D. van der Heijde

OP0262 A Physically Demanding Job May Amplify the Effect of Disease Activity on the Development of Syndesmophytes in Patients with As

Background We have shown that disease activity in AS leads to radiographic progression, which is accelerated in males, in those with a short disease duration, and also in smokers [1]. A plausible biological explanation for the last relationship, however, is lacking. We hypothesize that smoking is associated with occupations that require physically demanding activities, as these were associated with more radiographic damage [2], and that smoking is a confounder of this relationship. Alternatively, smoking can be associated with a lower socio-economic status, which in turn could be associated with radiographic progression. Objectives To investigate whether and how occupational physical activities and socio-economic status influence the longitudinal relationship between disease activity and radiographic damage. Methods Patients from OASIS were followed-up for 12 years, with biannual assessments. Two readers independently scored the x-rays according to the mSASSS. Disease activity was assessed by the ASDAS-CRP. The relationship between ASDAS and radiographic progression was investigated using GEE, with a focus on subgroups, according to occupational physical activities (“white vs blue collar” jobs, i.e. manual vs “intellectual” labor), education, baseline gross monthly personal income, and baseline gross monthly family income (Table). Smoking was investigated as a covariate. Results A total of 154 patients were included (77% males, mean (SD) age 41 (12) years, mean symptom duration 18 (11) years, 81% HLA-B27+). There was a (non-statistically significant) difference in the proportion of smokers per type of occupation (51% blue collar vs 34% white collar, p=0.077). The relationship between disease activity and radiographic progression was significantly different dependent on occupational activity (p=0.014) and on personal income (Table). In blue-collar workers, every additional unit of ASDAS resulted in a 2-year 1.19 mSASSS-units increase, compared to 0.20 mSASSS-units in white collar workers (6-fold amplification). Adjustment for smoking only partly diminished this contrast. Table 1. Effects of disease activity (one ASDAS-unit increase) on radiographic progression in subgroups 2-year increase in mSASSS [units, (95% CI)] A[RL1]: Occupation: “Blue collar” (n=65) 1.19 (0.58; 1.79) A: Occupation: “White collar” (n=71) 0.20 (−0.23; 0.64) B: Education: “non-unversity” (n=167) 0.74 (0.41; 1.07) B: Education: “University” (n=14) −0.18 (−1.91, 1.55) C: Personal income: < € 1588 (n=105) 0.93 (0.45, 1.41) C: Personal income: ≥ € 1588 (n=56) 0.14 (−0.21, 0.50) D: Family income: < € 3176 (n=90) 0.49 (0.09, 0.89) D: Family income: ≥ € 3176 (n=21) 0.15 (−0.35, 0.65) Conclusions Physically demanding occupational activities seem to amplify the deleterious effects of disease activity on radiographic damage in AS patients. This effect, which is partly explained by differences in socio-economic status, may be a consequence of forces acting on the spine [3], but may in part also be due to smoking habits. If confirmed, these findings may have implications for our commonly given advice to patients with SpA to strenuously exercise. References Ramiro 2013 ACR. Ward 2008 A&R. Benjamin 2009 ARD. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.2677

FRI0245 How Reliable is the Scoring of Msasss in Clinical Practice in Centers Participating in Desir? Comparison with the Gold Standard Central Reading

