POS0964 IS LOW VERTEBRAL BONE DENSITY ASSOCIATED WITH SUBSEQUENT BONE FORMATION AT THE SAME VERTEBRA IN AXIAL SPONDYLOARTHRITIS? – A MULTILEVEL ANALYSIS FROM THE SIAS COHORT

Background

In radiographic axial spondyloarthritis (r-axSpA) it has been hypothesized that inflammation-driven bone loss triggers bone repair at anatomically distinct sites of the same vertebra: bone loss occurring in the trabecular bone and ectopic bone formation in the periosteum1.

Objectives

To investigate whether inflammation is associated with lower bone density (surrogate of bone loss) and subsequently, if lower bone density is associated with 2-year bone formation in r-axSpA at the same vertebra.

Methods

Data from the Sensitive Imaging in Ankylosing Spondylitis (SIAS), a multicentre 2-year cohort, was used. Baseline vertebral bone density was assessed by Hounsfield Units (HU) on low dose Computed Tomography (ldCT) by two independent readers (Figure 1). Baseline magnetic resonance imaging (MRI) bone marrow edema (BME) status scores, and 2-year ldCT syndesmophyte formation or growth change scores were assessed by three and two readers respectively. Inter-reader reliability was assessed for each imaging scoring by vertebra. Average of readers´ continuous scores (bone density HU) or readers´ agreement in binary scores (MRI-BME and bone formation) were used at the same vertebra (1-present in ≥1 quadrant/0-absent in all quadrants). The hypothesised associations were tested in multilevel generalised estimating equations models adjusted for confounders, the unit of analysis being the vertebra.

Results

We analysed 1,100 vertebrae in 50 patients with r-axSpA. Intraclass correlation coefficients for HU measurements varied from 0.89 to 0.97, Fleiss Kappa values for MRI-BME were between 0.41-0.78 and Cohen´s kappa for syndesmophyte formation/growth change scores varied from 0.36 to 0.74. Bone density HU decreased from cranial to caudal vertebrae. Baseline MRI-BME was present in 300/985 (30%) and syndesmophytes in 588/910 (65%) vertebrae, both most prevalent at the thoracolumbar region. Syndesmophyte formation or growth was observed in 18% of at-risk vertebrae (124/691). A significant association was found between inflammation (MRI-BME) and lower bone density (regression coefficient=-51; 95% CI:-63;-39) (Table 1A). Bone density was not associated with 2-year syndesmophyte formation or growth (adjOR 1.00; 95% CI:0.99;1.00) (Table 1B).

Table 1.

Relationships between (A) baseline MRI detected spinal inflammation (MRI-BME) and bone density, and (B) baseline bone density and ldCT bone formation after two years, at the same vertebra.

A.Independent variablesBone density (Hounsfield Units)Univariable analysisMultivariable analysisReg coeff. (95% CI)Adj Reg coeff. (95% CI)N = 910 to 985N = 985MRI-BME (presence)-51 (-63 to -39)-51 (-63 to -39)Age (years)-1 (-2 to 1)-1 (-2 to 1)Gender (male)21 (-20 to 63)16 (-24 to 57)TNFi treatment (yes)26 (-7 to 59)27 (-6 to 61)Baseline syndesmophytes (presence)*-42 (-54 to -30)-B.Independent variablesSyndesmophyte formation or growth§Univariable analysisMultivariable analysisOR (95% CI)AdjOR (95% CI)N = 672 to 691N = 672Bone density (HU)1.00 (0.99 to 1.00)1.00 (0.99 to 1.00)Age (years)1.02 (0.99 to 1.06)1.02 (0.98 to 1.05)Gender (male)0.44 (0.13 to 1.52)0.56 (0.15 to 2.06)Smoking (current)0.89 (0.40 to 1.97)1.02 (0.42 to 2.44)Treatment with TNFi (yes)1.34 (0.56 to 3.21)1.30 (0.43 to 3.90)MRI-BME (presence)2.03 (1.23 to 3.71)1.73 (1.06 to 3.34)Baseline syndesmophytes (presence)*2.84 (1.83 to 4.41)-

*Multicollinearity with MRI-BME. § Absolute agreement of readers.

adjOR - adjusted odds ratio; CI-confidence interval; BME - bone marrow edema; HU - Hounsfield units; ldCT - low dose computed tomography; MRI - magnetic resonance imaging; TNFi – Tumour necrosis factor inhibitors. Statistical significance highlighted in bold.

