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Background Spondyloarthritis is associated with impaired physical function, health-related quality of life (HRQL), and work productivity. Adalimumab (ADA) is associated with improved clinical outcomes in patients with peripheral spondyloarthritis (pSpA). Objectives To evaluate the effect of ADA treatment on physical function, HRQL and work productivity in patients with pSpA. Methods ABILITY-2 is an ongoing multicenter, double-blind, randomized Phase III clinical trial of patients who fulfilled the Assessment of SpondyloArthritis international Society criteria for pSpA, did not have a diagnosis of psoriasis, psoriatic arthritis, or ankylosing spondylitis, and were biologic-naive. During the 12-week double-blind phase, patients were randomized 1:1 to receive ADA 40 mg every other week or placebo (PBO). Physical function was assessed using the disability index of the Health Assessment Questionnaire for SpA (HAQ-S), HRQL was assessed using the Short Form 36 Health Survey (SF-36) Physical Component Summary (PCS), and work productivity was assessed using the Work Productivity and Activity Impairment (WPAI) questionnaire. Changes in HAQ-S, SF-36 PCS, and work productivity at Week 12 were assessed using ANCOVA with adjustment for baseline scores. Changes in HAQ-S at Weeks 2, 4, 8, and 12 were further assessed using a linear mixed model with factors for treatment, week, and an interaction between treatment and week. Results A total of 165 patients were enrolled (84 received ADA, 81 received PBO). The mean age was 40 years, 45% were men, and the duration of SpA symptoms averaged approximately 7 years. Mean baseline HAQ-S scores indicated moderate impairment. For both groups, mean baseline SF-36 PCS scores were lower than the general US population average of 49.1 (34.5 for ADA, 34.6 for PBO). Baseline WPAI scores indicated substantial work impairment in terms of absenteeism (13.5% average reduction for ADA, 11.2% for PBO) and activity impairment (55.8% average reduction for ADA, 54.6% for PBO). There was marginally better improvement in HAQ-S for the ADA group compared with PBO at Week 12 (-0.3 vs. -0.2, P=.051). Accounting for additional data and an interaction effect between treatment and study week in a mixed linear model, the ADA group showed improvement in mean HAQ-S scores that increased over time and that was significantly larger than PBO at Week 12 (-0.3 vs. -0.2, P=.047). ADA was also associated with significantly greater improvements in SF-36 PCS score (6.7 vs. 2.4, P Conclusions In this first pivotal trial of ADA in patients with pSpA, patients had substantial impairment of physical function, HRQL and work productivity at baseline. After 12 weeks of therapy, the ADA group had significantly larger improvements in physical function, HRQL, and work productivity compared to the PBO group. Acknowledgements The authors would like to thank Eric Bertelsen and Cathryn M. Carter of Arbor Communications who provided medical writing and editing services in the development of this abstract. The financial support for these services was provided by AbbVie. Disclosure of Interest P. Mease Grant/research support from: AbbVie. Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, Consultant for: AbbVie. Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, Speakers bureau: AbbVie. Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, S. Rao Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., K. Betts Employee of: Analysis Group, under contract with AbbVie, M. Lu Employee of: Analysis Group, under contract with AbbVie, L. Fan Employee of: Analysis Group, under contract with AbbVie, A. Pangan Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., D. van der Heijde Grant/research support from: AbbVie, Amgen, AstraZeneca, BMS, Centocor, Chugai, Daiichi, Eli Lilly, GSK, Janssen Biologics, Merck, Novartis, Novo-Nordisk, Otsuka, Pfizer, Roche, Sanofi-Aventis, Schering-Plough, UCB, Vertex, Consultant for: AbbVie, Amgen, AstraZeneca, BMS, Centocor, Chugai, Daiichi, Eli Lilly, GSK, Janssen Biologics, Merck, Novartis, Novo-Nordisk, Otsuka, Pfizer, Roche, Sanofi-Aventis, Schering-Plough, UCB, Vertex, Employee of: Director of Imaging Rheumatology bv, M. Cifaldi Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract.