Background Spinal X-rays are considered as gold standard for assessing structural damage in the spine in AS, and a scoring system, the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) is the preferred assessment method. In clinical studies and therapeutic trials, the mSASSS scoring process is usually done by ≥1 trained readers. In daily practice, the ability of rheumatologists and radiologists to adequately use the mSASSS without a specific training is unknown. In addition, it is not known what the impact would be in studies when using the score of multiple readers in various centres as in daily practice, instead of using a centralized scoring with a few trained readers Objectives To compare the results of the mSASSS of the local reading of baseline spinal X-rays to the centralized reading as the gold standard Methods Patients aged 18-50 with recent chronic back pain (≥3 months, ≤3 years) from 25 participating centers in France were included in the DESIR (Devenir des Spondylarthropathies Indifferenciées Récentes) -cohort (n=708). All available baseline X-rays of cervical and lumbar spine were scored by the local radiologist/rheumatologist who might have access to clinical data, according to the mSASSS scoring method. In addition, 2 well-calibrated centralized readers independently scored the same X-rays, blinded for any other data. In case the centralized readers disagreed, an experienced radiologist served as adjudicator. Agreement between the 2 centralized readers, and between the local and centralized scores was calculated (Kappa; percentage agreement). To calculate the agreement between readers a cut-off of ≥1 for mSASSS was used. When comparing centralized readers with local readers the mSASSS of the centralized readers was combined Results Patients with complete X- ray data (n=664) were included in these analyses. The large majority of patients had a normal mSASSS both scored by the central and local readers. The agreement between the 2 centralized readers was 89.3% with a kappa of 0.50 (see Table 1). Comparing the local readings with the centralized scores there was an agreement in 72.2% of the cases with a kappa of 0.19. The local readers scored an mSASSS ≥1 in 169 cases, while this was in 119 cases if scored by central readers Table 1 Reader 2 Reader 1 mSASSS ≥1 mSASSS <1 mSASSS ≥1 45 29 mSASSS <1 42 548 Kappa = 0.50/Agreement = 89.3% Centralized score (2/3) Local score mSASSS ≥1 mSASSS <1 mSASSS ≥1 52 117 mSASSS <1 67 427 Kappa = 0.19/Agreement = 72.2% Conclusions The agreement between two trained central readers is better than between central and local readers. Local readers overestimate damage in the spine in comparison to the gold standard of central reading Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.1522

FRI0117 Disease Activity is Associated with Development of Inflammatory Bowel Disease in Ankylosing Spondylitis: 12-Year Results from Oasis

Background Little is known about the characteristics of patients with ankylosing spondylitis (AS) who develop extra-articular manifestations (EAM), such as acute anterior uveitis (AAU), inflammatory bowel disease (IBD), and psoriasis. Objectives To identify characteristics associated with the development of EAMs in a prevalence cohort of patients with AS. Methods 12-Year follow-up data from patients included in the Outcome in AS International Study (OASIS) were used. Additionally, two independent extractors checked medical charts for the presence of AAU, IBD or psoriasis. At baseline, logistic regression was performed to identify demographic, clinical, and radiographic characteristics associated with the presence of any EAM. Cox regression and survival analyses were performed to identify characteristics associated with development of any EAM over time, using both characteristics at baseline and at the time of diagnosis of an EAM. Results 216 patients were included (mean age 43.6 years (SD 12.7), 154 (71%) men, mean symptom duration 20.5 years (SD 11.7), 174 (85%) HLA-B27 positive and mean follow-up 8.3 years (SD 4.3)). At baseline, 59 (27%) patients had any EAM, of which 39 (18%) AAU, 15 (7%) IBD, and 9 (4%) psoriasis. Four patients (2%) had more than one EAM. At baseline, patients with AAU compared with patients without AAU were older (49.1 vs 42.4 years, p<0.01), had a longer symptom duration (25.9 vs 19.3 years, p<0.01), and more radiographic damage (modified Stoke AS Spinal Score 16.9 vs 10.6, p=0.03). Patients with psoriasis compared with patients without psoriasis were older (51.3 vs 43.3 years, p=0.05). There were no differences between patients with and without IBD. During follow-up 27 patients developed a new EAM; 19 AAU, 9 IBD, and 5 psoriasis with incidence rates of 0.9%, 0.4%, and 0.02% per year, respectively. The following characteristics at the time of diagnosis of the EAM were associated with the development of IBD in univariable analysis: ASDAS (Hazard Ratio [HR] 2.81, 95% Confidence Interval [95% CI] 1.43-5.53), BASDAI (HR 1.47 95% CI 1.09-1.98), CRP (HR 1.02, 95% CI 1.00-1.05), BASFI (HR 1.40, 95% CI 1.09-1.80) and BAS-G (HR 1.46, 95% CI 1.10-1.96). Moreover, CRP was weakly associated with the development of AAU (HR 1.02, 95% CI 1.01-1.04). No significant associations with development of psoriasis were found. Conclusions At baseline, a substantial number of patients already had an EAM in this prevalence cohort with relatively long symptom duration. Development of new EAMs was infrequently observed. In particular disease activity, but also physical function and patient global assessment, were associated with development of IBD. CRP was associated with the development of AAU. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.1857

