Pos0365 sex differences concerning experienced pain in patients with axial spondyloarthritis

Background Research shows that there are significant sex differences in experienced pain. Contributing factors are neuroanatomical, hormonal, neuroimmunological, psychological, social, cultural, and comorbidities. Women have more and different expression of nociceptors, and a stronger proinflammatory response to tissue damage than men. Women also use different coping styles regarding to pain and tend to engage more in pain catastrophizing. Therefore, women may experiencing more severe pain than men. Also in axial spondyloarthritis (axSpA), higher pain scores are observed in women compared to men with axSpA.[1] Sex differences in experienced pain within axSpA is not well studied. It is unclear if differences are related to the involvement of altered pain processing of the central nervous system (CNS) including central sensitization (CS) and/or psycho-social aspects. Objectives To explore sex differences in pain perception, coping with pain, pain catastrophizing and altered pain processing of the CNS in patients with axSpA. Methods A cross-sectional study of consecutive outpatients from the Groningen Leeuwarden axSpA (GLAS) cohort, fulfilling the ASAS classification criteria. Participants filled out the Central Sensitization Inventory (CSI), Pain Catastrophizing Scale (PCS) Coping with Rheumatic Stressors (CORS), and underwent Quantitative Sensory Testing (QST) according to a standardized protocol, including Pain Threshold Testing (PTT) at 11 sites, Temporal Summation (TS) at 3 sites and Conditioned Pain Modulation (CPM). Widespread low PPTs, high TS (both pain facilitation) and positive CPM (impaired pain inhibition) are indicators of CS. Independent Samples T Test and Mann-Whitney U Test were used for normally- and non-normally distributed data resp.. Bonferroni correction was applied for multiple significance testing and P-value was determined at 0.004. Results 201 patients were included, 128 men and 73 women with no significant differences in the patient characteristics; median age (50.8 vs 51.6 years), median symptom duration (22.0 vs 21.0 years) and median CRP (1.8 vs 2.5). Significant differences between men and women were observed for the classification radiographic axSpA (71.9% vs 50.7%), HLA-B27 status (84.1% vs 67.1%), mean BMI (27.2 ± 4.9 vs 29.0 ± 6.9), mean ASDAS CRP (2.1 ± 0.8 vs 2.5 ± 0.9) and mean BASDAI (3.4 ± 2.1 vs 4.7 ± 2.1). Women scored significantly higher on the CSI and used the coping styles comforting cognitions, decreased activities and diverted attention more often (CORS). Concerning the involvement of altered pain processing of the CNS, women had significantly lower PPTs. TS and CPM were comparable in men and women (Table 1). Conclusion In patients with axSpA, significant sex differences in pain coping styles, CSI score and PPTs were observed. Therefore, sex differences should be taken into account in the management of pain in daily clinical practice and in pain research in these patients. Reference [1]Rusman et al. Rheumatology 2020 Table 1. Characteristics and assessments stratified for sex (n=201) Men (n=128) Women (n=73) CSI-A (0-100) 30.6 ± 13.8 41.5 ± 13.6* PCS (0-52) 11.0 [5.0-20.0] 14.0 [5.0-19.5] CORS pain Comforting cognitions 27.8 ± 4.9 29.9 ± 4.1* Decreasing activities 18.8 ± 4.5 21.0 ± 4.3* Diverting attention 20.1 ± 4.7 22.3 ± 3.9* PPT (N) Thenar, left/right 37.4 ±17.5/40.6 ± 19.1 26.1 ± 12.1/29.0 ±14.2* M. trapezius, left/right 40.1 ± 22.8/39.4 ± 20.9 26.8 ± 13.5/26.8 ± 14.5* M. rectus femoris, left/right 58.0 ± 25.1/55.9 ± 26.8 35.2 ± 17.9/32.1 ± 16.3* M. abductor hallucis, left/right 37.0 ± 18.4/38.6 ± 19.8 27.5 ± 13.2/28.7 ± 15.1* Non-painful area 38.6 ± 22.1 25.0 ± 13.8* Painful area 32.2 [22.4-51.6] 19.8 [13.0-28.7]* TS (VAS) Non-dominant forearm 0.6 [0.1-1.2] 0.7 [0.2-2.1] Non-painful area 0.8 [0.2-1.5] 1.1 [0.2-2.2] Painful area 0.8 [0.2-1.6] 1.3 [0.3-2.7] CPM (N) Non-dominant m. rectus femoris 2.8 ± 13.5 0.2 ± 8.3 *Statistically significant at p<0.004 (Bonferroni correction). Acknowledgements: NIL. Disclosure of Interests: Yvonne van der Kraan: None declared, Davy Paap: None declared, Hans Timmerman: None declared, Freke Wink: None declared, Suzanne Arends: None declared, Michiel Reneman: None declared, Anneke Spoorenberg Grant/research support from: ReumaNederland Grant.