Test–Retest Reliability, Agreement and Responsiveness of Productivity Loss (iPCQ-VR) and Healthcare Utilization (TiCP-VR) Questionnaires for Sick Workers with Chronic Musculoskeletal Pain

Purpose: The purpose of this study was to assess test–retest reliability, agreement, and responsiveness of questionnaires on productivity loss (iPCQ-VR) and healthcare utilization (TiCP-VR) for sick-listed workers with chronic musculoskeletal pain who were referred to vocational rehabilitation. Methods Test–retest reliability and agreement was assessed with a 2-week interval. Responsiveness was assessed at discharge after a 15-week vocational rehabilitation (VR) program. Data was obtained from six Dutch VR centers. Test–retest reliability was determined with intraclass correlation coefficient (ICC) and Cohen’s kappa. Agreement was determined by Standard Error of Measurement (SEM), smallest detectable changes (on group and individual level), and percentage observed, positive and negative agreement. Responsiveness was determined with area under the curve (AUC) obtained from receiver operation characteristic (ROC). Results A sample of 52 participants on test–retest reliability and agreement, and a sample of 223 on responsiveness were included in the analysis. Productivity loss (iPCQ-VR): ICCs ranged from 0.52 to 0.90, kappa ranged from 0.42 to 0.96, and AUC ranged from 0.55 to 0.86. Healthcare utilization (TiCP-VR): ICC was 0.81, and kappa values of the single healthcare utilization items ranged from 0.11 to 1.00. Conclusions The iPCQ-VR showed good measurement properties on working status, number of hours working per week and long-term sick leave, and low measurement properties on short-term sick leave and presenteeism. The TiCP-VR showed adequate reliability on all healthcare utilization items together and medication use, but showed low measurement properties on the single healthcare utilization items