THU0013 Interaction between two common HLA antigens defines a subset of individuals at a very high risk for ankylosing spondylitis

Background Susceptibility to spondyloarthritis (SpA) is largely genetically determined. To understand increasingly complex genetic associations, one can look for interaction between genetic risk factors. Objectives In this study, we investigated interaction between common HLA class I risk antigens in ankylosing spondylitis (AS) the most typical form of SpA. Methods In 155 patients with AS and 5584 controls, common HLA class I antigens were analyzed for association with AS. Biologic interaction was analyzed by investigating whether the effects of the risk factors combined departed from additivity. Results Apart from an association with HLA-B27, we found an association between HLA-B60 and AS (OR 2,0; 95%CI 1.3-2.9; p<0.001). This was confirmed in meta-analysis of published studies (OR 2.3; CI 1.8 – 2.8). While 21.3% of AS patients had both HLA-B27 and HLA-B60, this combination was found in only 0.4% of controls. With HLA-B27-/HLA-B60- AS patients as the reference, the relative risk (RR) for HLA-B27-/HLA-B60+ patients was 2.3 (CI 0.9-5.8). For HLA-B27+/HLA-B60- the RR was 66 (CI 40-111) but increased to 342 (CI 167- 703) in HLA-B27+/HLA-B60+ patients. For the interaction, the relative excess risk (RERI) was 310 (95% CI 130-490), the attributable proportion (AP) was 0.8 (CI 0.7-0.9), and the synergy index (S) 5.7 (CI 3.8 -8.5). The interaction was confirmed in an independent cohort. Conclusions We report a strong interaction between HLA-B60 and HLA-B27 in AS susceptibility. As a result, individuals with the HLA-B27+/HLA-B60+ genotype are at a very high risk of developing AS. Disclosure of Interest None Declared

OP0189 Tumor necrosis factor inhibitor treatment reduces spinal radiographic progression in ankylosing spondylitis by decreasing disease activity: a longitudinal analysis in a large prospective cohort

