To examine the validity and test–retest reliability of the Valuation of Lost Productivity (VOLP) questionnaire among patients with rheumatoid arthritis (RA).
Absenteeism, presenteeism, and unpaid work loss due to health were measured. Patients with RA who had paid work at their recent follow-up were recruited from the Early RA Network cohort. The VOLP was administered on two occasions.
A total of 152 patients were included in our analysis. The correlations between VOLP and function, pain, fatigue, and disease activity ranged 0.24 to 0.42. The correlations between VOLP and Work Productivity and Activity Impairment questionnaire were 0.57 for absenteeism, 0.42 for presenteeism, and 0.39 for unpaid work loss. The Kappa statistics were greater than 0.6 except for unpaid work loss.
This study provides evidence for the validity of the VOLP in measuring time input loss among people with RA.
From the Centre for Health Evaluation and Outcome Sciences, St Paul's Hospital (Ms Zhang, Drs Bansback and Anis) and School of Population and Public Health, University of British Columbia (Ms Zhang, Drs Kopec and Anis), Vancouver, British Columbia, Canada.
Address correspondence to: Aslam H. Anis, PhD, Centre for Health Evaluation and Outcome Sciences, 620–1081 Burrard Street, Vancouver, British Columbia, Canada, V6Z 1Y6 (email@example.com)
This study was supported by Pfizer via a grant to the Arthritis Research Centre of Canada, where A.H.A. is a Senior Research Scientist. Early Rheumatoid Arthritis Network has received funding from Wyeth Pharmaceuticals and the Healthcare Commission.