Background The Rheumatoid Arthritis (RA) Impact of Disease (RAID) score is a patient developed questionnaire including 7 questions (pain, functional capacity, fatigue, physical and emotional wellbeing, quality of sleep and coping) converted to a score 0-10, with 10 indicating the worst status. In patients with recent onset RA high associations were found between RAID score and disease severity, while in established RA patients there was no correlation between RAID score and a comprehensive ultrasound (US) examination. Our hypothesis was that progress in catastrophizing (described as the tendency to magnify painful stimuli, to focus excessively on the negative aspects of pain and to amplify threatening information about pain) during severe RA might explain this discrepancy.
Objectives To explore the influence of pain catastrophizing on patient reported outcomes as well as on US, clinical and laboratory markers of disease activity in patients with established RA.
Methods A total of 139 RA patients (86% woman, aged (SD) 54 (13) years, disease duration 8 (6) years, 83% anti-CCP positive) were included when starting biologic medication (antiTNF 72%, rituximab 19%, abatacept 4%, tocilizumab 5%). Patients were examined at baseline and after 3 months with semi-quantitative (0-3) scores of grey scale (GS) and power Doppler (PD) US of 36 joints and 4 tendons (bilateral wrist/fingers, elbow, knee, ankle and MTPs), M-HAQ, DAS28, assessor's (study nurse) global VAS, ESR, CRP, the RAID questionnaire, patient global disease activity (total global) VAS and joint pain VAS. Pain catastrophizing was assessed by use of two questions from the Coping Strategies Questionnaire (CSQ, score 0-6). The patients were categorized into four groups with increasing levels of catastrophizing both at baseline and after 3 months. Other variables were compared across these four groups by use of ANOVA. Changes from baseline were assessed by paired T-test.
Results At baseline the mean (SD) results were: Sum scores GS 29 (20) and PD 14 (15), ESR 30 (23) mm/h, CRP 16 (24) mg/L, DAS28 4,8 (1,5), M-HAQ 0.7 (0.5), assessor's global VAS 33 (19), RAID 4.6 (2.3), total global VAS 53 (23) and joint pain VAS 49 (26). Mean (SD) of pain catastrophizing was 2.5 (1.5) and 2.2 (1.7) for the two questions. All variables improved after 3 months (p<0.001). Both at baseline and at 3 months the level of catastrophizing was highly associated with the RAID score (fig 1, baseline) (as well as with each of the seven separate RAID questions, p<0.001), the M-HAQ (p≤0.002), the total global VAS (p<0.001) (fig 1, baseline) and joint pain VAS (p<0.001), while DAS28 was associated only at baseline (p=0.02). However, neither US assessments, number of swollen or tender joints, assessor's global VAS nor laboratory markers were associated with the degree of catastrophizing at any time point.
Conclusions The level of pain catastrophizing was highly associated with all the patient reported outcomes, while there were no significant associations with any of the more objective assessments. Even if the patient reported outcomes give information about perceived health, these variables may not reflect inflammatory activity in patients with established RA. Thus the impact of catastrophizing should be taken into account in studies on disease activity in RA patients.
Disclosure of Interest : H. B. Hammer Grant/research support: AbbVie, Roche and Pfizer, T. Kvien: None declared