Determinants of health-related quality of life and global functioning and health in axSpA, pSpA, and PsA: results from the ASAS-PerSpA study

OBJECTIVES

We aim to identify determinants of health-related quality of life (HRQoL) and global functioning and health (GH) in axial spondyloarthritis (axSpA), peripheral spondyloarthritis (pSpA), and psoriatic arthritis (PsA).

METHODS

ASAS-perSpA study data were analyzed. Models for the three patient groups were performed separately to explore factors associated with HRQoL and GH, assessed by EQ-5D and ASAS-HI, respectively.

RESULTS

The analyses included 4185 patients: 2719 with axSpA, 433 with pSpA, and 1033 with PsA.In axSpA, disease activity (DA) (β=-0.061), physical function (β=-0.041), female sex (β=-0.019), and fibromyalgia (β=-0.068) were associated with worse HRQoL; age (β = 0.001) and university education (β = 0.014) with better HRQoL. In pSpA, DA (β=-0.04) and physical function (β=-0.054) were associated with worse HRQoL. In PsA, DA (β=-0.045), physical function (β=-0.053), axial disease (β=-0.041), and female sex (β=-0.028) were associated with worse HRQoL.In axSpA, DA (β = 0.889), physical function (β = 0.887), peripheral disease (β = 0.564), female sex (β = 0.812) and fibromyalgia (β = 1.639) were associated with worse GH; age (β=-0.013) and university education (β=-0.274) with better GH. In pSpA, physical function (β = 1.142), and female sex (β = 1.060) were associated with worse GH; university education (β=-0.611) with better GH. In PsA, DA (β = 0.703), physical function (β = 1.025), axial involvement (β = 0.659), female sex (β = 0.924), and fibromyalgia (β = 1.387) were associated with worse GH; age (β=-0.024) and university education (β=-0.856) with better GH.

CONCLUSIONS

DA and physical function are major HRQoL and GH determinants across spondyloarthritis types, and clinical characteristics and sociodemographic factors play an important role, highlighting the importance of a holistic approach for individual patients.

The effects of physical exercise on axial spondyloarthritis - a systematic review

AIM

To collect and summarize the available scientific evidence that evaluates the effects of physical exercise interventions on axial spondyloarthritis (axSpA).

METHODS

A systematic review was conducted in accordance to the guidance of Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) to collect randomized controlled trials on the PubMed, Embase and Web of Science Core Collection databases. The search strategy included terms regarding physical exercise interventions targeted to axSpA participants and all of its variants in multiple combinations adapted to each one of the databases regarding its own special requirements. Several outcomes were defined: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath ankylosing spondylitis functional index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI), ASDAS (Ankylosing Spondylitis Disease Activity Score), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), the 36-item short form health survey (SF-36) and the Ankylosing Spondylitis Quality of Life questionnaire (ASQoL). Two independent researchers screened the titles and abstracts followed by full-text analysis when suitable, using EndnoteTM online. Selected articles, according to exclusion/inclusion criteria defined, were submitted to data extraction and bias assessment was performed for each study's outcomes using the Cochrane risk-of-bias tool for randomized trials.

RESULTS

A total of 2063 articles were identified through the electronic databases search. After removal of duplicates, 1435 were eligible for screening, of which 45 articles went through full text evaluation. Only 24 articles met the inclusion/exclusion criteria. Physical exercise contributes for a statistically significant improvement of BASDAI in 13 studies, BASFI in 10, BASMI in 6, ASDAS in 3, CRP in 2, ESR in 1, SF-36 in 2 and ASQoL in 3.No major adverse effects were reported and an overall benefit was noted with the implementation of physical exercise as a treatment modality for axSpA.

CONCLUSION

Physical exercise seems to be an effective non-pharmacological therapy for axSpA, with positive effects in disease activity, physical function, and quality of life.

Health-related quality of life among spondyloarthritis and chronic low back pain patients: results from a nationwide population-based survey

PURPOSE

Both spondyloarthritis and chronic low back pain (CLBP) significantly impact health-related quality of life (HRQoL). It is important to clarify whether these disorders have different impacts on the several domains of HRQoL as different mechanisms may necessitate different treatment interventions. Moreover, the factors associated with HRQoL can inform more targeted group interventions to promote HRQoL.

METHODS

We used data from EpiReumaPt, a population-based survey conducted from September 2011 to December 2013. HRQoL was assessed with EuroQoL-5-Dimensions (EQ-5D). Spondyloarthritis was diagnosed by expert opinion (rheumatologist) and predefined criteria. CLBP was diagnosed if low back pain was present on the day of the interview and persisted for > 90 days. Univariable and multivariable linear regression analyses compared HRQoL among subjects with spondyloarthritis, CLBP, and no rheumatic diseases. Multivariable linear regression analyses evaluated HRQoL factors in spondyloarthritis and CLBP subjects.

RESULTS

We included 92 spondyloarthritis patients, 1376 CLBP patients, and 679 subjects without rheumatic diseases. HRQoL was similarly affected in spondyloarthritis and CLBP (ß =  - 0.03, 95% CI [- 0.08; 0.03]) in all EQ5D dimensions. A much lower HRQoL was found in spondyloarthritis and CLBP patients compared with subjects without rheumatic diseases (ß =  - 0.14, 95% CI [- 0.19; - 0.10]; ß =  - 0.12, 95% CI [- 0.14; - 0.09], respectively). In spondyloarthritis subjects, multimorbidity and active disease were associated with worse HRQoL (ß =  - 0.18; 95% CI [- 0.24; 0.03]; ß =  - 0.13; 95% CI [- 0.29; - 0.05], respectively), and regular physical exercise was associated with better HRQoL (ß = 0.18; 95% CI [0.10; 0.30]). In CLBP subjects, multimorbidity (β =  - 0.11; 95% CI [- 0.14; - 0.08]), obesity (β =  - 0.04; 95% CI [- 0.08; - 0.01]), and low back pain intensity (β =  - 0.02; 95% CI [- 0.03; - 0.02]) were associated with worse HRQoL, and regular physical exercise (β = 0.08; 95% CI [0.05; 0.11]) was significantly associated with better HRQoL.

CONCLUSION

Spondyloarthritis and CLBP subjects reported similar levels of impairment in the mental, physical, and social domains of HRQoL. Future health plans should address modifiable factors associated with HRQoL in these conditions to achieve better outcomes.

