P195 Defining the relationship between pain intensity and disease activity in patients with rheumatoid arthritis: a secondary analysis of six studies

Abstract Background/Aims Pain is the main concern of patients with rheumatoid arthritis (RA). Whilst rheumatologists often focus on reducing disease activity to improve pain the relationship between disease activity and pain in RA is incompletely characterised. Our aim was to better understand this, by defining the associations, discordance, and temporal relationships between pain intensity and disease activity in RA. Methods We undertook a secondary analysis of 1,132 patients with RA followed-up over 12 months in five trials and one observational study. Pain intensity was measured using a 100mm visual analogue scale (VAS), and disease activity using the DAS28-ESR. Relationships between 12-month pain VAS and DAS28-ESR (overall score and its components) were evaluated using Spearman correlations, linear regression models, Bland-Altman plots, and Kappa statistics. Temporal relationships were evaluated by describing mean pain intensity scores in patients over time stratified by disease activity status. Results: Associations: Linear regression models showed significant associations between pain intensity VAS and DAS28-ESR (Table). Patient global assessment (PtGA) scores explained 79.3% of the variance in pain VAS, and ESR only 19.7%. Correlations between pain intensity VAS and DAS28-ESR components were highest with PtGA (R = 0.88) and least with ESR (R = 0.10). Discordance: “fair” agreement was seen between categories of pain intensity scores (categorised as low=VAS ≤34, moderate=VAS 35-74, high=VAS >74 based on previous studies) and DAS28-ESR categories (Kappa statistic 0.287). 14% of patients in remission/low disease activity (LDA) had moderate/high pain scores; 18% of patients in high disease activity (HDA) had low pain scores. Bland-Altman plots showed many patients scored pain VAS and PtGA similarly. Temporal relationships: changes in disease activity and pain intensity scores over time mirrored each other. When patients with baseline active RA achieved 12-month remission/LDA mean pain VAS scores fell by > 60% from baseline. When patients in baseline remission/LDA had active RA at 12-months mean pain VAS scores increased by > 60% from baseline. Conclusion Whilst pain intensity is closely related to DAS28-ESR, discordance occurs in a substantial minority of patients. The relationship between DAS28-ESR and pain intensity VAS scores is largely attributable to its significant association and strong correlation with PtGA scores. Disclosure F. Ibrahim: None. M. Ma: None. D.L. Scott: None. I. Scott: None.