Background Rheumatoid arthritis (RA) can limit the daily activities of patients and restrict participation in important life activities including work. Indirect costs of RA due to losses such as reduced productivity are an important social issue in addition to rapidly increasing direct costs, but these costs have hardly been studied in Japan. Work status is strongly influenced by cultural differences among the races. Analyses of cost in Japan should be conducted by independently evaluating work disability and productivity in patients with RA in real-world settings.
Objectives To evaluate work productivity and activity impairment in patients with RA in Japan using the Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort.
Methods In RA patients who participated in the IORRA in October 2011, a cross-sectional analysis was conducted to determine the influence of RA on work performance as assessed using a well-validated instrument, the Work Productivity and Activity Impairment (WPAI) questionnaire. We also examined associations between work performance and disease activity (DAS28), physical disability (Japanese version of the HAQ; J-HAQ), or quality of life (EQ-5D) score.
Results Our analysis included the data of 5700 patients with RA (mean age, 60.3 years; duration of RA, 14.1 years; females, 84.5%; biologics used in 15.4% of the patients). Of these, 2162 patients (37.9%) were paid workers (mean age, 52.6 years: duration of RA, 11.3 years; females, 77.6%; biologics used in 18.3% of the patients). In these paid workers, the mean number of hours of work per week was 35.1, work absence due to RA per week was 1.2, and work absence due to other reasons per week was 5.3. The rates of absenteeism (percent work time missed due to RA), presenteeism (percent impairment while working due to RA, i.e., productivity loss associated with impaired work performance), work productivity loss (percent overall work impairment due to RA [presenteeism plus absenteeism]), and activity impairment (percent activity impairment due to RA) were 2.5%, 16.1%, 17.4%, and 19.8%, respectively (compared with 3.8%, 20.8%, 22.3%, and 27.2%, respectively, among patients treated with biologics). The rate of absenteeism was weakly correlated with DAS28, J-HAQ, and EQ-5D scores (r = 0.18 to 0.26). The rates of presenteeism, work productivity loss, and activity impairment were moderately or strongly correlated with DAS28, J-HAQ, and EQ-5D scores (r = 0.34 to 0.68), with the correlation to J-HAQ (r = 0.51 to 0.63) or EQ-5D (r = 0.56 to 0.68) score being stronger than that to DAS28 (r = 0.34 to 0.39) score. Among RA patients with a J-HAQ score of 1.5 or higher (n=136), the rates of absenteeism, presenteeism, work productivity loss, and activity impairment were 11.7%, 44.1%, 48.2%, and 53.0%, respectively, and were significantly worse compared with the 2.2%, 9.9%, 10.8%, and 11.1%, respectively, observed in RA patients with a J-HAQ score below 0.5 (n=1475).
Conclusions In Japanese patients with RA, work productivity and activity impairment are strongly correlated with the extent of physical disability and quality of life. The study results indicate that the key to indirect cost reduction is control of RA before it can cause physical disability and impaired QOL.
Disclosure of Interest E. Tanaka: None Declared, E. Inoue: None Declared, D. Hoshi: None Declared, K. Shidara: None Declared, N. Sugimoto: None Declared, Y. Inoue: None Declared, Y. Seto: None Declared, A. Nakajima: None Declared, S. Momohara: None Declared, A. Taniguchi: None Declared, H. Yamanaka Grant/research support from: IORRA study is supported by Asahikasei Kuraray Medical Co., Ltd., Abbott Japan Co., Ltd., Asahikasei Pharma Corporation, Astellas Pharma Inc., AstraZeneca K.K., Bristol-Myers Squibb, Chugai Pharmaceutical Co., Ltd., Daiichi Fine Chemical Co., Ltd., Daiichi Sankyo Co., Ltd., Dainippon Sumitomo Pharma Co., Ltd., Eisai Co., Ltd., GlaxoSmithKline K.K., Hisamitsu Pharmaceutical Co., Inc., Janssen Pharmaceutical K.K., Japan Tobacco Inc., Kaken Pharmaceutical Co., Ltd., Kissei Pharmaceutical Co., Ltd., Kowa Pharmaceutical Co. Ltd., Maruho Co., Ltd., Mitsubishi Chemical Medience Corporation, Mitsubishi Tanabe Pharma Corporation, Mochida Pharmaceutical Co. Ltd., MSD K.K., Mundipharma K.K., Nippon Chemiphar Co., Ltd., Nippon Shinyaku Co., Ltd., Novartis Pharma K.K., Otsuka Pharmaceutical Co., Ltd., Pfizer Japan Inc., Sanofi-Aventis K.K., Santen Pharmaceutical Co., Ltd., Sanwa Kagaku Kenkyusho Co., Ltd., Sekisui Medical Co., Ltd., Shionogi Co., Ltd., Taishotoyama Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co. LTD., Teijin Pharma Limited, Torii Pharmaceutical Co., Ltd., UCB Japan Co. Ltd., ZERIA Pharmaceutical Co., Ltd., Consultant for: Abbott Japan Co., Ltd, AstraZeneca K.K., Bristol-Myers Squibb, Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Janssen Pharmaceutical K.K., Mitsubishi Tanabe Pharma Corporation, Pfizer Japan Inc., Takeda Pharmaceutical Co. LTD., Teijin Pharma Limited, UCB Japan Co. Ltd.