Background Whether tumor necrosis factor inhibitors (TNFi) have an influence on radiographic progression in ankylosing spondylitis (AS) remains controversial. Objectives To investigate the impact of TNFi use on spinal radiographic progression in AS. Methods Patients fulfilling the modified NY Criteria for AS (as assessed by central reading) in the Swiss Clinical Quality Management Cohort with at least 2 years of clinical and radiographic follow-up were included. Spinal X-rays were taken every 2 years and scored independently by 2 blinded readers according to the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) in chronological time order. Average score of the readers was used. Radiographic progression was defined as an increase by ≥2 mSASSS units over 2 years. The relationship between TNFi use before a 2 year X-ray interval and progression within the interval was investigated using binomial generalized estimating equation models with adjustment for potential confounding and multiple imputation of missing covariate data. Ankylosing Spondylitis Disease Activity Score (ASDAS) was regarded as a potential intermediate variable mediating the effect of TNFi on radiographic progression. It was added to the model as a time-varying variable in a sensitivity analysis. Results A total of 420 patients with AS contributed to data for 597 x-ray intervals in adjusted analyses (1–5 intervals per patient); BL characteristics: male sex 66%, HLA-B27 81%, mean (SD) age 40.4 (10.9) years, disease duration 13.9 (9.8) years, mSASSS 6.4 (12.4), ASDAS 2.8 (1.1)). 39% of the patients were already on TNFi at first X-ray. Mean mSASSS progression in 2 years was 0.9 (2.7) units. The multivariable model (Table) shows that prior use of TNFi reduced the odds of progression in the next 2 year interval by 49% (odds ratio (OR) 0.51, 95% confidence interval (CI) 0.28–0.92, p=0.03). BL mSASSS and male sex also significantly affected progression. Adding ASDAS as a covariate to the model decreased the estimated effect of TNFi on progression: OR 0.65, 95% CI 0.36–1.17, p=0.15. In this model, a decrease in ASDAS by 1 unit would lower the odds for progression by 0.62 (p=0.001).Table 1. Longitudinal multivariable analysis of radiographic progression Variable OR 95% CI P value TNFi use prior to X-ray interval 0.51 0.28–0.92 0.03 NSAID use at start X-ray interval 0.81 0.40–1.63 0.55 mSASSS at start X-ray interval 1.06 1.04–1.07 <0.001 Male gender 3.01 1.56–5.77 0.001 Disease duration 1.01 0.99–1.04 0.38 Current smoking 0.94 0.55–1.61 0.83 HLA-B27 0.99 0.46–2.12 0.98 Nb of exercise sessions per week 0.93 0.80–1.08 0.35 Peripheral arthritis 1.00 0.56–1.79 1.00 Conclusions TNFi seem to reduce radiographic progression in patients with AS and this effect is mediated, at least in part, by a decrease in disease activity. Acknowledgements Supported by the Stiftung für Rheumaforschung and a research grant from the investigator initiated studies program of MSD. Disclosure of Interest C. Molnar: None declared, A. Scherer: None declared, X. Baraliakos: None declared, M. de Hooge: None declared, R. Micheroli: None declared, P. Exer: None declared, R. Kissling: None declared, G. Tamborrini: None declared, L. Wildi: None declared, M. Nissen: None declared, P. Zufferey: None declared, J. Bernhard Consultant for: Merck Sharp & Dohme, Pfizer, Roche, U. Weber Consultant for: Abbvie, R. Landewé: None declared, D. van der Heijde: None declared, A. Ciurea Consultant for: Abbvie, Celgene, Eli Lilly, Janssen-Cilag, Merck Sharp & Dohme, Novartis, Pfizer, UCB

THU0703 Systematic review of rheumatoid arthritis clinical studies: suboptimal statistical analysis of radiological data

Background Radiography is an inexpensive, reliable and reproducible method to detect and quantify progression of damage, an important outcome in rheumatoid arthritis (RA) trials and observational studies. However, the distribution of progression scores is skewed with many low or zero scores. Analysis of such data is challenging, and the choice of analysis technique may influence the result. Current analysis practice is unknown. Objectives We systematically searched the literature to identify current practice for the analysis of radiographic progression in clinical trials and observational studies of RA. Methods PubMed Embase and Cochrane databases were searched (2006–2016) to identify studies that described analysis techniques to compare radiographic progression in at least two groups. Studies in animals, children as well as conference abstracts and studies not written in English were excluded. Titles and abstracts were screened by one researcher (SM); a second investigator (LvT) evaluated the included cases, doubtful cases and a random sample of the excluded cases. Information on study design, sample size, assessment methods and analysis technique was extracted by one researcher (SM), in consultation with 3 others (LvT; MB and JT). Results Of 5980 identified papers, 252 were eligible. 226 of these reports were on a single study while 26 were on multiple studies in one paper. Of the 226 studies, 75 studies used parametric techniques, such as t-tests, ANOVA or linear regression to analyze the data. Of these only 12% took the skewed distribution into account. In 78 studies, the continuous data was categorized into two or more groups and analyzed with binomial or ordinal methods, such a chi-square tests or logistic regression analyses. 4 studies treated the outcome as a “count” outcome variable (2 studies applied a Poisson regression, 1 a negative binomial regression and 1 a zero-inflated binomial regression). 43% compared more than two groups. Median (IQR) sample size was 351 (range 163–608). 30% had one reader, 57% two readers, and 2% more than two; in 10% the number of readers was not recorded. Order of reading was random in 43%, sequential in 31%, and unknown in 26%. Most applied the Sharp van der Heijde scoring method (75%); 9% the Genant modification, and 16% other methods. Conclusions There is large heterogeneity in the analysis strategy of radiographic progression in recent RA clinical trials and observational studies: a large number of studies apply simple, suboptimal or inappropriate methods. In addition, key information (i.e. number of readers and order of readings) is poorly documented. Disclosure of Interest S. Mahmood: None declared, L. van Tuyl: None declared, L. Schoonmade: None declared, R. Landewé Employee of: director of Rheumatology Consultancy BV, D. van der Heijde Employee of: director of Rheumatology Consultancy BV, J. Twisk: None declared, M. Boers: None declared

