rate, several specific clinical patterns at diagnosis, and higher maximum dose of MTX during the follow up. In the final model for sustained clinical response older patients and more recurrences were independently associated to less discontinuation rate. CONCLUSIONS: We provide further data of the potential safety of long-term MTX in the management of GCA. We have also found several factors influencing the continuation of MTX.

Dose down-titration of biological DMARDs in patients with rheumatoid arthritis over time and in daily clinical practice.

OBJECTIVES: To describe and compare dosing optimisation in biological DMARDs (bDMARDs) and relapses after that, in a cohort of rheumatoid arthritis (RA) during clinical practice. METHODS: Observational retrospective longitudinal study of RA patients taking bDMARDs from December 1999 to November 2013. Optimisation was defined as a 15% decrease in dose either reducing single dose or separating dose interval administration, for at least 4 times the recommended period between dosages. Relapse was defined as suspension or starting again with the recommended dose after optimisation. Incidence rates (IR) per 100 patient-years were estimated using survival techniques. Cox multivariate models were conducted to compare bDMARDs expressed in hazard ratios (HR) and confidence intervals [95%CI]. RESULTS: 443 patients and 752 different courses of bDMARDs treatments were included. We observed 146 optimisations with an IR of 8.1. The HR of optimisation in: a) adalimumab, etanercept and rituximab compared to infliximab was 1.56 [1.01-2.4], 1.5 [0.9-2.4] and 0.6 [0.3-1.4], respectively; b) adalimumab, etanercept compared to rituximab were 2.3 [1.2-4.5] and 2.2 [1.2-4.3]. There were no statistically significant differences between adalimumab and etanercept. Following optimisation, 36% relapsed (78% due to disease activity). The IR related to disease activity was 6.3, and was lower for adalimumab and etanercept compared to infliximab (HR: 0.42; [0.19-0.94]; HR: 0.34; [0.13-0.89], respectively). There were no statistically significant differences between etanercept and adalimumab. No patients on rituximab relapsed. CONCLUSIONS: Optimisation was similar between adalimumab and etanercept, and was lower for infliximab and rituximab. After optimisation, rituximab did not relapse, but infliximab did with the highest hazard.

Treatment in rheumatoid arthritis and mortality risk in clinical practice: the role of biologic agents.

OBJECTIVES: To assess the mortality rate (MR) and the mortality risk of a rheumatoid arthritis (RA) inception cohort, with and without biologic agents (BAs). Other factors associated to mortality were also investigated. METHODS: Retrospective longitudinal study of RA patients, attending the rheumatology outpatient clinic of a tertiary Hospital (Madrid), collected over 5 years (2000-2004), and followed from the diagnosis of RA up to the patients' death, lost to follow-up or September 2013. The dependent variable was death and the independent variable was exposure to BAs. Covariables: sociodemographic, clinical and therapy variables. MR was expressed per 1,000 patient-years with the 95% confidence interval [CI]. BA influence on MR was analysed by multivariable Cox models. Clinical and therapy variables were used in a time-dependent manner. The results are expressed in hazard ratio (HR) and [CI]. RESULTS: We included 576 patients and 711 courses of therapy. 19.6% were taking BA, 86% disease-modifying anti-rheumatic drugs (DMARDs) (70% on methotrexate - MTX), and 12% were untreated. There were 133 deaths during 4,981.64 patient-years at risk. The MR for BA was 12.6 [6-26], for DMARDs was 22.3 [18.4-27.1], and for those without treatment was 89.1 [61.9-128.2]. The adjusted HR for mortality in those exposed to BA versus those not exposed was 0.75 [0.32-1.71]). Other variables independently associated with mortality were: age, rheumatoid factor, hospital admissions, Health Assessment Questionnaire (HAQ), and MTX use (HR: 0.44 [0.29-0.66]). CONCLUSIONS: BAs and standard DMARDs are more effective in decreasing mortality compared to no therapy. Patients exposed to Bas were not associated with a significant increase or decrease in mortality when compared to patients with non-biological DMARDs. The use of MTX remains the only drug that has independently shown a beneficial effect on mortality.

Influence of patient personality in the treatment of rheumatoid arthritis.