Background Evidence synthesis is becoming a standard approach for establishing the comparative effectiveness of rheumatoid arthritis (RA) treatments in health technology assessments. Numerous indirect and mixed treatment comparisons (MTCs) of biologic therapies for RA have been published. These have used varying methodological approaches to study selection as well as model specification. 1,2 Objectives To explore the impact of study heterogeneity on MTC estimates via the performance of a sensitivity analysis of the results of an investigation of anti–tumor necrosis factor agents (anti-TNFs) for treating RA in methotrexate (MTX) nonresponders. 3 Methods The authors’ published WinBugs code was modified to allow for additional analyses of the relative risk (RR) of ACR20 and ACR50 response as well as mean percent change in Health Assessment Questionnaire Disability Index (HAQ-DI) score. Analyses were performed in the original data set and in alternate data sets that excluded Asian studies, an outlying study based on observed HAQ-DI scores, or treatment arms using unlicensed doses. In each data set, models were fit using the authors’ specifications with or without adjustment for year of study publication, early escape in case of treatment nonresponse, or MTX dose. Summary statistics were generated for posterior parameter estimates, including medians, means, and 95% credible intervals (CrIs). History plots were examined to assess estimator convergence. Results In our base case analyses, we were able to replicate the authors’ point estimates. The authors had reported 80% CrIs for their point estimates. The estimation of conventional 95% CrIs reduced the frequency with which anti-TNFs were deemed to differ significantly from one another. The exclusion of studies had a limited effect on RR estimates for ACR response. However, in analyses of the percent change in HAQ-DI score, excluding unlicensed doses and the outlier study impacted estimates for etanercept relative to placebo and other anti-TNFs. The convergence criteria for models that included a covariate were generally unsatisfactory. However, the magnitude of parameter estimates varied with covariate adjustment, which suggested that the base case results could have been biased due to confounding. Conclusions Our results indicate that MTC estimates can be sensitive to study selection. We were unable to estimate reliably the effects of some key study differences due to collinearity between these features and the treatments investigated. The inability to control for potential sources of heterogeneity reflects inherent limitations in the evidence base and suggests that a cautious interpretation of the authors’ base case results is warranted. While including a broad body of evidence may be desirable for informed decision making, the resulting heterogeneity may reduce the validity of conclusions. Investigating and attempting to control for such heterogeneity is a necessary step for producing evidence syntheses that are both useful and reliable. References Nixon RM, et al. Stat Med. 2007;26:1237–54. Bergman GJD, et al. Semin Arthritis Rheum. 2010;39:425–41. Schmitz S, et al. Ann Rheum Dis. 2012;71:225–30. Disclosure of Interest A. Benedict Employee of: United BioSource, under contract with Abbott, D. Vanness Employee of: United BioSource, under contract with Abbott, J. Shaw Shareholder of: Abbott, Employee of: Abbott, M. Cifaldi Shareholder of: Abbott, Employee of: Abbott

Background The ASsessment in Ankylosing Spondylitis (ASAS) international Society working group has proposed and validated new classification criteria for patients with axial SpA. 1 Currently, there are no epidemiology data specific to axial SpA following the ASAS criteria. To our knowledge, this is the first study to estimate the prevalence of axial SpA using ASAS criteria. Objectives To estimate the prevalence of axial SpA in a representative sample of rheumatology practices and apply it to US census data. Methods 101 US rheumatology practices were selected in a stratified random fashion to assure geographic representativeness. Screening forms were used to identify at-risk patients aged 18 to 44 years with chronic low back pain, and medical records were randomly selected from this pool for review against ASAS