text: Worker’s Compensation, or other commercial insurance) 
  compared to private insurance, higher baseline disability 
  and worsening of pain. In the weighted analysis, subjects 
  with knee pain were less likely to utilize the emergency 
  room than those with low back pain. However, this rela- 
  tionship was not significant (p = .06) in the complete case 
  analysis. Of the significant predictors in both models, insur- 
  ance status was the strongest individual predictor of subse- 
  quent emergency room use. 
  
  services, suggesting injection may be the most difficult 
  service to predict with the included variable set. 
  
  Surgery 
  Baseline disability (OR = 3.13–3.25, p < 0.001), change in 
  disability (OR = 3.04–3.05, p = 0.01) and change in 
  10-item OSPRO-YF score (OR = 1.12–1.14, p < 0.05) 
  where consistent predictors of subsequent surgery. Not- 
  ably, magnitude of prediction was comparable between 
  change in disability and baseline disability. This was the 
  only parsimonious model to include an OSPRO tool. In 
  this case, an increase in pain-related psychological dis- 
  tress measured by the OSPRO-YF 10-item questionnaire 
  over the first 4 weeks was associated with higher odds of 
  surgery. The 3 predictors in this model explained just 
  over 30% of the variance in surgery utilization. 