The Work Instability Scale for Rheumatoid Arthritis Predicts Arthritis-Related Work Transitions Within 12 Months KENNETH TANG, 1 DORCAS E. BEATON, 1 MONIQUE A. M. GIGNAC, 2 DIANE LACAILLE, 3 WEI ZHANG, 4 CLAIRE BOMBARDIER, 5 AND THE CANADIAN ARTHRITIS NETWORK WORK PRODUCTIVITY GROUP Objective. Among people with arthritis, the need for work transitions may signal a risk for more adverse work outcomes in the future, such as permanent work loss. Our aim was to evaluate the ability of the Work Instability Scale for Rheumatoid Arthritis (RA-WIS) to predict arthritis-related work transitions within a 12-month period. Methods. Workers with osteoarthritis or rheumatoid arthritis (n  250) from 3 clinical sites participated in self- administered surveys that assessed the impact of health on employment at multiple time points over 12 months. Multivariable logistic regressions were conducted to assess the ability of the RA-WIS (range 0 –23, where 23  highest work instability) to predict 4 types of work transition: reductions in work hours, disability leaves of absence, changes in job/occupation, or temporary unemployment, assembled as a composite outcome. Covariates assessed include age, sex, education, marital status, income, pain intensity, disease duration, and the Health Assessment Questionnaire. Areas under the receiver operating characteristic curves (AUROCCs) were also assessed to further examine the predictive ability of the RA-WIS and to determine optimal cut points for predicting specific work transitions. Results. After 12 months, 21.7% (n  50 of 230) of the participants had indicated at least one arthritis-related work transition. Higher baseline RA-WIS was predictive of such an outcome (relative risk [RR] 1.05 [95% confidence interval (95% CI) 1.00 –1.11]), particularly at >17 (RR 2.30 [95% CI 1.11– 4.77]). The RA-WIS cut point of >13 was found to be most accurate for prediction (AUROCC 0.68 [95% CI 0.58 – 0.78]). Conclusion. The RA-WIS demonstrated the ability to predict arthritis-related work transitions within a short timeframe, and could be a promising measurement candidate for risk prognostication where work disability outcomes are of concern. INTRODUCTION The impact of arthritis on a person’s capacity to work is an important concern. Work disability is commonly experi- enced by individuals with rheumatoid arthritis (RA) (1–5), and is also a relevant issue for individuals with osteoar- thritis (OA). High economic costs associated with arthritis- Supported by the Canadian Arthritis Network (part of the Networks of Centres of Excellence) in partnership with The Arthritis Society of Canada, and by an unrestricted grant from Abbott. Mr. Tang is recipient of a Canadian Institutes of Health Research PhD Fellowship, a Canadian Arthritis Network Graduate Award, and a Syme Fellowship from the Institute for Work & Health. Dr. Beaton’s work was sup- ported by a Canadian Institutes of Health Research New Investigators award. Dr. Lacaille is the Nancy and Peter Paul Saunders Scholar and holds an Investigator Award from The Arthritis Society of Canada. Ms Zhang is recipient of a Canadian Institutes of Health Research Doctoral Re- search Award in the Area of Public Health Research and a Canadian Arthritis Network Graduate Award. Dr. Bombar- dier is recipient of a Canada Research Chair in Knowledge Transfer for Musculoskeletal Care. 1 Kenneth Tang, MSc(PT), MSc, Dorcas E. Beaton, PhD: St. Michael’s Hospital, University of Toronto, and Institute for Work & Health, Toronto, Ontario, Canada; 2 Monique A. M. Gignac, PhD: University of Toronto, University Health Net- work, and Arthritis Community Research & Evaluation Unit, Toronto, Ontario, Canada; 3 Diane Lacaille, MD, MHSc: Arthritis Research Centre of Canada and University of British Columbia, Vancouver, British Columbia, Canada; 4 Wei Zhang, MA: Centre for Health Evaluation and Outcome Sciences, Vancouver, British Columbia, Canada; 5 Claire Bombardier, MD: University of Toronto, Institute for Work & Health, University Health Network, and Mount Sinai Hos- pital, Toronto, Ontario, Canada. Dr. Bombardier has received consultant fees, speaking fees, and/or honoraria (less than $10,000 each) from Scher- ing, Roche, Biogen Idec, and PESI Healthcare, and (more than $10,000 each) from Wyeth, Abbott Canada, and Abbott International. Address correspondence to Dorcas E. Beaton, PhD, Mobil- ity Program Clinical Research Unit, St. Michael’s Hospital, 30 Bond Street, Toronto, Ontario, Canada, M5B 1W8. E- mail: beatond@smh.toronto.on.ca. Submitted for publication December 10, 2009; accepted in revised form May 26, 2010. Arthritis Care & Research Vol. 62, No. 11, November 2010, pp 1578 –1587 DOI 10.1002/acr.20272 © 2010, American College of Rheumatology ORIGINAL ARTICLE 1578