axial SpA criteria. Overall prevalence was estimated by calculating the ratio of Axial SpA patients who met ASAS criteria and applying this ratio to the total number of at-risk patients treated at participating sites. Following post-stratification weighting to reflect geographic distribution, the average proportion of patients with axial SpA treated at selected sites was multiplied by the total number of US rheumatology practices to obtain an estimate of total at-risk patients treated by rheumatologists. Finally, US census data 2 were used to obtain a national prevalence estimate. Results In a sample of 816 randomly selected records of at-risk patients, 553 (68%) were men, and 263 (32%) were women. 514 patients (63%) met ASAS criteria for prevalent axial SpA. Of these 389 (76%) were men, and 125 (24%) were women. By applying the prevalence estimates to the pool of 1,217,097 at-risk Americans, we estimated that 766,771 at-risk patients treated by rheumatologists would meet ASAS criteria for axial SpA. This estimate corresponds to a national prevalence of 0.70% or 701 per 100,000 individuals. Rheumatologists diagnosed axial SpA in 491 (60%) patients in the at-risk pool, regardless of whether or not they reported using ASAS criteria. The prevalence of axial SpA diagnosed by rheumatologists’ assessment was 0.66%. Finally, the prevalence estimate of non-radiographic axial SpA based on ASAS criteria was 0.35%. Conclusions This is the first systematic epidemiology study of axial SpA. The prevalence estimates according to ASAS criteria are 0.70% for axial SpA and 0.35% for non-radiographic axial SpA, with a proportionally higher prevalence in men than women. Overall, diagnosis of axial SpA in US rheumatology practices appears to be consistent with ASAS classification criteria. References Rudwaleit M, et al. Ann Rheum Dis. 2009;68:770–83. http://www.census.gov/population/www/projections/projectionsagesex.html. Disclosure of Interest S. Rao Shareholder of: Abbott, Employee of: Abbott, A. Shillington Employee of: EPI-Q, under contract with Abbott, V. Strand Consultant for: Abbott, M. McGuire Employee of: EPI-Q, under contract with Abbott, M. Cifaldi Shareholder of: Abbott, Employee of: Abbott

Background Within 2 to 3 years of disease, approximately 20 to 30% of patients with early rheumatoid arthritis (RA) become permanently work disabled (Allaire, 2008). Disability-associated ‘work instability’ defined as the mismatch between their functional capabilities and job demands, is a risk factor for loss of employment. The RA-WIS was developed to assess the level of risk for work disability in RA patients; however there is limited information on its responsiveness and minimal important difference (MID). Objectives The objective of this study was to evaluate the responsiveness and MID of the RA-WIS in patients with early RA. Methods A secondary analysis was conducted using data from PROWD study, a 56-week, randomized, and controlled trial of patients with early RA (Bejarano, 2008). Clinical measures included American College of Rheumatology (ACR) response and Disease Activity Score-28 (DAS28), and patient-reported outcomes included the RA-WIS and Health Assessment Questionnaire Disability Index (HAQ-DI), which were collected at Baseline and at Weeks 12, 16, 24 and 56. Responsiveness of the RA-WIS was evaluated at Weeks 24 and 56 based on DAS28 ( 3.2) and ACR response criteria ( Results A total of 148 patients were included in the analysis sample, and was 56% female, with a mean age of 46.8 years. Patients experienced RA symptoms for a mean 8.7 months with mean DAS scores of 5.9 and mean HAQ-DI scores of 1.3. Mean Baseline to Week 24 RA-WIS Total change scores were significantly different among ACR responder groups ( P ≤0.0001) and between DAS28 remission status groups ( P Conclusions These findings provide evidence on the responsiveness of the RA-WIS for evaluating work disability in RA patients. The MID for the RA-WIS is estimated at 5 to 7 points. Disclosure of Interest D. Revicki Consultant for: AbbVie, M. Cifaldi Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., S. Safikhani Consultant for: AbbVie, N. Chen Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., A. Ganguli Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract.