ASAS-EULAR recommendations for the management of axial spondyloarthritis: 2022 update

OBJECTIVES

To update the Assessment of SpondyloArthritis international Society (ASAS)-EULAR recommendations for the management of axial spondyloarthritis (axSpA).

METHODS

Following the EULAR Standardised Operating Procedures, two systematic literature reviews were conducted on non-pharmacological and pharmacological treatment of axSpA. In a task force meeting, the evidence was presented, discussed, and overarching principles and recommendations were updated, followed by voting.

RESULTS

Five overarching principles and 15 recommendations with a focus on personalised medicine were agreed: eight remained unchanged from the previous recommendations; three with minor edits on nomenclature; two with relevant updates (#9, 12); two newly formulated (#10, 11). The first five recommendations focus on treatment target and monitoring, non-pharmacological management and non-steroidal anti-inflammatory drugs (NSAIDs) as first-choice pharmacological treatment. Recommendations 6-8 deal with analgesics and discourage long-term glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) for pure axial involvement. Recommendation 9 describes the indication of biological DMARDs (bDMARDs, that is, tumour necrosis factor inhibitors (TNFi), interleukin-17 inhibitors (IL-17i)) and targeted synthetic DMARDs (tsDMARDs, ie, Janus kinase inhibitors) for patients who have Ankylosing Spondylitis Disease Activity Score ≥2.1 and failed ≥2 NSAIDs and also have either elevated C reactive protein, MRI inflammation of sacroiliac joints or radiographic sacroiliitis. Current practice is to start a TNFi or IL-17i. Recommendation 10 addresses extramusculoskeletal manifestations with TNF monoclonal antibodies preferred for recurrent uveitis or inflammatory bowel disease, and IL-17i for significant psoriasis. Treatment failure should prompt re-evaluation of the diagnosis and consideration of the presence of comorbidities (#11). If active axSpA is confirmed, switching to another b/tsDMARD is recommended (#12). Tapering, rather than immediate discontinuation of a bDMARD, can be considered in patients in sustained remission (#13). The last recommendations (#14, 15) deal with surgery and spinal fractures.

CONCLUSIONS

The 2022 ASAS-EULAR recommendations provide up-to-date guidance on the management of patients with axSpA.

ASAS-EULAR recommendations for the management of axial spondyloarthritis: 2022 update

OBJECTIVES

To update the Assessment of SpondyloArthritis international Society (ASAS)-EULAR recommendations for the management of axial spondyloarthritis (axSpA).

METHODS

Following the EULAR Standardised Operating Procedures, two systematic literature reviews were conducted on non-pharmacological and pharmacological treatment of axSpA. In a task force meeting, the evidence was presented, discussed, and overarching principles and recommendations were updated, followed by voting.

RESULTS

Five overarching principles and 15 recommendations with a focus on personalised medicine were agreed: eight remained unchanged from the previous recommendations; three with minor edits on nomenclature; two with relevant updates (#9, 12); two newly formulated (#10, 11). The first five recommendations focus on treatment target and monitoring, non-pharmacological management and non-steroidal anti-inflammatory drugs (NSAIDs) as first-choice pharmacological treatment. Recommendations 6-8 deal with analgesics and discourage long-term glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) for pure axial involvement. Recommendation 9 describes the indication of biological DMARDs (bDMARDs, that is, tumour necrosis factor inhibitors (TNFi), interleukin-17 inhibitors (IL-17i)) and targeted synthetic DMARDs (tsDMARDs, ie, Janus kinase inhibitors) for patients who have Ankylosing Spondylitis Disease Activity Score ≥2.1 and failed ≥2 NSAIDs and also have either elevated C reactive protein, MRI inflammation of sacroiliac joints or radiographic sacroiliitis. Current practice is to start a TNFi or IL-17i. Recommendation 10 addresses extramusculoskeletal manifestations with TNF monoclonal antibodies preferred for recurrent uveitis or inflammatory bowel disease, and IL-17i for significant psoriasis. Treatment failure should prompt re-evaluation of the diagnosis and consideration of the presence of comorbidities (#11). If active axSpA is confirmed, switching to another b/tsDMARD is recommended (#12). Tapering, rather than immediate discontinuation of a bDMARD, can be considered in patients in sustained remission (#13). The last recommendations (#14, 15) deal with surgery and spinal fractures.

CONCLUSIONS

The 2022 ASAS-EULAR recommendations provide up-to-date guidance on the management of patients with axSpA.

Identification of clinical phenotypes of peripheral involvement in patients with spondyloarthritis, including psoriatic arthritis: a cluster analysis in the worldwide ASAS-PerSpA study

Objective

To identify clusters of peripheral involvement according to the specific location of peripheral manifestations (ie, arthritis, enthesitis and dactylitis) in patients with spondyloarthritis (SpA) including psoriatic arthritis (PsA), and to evaluate whether these clusters correspond with the clinical diagnosis of a rheumatologist.

Methods

Cross-sectional study with 24 participating countries. Consecutive patients diagnosed by their rheumatologist as PsA, axial SpA or peripheral SpA were enrolled. Four different cluster analyses were conducted: one using information on the specific location from all the peripheral manifestations, and a cluster analysis for each peripheral manifestation, separately. Multiple correspondence analyses and k-means clustering methods were used. Distribution of peripheral manifestations and clinical characteristics were compared across the different clusters.

Results

The different cluster analyses performed in the 4465 patients clearly distinguished a predominantly axial phenotype (cluster 1) and a predominantly peripheral phenotype (cluster 2). In the predominantly axial phenotype, hip involvement and lower limb large joint arthritis, heel enthesitis and lack of dactylitis were more prevalent. In the predominantly peripheral phenotype, different subgroups were distinguished based on the type and location of peripheral involvement: a predominantly involvement of upper versus lower limbs joints, a predominantly axial enthesitis versus peripheral enthesitis, and predominantly finger versus toe involvement in dactylitis. A poor agreement between the clusters and the rheumatologist‘s diagnosis as well as with the classification criteria was found.

Conclusion

These results suggest the presence of two main phenotypes (predominantly axial and predominantly peripheral) based on the presence and location of the peripheral manifestations.