Individualized treatment of rheumatoid arthritis (RA) based on genetic/serologic factors is increasingly accepted. Moreover, patients are more actively involved in the management of their disease. However, personality has received little attention with respect to perception of the need and adherence to treatment. Our objective was to evaluate whether patient personality was associated with the acceptance or rejection of more aggressive early treatment. We performed a cross-sectional study in two hospitals with early arthritis clinics where sociodemographic, clinical, and therapeutic variables are systematically recorded. Patients completed Eysenck Personality Questionnaire, Multidimensional Health Locus of Control, Pain-Related Self-Statement Scale and Pain-Related Control Scale. Aggressive treatment was considered if patients received more than two DMARDs or biological agents during the first year of follow-up. Multivariate logistic regression analysis was performed to determine predictors of aggressive treatment. One hundred seventy-six RA patients were included (80 % women, disease begin median age 55 years). Treatment was considered aggressive in 57.9 % of the sample. Scores were high in extraversion in 50.8 % of patients, neuroticism in 29.5 % and psychoticism in 14.7 %. Neuroticism was the only factor associated with aggressive treatment, which was less probable (p = 0.04, OR = 0.40). Neuroticism also decreased the possibility of receiving a combination of biologics and DMARDs (p = 0.04, OR = 0.28). Patients with high scores on neuroticism are more worried, obsessive and hypochondriac, leading them to reject more aggressive therapy. It is important to educate about their disease so that they will accept more aggressive approaches in clear cases of poor outcome.

Genetic risk scores and number of autoantibodies in patients with rheumatoid arthritis.

OBJECTIVE: Certain HLA-DRB1 alleles and single-nucleotide polymorphisms (SNPs) are associated with rheumatoid arthritis (RA). Our objective was to examine the combined effect of these associated variants, calculated as a cumulative genetic risk score (GRS) on RA predisposition, as well as the number of autoantibodies (none, one or two present). METHOD: We calculated four GRSs in 4956 patients and 4983 controls from four European countries. All four scores contained data on 22 non-HLA-risk SNPs, and three scores also contained HLA-DRB1 genotypes but had different HLA typing resolution. Most patients had data on both rheumatoid factor (RF) and anti-citrullinated proteins antibodies (ACPA). The GRSs were standardised (std.GRS) to account for population heterogeneity. Discrimination between patients and controls was examined by receiveroperating characteristics curves, and the four std.GRSs were compared across subgroups according to autoantibody status. RESULTS: The std.GRS improved its discriminatory ability between patients and controls when HLA-DRB1 data of higher resolution were added to the combined score. Patients had higher mean std.GRS than controls (p=7.9×10(-156)), and this score was significantly higher in patients with autoantibodies (shown for both RF and ACPA). Mean std.GRS was also higher in those with two versus one autoantibody (p=3.7×10(-23)) but was similar in patients without autoantibodies and controls (p=0.12). CONCLUSIONS: The GRS was associated with the number of autoantibodies and to both RF and ACPA positivity. ACPA play a more important role than RF with regards to the genetic risk profile, but stratification of patients according to both RF and ACPA may optimise future genetic studies.

A genome-wide association study of rheumatoid arthritis without antibodies against citrullinated peptides.

INTRODUCTION: Rheumatoid arthritis (RA) patients can be classified based on presence or absence of anticitrullinated peptide antibodies (ACPA) in their serum. This heterogeneity among patients may reflect important biological differences underlying the disease process. To date, the majority of genetic studies have focused on the ACPA-positive group. Therefore, our goal was to analyse the genetic risk factors that contribute to ACPA-negative RA. METHODS: We performed a large-scale genome-wide association study (GWAS) in three Caucasian European cohorts comprising 1148 ACPA-negative RA patients and 6008 controls. All patients were screened using the Illumina Human Cyto-12 chip, and controls were genotyped using different genome-wide platforms. Population-independent analyses were carried out by means of logistic regression. Meta-analysis with previously published data was performed as follow-up for selected signals (reaching a total of 1922 ACPA-negative RA patients and 7087 controls). Imputation of classical HLA alleles, amino acid residues and single nucleotide polymorphisms was undertaken. RESULTS: The combined analysis of the studied cohorts resulted in identification of a peak of association in the HLA-region and several suggestive non-HLA associations. Meta-analysis with previous reports confirmed the association of the HLA region with this subset and an observed association in the CLYBL locus remained suggestive. The imputation and deep interrogation of the HLA region led to identification of a two amino acid model (HLA-B at position 9 and HLA-DRB1 at position 11) that accounted for the observed genome-wide associations in this region. CONCLUSIONS: Our study shed light on the influence of the HLA region in ACPA-negative RA and identified a suggestive risk locus for this condition.