Conclusion

While in r-axSpA vertebral inflammation associates with low vertebral bone density, lower vertebral bone density itself does not increase the risk for ectopic bone formation at the same vertebra.

References

[1]Lories RJ. Best Pract Res Clin Rheumatol. 2018 Jun;32(3):331–41.

Acknowledgements

To the Dutch Rheumatism Association for funding SIAS study.

Disclosure of Interests

Mary Lucy Marques: None declared, Nuno Pereira da Silva: None declared, Désirée van der Heijde Consultant of: AbbVie, Gilead, Glaxo-Smith-Kline, Lilly, Novartis, UCB Pharma, Rosalinde Stal: None declared, Xenofon Baraliakos: None declared, Juergen Braun: None declared, Monique Reijnierse: None declared, Caroline Bastiaenen: None declared, Floris A. van Gaalen: None declared, Sofia Ramiro: None declared

OP0008 DEVELOPMENT AND VALIDATION OF AN ALTERNATIVE ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE WHEN PATIENT GLOBAL ASSESSMENT IS UNAVAILABLE

Background:

Ankylosing Spondylitis Disease Activity Score (ASDAS) is a composite index measuring disease activity in axial spondyloarthritis (axSpA). It includes questions from the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Patient Global Assessment (PGA), and inflammation biomarkers. However, ASDAS calculation is not always possible because PGA is sometimes not collected.

Objectives:

To develop an alternative ASDAS to be used in research settings when PGA is unavailable.

Methods:

Longitudinal data from 4 axSpA cohorts and 2 RCTs were combined. Observations were randomly split in a development (N=1026) and a validation cohort (N=1059). Substitutes of PGA by BASDAI total score, single or combined individual BASDAI questions, and a constant value, were considered. In the development cohort, conversion factors for each substitute were defined by Generalized Estimating Equations. Validation was performed in the validation cohort according to the OMERACT filter, taking into consideration: 1) Truth (agreement with original-ASDAS in the continuous score, by intraclass correlation coefficient -ICC- and in disease activity states, by weighted kappa) 2) Discrimination (standardized mean difference –SMD- of ASDAS scores between high/low disease activity states defined by external anchors e.g Patient Acceptable Symptom State –PASS-; agreement -kappa- in the % of patients reaching ASDAS improvement criteria according to alternative vs. original formulae) 3) Feasibility.

Results:

Taking all psychometric properties into account and comparing the different formulae (Table), alternative-ASDAS using BASDAI total as PGA replacement proved to be: 1) truthful (agreement with original-ASDAS: ICC=0.98, kappa=0.90); 2) discriminative: it could discriminate between high/low disease activity states (e.g. scores between PASS no/yes: SMD=1.37 versus original-ASDAS SMD=1.43) and was sensitive to change (agreement with original-ASDAS in major improvement/clinically important improvement criteria: kappa=0.93/0.88; 3) feasible (BASDAI total often available; conversion coefficient≈1).

Table.

Psychometric properties of alternative ASDAS formulae

Conclusion:

Alternative-ASDAS using BASDAI total score as PGA replacement is the most truthful, discriminative and feasible instrument. This index enables ASDAS calculation in existing cohorts without PGA.

Disclosure of Interests:

Augusta Ortolan: None declared, Sofia Ramiro: None declared, Floris A. van Gaalen: None declared, Tore K. Kvien Grant/research support from: Received grants from Abbvie, Hospira/Pfizer, MSD and Roche (not relevant for this abstract)., Consultant of: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Paid instructor for: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Speakers bureau: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Robert B.M. Landewé Consultant of: AbbVie; AstraZeneca; Bristol-Myers Squibb; Eli Lilly & Co.; Galapagos NV; Novartis; Pfizer; UCB Pharma, Pedro M Machado Consultant of: PMM: Abbvie, Celgene, Janssen, Lilly, MSD, Novartis, Pfizer, Roche and UCB, Speakers bureau: PMM: Abbvie, BMS, Lilly, MSD, Novartis, Pfizer, Roche and UCB, Adeline Ruyssen-Witrand Grant/research support from: Abbvie, Pfizer, Consultant of: Abbvie, BMS, Lilly, Mylan, Novartis, Pfizer, Sandoz, Sanofi-Genzyme, Astrid van Tubergen Consultant of: Novartis, Caroline Bastiaenen: None declared, Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead Sciences, Inc., Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma; Director of Imaging Rheumatology BV