The role of muscle in the susceptibility and progression of axial Spondyloarthritis: The MyoSpA Study Protocol

BACKGROUND

Axial Spondyloarthritis (axSpA) is a chronic, inflammatory rheumatic disease that affects the axial skeleton, causing pain, stiffness, and fatigue. Genetics and environmental factors such as microbiota and microtrauma are known causes of disease susceptibility and progression. Murine models of axSpA found a decisive role for biomechanical stress as an inducer of enthesitis and new bone formation. Here, we hypothesize that muscle properties in axSpA patients are compromised and influenced by genetic background.

OBJECTIVES

To improve our current knowledge of axSpA physiopathology, we aim to characterize axial and peripheral muscle properties and identify genetic and protein biomarker that might explain such properties.

METHODS

A cross-sectional study will be conducted on 48 participants aged 18-50 years old, involving patients with axSpA (according to ASAS classification criteria, symptoms duration < 10 years) and healthy controls matched by gender, age, and levels of physical activity. We will collect epidemiological and clinical data and perform a detailed, whole body and segmental, myofascial characterization (focusing on multifidus, brachioradialis and the gastrocnemius lateralis) concerning: a) Physical Properties (stiffness, tone and elasticity), assessed by MyotonPRO®; b) Strength, by a dynamometer; c) Mass, by bioimpedance; d) Performance through gait speed and 60-second sit-to-stand test; e) Histological and cellular/ molecular characterization through ultrasound-guided biopsies of multifidus muscle; f) Magnetic Resonance Imaging (MRI) characterization of paravertebral muscles. Furthermore, we will perform an integrated transcriptomics and proteomics analysis of peripheral blood samples.

DISCUSSION

The innovative and multidisciplinary approaches of this project rely on the elucidation of myofascial physical properties in axSpA and also on the establishment of a biological signature that relates to specific muscle properties. This hitherto unstudied link between gene/protein signatures and muscle properties may enhance our understanding of axSpA physiopathology and reveal new and useful diagnostic and therapeutic targets.

Direct tissue-sensing reprograms TLR4+ Tfh-like cells inflammatory profile in the joints of rheumatoid arthritis patients

CD4⁺ T cells mediate rheumatoid arthritis (RA) pathogenesis through both antibody-dependent and independent mechanisms. It remains unclear how synovial microenvironment impinges on CD4⁺ T cells pathogenic functions. Here, we identified a TLR4⁺ follicular helper T (Tfh) cell-like population present in the blood and expanded in synovial fluid. TLR4⁺ T cells possess a two-pronged pathogenic activity whereby direct TLR4⁺ engagement by endogenous ligands in the arthritic joint reprograms them from an IL-21 response, known to sponsor antibody production towards an IL-17 inflammatory program recognized to fuel tissue damage. Ex vivo, synovial fluid TLR4⁺ T cells produced IL-17, but not IL-21. Blocking TLR4 signaling with a specific inhibitor impaired IL-17 production in response to synovial fluid recognition. Mechanistically, we unveiled that T-cell HLA-DR regulates their TLR4 expression. TLR4⁺ T cells appear to uniquely reconcile an ability to promote systemic antibody production with a local synovial driven tissue damage program.

In order to identify how the synovial microenvironment impinges on CD4+ T cells pathogenic functions in Rheumatoid Arthritis (RA), Amaral-Silva examined RA patient blood and synovial fluif and identified the presence of a TLR4+ follicular helper T (Tfh) cell-like population. They provided mechanistic insight into how TLR4⁺ T cells uniquely reconcile an ability to promote systemic antibody production with a local synovial driven-tissue damage program.

The Effect of ACTN3 and VDR Polymorphisms on Skeletal Muscle Performance in Axial Spondyloarthropathies

Background

Spondyloarthritis (SpA) are the most common group of chronic inflammatory rheumatic diseases affecting about 1.5% of the adult Caucasian population. Low back pain is the most common symptom. The aetiopathogenesis of SpA is multifactorial, with well-known genetic and environmental contributions. Furthermore, muscle properties might also be involved in the pathophysiological process and these could be modulated by the genetic background. Alpha-actinin-3 (ACTN3) and Vitamin D receptor (VDR) genes are well-known genes related with muscle performance. Our aim was to analyze four SNPs of these genes and to evaluate their influence in axial SpA (axSpA) susceptibility, phenotype and muscle properties.

Methods

We performed a pilot study based on case-control approach involving 56 participants: 28 axSpA patients and 28 healthy controls matched by age, gender and levels of physical activity. Clinical, epidemiological and muscle characterization data—muscle physical properties (stiffness, tone, and elasticity), strength, mass, and performance, were collected. Two different muscles were considered for analysis, the Multifidus and Gastrocnemius. Four SNPs of ACTN3 (rs1815739) and VDR (rs2228570, rs731236, and rs7975232), were selected, analyzed and correlated with clinical, epidemiological and muscle characterization data.

Results

In total, 51 individuals (27 axSpA patients and 24 matched controls) were eligible for further genetic analysis, 66.7% being male and with a mean age of 36 years. Muscle physical properties, muscle strength and muscle mass were similar in both groups; however, axSpA patients showed a decrease in muscle performance. None of the studied SNPs were associated with disease susceptibility/phenotype, muscle physical properties, muscle strength or muscle mass. However, ACTN3 rs1815739 and VDR rs2228570 were shown to be associated with muscle performance.

Conclusion

Our results suggest an association between ACTN3 and VDR polymorphisms and muscle performance in axSpA.

Prevalence and distribution of peripheral musculoskeletal manifestations in spondyloarthritis including psoriatic arthritis: results of the worldwide, cross-sectional ASAS-PerSpA study

OBJECTIVES

To characterise peripheral musculoskeletal involvement in patients with spondyloarthritis (SpA) including psoriatic arthritis (PsA), across the world.

METHODS

Cross-sectional study with 24 participating countries. Patients with a diagnosis of axial SpA (axSpA), peripheral SpA (pSpA) or PsA according to their rheumatologist were included. The investigators were asked which diagnosis out of a list of six (axSpA, PsA, pSpA, inflammatory bowel disease-associated SpA, reactive arthritis or juvenile SpA (Juv-SpA)) fitted the patient best. Peripheral manifestations (ie, peripheral joint disease, enthesitis, dactylitis and root joint disease), their localisation and treatments were evaluated.