Background Clinical evidence points to an increased risk of renal comorbidity in ankylosing spondylitis (AS) compared to the general population. However, there are no population-based estimates available in the literature. An increased risk of renal comorbidity would have substantial implications for the monitoring and treatment of AS because the mainstay of pharmacological treatment is the use of non-steroidal anti-inflammatory agents (NSAIDs). Objectives To estimate the prevalence and age- and sex-standardized increased risk of renal comorbidity, including acute and chronic kidney disease, and amyloidosis in a population-based cohort of persons diagnosed with AS in Quebec between 1996 and 2006, compared to the general population. Methods A retrospective cohort study was conducted using the administrative physician-billing database of the Regie de l’Assurance Maladie du Quebec. The cohort included individuals with at least one International Classification of Diseases, 9th Revision (ICD-9) billing code for AS between 1996 and 2006. A comparison cohort was generated using a 1% random sample of individuals without AS. Renal complications were identified by ICD-9 codes for amyloidosis, hypertensive chronic renal disease, acute and chronic renal disease. Age- and sex-stratified prevalence, and standardized prevalence ratios with 95% confidence intervals (CI), of renal complications in AS compared with the general population were calculated. Sensitivity analysis was conducted using two ICD-9 codes for AS. Results There were 8,616 individuals identified with AS; 56% were male and the median age at diagnosis was 42 years. Overall, renal complications were diagnosed among 3.4% and 2.1% of males and females with AS, compared to 2.0% and 1.6% of males and females in the general population cohort, respectively. Prevalence of renal complications increased with age in both the AS and general population cohort. Age- and sex-stratified prevalence ratios, comparing the risk of renal complications among those with AS to the general population, demonstrated a significantly excess risk of renal complications that was highest among younger individuals with AS. Overall, individuals with AS were at a significantly increased risk of renal complications compared to members of the general population (irrespective of a coding for hypertension), with a standardized prevalence ratio of 1.7 (1.5-2.0). Standardized prevalence ratios were 6.0 (2.0-18.0) for amyloidosis; 1.7 (1.4-2.0) for chronic kidney disease; 3.2 (0.8 – 12.4) for hypertensive kidney disease, and 1.9 (1.5 – 2.3) for acute kidney disease. The excess risk was highest among younger individuals with AS, and results were similar when two ICD codes were used to identify AS. Conclusions This population-based analysis shows that individuals with AS are at increased risk of many types of renal complications, with the excess risk being greatest among younger individuals. These data highlight the importance of careful monitoring for renal complications among those with AS, particularly during long-term continuous use of NSAIDs. Disclosure of Interest None Declared

Background Axial spondyloarthritis (axSpA) is a new classification that includes ankylosing spondylitis (AS) and nonradiographic axSpA (nr-axSpA). Little is known about the severity and progressive nature of nr-axSpA relative to AS. An analysis of the German Spondyloarthritis Inception Cohort (GESPIC) indicated that clinical manifestations and disease activity measures are highly comparable between nr-axSpA and early AS. 1 We analyzed data from Phase III clinical trials of adalimumab in patients with AS and nr-axSpA compared to the results from the GESPIC study. Objectives To compare the burden of disease experienced by patients with nr-axSpA to that of AS patients with similar disease duration and AS patients with differing disease duration. Methods Baseline data from the ATLAS (N=315) and ABILITY-1 (N=185) trials were used. These were both Phase III trials to evaluate the safety and efficacy of adalimumab in the treatment of moderate to severe AS and nr-axSpA, respectively. Three cohorts were established: those with nr-axSpA ≤5 years’ duration, established AS ≤5 years’ duration, and AS >5 years’ duration. Clinical impairment, pain, and physical function were measured using the Bath AS Disease Activity Index (BASDAI), total back pain (TBP) VAS, Patient’s Global Assessment (PGA), and Bath AS Functional Index (BASFI) scales. Spinal mobility was assessed with the Bath AS Metrology Index (BASMI). Statistical methods included the Student t -test comparing the 2 groups with baseline scores. P -values Results AS patients with longer disease duration were older and had significantly less mobility than those with a shorter disease duration (BASMI 4.3 vs. 3.3, P P Conclusions AS and nr-axSpA patients experienced a similar burden of disease with a relatively high degree of clinical and functional impairment. Impairment of spinal mobility, as measured by BASMI, appears to be progressive, with less involvement in nr-axSpA, more involvement in AS, and a clear increase over time. Therefore, BASMI potentially could be an indicator of progression in nr-axSpA. References Rudwaleit M. Arthritis Rheum. 2009;60:717–27. Disclosure of Interest J. Sieper Grant/Research support from: Abbott, Consultant for: Abbott, Speakers Bureau: Abbott, S. Rao Shareholder of: Abbott, Employee of: Abbott, N. Chen Shareholder of: Abbott, Employee of: Abbott, M. Cifaldi Shareholder of: Abbott, Employee of: Abbott

Background Axial spondyloarthritis (axSpA) is a new umbrella term including patients with ankylosing spondylitis (AS), as well as those with non-radiographic axSpA (nr-axSpA). The new classification provides accepted evidence-based criteria to diagnose these patients. However, in practice, patients may be diagnosed using an earlier disease concept—undifferentiated SpA (uSpA)—for which an ICD-9 code exists. While clinical studies have found that a proportion of nr-axSpA patients experience radiographic progression (ie, to AS), little is known about progression to AS in a real-world setting. Objectives Explore the rate at which patients diagnosed with uSpA were subsequently diagnosed with AS using a large claims database. Methods Patients were selected from a de-identified US private insurer claims database (2000–2010). Potential nr-axSpA patients were defined as patients with ≥1 diagnosis for uSpA (ICD-9: 720.9) and a history of back disorders (724.0-724.9) prior to uSpA diagnosis. The date of first uSpA diagnosis was used as the study index date. Patients were required to have ≥6 months of continuous enrollment in a health plan prior to index (baseline period); be ≥18 years old on index; have no diagnoses for rheumatoid arthritis (714.0) or any type of SpA (AS: 720.0; Psoriatic Arthritis: 696.0; Reactive Arthritis: 099.3, 711.1; Inflammatory Bowel Disease: 713.1) on or before index; and have no diagnoses for any type of SpA other than AS post-index. Patients were followed until the earliest of: (a) diagnosis of AS (progression); (b) end of continuous eligibility; or (c) end of data availability. Baseline characteristics were measured separately for patients who were subsequently diagnosed with AS, and compared with those with no diagnosed progression. Results 6045 patients met the sample selection criteria. Median (IQR) available follow up was 14.2 (5.8-29) months. Two years post index, 8.9% of patients were diagnosed with AS, increasing to 13.7% by the 7 year mark. 5590 patients had no subsequent AS diagnosis. These patients averaged 47.6 years of age, and 61.4% were female. In comparison, patients progressing to AS were younger (43.8 years, P P =.002). AS progressors also had higher baseline rates of uveitis (8.4% vs. 1.5%, P P P Conclusions In a database study of real-world diagnostic patterns, approximately 14% of patients diagnosed with uSpA and with a history of back disorders progressed to AS over a 7 year period. Patients progressing to AS were younger and more likely to have a history of uveitis. To the extent that the combination of these ICD-9 codes serves as a proxy for nr-axSpA, the observed progression rates are on the lower end of previously reported findings in clinical studies. Disclosure of Interest A. Boonen: None Declared, N. Kirson Consultant for: Under contract with Abbott, Employee of: Analysis Group, S. Rao Shareholder of: Abbott, Employee of: Abbott, H. Birnbaum Consultant for: Under contract with Abbott, Employee of: Analysis Group, E. Swallow Consultant for: Under contract with Abbott, Employee of: Analysis Group, Y. Yushkina Consultant for: Under contract with Abbott, Employee of: Analysis Group, J. Jarvis Consultant for: Under contract with Abbott, Employee of: Analysis Group, P. Mease Consultant for: Abbott, M. Cifaldi Shareholder of: Abbott, Employee of: Abbott

