Background: Fibromyalgia (FM) is a chronic pain (CP) syndrome with a prevalence rate ranging between 0.2% and 6.6%, with significant higher rates in women (2.4% - 6.8%) [1]. From 39% to 76% of FM patients suffers from multiple CP comorbidities primarily: tension-type or migraine headache, irritable bowel syndrome, lower back pain, myofascial pain syndrome, and temporomandibular disorders [2]. Central Sensitivity (CS) is defined by the International Association for the Study of Pain (IASP) as an increased responsiveness of nociceptive neurons in the central nervous system to normal or subthreshold inputs [3]. International literature has connected CS to the psychological burden associated to several CP conditions, including FM and chronic headache (CH) [4], nevertheless a comparison between FM patients and those presenting also other CP comorbidities on CS is a quite neglected area of investigation.

Objectives: To investigate whether CS discriminates between FM and FM with different CP conditions as well as between FM groups and CH and healthy controls (HCs).

Methods: A total of 944 women participated (n=240 CH; n=204 FM; n=376 FM with comorbidities; n=124 HCs) and completed an online self-administered protocol consisting in Central Sensitivity Inventory [5] and socio-anamnestic information. Data collection was between April and December 2023. A general linear model ANCOVA was performed to test differences in CSI scores covariate for age values since age resulted significantly different among groups.

Results: Data analysis showed a good fit of the model (R² Adjusted=.340; df=4; F=116; p<.001) and a significant difference between groups in CSI scores (p<.001). Post hoc test with Bonferroni test were performed showing that all the clinical groups scored significantly higher than HCs (all p<.001); FM and FM with comorbidities clinical groups scored significantly higher than CH group (both p<.001), FM with comorbidities group scored significantly higher than FM (p=.015), thus FM with different comorbidities reported scored significantly higher to all other groups.

Conclusion: A discriminating role of CS seems conceivable among CP conditions, especially in FM associated to other CPs. It seems relevant to include this dimension in the clinical evaluation performed with CP patients in order to better understand the complex connection between CP and mental health.

REFERENCES: [1] Sarzi-Puttini P, Giorgi V, Marotto D, Atzeni F. Fibromyalgia: an update on clinical characteristics, aetiopathogenesis and treatment. Nat Rev Rheumatol. 2020 Nov;16(11):645–60.

[2] Kleykamp BA, Ferguson MC, McNicol E, Bixho I, Arnold LM, Edwards RR, et al. The Prevalence of Psychiatric and Chronic Pain Comorbidities in Fibromyalgia: an ACTTION systematic review. Semin Arthritis Rheum. 2021 Feb;51(1):166–74.

[3] IASP, International Association for the Study of Pain. International Association for the Study of Pain (IASP) Terminology. Washington, DC, USA; 2017.

[4] Adams GR, Gandhi W, Harrison R, Van Reekum CM, Wood-Anderson D, Gilron I, et al. Do “central sensitization” questionnaires reflect measures of nociceptive sensitization or psychological constructs? A systematic review and meta-analyses. Pain. 2023 Jun;164(6):1222–39.

[5] Chiarotto A, Viti C, Sulli A, Cutolo M, Testa M, Piscitelli D. Cross-cultural adaptation and validity of the Italian version of the Central Sensitization Inventory. Musculoskelet Sci Pract. 2018 Oct;37:20–8.

Acknowledgements: NIL.

Disclosure of Interests: None declared.