RESULTS

A total of 4465 patients were included (61% men, mean age 44.5 years) from four geographic areas: Latin America (n=538), Europe plus North America (n=1677), Asia (n=975) and the Middle East plus North Africa (n=1275). Of those, 78% had ever suffered from at least one peripheral musculoskeletal manifestation; 57% had peripheral joint disease, 44% had enthesitis and 15% had dactylitis. Latin American had far more often peripheral joint disease (80%) than patients from other areas. Patients with PsA had predominantly upper limb and small joint involvement (52%).Hip and shoulder involvement was found in 34% of patients. The prevalence of enthesitis ranged between 41% in patients with axSpA and 65% in patients with Juv-SpA. Dactylitis was most frequent among patients with PsA (37%).

CONCLUSION

These results suggest that all peripheral features can be found in all subtypes of SpA, and that differences are quantitative rather than qualitative. In a high proportion of patients, axial and peripheral manifestations coincided. These findings reconfirm SpA clinical subtypes are descendants of the same underlying disease, called SpA.

Effect of biologic disease-modifying anti-rheumatic drugs targeting remission in axial spondyloarthritis: systematic review and meta-analysis

OBJECTIVES

To assess the efficacy of biologic DMARDs (bDMARDs) in achieving Assessment of Spondyloarthritis International Society partial remission (ASAS-PR) and/or Ankylosing Spondylitis Disease Activity Score inactive disease (ASDAS-ID), as remission-like surrogates, in axial SpA (axSpA).

METHODS

Data from randomized controlled trials (RCTs), including long-term extensions, were included. A systematic literature review was performed using the MEDLINE database (first search May 2018, updated February 2020) and PICO criteria according to Patients-adults with radiographic or non-radiographic axSpA; Intervention-any bDMARD; Comparator-placebo and/or any different drug; Outcomes-ASAS-PR and/or ASDAS-ID as primary or secondary endpoints. Meta-analysis was performed after assessment of the homogeneity of study designs, populations and outcomes.

RESULTS

After screening 155 references, a total of 22 RCTs and 28 long-term extensions were retrieved. ASAS-PR was the dominant remission-like definition used. Concerning TNF inhibitors, 14/17 RCTs provided evidence of efficacy in reaching remission at different time points: 12, 16, 24 and 28 weeks (ASAS-PR in 16-62% of patients and ASDAS-ID in 24-40% of patients). With a limited number of studies available, IL-17A inhibitors exhibited remission rates of 15-21% for ASAS-PR and 11-16% for ASDAS-ID at week 16. A meta-analysis regarding ASAS-PR was performed considering RCTs with a similar duration (12, 16 or 24 weeks). The relative risk for achieving remission was 3.864 (95% CI 2.937, 5.085).

CONCLUSION

bDMARDs have a clear impact in axSpA remission evaluated by ASAS-PR. Nevertheless, these data show an unmet need for improved reporting of remission-like outcomes.

Biologic disease-modifying anti-rheumatic drugs and patient-reported outcomes in axial SpA: a systematic review and a call for action

This paper is to assess the efficacy of different biologic DMARDs (bDMARDs) on several patient-reported outcomes (PROs) in randomized controlled trials (RCT) in axial spondyloarthritis (axSpA). A systematic literature review (SLR) was performed. MEDLINE (May 1, 2018) was used with the filters "published in the last 10 years" and "humans." The PICO criteria used were Patients: adults with radiographic axSpA (r-axSpA) or non-radiographic axSpA (nr-axSpA); Intervention: any bDMARD; Compararator: placebo (PBO)/any different drug; Outcome: the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), the Ankylosing Spondylitis Quality of Life (ASQoL), the EuroQol-5D (EQ-5D), the Short Form 36 Health Survey physical component summary (SF36-PCS), the Short Form 36 Health Survey mental component summary (SF36-MCS), and the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F). After screening 84 initial references and manually selecting other 9, 24 publications, assessing TNF inhibitors (TNFi) or IL17A inhibitors (IL17Ai) were selected. Four RCTs quantified the minimal clinical important difference (MCID) between treatment arms. Most of the RCTs compared the mean difference of PROs between different timepoints. Overall, the treatment arm was superior to the comparator. PROs were often underreported or highly heterogeneously presented. MCID was seldom mentioned. There is a need to raise the standard of care on SpA by aiming at remission and PRO associated improvements. In order to achieve this goal, the target must be clearly defined, reported, and tested.

GO-DACT: a phase 3b randomised, double-blind, placebo-controlled trial of GOlimumab plus methotrexate (MTX) versus placebo plus MTX in improving DACTylitis in MTX-naive patients with psoriatic arthritis

Objectives

To assess the efficacy of golimumab in combination with methotrexate (MTX) versus MTX monotherapy in psoriatic arthritis (PsA) dactylitis.

Methods

Multicentre, investigator-initiated, randomised, double-blind, placebo-controlled, parallel-design phase 3b trial in 11 Portuguese rheumatology centres. Patients with PsA along with active dactylitis and naive to MTX and biologic disease-modifying antirheumatic drugs (bDMARDs) were randomly assigned to golimumab or placebo, both in combination with MTX. The primary endpoint was Dactylitis Severity Score (DSS) change from baseline to week 24. Key secondary endpoints included DSS and Leeds Dactylitis Index (LDI) response, and changes from baseline in the LDI and MRI dactylitis score. Analysis was by intention-to-treat for the primary endpoint.

Results

Twenty-one patients received golimumab plus MTX and 23 MTX monotherapy for 24 weeks. One patient from each arm discontinued. Patient inclusion was halted at 50% planned recruitment due to a favourable interim analysis. Median baseline DSS was 6 in both arms. By week 24, patients treated with golimumab plus MTX exhibited significantly greater improvements in DSS relative to MTX monotherapy (median change of 5 vs 2 points, respectively; p=0.026). In the golimumab plus MTX arm, significantly higher proportions of patients achieved at least 50% or 70% improvement in DSS and 20%, 50% or 70% improvement in LDI in comparison to MTX monotherapy.

Conclusions

The combination of golimumab and MTX as first-line bDMARD therapy is superior to MTX monotherapy for the treatment of PsA dactylitis.

