POS0227 CLUSTER ANALYSIS IDENTIFIES PARTICULAR PAIN PROFILES IN PATIENTS WITH RADIOGRAPHIC AXIAL SPONDYLOARTHRITIS RECEIVING BIOLOGICAL DISEASE-MODIFYING ANTIRHEUMATIC DRUGS
Authors: F. Al Mohamad, V. Rios Rodriguez, H. Haibel, M. Protopopov, J. Rademacher, J. Sieper, M. Torgutalp, H. Käding, F. Proft, D. Poddubnyy
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Despite proper treatment with biologic disease modifying antirheumatic drugs (bDMARDs) patients with axial spondyloarthritis (axSpA) may suffer from residual symptoms. Both nociplastic and neuropathic pain components (NoP and NP) are thought to be contributors to the residual symptoms in axSpA. <h3>Objectives:</h3> To identify specific pain profiles according to common features of NoP and NP in patients with radiographic axSpA (r-axSpA) on stable treatment with bDMARDs. <h3>Methods:</h3> Patients were recruited between 2015 and 2019 in an extension of the German Spondyloarthritis Inception Cohort (GESPIC). The Widespread Pain Index (WPI) was used to quantify NoP. The 19 regions of the WPI were used in a hierarchical cluster analysis with Ward's method. Distances were calculated with the Jaccard method. NP was quantified using the PainDETECT questionnaire (PD). The seven main items of the PD assess the severity of different sensory symptoms that are common in NP. To eradicate interindividual differences, the mean of these items was calculated for every patient and subtracted from each item. The resulting normalized values were used in a hierarchical cluster analysis with Ward's method using Euclidean distances. <h3>Results:</h3> A total of 78 patients with r-axSpA receiving a bDMARD for at least 3 months were included in this analysis. At the time-point of the assessment, the mean duration of bDMARD therapy was 3.52±0.99 years. While 36 (46.2%) patients have a WPI score &gt;2 indicating a probable NoP component only 7 (9%) patients have a PD score &gt; 12 indicating a probable NP component. The cluster analysis of the WPI regions revealed three distinct pain distribution profiles as seen in Figure 1. Patients in cluster 1 show a diffuse distribution of pain over many pain regions especially the torso that indicates activation of the nociplastic pain mechanisms. Whereas in patients in cluster 2 pain is mainly localized in the lower back and neck that might be an indicator of the local pathology, either mechanical or residual inflammatory. Patients in cluster 3 did not indicate any painful regions and can be considered as good treatment responders. Patients in cluster 1 showed the highest values for WPI (4.1±2.1) and PD (7.6±5.4). Figure 2 shows the results of the cluster analysis of the PD items, which revealed 4 clusters with distinct sensory symptom profiles. Patients in cluster 1 mainly experience sudden pain attacks and pressure sensitivity that might be indicative of the presence of radiculopathy. For patients in cluster 2 pressure sensitivity with mild thermal sensitivity is prominent that might indicate nociplastic contribution. Whereas patients in cluster 3 suffer primarily from sudden pain attacks, which might be indicative of the neuropathic pain component. Most patients in cluster 4 did not suffer from any of the examined symptoms indicating good symptom control. The highest PD and WPI values were found in cluster 3 (PD: 8.8±5.6, WPI: 3.5±2.8) with cluster 1 having similarly high PD values (8.6±2.9). <h3>Conclusion:</h3> Patients with r-axSpA can be divided into subgroups with specific pain distribution profiles and sensory symptom profiles that can provide clinically useful information on the leading mechanism of the residual symptoms. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> We would like to express our gratitude to Prof. Martin Rudwaleit for his contributions to the development of the initial cohort. Additionally, we extend our thanks to Dr. Susanne Lüders, Dr. Burkhard Muche, Dr. Laura Spiller, Dr. Uta Syrbe, and Dr. Anne-Katrin Weber for their valuable efforts in patient recruitment and follow-up during the cohort extension. Special appreciation goes to Sabrina Igel, Claudia Lorenz, Bianca Mandt, Caroline Höppner, and Sandra Päßler for the management of the cohort. Lastly, we appreciate the patients for their essential contributions to this research project. <h3>Disclosure of Interests:</h3> Fares Al Mohamad: None declared, Valeria Rios Rodriguez: None declared, Hildrun Haibel AbbVie, Janssen, MSD, Novartis, Pfizer, Roche, UCB and Sobi, BI, Janssen, MSD, Novartis, SOBI and Roche., SOBI, Mikhail Protopopov: None declared, Judith Rademacher: None declared, Joachim Sieper Abbvie, Novartis, Merck, UCB, Murat Torgutalp: None declared, Henriette Käding: None declared, Fabian Proft grants and personal fees from Novartis, Eli Lilly and UCB and personal fees from AbbVie, AMGEN, BMS, Celgene, Galapagos, Hexal, Janssen, Medscape, MSD, Pfizer and Roche., Denis Poddubnyy AbbVie, Canon, DKSH, Eli Lilly, Janssen, MSD, Medscape, Novartis, Peervoice, Pfizer, and UCB., AbbVie, Biocad, Bristol-Myers Squibb, Eli Lilly, Janssen, Moonlake, Novartis, Pfizer, and UCB., AbbVie, Eli Lilly, MSD, Novartis, Pfizer.