POS1450 PSYCHOMETRIC PROPERTIES OF THE CENTRAL SENSITIZATION INVENTORY IN PATIENT WITH FIBROMYALGIA

Background Patients with fibromyalgia (FM) complain many symptoms besides musculoskeletal pain: e.g. fatigue, sleep difficulties, a swollen feeling in tissues, paresthesia, cognitive dysfunction, dizziness, and symptoms of overlapping conditions such as irritable bowel syndrome, headaches and restless legs syndrome. These conditions can be grouped under the umbrella term of central sensitization (CS) syndromes. Objectives The goal of the present study was to explore additional evidence of convergent and discriminant validity of the Central Sensitization Inventory (CSI) in a large sample of subjects with fibromyalgia (FM). Methods Patients were consecutively enrolled for a cross-sectional assessment comprehensive of three FM-specific measures (the revised Fibromyalgia Impact Questionnaire [FIQR], the modified Fibromyalgia Assessment Status [modFAS], and the Polysymptomatic Distress Scale [PDS]) and of CSI. To test the convergent validity, the Spearman’s rho was used to measure the degree of correlation between the variables CSI and the FM-specific measures. To assess discriminant validity, CSI scores were grouped according to FIQR disease severity states, and differences between these groups studied with the Kruskal-Wallis test. Interpretative cut-offs were established with the interquartile reconciliation approach. Results The study included 562 FM patients, 199 (35.4%) were classified as having central sensitization syndrome (CSI ≥40). CSI was largely correlated with modFAS (rho = 0.580; p <0.0001), FIQR (rho = 0.542; p <0.0001), and PDS (rho = 0.518; p <0.0001). The differences between the CSI scores in accordance with the FIQR were significant (p <0.000001). CSI cut-offs proposed for FM: 21 between remission and mild severity, 30 between mild and moderate severity, 37 between moderate and severe disease, and 51 between severe and very severe disease. Conclusion The current study successfully showed additional evidence of the convergent and discriminant validity of the CSI in FM patients. References [1]Salaffi F, Mozzani F, Draghessi A, et al. Identifying the symptom and functional domains in patients with fibromyalgia: results of a cross-sectional Internet-based survey in Italy. J Pain Res. 2016;9:279-86. [2]Yunus MB. Role of central sensitization (CS) in symptoms beyond muscle pain, and the evaluation of a patient with widespread pain. Best Pract Res Clin Rheumatol. 2007;21:481-497. [3]Salaffi F, Franchignoni F, Giordano A, et al. Psychometric characteristics of the Italian version of the revised Fibromyalgia Impact Questionnaire using classical test theory and Rasch analysis. Clin Exp Rheumatol. 2013; 31(Suppl 79):41–49. Figure 1. Distribution of the CSI score according to the different CSI score ranks of the overall cohort. Bars show median and interquartile range. CSI, central sensitization inventory Figure 2. Spydergrams of the individual CSI scores in FM patients (n° 562 ) Disclosure of Interests None declared