Trial registration number

NCT02065713

Muscle Evaluation in Axial Spondyloarthritis-The Evidence for Sarcopenia

Sarcopenia is a syndrome defined as a progressive and generalized skeletal muscle disorder associated with an increased likelihood of adverse outcomes such as falls, fractures, physical disability, and death. The actual definition of sarcopenia is based on a reduction in the values of three parameters: strength, muscle mass quantity or quality, and physical performance (the determinant of severity). Muscle wasting is a common feature in several chronic diseases, such as spondyloarthritis (SpA), and significantly increases patient morbidity and mortality. Although there has been huge progress in this field over recent years, the absence of a clear definition and clear diagnostic criteria of sarcopenia has resulted in inconsistent information regarding muscle-involvement in SpA. Thus, the aim of this review is to collect relevant evidence on muscular changes occurring during the disease process from the published literature, according to the recommended tools for sarcopenia evaluation proposed by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2). In addition, data from histological, electromyography, and biochemical muscle analyses of SpA patients are also reviewed. Overall, a reduction in muscle strength with a systemic decrease in lean mass seems to be associated with a gait speed compromise. This information is usually fragmented, with no studies considering the three parameters together. This paper represents a call-to-action for the design of new studies in the future.

Prognostic factors for recovery and non-recovery in patients with non-specific neck pain: a protocol for a systematic literature review

INTRODUCTION

Neck pain is a common musculoskeletal disorder worldwide. It can result in significant disability and impaired quality of life. More than 50% of patients with neck pain still report symptoms 1 year later despite receiving different forms of non-pharmacological and pharmacological treatment. Identifying patient characteristics that are modifiable or predict recovery and non-recovery for an individual patient might identify ways of improving outcomes. This systematic review aims to comprehensively summarise the existing evidence regarding baseline patient characteristics associated with recovery and non-recovery, as defined by measures of pain intensity, disability and global perceived improvement.

METHODS AND ANALYSIS

Six electronic databases, PubMed, CINAHL, PEDro Database, EMBASE, Cochrane Library and Web of Science, will be searched, with terms related to the review question such as neck pain, prognostic or predictive research, from inception to 28 September of 2018. Studies will be included if they have investigated an association between patient characteristics and outcomes, with at least one follow-up time point. Two independent reviewers will screen the titles and abstracts followed by a full-text review to assess papers regarding their eligibility. Data from included papers will be extracted using standardised forms, including study and participants' characteristics, outcomes, prognostic factors and effect size of the association. The risk of bias of each study will be assessed using the Quality in Prognostic Studies tool. A narrative synthesis will be conducted considering the strength, consistency of results and the methodological quality.

ETHICS AND DISSEMINATION

This systematic review does not require ethical approval. The results will be disseminated through publication in a peer-review journal, as a chapter of a doctoral thesis and through presentations at national and international conferences.

PROSPERO REGISTRATION NUMBER

CRD42018091183.

Translation, cross-cultural adaptation and validation of the Osteoarthritis Quality of Life (OAQoL) questionnaire for use in Portugal

Osteoarthritis (OA) is the most prevalent rheumatic disease and is a leading cause of decreased quality of life (QoL). The OA Quality of Life questionnaire (OAQoL) is an OA-specific patient-reported outcome measures. The aim of this study was to translate and validate the original UK English version of the Osteoarthritis Quality of Life (OAQoL) questionnaire into European Portuguese. The translation of the questionnaire was carried out according to a dual panel methodology (bilingual panel followed by lay panel). This was followed by cognitive debriefing interviews (CDIs) with OA patients to assess comprehension and relevance of the translated questionnaire. Finally, a validation survey was conducted to assess its psychometric properties. The Portuguese OAQoL, a comparator scale (the Nottingham Health Profile-NHP) as well as questions relating to demographic and disease information were administered to OA patients. A sub-sample of patients also completed the Portuguese OAQoL two weeks later, to assess test-retest reliability. The internal consistency, construct validity and known group validity (according to perceived OA severity) of the scale was also assessed. Both the bilingual and lay panels consisted of five individuals and no major difficulties relating to the translation process were identified. A total of ten patients with OA participated in the CDIs. The mean time to complete the questionnaire was 5 min. These interviews revealed that the Portuguese version of the OAQoL was clear, relevant and easy to complete. Finally, 53 OA patients (44 females; mean age of 67.6 years) completed the validation survey. Cronbach's alpha coefficient was 0.87, demonstrating high internal consistency. Test-retest reliability, assessed by Spearman's rank correlation coefficient, was 0.86. Moderate correlations were found with the majority of the NHP sections, providing evidence of construct validity. Significant differences in OAQoL scores were found between patients who differed according to their perceived OA severity, providing evidence of known group validity. The Portuguese version of the OAQoL is a valid and reliable questionnaire that can be used to assess QoL in OA, both in clinical practice and for research purposes.

Portuguese recommendations for the prevention, diagnosis and management of primary osteoporosis - 2018 update

BACKGROUND

Advances in osteoporosis (OP)case definition, treatment options, optimal therapy duration and pharmacoeconomic evidence in the national context motivated the Portuguese Society of Rheumatology (SPR) to update the Portuguese recommendations for the diagnosis and management of osteoporosis published in 2007.

METHODS

SPR bone diseases' working group organized meetings involving 55 participants (rheumatologists, rheumatology fellows and one OP specialist nurse) to debate and develop the document. First, the working group selected 11 pertinent clinical questions for the diagnosis and management of osteoporosis in standard clinical practice. Then, each question was investigated through literature review and draft recommendations were built through consensus. When insufficient evidence was available, recommendations were based on experts' opinion and on good clinical practice. At two national meetings, the recommendations were discussed and updated. A draft of the recommendations full text was submitted to critical review among the working group and suggestions were incorporated. A final version was circulated among all Portuguese rheumatologists before publication and the level of agreement was anonymously assessed using an online survey.

RESULTS

The 2018 SPR recommendations provide comprehensive guidance on osteoporosis prevention, diagnosis, fracture risk assessment, pharmacological treatment initiation, therapy options and duration of treatment, based on the best available evidence. They attained desirable agreement among Portuguese rheumatologists. As more evidence becomes available, periodic revisions will be performed. Target audience and patient population: The target audience for these guidelines includes all clinicians. The target patient population includes adult Portuguese people. Intended use: These recommendations provide general guidance for typical cases. They may not be appropriate in all situations - clinicians are encouraged to consider this information together with updated evidence and their best clinical judgment in individual cases.

