POS0539 PAIN IS AN INDEPENDENT ASSOCIATED FACTOR ON FUNCTIONAL LIMITATION IN CHINESE PATIENTS WITH EARLY RHEUMATOID ARTHRITIS
Authors: Y. W. Zou, C. Chen, Q. Zhang, S. Y. Lian, K. M. Yang, Y. H. Xu, J. Lin, J. D. Ma, Y. Y. Zou, L. Dai
Journal: Annals of the Rheumatic Diseases (2021)

Background: Rheumatoid arthritis (RA) is a leading cause of extremity disability in Chinese female population according to 2006 national survey. However, less epidemiological data about functional limitation in Chinese RA patients have been published. Objectives: To investigate the prevalence, characteristics and associated factors of functional limitation in Chinese RA patients. Methods: Consecutive patients with RA were recruited. The demographic and clinical data were collected including indicators of disease activity, functional assessment and radiographic assessment. According to Health Assessment Questionnaire Disease Index (HAQ-DI), functional limitation was defined as: mild (0 &lt; HAQ-DI ≤ 1), moderate (1 &lt; HAQ-DI ≤ 2), and severe (2 &lt; HAQ-DI ≤ 3). Results: There were 643 RA patients recruited with 82.3% female and mean age 49.7 ± 12.9 years. The median (IQR) of total HAQ-DI was 0.25 (0.00-0.75) and there were 399 (62.1%) RA patients with functional limitation including 293 (45.6%), 73 (11.4%), 33 (5.1%) with mild, moderate, and severe functional limitation, respectively. The highest prevalence of functional limitation subdimension was ‘‘walking’’ (43.5%), followed by “grip” (36.1%), ‘‘reach’’ (35.5%), ‘‘common daily activities’’ (33.4%), ‘‘hygiene’’ (33.0%), ‘‘dressing and grooming’’ (29.7%), ‘‘arising’’ (29.1%), while the lowest was ‘‘eating’’ (18.4%). Further age stratification showed that the prevalence of functional limitation was increased with age ( P &lt; 0.001), but no difference between male and female RA patients (58.8% vs. 62.8%, P = 0.426). The prevalence of functional limitation of RA patients with disease duration &lt; 1 years (early), 1-10 years (intermediate) and ≥ 10 years (long) were 70.2%, 55.9% and 74.5% respectively, showing a U-shaped curve (Figure 1A), which indicated that early RA also had high rate of functional limitation. Furthermore, early RA patients had the highest proportion of severe functional limitation (14.3% vs. 2.0% vs. 8.7%, Figure 1B), together with higher prevalence of functional limitation of all eight subdimension than those with intermediate disease duration ( P &lt; 0.05, Figure 1C). There were significant differences in Pain VAS, indicators of disease activity, functional and radiographic assessment among RA patients with different disease duration. Compared with those with intermediate disease duration, early RA patients had higher Pain VAS, higher disease activity indicator (including ESR, CRP, CDAI), higher HAQ-DI, but lower radiographic indicators (all P &lt; 0.05). There was no significant difference in disease activity and functional indicators between early RA patients and those with long disease duration. Multivariate ordered logistic regression analysis showed that Pain VAS ( OR = 2.116, 95% CI : 1.483-3.019), disease activity indicators [including CRP ( OR = 1.047, 95% CI : 1.011-1.084) and CDAI ( OR = 1.128, 95% CI : 1.054-1.208)] were associated factors of functional limitation in early RA patients. Figure 1. The prevalence of function limitation in RA patients. (A) The prevalence of functional limitation in different disease duration groups of RA patients. (B) The different degrees of functional limitation in different disease duration groups of RA patients. (C) The subdimension characteristics of functional limitation in different disease duration groups of RA patients. Conclusion: Near two third early RA patients have functional limitation, in which both pain and active disease are independent associated factors. Management of pain and target treatment in early RA patients should be emphasized. Fund program: National Natural Science Foundation of China (81801605, 81801606, 81971527); Guangdong Natural Science Foundation (2018A030313541, 2018A030313690, 2019A1515011928); Guangzhou Science and Technology Program (201904010088); Guangdong Basic and Applied Basic Research Foundation (2020A1515110061); Guangdong Medical Scientific Research Foundation (A2018062) Disclosure of Interests: None declared