Background Pain is a dominant symptom in rheumatoid arthritis (RA).
Objectives Investigate unacceptable pain (VAS-pain ≥40) during the first year of the disease and whether it can be predicted from baseline disease characteristics.
Methods The cohort included all incident RA cases from the Swedish population-based case-control Epidemiological Investigation of Rheumatoid Arthritis study (EIRA), who also were in the Swedish Rheumatology Register. Unacceptable pain was defined as scoring 40 mm or above on the pain visual analog scale (VAS) (i.e. not reaching the patient acceptable symptom state (PASS) (1)), and the proportion of patients going in and out of PASS was traced over the first year. Association between baseline parameters, divided into quartiles, and unacceptable pain at one year was assessed using modified Poisson regression and expressed as risk ratios with 95% confidence intervals (95% CI), adjusted for sex and age at diagnosis.
Results A total of 2808 patients were included in the study and 33.8% of the patients presented with PASS (i.e.VAS pain below 40) at inclusion. If a patient had PASS at any given visit, there was over 70% chance that the patient remained in PASS at the following visit. The most common PASS pattern (25.6%), was to present with unacceptable pain, reach PASS at the 3 month visit, and then remain in PASS. However, one year after diagnosis, only two thirds of the patients had PASS. Higher disability (measured as HAQ) at baseline was significantly and independently associated with an increased risk for unacceptable pain at one year (for the highest quartile of HAQ; RR=1.97 [95% CI:1.60–2.42]). Also high tender joint count at baseline was associated with an increased risk for unacceptable pain; RR=1.40 [95% CI: 1.18–1.65] for the highest quartile, whereas high swollen joint count at baseline was associated with a decreased risk; RR=0.79 [95% CI: 0.66–0.95] for the highest quartile.
Conclusions The results highlight the need for efficient pain treatment strategies early in the disease.
Tubach F, Ravaud P, Martin-Mola E, Awada H, Bellamy N, Bombardier C, et al. Minimum clinically important improvement and patient acceptable symptom state in pain and function in rheumatoid arthritis, ankylosing spondylitis, chronic back pain, hand osteoarthritis, and hip and knee osteoarthritis: Results from a prospective multina. Arthritis Care Res (Hoboken) 2012;64:1699–1707.
Acknowledgements We would like to acknowledge the EIRA study group and the EIRA data collectors.
Disclosure of Interest None declared