Translation and cross-cultural adaptation of the ASAS Health Index and ASAS Environmental Factors Item Set into European Portuguese Language

OBJECTIVE

There is a lack of outcome measures to assess the impact of axial spondyloarthritis (axSpA) on health, function and quality of life. The Assessment of SpondyloArthritis International Society (ASAS) group developed the ASAS Health Index (ASAS-HI) and the ASAS Environmental Factors Item Set (ASAS-EF) to measure functioning and health across all aspects of health that are typically affected and relevant for patients with axSpA, based on the International Classification of Functioning, Disability and Health (ICF). The aim of this paper was to describe the translation and cross-cultural adaptation of both questionnaires into European Portuguese among patients with radiographic and non-radiographic axial SpA (nr-axSpA) and test the conceptual equivalence of the translated version in the Portuguese context.

MATERIAL AND METHODS

The ASAS-HI and ASAS-EF were firstly translated into European Portuguese and then back-translated into English, following forward-backward procedure. After the review of the Portuguese version by an expert committee, the field test with cognitive debriefing involved a sample of 10 axSpA patients with different gender, age, disease duration, and educational background.

RESULTS

Minor difficulties arose from the translation process of the ASAS-HI. The EF Item Set offered more difficulties indicating that concepts underlying the contextual factors may be more culture-dependent. A total of 10 patients with axSpA [8 males, mean age of 41.4 (±13.7)] participated in the field test. Cognitive debriefing showed that items of the ASAS-HI and EF Item Set of the Portuguese version are clear, relevant, understandable and easy to complete. As a result of cognitive debriefing, the wording of four items had to be changed to avoid misunderstandings or unintended interpretations, and a new response option "not applicable" was added to two items of the ASAS-HI to improve appropriateness.

CONCLUSIONS

The resulting Portuguese version of the ASAS-HI and ASAS-EF showed acceptable linguistic validity and has potential for use in both clinical practice and research settings. Nevertheless, before European Portuguese versions can be fully implemented, its psychometric properties (validity and reliability) need to be evaluated.

2016 update of the ASAS-EULAR management recommendations for axial spondyloarthritis

To update and integrate the recommendations for ankylosing spondylitis and the recommendations for the use of tumour necrosis factor inhibitors (TNFi) in axial spondyloarthritis (axSpA) into one set applicable to the full spectrum of patients with axSpA. Following the latest version of the European League Against Rheumatism (EULAR) Standardised Operating Procedures, two systematic literature reviews first collected the evidence regarding all treatment options (pharmacological and non-pharmacological) that were published since 2009. After a discussion of the results in the steering group and presentation to the task force, overarching principles and recommendations were formulated, and consensus was obtained by informal voting. A total of 5 overarching principles and 13 recommendations were agreed on. The first three recommendations deal with personalised medicine including treatment target and monitoring. Recommendation 4 covers non-pharmacological management. Recommendation 5 describes the central role of non-steroidal anti-inflammatory drugs (NSAIDs) as first-choice drug treatment. Recommendations 6-8 define the rather modest role of analgesics, and disprove glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) for axSpA patents with predominant axial involvement. Recommendation 9 refers to biological DMARDs (bDMARDs) including TNFi and IL-17 inhibitors (IL-17i) for patients with high disease activity despite the use (or intolerance/contraindication) of at least two NSAIDs. In addition, they should either have an elevated C reactive protein and/or definite inflammation on MRI and/or radiographic evidence of sacroiliitis. Current practice is to start with a TNFi. Switching to another TNFi or an IL-17i is recommended in case TNFi fails (recommendation 10). Tapering, but not stopping a bDMARD, can be considered in patients in sustained remission (recommendation 11). The final two recommendations (12, 13) deal with surgery and spinal fractures. The 2016 Assessment of SpondyloArthritis international Society-EULAR recommendations provide up-to-date guidance on the management of patients with axSpA.

Measuring impairments of functioning and health in patients with axial spondyloarthritis by using the ASAS Health Index and the Environmental Item Set: translation and cross-cultural adaptation into 15 languages

Introduction

The Assessments of SpondyloArthritis international society Health Index (ASAS HI) measures functioning and health in patients with spondyloarthritis (SpA) across 17 aspects of health and 9 environmental factors (EF). The objective was to translate and adapt the original English version of the ASAS HI, including the EF Item Set, cross-culturally into 15 languages.

Methods

Translation and cross-cultural adaptation has been carried out following the forward–backward procedure. In the cognitive debriefing, 10 patients/country across a broad spectrum of sociodemographic background, were included.

Results

The ASAS HI and the EF Item Set were translated into Arabic, Chinese, Croatian, Dutch, French, German, Greek, Hungarian, Italian, Korean, Portuguese, Russian, Spanish, Thai and Turkish. Some difficulties were experienced with translation of the contextual factors indicating that these concepts may be more culturally-dependent. A total of 215 patients with axial SpA across 23 countries (62.3% men, mean (SD) age 42.4 (13.9) years) participated in the field test. Cognitive debriefing showed that items of the ASAS HI and EF Item Set are clear, relevant and comprehensive. All versions were accepted with minor modifications with respect to item wording and response option. The wording of three items had to be adapted to improve clarity. As a result of cognitive debriefing, a new response option ‘not applicable’ was added to two items of the ASAS HI to improve appropriateness.

Discussion

This study showed that the items of the ASAS HI including the EFs were readily adaptable throughout all countries, indicating that the concepts covered were comprehensive, clear and meaningful in different cultures.

DAS28, CDAI and SDAI cut-offs do not translate the same information: results from the Rheumatic Diseases Portuguese Register Reuma.pt

OBJECTIVES

. The 28-joint DAS (DAS28), clinical disease activity index (CDAI) and simplified disease activity index (SDAI) are indices frequently used to assess disease activity in RA patients. Cut-off values were defined to classify the states of RA disease activity: remission, low, moderate and high. The aim of this work was to assess disease activity states classified by DAS28, CDAI and SDAI and to analyse their agreement in the Rheumatic Diseases Portuguese Register Reuma.pt.

METHODS

. A total of 2795 patients and 14 440 visits were selected from Reuma.pt for analysis. Pearson's correlation coefficients (PCCs) were calculated for the three indices. McNemar's chi-squared tests, PCCs and kappa statistics were performed to analyse and compare the distribution of visits among all disease activity states and indices.

