A prediction rule for duration of disability benefits in workers with non specific low back pain

Introduction:  This study examines factors collected within the first 4 weeks of work disability to predict outcomes for workers on benefits due to back pain at 6 & 24 months. The following time points were chosen as important milestones in the life of a claim: 4 weeks, 6 months and 24 months.  

Methods:  Routinely collected information from the compensation agency on: age, gender, occupation, earnings, nature and event of injury, language, job tenure, history of prior claims, physical work, health care and opioid use are analyzed. Additional data was extracted via claim file review: need for a translator, previous claims in other jurisdictions, workplace offer of modified work, and work limitations suggested by health professional. Data from the Readiness for Return to Work cohort study on health, functional status pain, mental health, expectations for recovery, job satisfaction, and supervisor’s response are available for a subset of workers. Benefits status at 6 months will be studied using logistic regression. Cox regression and mover stayer models are used for time on benefits and recurrences. Self report of work status will be examined in the R-RTW cohort.  

Results:  6,657 workers were selected. 1,442 were still on full benefits at 4 weeks. 38% were female, 81% of workplaces reported to offer workplace accommodation, 48% of workers were represented by a union. 300 workers were still off work 6 months after date of injury. Analysis of routinely collected data indicates that age, a prescription of opioids, and manual work are indicators for both duration of length of disability and recurrences.  

Discussion:  A prediction tool that provides projections of different injured worker outcomes such as time remaining on benefits and likelihood of a recurrence will be presented. Sensitivity and specificity of the prediction tool and its usability in practise will be discussed.