Identification of secreted phosphoprotein 1 gene as a new rheumatoid arthritis susceptibility gene.

OBJECTIVE: To evaluate the contribution of the SPP1 rs11439060 and rs9138 polymorphisms, previously reported as autoimmune risk variants, in the rheumatoid arthritis (RA) genetic background according to anti-citrullinated protein antibodies (ACPAs) status of RA individuals. METHODS: We analysed a total of 11,715 RA cases and 26,493 controls from nine independent cohorts; all individuals were genotyped or had imputed genotypes for SPP1 rs11439060 and rs9138. The effect of the SPP1 rs11439060 and rs9138 risk-allele combination on osteopontin (OPN) expression in macrophages and OPN serum levels was investigated. RESULTS: We provide evidence for a distinct contribution of SPP1 to RA susceptibility according to ACPA status: the combination of ≥3 SPP1 rs11439060 and rs9138 common alleles was associated mainly with ACPA negativity (p=1.29×10(-5), ORACPA-negative 1.257 (1.135 to 1.394)) and less with ACPA positivity (p=0.0148, ORACPA-positive 1.072 (1.014 to 1.134)). The ORs between these subgroups (ie, ACPA-positive and ACPA-negative) significantly differed (p=7.33×10(-3)). Expression quantitative trait locus analysis revealed an association of the SPP1 risk-allele combination with decreased SPP1 expression in peripheral macrophages from 599 individuals. To corroborate these findings, we found an association of the SPP1 risk-allele combination and low serum level of secreted OPN (p=0.0157), as well as serum level of secreted OPN correlated positively with ACPA production (p=0.005; r=0.483). CONCLUSIONS: We demonstrate a significant contribution of the combination of SPP1 rs11439060 and rs9138 frequent alleles to risk of RA, the magnitude of the association being greater in patients negative for ACPAs.

High-density genotyping of immune loci in Koreans and Europeans identifies eight new rheumatoid arthritis risk loci.

OBJECTIVE: A highly polygenic aetiology and high degree of allele-sharing between ancestries have been well elucidated in genetic studies of rheumatoid arthritis. Recently, the high-density genotyping array Immunochip for immune disease loci identified 14 new rheumatoid arthritis risk loci among individuals of European ancestry. Here, we aimed to identify new rheumatoid arthritis risk loci using Korean-specific Immunochip data. METHODS: We analysed Korean rheumatoid arthritis case-control samples using the Immunochip and genome-wide association studies (GWAS) array to search for new risk alleles of rheumatoid arthritis with anticitrullinated peptide antibodies. To increase power, we performed a meta-analysis of Korean data with previously published European Immunochip and GWAS data for a total sample size of 9299 Korean and 45,790 European case-control samples. RESULTS: We identified eight new rheumatoid arthritis susceptibility loci (TNFSF4, LBH, EOMES, ETS1-FLI1, COG6, RAD51B, UBASH3A and SYNGR1) that passed a genome-wide significance threshold (p<5×10(-8)), with evidence for three independent risk alleles at 1q25/TNFSF4. The risk alleles from the seven new loci except for the TNFSF4 locus (monomorphic in Koreans), together with risk alleles from previously established RA risk loci, exhibited a high correlation of effect sizes between ancestries. Further, we refined the number of single nucleotide polymorphisms (SNPs) that represent potentially causal variants through a trans-ethnic comparison of densely genotyped SNPs. CONCLUSIONS: This study demonstrates the advantage of dense-mapping and trans-ancestral analysis for identification of potentially causal SNPs. In addition, our findings support the importance of T cells in the pathogenesis and the fact of frequent overlap of risk loci among diverse autoimmune diseases.