RESULTS

A strong correlation was found between the three indices throughout the 14 440 visits: r = 0.874 for DAS28/CDAI, r = 0.877 for DAS28/SDAI and r = 0.984 for CDAI/SDAI (all PCCs with P < 0.0001). However, when categorization in the different disease activity states was analysed, McNemar's chi-squared tests and PCCs revealed significant disagreement between the cut-offs of the three indices.

CONCLUSION

DAS28, CDAI and SDAI cut-offs do not translate into the same clinical information in Reuma.pt. Although this might be expected for the original DAS28 cut-offs, when compared with CDAI and SDAI significant disagreement was also found for the DAS28 modified cut-offs. For visits where patients are in CDAI or SDAI remission, we also find disagreement between these two indices, which may contradict previous conclusions that acute phase reactants add little to composite disease activity indices for RA.

The Portuguese Society of Rheumatology position paper on the use of biosimilars

Biotechnological drugs have become a fundamental resource for the treatment of rheumatic patients. Patent expiry of some of these drugs created the opportunity for biopharmaceutical manufacturers to develop biosimilar drugs intended to be as efficacious as the originator product but with a lower cost to healthcare systems. Due to the complex manufacturing process and highly intricate structure of biologicals, a biosimilar can never be an exact copy of its reference product. Consequently, regulatory authorities issued strict preclinical and clinical guidelines to ensure safety and efficacy equivalence and, in September 2013, the biosimilar of infliximab was the first biosimilar monoclonal antibody to be authorized for use in the European Union. The current document is a position statement of the "Sociedade Portuguesa de Reumatologia" (Portuguese Society of Rheumatology) on the use of biosimilar drugs in rheumatic diseases. Two systematic literature reviews were performed, one concerning clinical trials and the other one concerning international position papers on biosimilars. The results were presented and discussed in a national meeting and a final position document was discussed, written and approved by Portuguese rheumatologists. Briefly, this position statement is contrary to automatic substitution of the originator by the biosimilar, defends either a different INN or the prescription by brand name, supports that switching between biosimilars and the originator molecule should be done after at least 6 months of treatment and based on the attending physician decision and after adequate patient information, recommends the registration of all biosimilar treated patients in Reuma.pt for efficacy, safety and immunogenicity surveillance, following the strategy already ongoing for originators, and opposes to extrapolation of indications approved to the originator to completely different diseases and/or age groups without adequate pre-clinical, safety or efficacy data.

HLA alleles and HLA-B27 haplotypes associated with susceptibility and severity of ankylosing spondylitis in a Portuguese population

Human leukocyte antigen (HLA)-B27 is the mostly known major histocompatibility complex (MHC) gene associated with ankylosing spondylitis (AS). Nonetheless, there is substantial evidence that other MHC genes appear to be associated with the disease, although it has not yet been established whether these associations are driven by direct associations or by linkage disequilibrium (LD) mechanisms. We aimed to investigate the contributions of HLA class I and II alleles and B27-haplotypes for AS in a case-control study. A total of 188 HLA-B27 AS cases and 189 HLA-B27 healthy controls were selected and typed for HLA class I and II by the Luminex polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) method. Allelic and haplotypic distributions were estimated by maximum likelihood method using Arlequin v3.11 and statistical analysis were performed by Stata10.1. No associations were found between non-HLA-B27 loci and AS susceptibility, but several associations were observed for phenotypic features of the disease. DRB1*08 was identified as a risk factor for uveitis and DQB1*04 seems to provide protection for AS severity (functional, metrological and radiological indexes). A*02/B27/C*02/DRB1*01/DQB1*05 [P<0.0001; odds ratio (OR) = 39.06; 95% confidence interval (CI) (2.34-651)] is the only haplotype that seems to confer susceptibility to AS. Moreover, the haplotype A*02/B27/C*01/DRB1*08/DQB1*04 seems to provide protection for disease functional and radiological repercussions. Our findings are compatible with the hypothesis that other genes within the HLA region besides HLA-B27 might play some role in AS susceptibility and severity.

Comparative effectiveness and predictors of response to tumour necrosis factor inhibitor therapies in rheumatoid arthritis

OBJECTIVES

Adalimumab, etanercept and infliximab are effective TNF inhibitors (TNFis) in the treatment of RA, but no randomized clinical trials have compared the three agents. Prior observational data are not consistent. We compared their effectiveness over 1 year in a prospective cohort.

METHODS

Analyses were performed on subjects' first episode of TNFi use in the Rheumatic Diseases Portuguese Register, Reuma.pt. The primary outcome was the proportion of patients with European League Against Rheumatism good response sustained at two consecutive observations separated by 3 months during the first year of TNFi use. Comparisons were performed using conventional adjusted logistic regression, as well as matching subjects across the three agents using a propensity score. In addition, baseline predictors of treatment response to TNFi were identified.

RESULTS

The study cohort included 617 RA patients, 250 starting etanercept, 206 infliximab and 161 adalimumab. Good response was achieved by 59.6% for adalimumab, 59.2% for etanercept and 51.9% for infliximab (P = 0.21). The modelled probability of good response did not significantly differ across agents (etanercept vs adalimumab OR = 0.97, 95% CI 0.55, 1.71; etanercept vs infliximab OR = 1.25, 95% CI 0.74, 2.12; infliximab vs adalimumab OR = 0.80, 95% CI 0.47, 1.36). Matched propensity score analyses also showed no significant treatment response differences. Greater educational attainment was a predictor of better response, while smoking, presence of ACPA, glucocorticoid use and worse physician assessment of disease activity at baseline each predicted a reduced likelihood of treatment response.

CONCLUSION

Over 1 year, we found no difference in effectiveness between adalimumab, etanercept and infliximab.

A high density SNP genotyping approach within the 19q13 chromosome region identifies an association of a CNOT3 polymorphism with ankylosing spondylitis

OBJECTIVE

To identify genomic variants in the 19q13 chromosome region associated with ankylosing spondylitis (AS) in human leucocyte antigen (HLA)-B27-positive populations.

METHODS

High-throughput genotyping of 1536 haplotype-tag single nucleotide polymorphisms (SNPs) was performed in 249 patients with AS and 302 healthy controls. Some of the identified associations were validated by genotyping four SNPs in two additional cohorts consisting of 412 cases/301 controls and 144 cases/203 controls. All individuals selected (both cases and controls) were HLA-B27-positive.

