Objective: The 19-item return-to-work self-efficacy (RTWSE-19) scale is a new self-report measure intended to assess workers' beliefs of their current ability to resume normal job responsibilities following pain onset. The aim of this study was to evaluate the factor structure, internal consistency, and predictive and concurrent validity of RTWSE-19 among workers with acute low-back pain.
Methods: Patients (N=399, 59% male, mean age 37 years) consulting for acute, work-related low-back pain completed an original 28-item version of the new scale along with concurrent measures of pain, functional limitation, activity avoidance, workplace physical demands, and pain catastrophizing. The assessment was repeated at visit 2, and work limitations and duration of sickness absence were assessed by questionnaire at 3-month follow-up. Exploratory factor analysis (principal component analysis with varimax rotation) was used to assess content validity of the scale, and scores were compared to concurrent pain measures and with disability outcomes at 3 months.
Results: The full response range (1-10) was utilized on all 28 items, and there were no ceiling or floor effects. Mean item scores ranged from 4.9 ("reducing physical workload") to 8.3 ("describing injury to supervisor"). The exploratory factor analysis supported three underlying factors (eigenvalue >1.0): (i) meeting job demands; (ii) modifying job tasks; and (iii) communicating needs to others. Internal consistency (alpha) for the three scales were 0.98, 0.92, and 0.81 respectively. At visit 2, self-efficacy scores improved for "meeting job demands" and "modifying job tasks", but not for "communicating needs to others". After controlling for pain and functional limitation, both sickness absence and persistent work limitations were predicted by self-efficacy assessed at visit 2 (P<0.05), but self-efficacy assessed at visit 1 did not predict sickness absence.
Conclusions: The RTWSE-19 is a new measure with adequate reliability and validity to measure the confidence of workers to meet job demands, modify job tasks, and communicate needs to co-workers and supervisors. When assessed 1-2 weeks after pain onset, the scale is predictive of disability outcomes.