Background Indirect costs of rheumatoid arthritis (RA) due to losses such as reduced productivity are an important social issue in addition to rapidly increasing direct costs; however, indirect costs have not been thoroughly assessed in Japan. With the recent changes in socioeconomic structure, the number of female paid workers has been increasing; thus, the impact of RA on the work impairment of Japanese patients has been rapidly increasing. Furthermore, work status is strongly influenced by cultural differences among races. Longitudinal analyses of factors contributing to the worsening of work impairment should be conducted in patients with RA in real-world settings.
Objectives To identify factors contributing to early worsening of absenteeism in patients with RA in daily practice.
Methods The study population consisted of patients with RA who were working for pay and who participated in the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort study in 2012 to 2013, had an absenteeism score of 0 as determined by the Work Productivity and Activity Impairment (WPAI) questionnaire at baseline, and could be followed up for WPAI assessments for at least 6 months to a maximum of 18 months. The time to 10% or more absenteeism (percent work time missed due to RA) was the primary outcome. A Cox regression analysis was used to identify factors contributing to the worsening of absenteeism.
Results The study included 1,941 patients with RA (mean age, 50.6 years; RA duration, 10.8 years; females, 79.3%; DAS28, 2.6; Japanese version of the Health Assessment Questionnaire [J-HAQ], 0.32). Absenteeism first exceeded 10% at 6, 12 and 18 months in 47 (cumulative probability of worsening: 2.4% [95% CI: 1.7%>3.1%]), 33 (4.5% [95% CI: 3.5%>5.4%]) and 20 (6.2% [95% CI: 5.0%>7.4%]) patients, respectively. Results of a multivariate Cox regression analysis showed that lower EQ-5D scores at baseline (p=0.01) and steroid dosage at baseline (p=0.01) were significantly associated with earlier worsening of absenteeism, and that the use of biologics did not have a significant impact (p=0.46).
Conclusions Factors contributing to earlier worsening of absenteeism were identified in patients with RA in daily practice. The results suggest that preventing quality of life deterioration without steroid use might be important in stopping the progression of work impairment.
Disclosure of Interest E. Tanaka: None declared, E. Inoue: None declared, R. Yamaguchi: None declared, Y. Shimizu: None declared, N. Sugimoto: None declared, D. Hoshi: None declared, K. Shidara: None declared, E. Sato: None declared, Y. Seto: None declared, A. Nakajima: None declared, S. Momohara Consultant for: AbbVie, Bristol-Myers-Squibb, Eisai, Mitsubishi-Tanabe, and Takeda., A. Taniguchi Grant/research support from: Takeda., Consultant for: AbbVie, Eisai, Mitsubishi-Tanabe, and Teijin., H. Yamanaka Grant/research support from: AbbVie, Asahikasei Pharma, Astellas, Bristol-Myers-Squibb, Chugai, Daiichi-Sankyo, Eisai, GlaxoSmithKline, Janssen, Mitsubishi-Tanabe, MSD, Nippon Kayaku, Pfizer, Santen, Taisho-Toyama, Takeda, and Teijin Pharma., Consultant for: Teijin Pharma, Chugai, Astellas, Bristol-Meyers, AbbVie, Daiichi-Sankyo, Nihon-Kayaku, Mitsubishi-Tanabe, Pfizer, Takeda, and UCB.