OMERACT Community Forum - Recent Posts

Answer to: varying attribution to the disease in the domain definitions

omeractadmin — Thu, 30 Oct 2025 13:53:18 +0000

Thanks for your supportive comments. Re attribution of symptoms, in general, these have been defined as ‘due to CPPD” or ‘affected joint’ in the definitions, and in the case of acute CPP crystal arthritis domains, tenderness and swelling of ‘the index joint’. It can be challenging to differentiate between symptoms due to CPPD and osteoarthritis, and in general, we have tried to make the outcomes specific to CPPD. We agree that this will need to be reviewed in detail as part of the instrument development, and we’ll put this on the agenda for this next step.

varying attribution to the disease in the domain definitions

omeractadmin — Thu, 30 Oct 2025 13:52:50 +0000

First of all, my compliments for a great process so far. Very clear, understandable, and reasonable.

This question pertains to the extent to which the domain is attributed to the disease. In the definitions this attribution is variable. I'm happy with any choice the group makes, but I think it would help the instrument phase if the attribution (or the lack of it) were made more explicit. My hunch is that in CPPD it makes sense to define target joints and do the assessments in those, not in the least because OA is such a concurrent condition.

Pain intensity: 'pain due to CPPD disease' but it doesn't say 'joint' even though that is added in the explanation.

Joint tenderness: ‘the affected joints’ I assume 'by the disease'?

Joint swelling: ‘joints affected by effusion or synovitis’ which suggests assessing all joints

Joint damage: no mention of affected joint, so again assessment of many joints, just a few, or only one?

Answer to: Endorsement of the OMERACT CPPD Core Domain Sets

omeractadmin — Tue, 28 Oct 2025 13:09:27 +0000

Thank you, Professor Caso, for your kind words and thoughtful support of the CPPD Core Domain Sets. We truly appreciate your recognition of the methodological and patient-centered rigour that guided this work.

We’ve added you to the CPPD Working Group mailing list so you’ll receive future updates and invitations to participate in upcoming activities and discussions.

We’re delighted by your interest in contributing to the next stages of this important initiative and look forward to your continued engagement.

Warm regards,
The OMERACT CPPD Working Group

Answer to: 2 different core sets or just one?

omeractadmin — Tue, 28 Oct 2025 13:00:55 +0000

Thanks for this comment. The decision to develop two core sets was made very early in the development process, with a vote to take this approach at a virtual OMERACT SIG in 2020. We used this approach in all the Delphi exercises. This aligns with the approach taken for the OMERACT core domains for gout, another crystal arthritis (gout flare domains and long-term gout domains). For CPPD, the core outcomes for acute CPP crystal arthritis and the core outcomes for chronic and recurrent CPPD disease are not the same, although there are some overlapping domains (for example pain intensity, overall function, and patient global assessment).

2 different core sets or just one?

Maarten Boers — Mon, 27 Oct 2025 12:12:20 +0000

I think you should go ahead with what you have now, we don't want to delay things. But having arrived at this point, I note the core sets show strong overlap, so in a revision you could merge them and make the differences situation-specific.

Endorsement of the OMERACT CPPD Core Domain Sets

Francesco Caso — Sat, 25 Oct 2025 06:45:31 +0000

Endorsement of the OMERACT CPPD Core Domain Sets

I fully support the proposed CPPD Core Domain Sets, an excellent and methodologically robust initiative by the OMERACT CPPD Working Group.
This work provides a rigorous, patient-centered framework that will greatly enhance the consistency, comparability, and clinical relevance of CPPD research.

I would also be pleased to contribute actively to the ongoing activities and future work of the CPPD Working Group, should the opportunity arise.

Congratulations to the Working Group for this outstanding and collaborative achievement.

Francesco Caso, MD, PhD, MSc, Professor of Rheumatology, University of Naples Federico II, Naples, Italy

Answer to: Additional considerations from the CPPD working group Discussed in working group and felt to be a circumstance dependent domain as only relevant in clinical trials evaluating structure modifying treatments. It would not make sense for all ...

omeractadmin — Fri, 17 Oct 2025 19:56:12 +0000

Thanks for your comment. ‘Joint damage on imaging tests’ is a circumstances dependent core domain under the proposed framework. This means that this domain was recognised as very important, but may not be appropriate in all CPPD studies. In particular, in trials in which structure modification is unlikely to occur, this isn’t considered a core domain. Examples of such studies might be a trial of regular paracetamol vs placebo, or a trial of occupational therapy plus patient education vs patient education alone. The core domains listed in the central part of the onion are those that should be measured in every study.

Answer to: Duration of acute CPP crystal arthritis flare :While the domain is defined as “the length of time a person experiences a flare, measured in days,” could the working group clarify how flare resolution is defined?

omeractadmin — Fri, 17 Oct 2025 13:43:29 +0000

Thanks, this domain captures the number of days that the person experiences an acute CPP crystal arthritis flare. As part of the instrument development/validation for this domain, it will be important to identify instruments to measure the state of flare and also define flare resolution. These instruments will be patient-reported, but will need to be validated against other measures (such as rheumatologist assessment and imaging findings).

There are validated definitions for patient-reported flare (Cipolletta Rheumatology (Oxford) 2025, DOI: 10.1093/rheumatology/keae681), and it is likely that these definitions will be used to inform instrument development for this domain in the next phase of the OMERACT process. These definitions take into account patient-reported flare, together with patient-reported joint warmth and joint swelling.

Flare resolution is a very topical issue in the field of crystal arthritis! At this stage, resolution of an acute CPP crystal arthritis flare hasn’t been defined, and this is work that will be required as part of the instrument development/validation for this domain. We anticipate that flare resolution will be a patient-reported outcome, and will be defined by improvement of pain and function to baseline levels, and potentially other measures such as improvement of patient-reported joint warmth, swelling and tenderness to baseline levels.

Additional considerations from the CPPD working group Discussed in working group and felt to be a circumstance dependent domain as only relevant in clinical trials evaluating structure modifying treatments. It would not make sense for all long-term s

Iwona — Fri, 17 Oct 2025 11:16:26 +0000

As a radiologist I am a bit surprised with that final conclusion :"It would not make sense for all long-term studies to measure damage to joints on imaging. " since CPPD disease may lead to serious complications, e.g. joints instability (wrist), protrusio acetabuli, cervical spine subluxation, dens fracture, nerves compression- complications requiring constant survailance, not rarely surgical treatment.

Duration of acute CPP crystal arthritis flare :While the domain is defined as “the length of time a person experiences a flare, measured in days,” could the working group clarify how flare resolution is defined?

victoriachiarvetto — Thu, 16 Oct 2025 20:37:19 +0000

For example, is resolution determined by patient-reported complete relief of pain, or by clinician-assessed absence of tenderness/swelling, or both?
This might affect how the duration domain is measured consistently across studies.