THU0239 Performance of Disease Activity Measures in Juvenile Spondyloarthritis in A Placebo Controlled Trial with Infliximab

Background Several outcome measures in trials with juvenile-onset spondyloarthritis (Jo-SpA) have been borrowed from trials in juvenile idiopathic arthritis and from adult spondyloarthritis, but a proper psychometric analysis has never been conducted in patients with Jo-SpA. Objectives To assess discriminatory aspects of several disease activity outcome measures and response criteria for Jo-SpA. Methods Data from a previously reported 12-week RCT comparing infliximab (IFX) and placebo (PBO) in patients <18 years with Jo-SpA and onset <16 years of age were analyzed. The primary endpoint of the trial was the number of active joints (both swollen and tender). Several other disease activity measures and response criteria were also tested (Table). Statistics to determine how well disease activity measures could discriminate between IFX and PBO included “standardized mean difference” (SMD) and “Guyatts effect size”. Both statistics are standardized measures to compare change from baseline per group. For categorical response criteria, the chi-square test (χ2) was used. Higher numbers indicate better discriminatory capacity. Results Patients were randomised to IFX (n=12) and PBO (n=14). Of the continuous measures, the ASDAS showed the best and very good discrimination between IFX and PBO (SMD:1.98; Guyatt: 4.28) (Table). The physicians global, CRP, JADAS and JSpADA also discriminated well. The BASDAI (or its separate items), BASFI and spinal mobility measures performed worse. Of the response criteria ASAS40 and ACR Pedi 90 discriminated best between IFX and PBO (Table). ASDAS response criteria and ACR Pedi 30–70 also performed well. Conclusions Of all continuous measures tested in adult axial SpA the ASDAS discriminates best between active treatment and PBO in patients with Jo-SpA. But the child specific JSpADA also performs well. Of all response criteria tested the child-specific ACR Pedi 30 to 90, as well as the adult ASAS40 and ASDAS response criteria work well. One of these measures should be used as primary endpoint in trials with Jo-SpA. Acknowledgement Schering-Plough Mexico funded this trial as an investigator-initiated study Disclosure of Interest None declared

OP0088 Inflammation on MRI of The Spine Is Longitudinally Related To Disease Activity in Smokers but Not in Non-Smokers in Axial Spondyloarthritis: 2-Year Data from The Desir Cohort

