Efficacy assessed in follow-ups of clinical trials: methodological conundrum

Increasingly, we see papers describing the long-term follow-up results of randomised clinical trials. Sometimes, like the article by Rantalaiho and colleagues in the previous issue of Arthritis Research & Therapy, the follow-up extends to more than 10 years. It is not uncommon that authors of such articles describe their results as a comparison of the original treatment groups in the original randomised clinical trial. Methodologically, such a comparison is fallible for several reasons. In this editorial, two important sources of bias that may jeopardise the results of such follow-up studies are discussed: confounding by indication and confounding by trial completion

Goodbye to the term 'ankylosing spondylitis', hello 'axial spondyloarthritis': time to embrace the ASAS-defined nomenclature

Ankylosing spondylitis (AS) is the historic term used for decades for the HLA-B27-associated inflammatory disease affecting mainly the sacroiliac joints (SIJ) and spine. Classification criteria for AS have radiographic sacroiliitis as a dominant characteristic. However, with the availability of MRI of SIJ, it could be demonstrated that the disease starts long before definite SIJ changes become visible on radiographs. The Assessment of SpondyloArthritis international Society, representing a worldwide group of experts reached consensus on changes in the nomenclature pertaining to axial spondyloarthritis (axSpA), such as the terminology of diagnosis and of assessment of disease activity tools. These are important changes in the field, as experts in axSpA are now in agreement that the term axSpA is the overall term for the disease. A further differentiation, of which radiographic versus non-radiographic is only one aspect, may be relevant for research purposes. Another important decision was that the terms AS and radiographic axSpA (r-axSpA) can be used interchangeably, but that the preferred term is r-axSpA. Based on the decision that axSpA is the correct terminology, a proposal was made to officially change the meaning of the ASDAS acronym to 'Axial Spondyloarthritis Disease Activity Score'. In addition, for simplification it was proposed that the term ASDAS (instead of ASDAS-CRP) should be preferred and applied to the ASDAS calculated with C reactive protein (CRP). It is hoped that these changes will be used consequently for education, in textbooks, manuscripts and presentations

Instrument selection for the ASAS core outcome set for axial spondyloarthritis

OBJECTIVES: To define the instruments for the Assessment of SpondyloArthritis international Society-Outcomes Measures in Rheumatology (ASAS-OMERACT) core domain set for axial spondyloarthritis (axSpA). METHODS: An international working group representing key stakeholders selected the core outcome instruments following a predefined process: (1) identifying candidate instruments using a systematic literature review; (2) reducing the list of candidate instruments by the working group, (3) assessing the instruments' psychometric properties following OMERACT filter 2.2, (4) selection of the core instruments by the working group and (5) voting and endorsement by ASAS. RESULTS: The updated core set for axSpA includes seven instruments for the domains that are mandatory for all trials: Ankylosing Spondylitis Disease Activity Score and Numerical Rate Scale (NRS) patient global assessment of disease activity, NRS total back pain, average NRS of duration and severity of morning stiffness, NRS fatigue, Bath Ankylosing Spondylitis Function Index and ASAS Health Index. There are 9 additional instruments considered mandatory for disease-modifying antirheumatic drugs (DMARDs) trials: MRI activity Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joints and SPARCC spine, uveitis, inflammatory bowel disease and psoriasis assessed as recommended by ASAS, 44 swollen joint count, Maastricht Ankylosing Spondylitis Enthesitis Score, dactylitis count and modified Stoke Ankylosing Spondylitis Spinal Score. The imaging outcomes are considered mandatory to be included in at least one trial for a drug tested for properties of DMARD. Furthermore, 11 additional instruments were also endorsed by ASAS, which can be used in axSpA trials on top of the core instruments. CONCLUSIONS: The selection of the instruments for the ASAS-OMERACT core domain set completes the update of the core outcome set for axSpA, which should be used in all trials

Is treat-to-target really working in rheumatoid arthritis? a longitudinal analysis of a cohort of patients treated in daily practice (RA BIODAM).

OBJECTIVES: To investigate whether following a treat-to-target (T2T)-strategy in daily clinical practice leads to more patients with rheumatoid arthritis (RA) meeting the remission target. METHODS: RA patients from 10 countries starting/changing conventional synthetic or biological disease-modifying anti-rheumatic drugs were assessed for disease activity every 3 months for 2 years (RA BIODAM (BIOmarkers of joint DAMage) cohort). Per visit was decided whether a patient was treated according to a T2T-strategy with 44-joint disease activity score (DAS44) remission (DAS44 <1.6) as the target. Sustained T2T was defined as T2T followed in ≥2 consecutive visits. The main outcome was the achievement of DAS44 remission at the subsequent 3-month visit. Other outcomes were remission according to 28-joint disease activity score-erythrocyte sedimentation rate (DAS28-ESR), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI) and American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Boolean definitions. The association between T2T and remission was tested in generalised estimating equations models. RESULTS: In total 4356 visits of 571 patients (mean (SD) age: 56 (13) years, 78% female) were included. Appropriate application of T2T was found in 59% of the visits. T2T (vs no T2T) did not yield a higher likelihood of DAS44 remission 3 months later (OR (95% CI): 1.03 (0.92 to 1.16)), but sustained T2T resulted in an increased likelihood of achieving DAS44 remission (OR: 1.19 (1.03 to 1.39)). Similar results were seen with DAS28-ESR remission. For more stringent definitions (CDAI, SDAI and ACR/EULAR Boolean remission), T2T was consistently positively associated with remission (OR range: 1.16 to 1.29), and sustained T2T had a more pronounced effect on remission (OR range: 1.49 to 1.52). CONCLUSION: In daily clinical practice, the correct application of a T2T-strategy (especially sustained T2T) in patients with RA leads to higher rates of remission

No efficacy of anti-IL-23 therapy for axial spondyloarthritis in randomised controlled trials but in post-hoc analyses of psoriatic arthritis-related 'physician-reported spondylitis'?

The three monoclonal antibodies ustekinumab, guselkumab and risankizumab targeting the p 40 or the 19 subunit of interleukin -23 have now been approved for the indication psoriasis and the former two also for psoriatic arthritis (PsA). Ustekinumab and risankizumab have appeared ineffective in randomised controlled trials with patients with axial spondyloarthritis (axSpA), but post-hoc analyses of PsA trials have now suggested that they may improve back pain symptoms potentially induced by axial inflammation based on PsA. Here we argue that, based on the absence of efficacy in axSpA, this is unlikely and more probably due to generic, non-specific effects, which are not adequately covered by the tools developed for the assessment of inflammation in axSpA