Reproducibility of Task-Oriented Bimanual and Unimanual Strength Measurement in Children with Unilateral Cerebral Palsy

Aim: To examine reproducibility of the arm-hand strength measured while performing the bimanual crate task and the unimanual pitcher task. Methods: 105 children diagnosed with unilateral Cerebral Palsy, aged between 6 and 18 years, participated in this study. The test-retest reliability of the force generated during bimanual crate task and unimanual pitcher task of the Task-oriented Arm-hAnd Capacity instrument was investigated using intraclass correlation two-way random model with absolute agreement. The intraclass correlations were calculated for two age groups (6-12 and 13-18 years old). Results: The results showed good test-retest reliability for the crate and pitcher task with the non-affected hand for both age groups. The results of the pitcher task for the affected hand showed moderate test-retest reliability for both age groups. Conclusion: The Task-oriented Arm-hAnd Capacity instrument has moderate to good test-retest reliability. It is a simple and objective instrument to assess task-oriented strength in children with unilateral cerebral palsy.

Validation of the Orebro musculoskeletal pain screening questionnaire in patients with chronic neck pain

OBJECTIVES

To validate the German version of OMPSQ (OMPSQ-G) for patients with chronic neck pain.

RESULTS

After translating OMPSQ to German, we assessed the discriminant validity between patients and healthy adults. Convergent validity was assessed using Pearson's correlation coefficients between domains of OMPSQ-G and the German version of neck disability index (NDI-G) and visual analogue scale (VAS) of neck pain intensity. Floor and ceiling effects, internal consistency, test-retest and relative reliability were assessed. Fifty patients with chronic neck pain (mean age, 43.6 years; 34 females) and 24 healthy adults (mean age, 50.4 years; 18 females) participated. Mann-Whitney U tests showed significant differences in OMPSQ scores between both groups at the baseline (z = - 4.6; p < 0.001) and second time point (z = - 4.8; p < 0.001). OMPSQ-G scores highly and moderately correlated with NDI-G (ρ = 0.70) and VAS (ρ = 0.41) scores, respectively. There were no floor or ceiling effects. Cronbach's alpha was 0.94. OMPSQ-G showed high reliability (intraclass correlation 2.1: 0.93; standard error of measurement, 6.9; smallest detectable change, 20 points). The Bland-Altman plot indicated no systematic error. OMPSQ-G showed good validity and reliability in patients with neck pain. Trial registration NCT02540343.

Effectiveness of automated locomotor training in patients with acute incomplete spinal cord injury: a randomized controlled multicenter trial

Background

A large proportion of patients with spinal cord injury (SCI) regain ambulatory function. However, during the first 3 months most of the patients are not able to walk unsupported. To enable ambulatory training at such an early stage the body weight is partially relieved and the leg movements are assisted by two therapists. A more recent approach is the application of robotic based assistance which allows for longer training duration. From motor learning science and studies including patients with stroke, it is known that training effects depend on the duration of the training. Longer trainings result in a better walking function. The aim of the present study is to evaluate if prolonged robot assisted walking training leads to a better walking outcome in patients with incomplete SCI and whether such training is feasible or has undesirable effects.

Methods/Design

Patients from multiple sites with a subacute incomplete SCI and who are not able to walk independently will be randomized to either standard training (3-5 sessions per week, session duration maximum 25 minutes) or an intensive training (3-5 sessions per week, session duration minimum 50 minutes). After 8 weeks of training and 4 months later the walking ability, the occurrence of adverse events and the perceived rate of exertion as well as the patients' impression of change will be compared between groups.

Trial registration

This study is registered at clinicaltrials.gov, identifier: NCT01147185.