PAIN AND STRUCTURAL OA PHENOTYPES: A POLL OF ATTENDEES AT THE OARSI 2024 IMAGING DISCUSSION GROUP SESSION

Abstract

INTRODUCTION

The OARSI Imaging Discussion Group was established to stimulate discussion of imaging related research and developments at OARSI with an inclusive group including clinicians, radiologists, imaging researchers and representatives from the pharmaceutical industry. The focus of the 2024 Discussion Group was ‘Pain and Structural Phenotypes’.

OBJECTIVE

To gain insights on the relationship between pain and structural damage in OA from attendees at the 2024 OARSI World Congress on Osteoarthritis.

METHODS

After short presentations on OA pain phenotypes, structure phenotypes, and the pain and structure challenge, attendees participated in an online poll. Questions were as follows: 1) Which pain questionnaire best captures structural damage? 2) What changes in imaging features are best associated with changes in pain in the same direction? 3) Does structure/composition explain pain? 4a) Should patients with pain sensitization/neuropathic pain be excluded from trials of DMOAD? 4b) If yes – How should we exclude them? 5) Does the relationship between pain and structure differ between joints? 6) Does the relationship between pain and structure differ according to disease stage? 7) What is the reason why we do not find a satisfactory relationship between structure and pain in clinical trials?

RESULTS

The number of respondents varied between 18 (Q3-6) and 23 (Q2); 45% of respondents stated that WOMAC pain scores best capture structural damage, followed by KOOS (25%), ICOAP (20%) and VAS (10%). 22% Responded that structure explains pain while 50% and 22% stated that it will once we find the right structural measures or pain measures, respectively. Two of three participants indicated that patients with sensitization/neuropathic pain should be excluded from DMOAD trials; most (78%) stated that this should be done with a questionnaire such as PainDETECT, and 17% with quantitative sensatory testing. 50% of respondents indicated that there is variation between pain and structure in weight-bearing versus non-weight-bearing joints or all joints (39%). All but one participant (94%) indicated that the relationship between pain and structure differs according to both clinical and structural disease stage; the remaining respondent answered that it varies according to structural disease stage only. BMLs and synovitis were identified as imaging features best associated with pain changes (Figure 1). The heterogeneity of patient populations (regarding pain and structure) was the most common reason for lack of a relationship between pain and structure in clinical trials.

CONCLUSION

The heterogeneity of pain and structure in OA populations remains a challenge for clinical trials. Considerations should be given to excluding patients with pain due to non-nociceptive pain.