Background Increasing attention has been focused on patient-reported outcomes (PROs) and work productivity as important outcomes in RA. In the Optimal Protocol for Treatment Initiation with Methotrexate (MTX) and Adalimumab (ADA) (OPTIMA) trial, results at 26 weeks (wks) showed a significant advantage of treatment with ADA vs. placebo (PBO) for achieving improved PROs. Objectives To evaluate the impact of ADA discontinuation on PROs and work productivity, and variation in these outcomes with maintenance of low disease activity (LDA), in early RA patients who achieved LDA following 26 wks of ADA+MTX therapy. Methods Patients were randomized to ADA+MTX (N=515) or PBO+MTX (N=517) for 26 wks. Those who achieved stable LDA (DAS28CRP Results Of 466 patients who completed 26 wks of ADA+MTX treatment, 207 (44.4%) achieved LDA at wks 22 and 26. Of these, 102 (49.3%) were assigned to discontinue ADA treatment (Arm 1), whilst 105 (50.7%) were assigned to continue treatment (Arm 2). There were no significant PRO differences between Arms 1 and 2 at the time of re-randomization. Compared with Arm 1, Arm 2 patients exhibited a lower mean WIS score (P=.004) and lower mean HAQ Disability Index (HAQ-DI) score (P=.012) at wk 52 as well as a lower mean WPAI Activity Impairment (WPAI-AI) score (P=.049) and superior level of PASS response (P=.045) at wk 66. PRO differences at wk 78 (end of study) were statistically insignificant. More patients in Arm 2 maintained LDA (91%) than did patients in Arm 1 (81%). In the combined group consisting of Arms 1 and 2, patients with sustained LDA between wks 26 and 78 maintained or improved work productivity and PROs, whilst those who did not sustain LDA worsened with respect to these outcomes (Table). Conclusions Patients with sustained LDA maintain or improve upon work productivity and PRO gains, whilst those with increased disease activity deteriorate over time. Continued ADA+MTX treatment yields some benefits with respect to work productivity and PROs for patients who achieve LDA following 26 wks of ADA+MTX treatment. Disclosure of Interest A. Kavanaugh Grant/Research support from: Abbott, Consultant for: Abbott, P. Emery Consultant for: Abbott, R. van Vollenhoven Grant/Research support from: Abbott, Consultant for: Abbott, M. Cifaldi Shareholder of: Abbott, Employee of: Abbott, J. Shaw Shareholder of: Abbott, Employee of: Abbott, N. Chen Shareholder of: Abbott, Employee of: Abbott, J. Smolen Grant/Research support from: Abbott, Consultant for: Abbott

Background The ASsessment in Ankylosing Spondylitis (ASAS) international Society working group has proposed and validated new classification criteria specific for axial SpA. 1 Objectives We applied these criteria to clinical data from a sample of German rheumatology practices to estimate the overall prevalence of nonradiographic axial SpA (nr-axSpA) and ankylosing spondylitis (AS) in Germany. Methods Patients experiencing chronic low back pain (at risk cohort) with age of onset between 18–44 years were identified among the patients in 41 German rheumatology practices. The at risk cohort was an estimate provided by the rheumatologists. Medical records were randomly selected from this at-risk cohort for review against ASAS axial SpA criteria. The proportion of patients meeting the ASAS criteria or using the diagnostic algorithm 2 was compared to an estimate of the total number of at risk patients treated at participating sites and was extrapolated to 1550 German rheumatology practices. Assuming 41 rheumatologists selected in this study are representative of the universe of rheumatologists in Germany, the prevalence estimate was calculated by dividing the estimate of patients with axial SpA by the total population aged ≥18 years. 3 Results In a sample of 206 randomly selected records of at-risk patients, rheumatologists diagnosed 179 (87%) patients with axial SpA of which 45.3% were considered to have nr-axSpA and 54.7% were considered to have AS. The diagnostic algorithm identified between 84–98 (40.7–47.5%) patients with nr-axSpA, based on the upper/lower range of probabilities and 53 (26%) patients with AS. The ASAS criteria was assessed against a population of 138 patients with radiographic imaging results (X-ray and MRI), 114 patients met the criteria for axial SpA of whom 61 (42.3%) had nr-axSpA and 53 (57.7%) patients with AS. By applying each of these ratios to the total pool of 209,250 at-risk patients, 174,375 patients were projected to meet ASAS criteria. This projection corresponds to a national prevalence estimate of 0.25% (ASAS; 95% CI: 0.23–0.27%). Similarly, our prevalence numbers of nr-axSpA estimated 0.13% (ASAS; 95% CI: 0.11–0.16%) and 0.12–0.14% (diagnostic algorithm; 95% CI: 