Background In axSpA, the effect of disease activity on radiographic progression over time is more pronounced in males and smokers, but the reason for this is unclear. Recently, we have demonstrated a longitudinal relationship between MRI-inflammatory lesions and clinical disease activity measures (DA) in males, but not in females. However, whether or not there is also a disparity in this relationship based on the smoking status is unknown. Objectives To investigate the role of smoking status in the longitudinal relationship between inflammatory lesions on MRI of the spine and DA in patients with axSpA. Methods Two-year follow-up data from 164 patients fulfilling ASAS axSpA criteria in the DESIR cohort with ≥2 MRIs of the spine available during this period were analysed. Interactions were tested between smoking status and DA (ASDAS, BASDAI, patients global disease activity, night pain, CRP and ESR) on the longitudinal relationship with MRI of the spine (Berlin score), analysed with a GEE model of i) absolute and ii) change scores. All models were adjusted for age, symptom duration and HLA-B27. Since there was a significant interaction with gender in previous analyses, analyses were repeated in males and females separately. Results Baseline characteristics of patients included were: 50% males, mean (SD) age: 33 (9) years, 39% smokers, 82% HLA-27+ and symptom duration: 18 (11) months. A significant interaction with smoking status was found for most of the DA, indicating that the relationship between MRI-inflammatory lesions and DA was different in smokers than in non-smokers. In the model of absolute scores (i), MRI-scores were statistically significantly related to most of the DA in smokers, while only CRP was significantly and weakly related in non-smokers (Table 1A). In the model of changes (ii), ASDAS and pain at night remained significantly related to MRI-inflammatory lesions, but no statistically significant relationship between MRI and DA was found in non-smokers (Table 1B). When stratifying for gender, the subgroups were small and the relationships were no longer statistically significant. Smokers Non-smokers Beta 95% CI Beta 95% CI Table 1A ASDAS 0.400 0.009 to 0.792 0.256 −0.069 to 0.581 BASDAI (0–10) −0.002 −0.162 to 0.157 −0.064 −0.131 to 0.002 Night pain (0–10) 0.191 0.050 to 0.332 0.0041 −0.020 to 0.101 Pts gb disease (0–10) 0.089 −0.042 to 0.220 0.003 −0.059 to 0.066 ESR (mm/h) 0.049 −0.005 to 0.103 0.029 −0.027 to 0.085 CRP (mg/L) 0.090 0.029 to 0.151 0.047 0.011 to 0.084 Table 1B ASDAS 0.733 0.137 to 1.137 0.103 −0.109 to 0.315 BASDAI (0–10) 0.214 −0.047 to 0.529 0.018 −0.058 to 0.094 Night pain (0–10) 0.298 0.101 to 0.495 0.042 −0.005 to 0.089 Pts gb disease (0–10) 0.187 −0.030 to 0.403 0.055 −0.002 to 0.111 CRP (mg/L) 0.020 −0.001 to 0.041 −0.003 −0.032 to 0.025 Conclusions In patients with axSpA, there is a longitudinal relationship between MRI inflammatory lesions of the spine and DA in smokers, but not in non-smokers. This disparity may explain the stronger effect of disease activity on radiographic progression observed in smokers. Whether both gender and smoking have an effect on this relationship between MRI and DA remains to be elucidated. Acknowledgement Pfizer Disclosure of Interest None declared

OP0089 Are Individual or Country Level Socio-Economic Determinants Related To Disease Activity and Self-Reported Physical Function in Patients with Spondyloarthritis? Results from Multi-National Cross-Sectional Study Asas-Comospa

