Test-retest reliability and correlations of 5 global measures addressing at-work productivity loss in patients with rheumatic diseases

OBJECTIVE: Several global measures to assess at-work productivity loss or presenteeism in patients with rheumatic diseases have been proposed, but the comparative validity is hampered by the lack of data on test-retest reliability and comparative concurrent and construct validity. Our objective was to test-retest 5 global measures of presenteeism and to compare the association between these scales and health-related well-being. METHODS: Sixty-five participants with inflammatory arthritis or osteoarthritis in paid employment were recruited from 7 countries (UK, Canada, Netherlands, France, Sweden, Romania, and Italy). At baseline and 2 weeks later, 5 global measures of presenteeism were evaluated: the Work Productivity Scale-Rheumatoid Arthritis (WPS-RA), Work Productivity and Activity Impairment Questionnaire (WPAI), Work Ability Index (WAI), Quality and Quantity questionnaire (QQ), and the WHO Health and Performance Questionnaire (HPQ). Agreement between the 2 timepoints was assessed using single-measure intraclass correlations (ICC) and correlated between each other and with visual analog scale general well-being scores at followup by Spearman correlation. RESULTS: ICC between measures ranged from fair (HPQ 0.59) to excellent (WPS-RA 0.78). Spearman correlations between measures were moderate (Qquality vs WAI, r = 0.51) to strong (WPS-RA vs WPAI, r = 0.88). Correlations between measures and general well-being were low to moderate, ranging from -0.44