0.10-0.14–0.12-0.16), showing a degree of overlap between the 2 methods in identifying nr-axSpA. The prevalence estimates for AS are 0.12% (95% CI: 0.09–0.15%). The ratio of axial SpA diagnosed by rheumatologists corresponds to a prevalence of 0.26% (95% CI: 0.25–0.28%). Conclusions This is the first retrospective epidemiology study of Axial SpA among rheumatologists in Germany. The prevalence of axial SpA based on the ASAS classification criteria was estimated to be approximately 0.25%, including 0.13% for nr-axSpA and 0.12% for AS. Sampling bias present from rheumatologist recruitment methodology and the projection of data to registered rheumatologists may have an indeterminate affect on the external validity of the results. Additionally, this study is only based on the patient population seen by rheumatologists and does not take into account patients that could be treated by orthopedics. References Rudwaleit M, et al. Ann Rheum Dis. 2009;68:770–83. Rudwaleit M, et al. Ann Rheum Dis. 2004;63:535–43. Statistisches Bundesamt, Wiesbaden 2009. Acknowledgements The authors would like to thank Eric Bertelsen and Cathryn M. Carter of Arbor Communications who provided medical writing and editing services in the development of this abstract. The financial support for these services was provided by AbbVie. Disclosure of Interest S. Rao Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., M. Cifaldi Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., A. Joshi Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., A. Shillington Employee of: EPI-Q, under contract w/AbbVie, M. McGuire Employee of: Medical Data Analytics, under contract w/AbbVie, B. Wittig Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., M. Rudwaleit Speakers bureau: AbbVie, BMS, MSD, Pfizer, Roche, UCB

Background The definition of axial spondyloarthritis is evolving with a new ASAS classification. Maintenance of physical function and patient mobility are primary goals in the treatment of ankylosing spondylitis (AS) and nonradiographic axial SpA (nr-axSpA). Bath AS Functional Index (BASFI) and Bath AS Mobility Index (BASMI) were developed to measure physical function and mobility in AS patients. HAQ-S is a measure of physical function for Spondyloarthropathies. Predictors for these outcomes may be different for nr-axSpA. Objectives To identify physical function and mobility predictors in nr-axSpA and AS patients. Methods Baseline data from ABILITY-1 (N=185) and ATLAS (N=315) clinical trials were analyzed. Separate stepwise regression analyses were conducted for AS and nr-axSpA groups. For physical function, the dependent variables were BASFI for (AS) and HAQ-S for (nr-axSpA). Model selection included age, sex, disease duration, Bath AS Disease Activity Index (BASDAI), CRP level, SF-36 Mental Component Summary (MCS), nocturnal pain, total back pain, Patient’s Global Assessment (PGA), Physician’s Global Assessment (PhGA), and BASMI. For mobility the dependent variable was BASMI for both diseases. Model selection included the same variables plus other measures of physical function; BASFI, SF-36 Physical Component Summary (PCS), and SF-36 Physical Function (PF). Results Physical Function: Based on the stepwise regression, disease activity, age and mobility were predictors in both AS and nr-axSpA. For nr-axSpA, these were the only predictors for physical function. For AS patients, PGA of disease activity explained most of the variance in the model. CRP levels were also significant predictors of physical function in AS (Table 1). Mobility: Based on the stepwise regression, age and physical function were predictors of mobility in AS (BASFI) and nr-axSpA patients (HAQ-S) (Table 2). For AS patients, disease activity, PhGA of disease activity, and disease duration were also predictors of BASMI. Conclusions In AS and nr-axSpA, age, disease severity, and mobility predict physical functioning at baseline, while physical function and age are consistent predictors for mobility. Both emphasize the importance of early treatment. Self-assessment of disease activity is a key predictor of physical function in AS, suggesting that these patients judge disease activity based on ability to function. For mobility, physician’s assessment of disease activity is a key predictor. Disclosure of Interest J. Sieper Grant/Research support from: Abbott, Consultant for: Abbott, Speakers Bureau: Abbott, S. Rao Shareholder of: Abbott, Employee of: Abbott, N. Chen Shareholder of: Abbott, Employee of: Abbott, M. Cifaldi Shareholder of: Abbott, Employee of: Abbott