RESULTS

Two markers in two different genes (CNOT3 and LAIR2) showed significant association (p<10(-3)) with AS. In addition, sliding windows analysis showed association of groups of adjacent SNPs in regions located around CNOT3 (Chr19: 59347459-59356564, p=2.43 × 10(-4) to 6.54 × 10(-4)). The associations were validated by genotyping four SNPs from regions located near LAIR2 and CNOT3 genes (rs1055234, rs8111398, rs2287828 and rs4591276) in two additional cohorts. The CNOT3 polymorphism (rs1055234) remained associated with AS (combined p=9.73 × 10(-6)). One SNP, located downstream of KIR3DL1, was detected which, tested in combination with HLA-Bw4I80, was associated with AS.

CONCLUSION

A novel significant association was detected between SNP rs1055234 and AS susceptibility.

Differential features between primary ankylosing spondylitis and spondylitis associated with psoriasis and inflammatory bowel disease

OBJECTIVE

To describe differential characteristics of axial involvement in ankylosing spondylitis (AS) as compared with that seen in psoriatic arthritis (PsA) and inflammatory bowel disease (IBD) in a cohort of Ibero-American patients.

METHODS

This study included 2044 consecutive patients with spondyloarthritis (SpA; ESSG criteria). Demographic, clinical, disease activity, functional ability, quality of life, work status, radiologic, and therapeutic data were evaluated and collected by RESPONDIA members from different Ibero-American countries between June and December 2006. Patients selected for analysis met modified New York criteria (mNY) for AS.

RESULTS

A total of 1264 patients met the New York criteria for AS: 1072 had primary AS, 147 had psoriatic, and 45 had IBD-associated spondylitis. Median disease duration was comparable among the 3 patient groups. Patients with primary AS were significantly younger (p = 0.01) and presented a higher frequency of males (p = 0.01) than the other 2 groups. Axial manifestations such as inflammatory back pain and sacroiliac pain were significantly more frequent in patients with primary AS (p = 0.05) versus other groups, whereas frequency of dactylitis, enthesitis, and peripheral arthritis was more common in patients with psoriatic spondylitis (p = 0.05). Spinal mobility was significantly more limited in patients with primary AS versus the other 2 groups (p = 0.0001). Radiologic changes according to BASRI total score were equally significant in primary AS. Disease activity (BASDAI), functional ability (BASFI), and quality of life (ASQoL) scores were comparable in the 3 groups.

CONCLUSION

Patients with primary AS had more severe axial involvement than those with spondylitis associated with psoriasis or IBD. Functional capacity, disease activity, and quality of life were comparable among the groups studied.

Whole blood transcriptional profiling in ankylosing spondylitis identifies novel candidate genes that might contribute to the inflammatory and tissue-destructive disease aspects

INTRODUCTION

A number of genetic-association studies have identified genes contributing to ankylosing spondylitis (AS) susceptibility but such approaches provide little information as to the gene activity changes occurring during the disease process. Transcriptional profiling generates a 'snapshot' of the sampled cells' activity and thus can provide insights into the molecular processes driving the disease process. We undertook a whole-genome microarray approach to identify candidate genes associated with AS and validated these gene-expression changes in a larger sample cohort.

METHODS

A total of 18 active AS patients, classified according to the New York criteria, and 18 gender- and age-matched controls were profiled using Illumina HT-12 whole-genome expression BeadChips which carry cDNAs for 48,000 genes and transcripts. Class comparison analysis identified a number of differentially expressed candidate genes. These candidate genes were then validated in a larger cohort using qPCR-based TaqMan low density arrays (TLDAs).

RESULTS

A total of 239 probes corresponding to 221 genes were identified as being significantly different between patients and controls with a P-value <0.0005 (80% confidence level of false discovery rate). Forty-seven genes were then selected for validation studies, using the TLDAs. Thirteen of these genes were validated in the second patient cohort with 12 downregulated 1.3- to 2-fold and only 1 upregulated (1.6-fold). Among a number of identified genes with well-documented inflammatory roles we also validated genes that might be of great interest to the understanding of AS progression such as SPOCK2 (osteonectin) and EP300, which modulate cartilage and bone metabolism.

CONCLUSIONS

We have validated a gene expression signature for AS from whole blood and identified strong candidate genes that may play roles in both the inflammatory and joint destruction aspects of the disease.

Association of IL23R and ERAP1 genes with ankylosing spondylitis in a Portuguese population

OBJECTIVE

Association between ankylosing spondylitis (AS) and two genes, ERAP1 and IL23R, has recently been reported in North American and British populations. The population attributable risk fraction for ERAP1 in this study was 25%, and for IL23R, 9%. Confirmation of these findings to ERAP1 in other ethnic groups has not yet been demonstrated. We sought to test the association between single nucleotide polymorphisms (SNPs) in these genes and susceptibility to AS among a Portuguese population. We also investigated the role of these genes in clinical manifestations of AS, including age of symptom onset, the Bath Ankylosing Spondylitis Disease Activity, Metrology and Functional Indices, and the modified Stoke Ankylosing Spondylitis Spinal Score.

METHODS

The study was conducted on 358 AS cases and 285 ethnically matched Portuguese healthy controls. AS was defined according to the modified New York Criteria. Genotyping of IL23R and ERAP1 allelic variants was carried out with TaqMan allelic discrimination assays. Association analysis was performed using the Cochrane-Armitage and linear regression tests of genotypes as implemented in PLINK for dichotomous and quantitative variables respectively. A meta-analysis for Portuguese and previously published Spanish IL23R data was performed using the StatsDirect Statistical tools, by fixed and random effects models.

RESULTS

A total of 14 nsSNPs markers (8 for IL23R, 5 for ERAP1, 1 for LN-PEP) were analysed. Three markers (2 for IL23R and 1 for ERAP1) showed significant single-locus disease associations, confirming that the association of these genes with AS in the Portuguese population. The strongest associated SNP in IL23R was rs1004819 (OR=1.4, p=0.0049), and in ERAP1 was rs30187 (OR=1.26, p=0.035). The population attributable risk fractions in the Portuguese population for these SNPs are 11% and 9.7% respectively. No association was seen with any SNP in LN-PEP, which flanks ERAP1 and was associated with AS in the British population. No association was seen with clinical manifestations of AS.

CONCLUSION

These results show that IL23R and ERAP1 genes are also associated with susceptibility to AS in the Portuguese population, and that they contribute a significant proportion of the population risk for this disease.