P103 Centralised pain in early rheumatoid arthritis predicts worse bodily pain outcomes
Authors: Kelleher Eoin , Wall Amanda J , Sanchez-Santos Maria T , Wanigasekera Vishvarani , Irani (nee Soni) Anushka 
Published: April 2024

Abstract

Background/Aims
Features of centralised pain, encompassing widespread pain and non-pain features such as multisensory hypersensitivity, fatigue, and sleep disturbance are common in RA. We hypothesise that centralised pain in early RA affects response to standard first-line treatment.

Methods
Prospective cohort study of adults with a clinical diagnosis of RA recruited from the early inflammatory arthritis clinic, Oxford University Hospitals, who completed an online assessment within two weeks of starting a DMARD. Centralised pain was assessed using three measures: the 2016 Fibromyalgia Survey Criteria (0-31), Central Sensitisation Inventory (CSI, 0-100), and PainDetect (0-38). The primary outcome, bodily pain, was assessed using the Short Form-36 Bodily Pain Scale (BPS), where lower scores indicate worse pain severity. During follow-up, participants completed three sets of follow-up questionnaires at 3-, 6- and 12-months. Linear mixed effects models were used to account for repeated measurements and patient variability. Three models were fitted, for an association between baseline values of each centralised pain measure with BPS over time. An interaction between centralised pain scores with time was fitted to assess for effect of the exposure on change over time. Age, sex, and symptom duration at baseline were included as confounding variables. Ethical approval was granted by South Central Oxford B Research Ethics Committee.

Results
Of 149 participants, 117 (79%) completed follow-up: median (IQR) age 59.8 (24.6) years; 36% male; 30% with symptoms &gt;1 year at baseline. There were no significant baseline differences among those lost to follow-up, apart from a longer symptom duration (53% vs 30% symptom duration &gt;1 year; P = 0.033). At baseline, median (IQR) Fibromyalgia Survey Criteria, CSI, and PainDetect scores were 12 (6), 36 (17), and 14 (9) respectively. The median (IQR) BPS at baseline was 32.5 (22.5). Measures of centralised pain were moderately-to-strongly correlated with each other, and with BPS. Individuals with symptoms for &gt;1 year had higher scores on the PainDetect (P = 0.0015), but not the CSI (P = 0.0545) or Fibromyalgia Survey Criteria (P = 0.672). After adjusting for age, sex, and symptom duration, there was a significant association between centralised pain at baseline and BPS over follow-up, e.g.; for every unit increase in the fibromyalgia survey criteria at baseline, the BPS decreased by 2.40 (95%CI -3.29, -1.49; P &lt; 0.001) points over follow-up. Similar relationships were seen with the CSI and PainDetect scores.

Conclusion
Centralised pain measures in early RA patients can be indicative of the severity of bodily pain experienced during the subsequent 12 months after starting a DMARD treatment. Recognising and assessing centralised pain in early RA patients may enable us to tailor more effective and individualised treatment regimens. Further studies, especially those utilising neuroimaging and QST, are essential to elucidate the neural mechanisms underlying the impact of centralised pain on treatment outcomes in RA.

Disclosure
E. Kelleher: None. A.J. Wall: None. M.T. Sanchez-Santos: None. V. Wanigasekera: None. A. Irani (nee Soni): None.