The Work Productivity and Activity Impairment Questionnaire for Patients with Gastroesophageal Reflux Disease (WPAI-GERD): Responsiveness to Change and English Language Validation
Peter Wahlqvist (AstraZeneca R&D, Molndal, Sweden) Gordon H. Guyatt (McMaster University, Hamilton, Ontario, Canada) David Armstrong (McMaster University, Hamilton, Ontario, Canada) Alessio DeglInnocenti (AstraZeneca R&D, Molndal, Sweden) Diane Heels-Ansdell (McMaster University, Hamilton, Ontario, Canada) Samer El-Dika (University at Buffalo, State University of New York, Buffalo, New York, USA) Ingela Wiklund (AstraZeneca R&D, Molndal, Sweden) Carlo A. Fallone (The McGill University Health Center, McGill University, Montreal, Quebec, Canada) Lisa Tanser (AstraZeneca Canada, Mississauga, Ontario, Canada) Sander Veldhuyzen van Zanten (Dalhousie University, Halifax, Nova Scotia, Canada) Peggy Austin (McMaster University, Hamilton, Ontario, Canada) Alan N. Barkun (The McGill University Health Center, McGill University, Montreal, Quebec, Canada) Naoki Chiba (McMaster University, Hamilton, Ontario, Canada) Holger J. Schunemann (Department of Epidemiology, Italian National Cancer Institute, Regina Elena, Rome, Italy)
Abstract
Background: A validated productivity questionnaire, the Work Productivity and Activity Impairment questionnaire for Gastroesophageal Reflux Disease (WPAI-GERD), exists for Swedish patients with GERD. Objective: To assess responsiveness to change of the WPAI-GERD and construct validity of the English language version. Methods: We used the WPAI-GERD in a before-after treatment clinical study of Canadian GERD patients with moderate or severe symptoms treated with esomeprazole 40mg once daily for 4 weeks. We measured productivity variables including GERD-specific absence from work, reduced productivity while at work and reduced productivity while carrying out regular daily activities other than work during the preceding week. Results: The analysis included 217 patients, of whom 71% (n Cross-sectional correlation coefficients of WPAI variables with symptoms (range 0.04-0.63) and health-related quality of life (HR-QOL; range 0.02-0.65) supported cross-sectional construct validity. Corresponding change score correlations between WPAI variables and HR-QOL (range 0.05-0.56) supported longitudinal construct validity of the WPAI-GERD while low change score correlations between productivity variables and relevant symptoms (range 0.06-0.34) did not. Conclusion: The English version of the WPAI-GERD showed good cross-sectional construct validity, and results indicated that the WPAI-GERD is responsive to change. Although the results also indicated that longitudinal construct validity may be poor, the overall findings suggest that further study of the instrument remains warranted.
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Article provided by Wolters Kluwer Health | Adis in its journal PharmacoEconomics.
Volume (Year): 25 (2007) Issue (Month): 5 () Pages: 385-396 Download reference. The following formats are available: HTML,
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