Background In RA, previous studies observed inequalities in health across countries as well as across individual level socio-economic factors, and unequal uptake of biologic DMARDs (bDMARDs) played an important role in these inequalities. It is not known whether the same pattern is present for patients with spondyloarthritis (SpA). Objectives To assess: (1) independent associations of individual and country level socio-economic determinants with health outcomes in patients with SpA and (2) if confirmed, whether this relation is mediated by uptake of bDMARDs. Methods Data from the cross-sectional multinational COMOrbidities study in SpA (COMOSPA) were used. Contribution of individual socioeconomic factors (age, gender, education) and country of residence to ASDAS and BASFI was explored in regression models, adjusting for clinical confounders. Next, country of residence was replaced by gross domestic product adjusted for purchasing power parity (GDP PPP) (low, medium, and high, based on tertile distribution). Finally, the role of bDMARDs uptake in the relationship between education or GDP and ASDAS was explored by testing indirect effects. Results In total 3,984 patients with SpA from 22 countries were included: 65% males, mean age 44 (SD14), ASDAS 2.0 (±1.1) and BASFI 3.0 (±2.7). Five to 68% of patients were currently treated with bDMARDs. Females (vs. males) had higher ASDAS (β=0.21 [95%CI 0.13;0.28]) and BASFI (β=0.45 [95%CI 0.31;0.59]). The effect of age was negligible for both outcomes. Low vs high educated individuals had higher ASDAS and BASFI (β=0.29 [0.21;0.36] and β=0.46 [0.24;0.69], respectively) (Table). Independent of the individual confounders, large country differences were observed. Low GDP (vs. high GDP) was associated with higher ASDAS (β=0.27 [0.17;0.36]) and higher BASFI (β=0.20 [0.03;0.38] (Table). Current uptake of bDMARDs did not mediate relationship between education or GDP with ASDAS.Table 1. Association between individual and country level (GDP) factors with ASDAS and BASFI ASDAS-crp (β [95% CI]) BASFI (β [95% CI]) Age, years −0.01 [−0.01; −0.00] 0.02 [0.01; 0.02] Gender (female vs male) 0.21 [0.13; 0.28] 0.45 [0.31; 0.59] Education  Low education vs. University diploma 0.29 [0.21; 0.36] 0.46 [0.24; 0.69]  Secondary education vs. University diploma 0.25 [0.14; 0.37] 0.29 [0.15; 0.43] Rheumatic diseases comorbidity index (RDCI, 0–9) 0.17 [0.14; 0.21] 0.39 [0.32; 0.46] Disease duration, years Not included 0.02 [0.01; 0.03] Body Mass Index (BMI)  Underweight vs normal 0.19 [−0.03; 0.41] −0.13 [−0.53 ; 0.27]  Overweight vs normal 0.08 [ −0.00; 0.16] 0.21 [0.06; 0.36]  Obesity vs normal 0.22 [0.11; 0.32] 0.56 [0.38; 0.75] Presence of axial SpA (yes vs no) 0.18 [0.08; 0.28] 0.58 [0.40; 0.76] GDP  Middle vs High GDP −0.09 [−0.18; 0.01] −0.00 [−0.17; 0.16]  Low vs High GDP 0.27 [0.17; 0.36] 0.20 [0.03; 0.38] Conclusions Health inequalities across individual and country level socio-economic factors exist also among SpA patients. Females, lower educated patients and patients from low income countries had higher disease activity and physical function. Disclosure of Interest None declared

FRI0571 The Association between Comorbidities and Disease Activity, Functional Ability and Quality of Life in Patients with Spondyloarthritis: Results from The Multi-National ASAS-Comospa Study

Background Comorbidities in rheumatoid arthritis are known to add to the burden of disease and its complexity, with implications on disease outcomes and prognosis. In Spondyloarthritis (SpA), the impact of comorbidities on outcomes is less well studied; yet, their prevalence is high. Objectives To investigate the relationship between the comorbidity burden in SpA as measured by the Rheumatic Disease Comorbidity Index (RDCI) and: (1) disease activity; (2) function; (3) quality of life. Methods Analysis was based on data from the ASAS COMOrbidities SPA study, ASAS-COMOSPA, a cross-sectional, multinational study involving 22 countries across four continents. Patients fulfilling the ASAS SPA criteria were included. Comorbidities were computed according to the Rheumatic Diseases Comorbidity Index (RDCI), which includes ischaemic heart disease, stroke, hypertension, lung disease (COPD), malignancy, fractures, depression, diabetes and gastrointestinal disease; range 0–9 (higher score indicating higher comorbidity burden). Univariable, followed by multivariable multilevel mixed-effects linear regression models were used to investigate the relationship between the RDCI and ASDAS(CRP), BASDAI, patient global, BASFI, and EQ5D, adjusting for clinical confounders (table). Patients were nested into their country of origin, which formed the basis of the multilevel analysis. Results A total of 3558 patients were included in the study; 66% males, mean age 43 (SD 14), median disease duration 5 years (IQR 11) and mean RDCI 0.72 (1.08). An increase in RDCI was associated with higher BASFI, BASDAI, ASDAS and patient global score and lower EQ5D (all p<0.001) (see table). For instance a patient with an RDCI score of 2 compared to 0 had on average 0.7 point higher on the BASFI, one point higher on the BASDAI and patient global, 0.24 units higher on the ASDAS and a 0.06 points lower on the EQ-5D.Table 1. Relationship between comorbidities and disease outcomes OUTCOME RDCI (β [95% CI]) BASFI