Background: Rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (ax-SpA) may have a devastating impact on patients’ lives, including chronic and relapsing pain. One factor contributing to bio-psycho-social model of pain in these diseases, is pain catastrophizing (PC) defined as tendency to report pain experience in exaggerated terms, to ruminate more or to feel helpless about it. In one RA study PC has been shown to be associated with patient reported outcomes e.g. reduced likelihood of remission using composite measures.
Objectives: Main objective of this study was to explore if pain catastrophizing score is associated with remission rates in the chronic inflammatory joint disorders RA, PsA and ax-SpA.
Methods: Patients were recruited during routine assessment at an outpatient clinic in Norway. Variables collected included demographics, treatment, disease duration, global pain VAS, pain catastrophizing score (PCS), and disease activity scores: DAS28-CRP for RA, BASDAI for ax-SpA and DAPSA for PsA. Cut off definitions of remission was for DAS28 <2.6, for BASDAI <4.0 and for DAPSA ≤4.0. Two questions from Coping Strategies Questionnaire as recommended by Jensen et al  were used to describe PC, range PC total score (PCS) 0–6. Patients with PCS ≥ 4 were defined as high pain catastrophizers. Statistics included Chi-Square test and adjusted logistic regression (enter procedure).
Results: For RA (N=580), PsA (N=394) and ax-SpA (N=225) mean age (SD) was 61.5 (13.1), 54.4 (12.9) and 47.5 (12.9) years, mean disease duration 12.6 (10.9), 10.2 (8.4) and 12.2 (10.7) years and percentage of women 66.7%, 47.0% and 38.4%. Mean (SD) DAS28-CRP in RA was 2.3 (1.0), BASDAI for ax-SpA 3.7 (2.3) and DAPSA for PsA 10.8 (8.5). Mean (SD) global pain (VAS 0-100mm) was for RA 32.0 (25.6), for PsA 35.5 (25.4) and for ax-SpA 39.4 (25.4) mm. Conventional synthetic DMARDs were used by 65.0% of RA patients, 54.8% by PsA and 9.8% in ax-SpA and for biologic DMARDs the corresponding numbers were 36.7%, 43.9%, 65.9%, respectively.
Percentage of patients in remission was significantly lower in high pain catastrophizers compared with low pain catastrophizers in RA (34.1% vs 70.3%, p<0.01) and ax-SpA patients (17.9% vs 64.5%, p<0.01) but not in PsA (10.3% vs 26.7%, p=0.06).
In analysis adjusting for age, gender, disease duration and global pain (Tab. 1), PC was independently associated with lower remission rate in RA (OR 0.79 (95% CI 0.63, 0.99), p=0.04) and in ax-SpA (OR 0.65 (95% CI 0.46, 0.93), p=0.02) but not in PsA (OR 0.83 (95% CI 0.55, 1.25), p=0.37)
Conclusion: Our data indicates that high level of patient’s PC may reduce likelihood of achieving remission in RA and ax-SpA. Interestingly, this was not shown in PsA patients. Further studies are needed to reveal the importance of PC and its influence on composite disease activity measures used to define disease status e.g. remission.
References: Hammer HB et al Pain Catastrophizing, Subjective Outcomes, and Inflammatory Assessments Including Ultrasound: Results From a Longitudinal Study of Rheumatoid Arthritis Patients. Arthritis Care Res. 2018;70:703-12.
Jensen MP, et al. One- and two-item measures of pain beliefs and coping strategies. Pain 2003;104:453-69.
Acknowledgements: Nurses and doctors from Division of Rheumatology at Sørlandet Hospital in Kristiansand, Norway contributed to data collection.
Disclosure of Interests: None declared
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