Background/Purpose: Swelling or tenderness of specific joints may differentially impact the ability of rheumatoid arthritis (RA) patients to perform daily activities and work. The aim of this analysis was to explore the relationship between specific joint involvement and work or activity impairment due to RA.  

Methods: The Abatacept Best Care Study (ABC) is a prospective, multicenter, observational study evaluating the usefulness and adherence to a T2T approach vs. standard of care in real-life management of patients with active RA starting subcutaneous (SC) abatacept 125 mg once weekly. Interim data were used. Based on joint involvement evaluated with the 28-joint count, five groups were created: shoulder(s), elbow(s), wrist(s), hand(s), and knee(s). The impact of specific joints on % activity impairment (AI) and overall work impairment (WI) due to health at baseline as well as their change from baseline to 12 months, as measured with the Work Productivity and Activity Impairment (WPAI) questionnaire were assessed with general linear regression adjusting for age, gender, and total swollen and tender joint counts.

Results: 255 patients (74.8% females) were included with a mean (SD) age of 59.5 (11.6) years, 7.9 (4.7) swollen joints, and 9.7 (6.2) tender joints at baseline. Of these, 86 (33.7%) had information on WI at BL. At 12 months, 182 (71.4) and 58 (22.7%) had information on AI and WI, respectively. 

At baseline, increased number of tender, but not swollen, joints was associated with significantly increased AI (increase by 1.3 percentile units for each additional tender joint, p<0.001) and WI (increase by 1.9 percentile units for each additional tender joint, p=0.002). For specific joints, swollen shoulder(s) and knee(s), and tender shoulder(s) and elbow(s) were associated with increased, but not statistically significant, AI. Swollen shoulder(s) and elbow(s), and tender shoulder(s) and elbow(s), were associated with numerically, but not statistically, higher WI. For hand(s), nearly all patients had swollen and tender MCPs and/or PIPs so a baseline association was not performed.

At 12 months, swollen/tender wrist(s) (p=0.015/p=0.003) and hands (p<0.001/p<0.001) were associated with significantly lower improvement from baseline in AI (Table 1). Similarly, swollen/tender wrist(s) (p=0.002/p<0.001) and hands (p<0.001/p<0.001), as well as tender elbows (p=0.032) were associated with significantly lower improvement in WI.

Conclusion: Swelling and tenderness at specific joints has differential impact on the ability to work and perform daily activities. Residual involvement of upper limb joints after 12 months of treatment was associated with persistent activity and work impairment.

Table 1. Relationship Between Specific Joint Involvement at 12 Months and Improvement in AI/WI from Baseline